Use and clinical interpretation of pneumococcal antibody measurements in the evaluation of humoral immune function

Streptococcus pneumoniae serotype distribution in Bangladeshi under-fives with community-acquired pneumonia pre-10-valent pneumococcal conjugate vaccination

BACKGROUND

Streptococcus pneumoniae is the most frequent causative pathogen of bacterial pneumonia in children worldwide. Bangladesh introduced the 10-valent pneumococcal conjugate vaccine (PCV10) in their national immunization program for infants in 2015. We assessed its potential coverage in under-fives with community-acquired pneumonia (CAP) in the years before PCV10 was introduced.

METHODS

A total of 1502 childhood pneumonia cases (< 5 year olds living in the urban section Kamalapur, Dhaka) were enrolled between 2011 and 2013. Acute phase and late (convalescent) serum samples were collected from 1380 cases. Serotype-specific pneumococcal antibody concentrations were measured using a 25-plex immunoassay panel. Pneumococcal CAP was diagnosed based on a serotype-specific pneumococcal antibody response.

RESULTS

S. pneumoniae was serologically identified as causative pathogen in 406/1380 (29%) cases. The five most prevalent serotypes were (in descending order) 11A, 22F, 3, 2 and 19F. Based on the percentage of pneumonia cases associated with PCV10 vaccine types, the potential PCV10 coverage was 29% (116/406).

CONCLUSIONS

In almost a third of the studied cases S. pneumoniae was identified as a causative pathogen. Because of the characteristics of the immunoassay, this might well be a gross underestimation. Nevertheless, the potential PCV10-coverage was low. Given the high serotype diversity, the region might benefit greatly from a higher-coverage PCV or recombinant protein vaccine.

Humoral Immunity and Antibody Responses against Diphtheria, Tetanus, and Pneumococcus after Immune Effector Cell Therapies: A Prospective Study

Patients undergoing immune effector cell therapy (IECT) are at high risk for infections. We assessed seropositivity against pneumococcus, tetanus, and diphtheria in patients before and after IECT and the patients' response to vaccination. We enrolled patients who underwent IECT from January 2020 to March 2022. Antibody levels for diphtheria, tetanus, and pneumococcus were measured before IECT, at 1 month, and 3-6 months after. Eligible patients were vaccinated after IECT. In non-seroprotected patients, we discontinued testing. Before IECT, most patients had seroprotective antibody levels against tetanus (68/69, 99%) and diphtheria (65/69, 94%), but fewer did against pneumococcus (24/67, 36%). After IECT, all patients had seroprotective antibody levels for tetanus at 1 month (68/68) and 3-6 months (56/56). For diphtheria, 65/65 patients (100%) had seroprotective antibody levels at 1 month, and 48/53 (91%) did at 3-6 months. For pneumococcus, seroprotective antibody levels were identified in 91% (21/23) of patients at 1 month and 79% (15/19) at 3-6 months following IECT. Fifteen patients received a pneumococcal vaccine after IECT, but none achieved seroprotective response. One patient received the tetanus-diphtheria vaccine and had a seroprotective antibody response. Because some patients experience loss of immunity after IECT, studies evaluating vaccination strategies post-IECT are needed.

Naturally acquired antibodies against 4 Streptococcus pneumoniae serotypes in Pakistani adults with type 2 diabetes mellitus

Immune response elicited during pneumococcal carriage has been shown to protect against subsequent colonization and infection by Streptococcus pneumoniae. The study was designed to measure the baseline serotype-specific anti-capsular IgG concentration and opsonic titers elicited in response to asymptomatic carriage in adults with and without type 2-diabetes. Level of IgG to capsular polysaccharide was measured in a total of 176 samples (124 with type 2 diabetes and 52 without type 2 diabetes) against serotype 1, 19F, 9V, and 18C. From within 176 samples, a nested cohort of 39 samples was selected for measuring the functional capacity of antibodies by measuring opsonic titer to serotypes 19F, 9V, and 18C. Next, we measured levels of IgG to PspA in 90 samples from individuals with and without diabetes (22 non-diabetes and 68 diabetes). Our results demonstrated comparable IgG titers against all serotypes between those with and without type 2-diabetes. Overall, we observed higher opsonic titers in those without diabetes as compared to individuals with diabetes for serotypes 19F and 9V. The opsonic titers for 19F and 9V significantly negatively correlated with HbA1c. For 19F, 41.66% (n = 10) showed opsonic titers ≥ 1:8 in the diabetes group as compared to 66.66% (n = 10) in the non-diabetes group. The percentage was 29.6% (n = 7) vs 66.66% (n = 10) for 9V and 70.83% (n = 17) vs 80% (n = 12) for 18C in diabetes and non-diabetes groups respectively. A comparable anti-PspA IgG (p = 0.409) was observed in those with and without diabetes, indicating that response to protein antigen is likely to remain intact in those with diabetes. In conclusion, we demonstrated comparable IgG titers to both capsular polysaccharide and protein antigens in those with and without diabetes, however, the protective capacity of antibodies differed between the two groups.

Multiple vaccine comparison in the same adults reveals vaccine-specific and age-related humoral response patterns: an open phase IV trial

Vaccine responsiveness is often reduced in older adults. Yet, our lack of understanding of low vaccine responsiveness hampers the development of effective vaccination strategies to reduce the impact of infectious diseases in the ageing population. Young-adult (25-49 y), middle-aged (50-64 y) and older-adult ( ≥ 65 y) participants of the VITAL clinical trials (n = 315, age-range: 28-98 y), were vaccinated with an annual (2019-2020) quadrivalent influenza (QIV) booster vaccine, followed by a primary 13-valent pneumococcal-conjugate (PCV13) vaccine (summer/autumn 2020) and a primary series of two SARS-CoV-2 mRNA-1273 vaccines (spring 2021). This unique setup allowed investigation of humoral responsiveness towards multiple vaccines within the same individuals over the adult age-range. Booster QIV vaccination induced comparable H3N2 hemagglutination inhibition (HI) titers in all age groups, whereas primary PCV13 and mRNA-1273 vaccination induced lower antibody concentrations in older as compared to younger adults (primary endpoint). The persistence of humoral responses, towards the 6 months timepoint, was shorter in older adults for all vaccines (secondary endpoint). Interestingly, highly variable vaccine responder profiles overarching multiple vaccines were observed. Yet, approximately 10% of participants, mainly comprising of older male adults, were classified as low responders to multiple vaccines. This study aids the identification of risk groups for low vaccine responsiveness and hence supports targeted vaccination strategies. Trial number: NL69701.041.19, EudraCT: 2019-000836-24.

Evaluating patient immunocompetence through antibody response to pneumococcal polysaccharide vaccine using a newly developed 23 serotype multiplexed assay

Assessing T-cell independent antibody response to polysaccharide vaccines is crucial for diagnosing humoral immune deficiencies. However, immunocompetence criteria based on S. pneumoniae vaccination remain unclear. We evaluated IgG antibody vaccine response in healthy individuals to establish interpretive criteria. Pre- and 4-week post-vaccination sera were collected from 79 adults. Antibody concentrations to PNEUMOVAX 23 serotypes were measured using a multiplexed platform. Immunocompetence was determined by fold increase in post-vaccination response, percentage of serotypes achieving 4- or 2-fold antibody ratio, and post-vaccination concentration ≥ 1.3 μg/mL. Immunogenicity varied widely across the 23 serotypes (26.6% to 94.9% for ≥4-fold increase, 51.9% to 98.7% for ≥2-fold increase). Immunocompetence based on historic criteria of ≥4-fold increase in antibody ratio to ≥70% of serotypes was low (72.2%), but increased to 98.7% with criteria of at least a 2-fold increase and/or post-vaccination concentration ≥ 1.3 μg/mL. Current criteria for assessing immunocompetence may be overly stringent and require updating.

Suboptimal Response to Biologics in Severe Asthma-A Marker of Humoral Immunodeficiencies

BACKGROUND

Asthmatic patients with antibody deficiencies (AD) have more severe disease and higher risk of exacerbations. No data exist about the efficacy of biologics in severe asthma (SA) patients with AD.

OBJECTIVE

To evaluate the efficacy of biologics in SA patients with and without AD.

METHODS

A case-control real-life study was conducted including 68 patients divided into 2 groups: group 1 with SA-AD and group 2 with SA.

RESULTS

Treatment with biologics for 6 months was effective for decreasing the number of exacerbations, hospitalizations, and emergency department (ED) visits and improving the Asthma Control Questionnaire (ACQ) score; biologics also proved a systemic corticosteroid-sparing effect. Despite benefits, the number of exacerbations, hospitalizations, and ED visits, the mean ACQ score, and the cumulative dose of systemic corticosteroids remain higher in group 1 than in group 2, with lower lung function parameters. The rates of responses in group 1 were inferior to those in group 2, with a decrease by ≥50% of exacerbation rate in 76% versus 97% of patients (P = .006), no hospitalization in 44% versus 91% of patients (P < .001), no ED visit in 56% versus 82% of patients (P = .018), a significant improvement of the ACQ score by ≥0.5 in 68% versus 100% of patients (P < .001), and an increase of forced expiratory volume in the first second by >10% in 32% versus 65% of patients (P = .007).

CONCLUSIONS

Despite evident benefits, SA patients with AD have suboptimal responses to biologics compared with those immunocompetent. A multidisciplinary approach is necessary to optimize the management of these patients in practice.

Combined deficient response to polysaccharide-based and protein-based vaccines predicts a severe clinical phenotype

OBJECTIVES

Antibody response on polysaccharide- and protein-based vaccines is useful to test B cell functionality. As only few studies have explored the value of studying immune response to both vaccines, we evaluated the clinical value of anti-polysaccharide and anti-protein Luminex-based multiplex assays in context of primary immunodeficiency (PID) diagnosis.

METHODS

A 10-plex Luminex-based assay detecting antibodies to ten pneumococcal polysaccharide (PnPS) serotypes [present in unconjugated Pneumovax, not in 13-valent pneumococcal conjugated vaccine (PCV)] and a 5-plex assay detecting antibodies to five protein antigens (present in DTap/Tdap) were clinically validated in healthy individuals (n=99) and in retrospective (n=399) and prospective (n=108) patient cohorts. Clinical features of individuals with impaired response to PnPS and/or proteins were compared to those with normal response.

RESULTS

Antigen-specific antibody thresholds were determined in healthy individuals. Individuals with impaired anti-PnPS responses and deficient immunoglobulin levels suffered more from autoimmune diseases and had lower B cell levels compared to individuals with impaired anti-PnPS response with normal immunoglobulin levels. Individuals with combined impaired response to PnPS and proteins showed more severe clinical manifestations compared to individuals with isolated impaired response to PnPS or proteins. Eight of the 11 individuals with severely impaired responses to both PnPS and proteins had common variable immunodeficiency. Evaluation of the anti-PnPS response to four serotypes not contained in 20-valent PCV was comparable to evaluation to ten serotypes not contained in 13-valent PCV.

CONCLUSIONS

Multiplexed assessment of anti-PnPS and anti-protein responses combined with immunoglobulin quantification provides useful clinical information to support PID diagnosis.

No Waning of Pneumococcal Vaccine Responses over Time in People with Inflammatory Arthritis: Findings from a Single Centre Cohort

BACKGROUND

Vaccination against pneumococcus reduces the risk of infective events, hospitalisation, and death in individual with inflammatory arthritis, particularly in those on immunomodulating therapy who are at risk of worse outcomes from pneumococcal disease. The objective of this study was to investigate the serological protection following vaccination against pneumococcal serovars over time. Methods: This was a single centre, retrospective cohort study of individuals with rheumatoid arthritis, psoriatic arthritis, or axial spondylarthritis who had previously received the PPSV23 polysaccharide pneumococcal vaccine (Pneumovax). Data were retrieved between January 2021 to August 2023. Dates of previous pneumococcal vaccination were identified using linked primary care records. Serum serotype levels were collected. The primary outcome was serological response defined as a titre ≥0.35 mcg/mL in at least five from a total of 12 evaluated pneumococcal serovars, examined using a Luminex platform. Multivariate logistic regression models adjusting for age, gender, ethnicity, co-morbidities, and the use of prednisolone, conventional synthetic and biological DMARDs were used to determine the odds of a sustained serological response according to time categorised into ≤5 years, 5-10 years, and ≥10 years since vaccination. Results: Serological response was measured in 296 individuals with inflammatory arthritis, with rheumatoid arthritis the most common diagnosis (74% of patients). The median time between pneumococcal vaccine administration and serological assessment was 6 years (interquartile range 2.4 to 9.9). A positive serological response to at least 5 serovars was present in 195/296 (66%) of patients. Time since vaccination did not significantly associate with serological protection compared with those vaccinated <5 years, the adjusted ORs of vaccine response was 1.15 (95% CI 0.64 to 2.07) in those 5-10 years and 1.26 (95% CI: 0.64 to 2.48) in those vaccinated over 10 years ago. No individual variable from the multivariate model reached statistical significance as an independent predictor of vaccine response, although steroid use at the time of vaccine had a consistent detrimental impact on serological immunity. Conclusions: We demonstrated that antibody titres following vaccination against pneumococcal serovars do not appear to wane over time. It appears more critical to focus on maximising the initial vaccine response, which is known to be diminished in this patient population.

Vaccine Immunity in Children After Hematologic Cancer Treatment: A Retrospective Single-center Study

BACKGROUND

Children lose their vaccine-induced protection and are particularly vulnerable to vaccine-preventable diseases after chemotherapy. However, revaccination guidelines are heterogeneous, and there is often a lack of revaccination post-treatment.

AIMS

We conducted a retrospective study of children with hematologic cancer to evaluate vaccine immunity before and after the end of treatment and to determine whether the current institutional revaccination program based on vaccine serology results was followed and effective.

MATERIALS AND METHODS

Data of all children treated by chemotherapy between April 2015 and July 2021 were extracted from hospital medical records for analysis. Serum antibody levels and time of vaccination were evaluated for diphtheria, tetanus, Streptococcus pneumoniae , Haemophilus influenzae type b (Hib), measles, varicella, and hepatitis B.

RESULTS

We included 31 patients (median age, 9 years). At cancer diagnosis, 90% of children were protected against tetanus, diphtheria, and measles; 65% to 67% were protected against pneumococcus and varicella; and 25% against hepatitis B. At the end of chemotherapy, 67% to 71% of patients were protected against tetanus, varicella, and measles; 40% remained protected against hepatitis B; and 27% to 33% against pneumococcus and diphtheria. Patients were revaccinated at various times after the end of treatment but not systematically. During the first-year post-treatment, 20% to 25% of children remained unprotected against pneumococcus, measles, and hepatitis B, one third against diphtheria, but all were protected against tetanus and varicella.

CONCLUSIONS

An effective individualized vaccination program post-cancer based on serology results should be accompanied by an appropriate serology tracking method and follow-up to assess if booster doses are necessary. Our study supports vaccinating all children with a dose of the 13-valent pneumococcal conjugate at cancer diagnosis and at 3 months post-treatment with the combined diphtheria-tetanus-acellular pertussis/poliomyelitis vaccine/hepatitis B virus plus or minus Hib and 13-valent pneumococcal conjugate and meningococcal vaccine, including measles/mumps/rubella-varicella zoster virus vaccine if good immune reconstitution is present.

Vaccine response after pneumococcal vaccination in allogeneic hematopoietic stem cell transplant recipients

Current guidelines for vaccination in allogeneic hematopoietic stem cell transplant (HCT) recipients recommend initiation of pneumococcal vaccination series three to six months post-HCT, with most data supporting initiation at six months due to a more robust immune response. This single-center, retrospective, observational chart review aimed to evaluate the impact of initiating the pneumococcal vaccine series at three months post-HCT compared to six months post-HCT. The primary endpoints were defined as a percentage of patients with a serologic response of >1 and >1.3 µg/mL for over 50% of the defined serotypes. Outcomes showed no difference in immunologic response between the two groups.

Non-protective immunity after standard pneumococcal vaccination series identified as a potential contributing risk factor for refractory otolaryngologic conditions in children

OBJECTIVE

To examine the relationship between conferred immunity after standard pneumococcal series and refractory otolaryngologic infections in pediatric patients using post-vaccination antibody titers, and to identify contributory underlying conditions revealed when vaccination/re-vaccination fails to confer protective immunity.

STUDY DESIGN

IRB-reviewed and "exempt" retrospective case series with chart review using the Epic® Electronic Medical Record system from 2013 to 2021.

SETTING

Dedicated tertiary referral children's hospital.

METHODS

Pneumococcal antibody titer results were assessed for children ages 0 to 21 years and: (1) at least 1 of 7 otolaryngologic disease diagnoses and (2) having received the 4-dose schedule of pneumococcal conjugate vaccine (PCV 7 or 13).

RESULTS

A total of 241 subjects met inclusion criteria with 356 laboratory tests. Recurrent acute otitis media, chronic rhinitis, and chronic otitis media with effusion were the 3 most frequent diagnoses. At presentation, only 27.0% of subjects had titers conferring immunity from their prior vaccinations with PCV. About 85 subjects had been subsequently revaccinated with Pneumococcal Polysaccharide Vaccine (PPSV), and antibody responses conferring immunity reached 91.8%. Seven subjects never developed adequate responses; 5 of these had recurrent acute otitis media as the primary otolaryngologic diagnosis. Secondary "revealed" diagnoses included Juvenile Rheumatoid Arthritis (n = 1), unresolved specific antibody deficiency (n = 2), and Hypogammaglobulinemia (n = 1).

CONCLUSION

In pediatric patients with recurrent infectious otolaryngologic disease refractory to traditional medical and surgical therapy, inadequate responses to pneumococcal vaccination may be revealed. This correlation represents a potential pathway for diagnosis and therapy.

Pneumococcal Conjugate Vaccine Does Not Induce Humoral Response When Administrated Within the Six Months After CD19 CAR T-Cell Therapy

CD19 targeted chimeric antigen receptor-modified T cell therapy (CAR-T) leads to B cell aplasia and low serum immunoglobulin levels. Long-lived CD19-negative plasma cells may persist through the therapy and generate antibodies. There is a paucity of data describing how CAR-T impacts the persistence of antibodies against vaccine-related antigens and the degree to which CAR-T recipients may respond to vaccines. We characterized the effect of CAR-T on pneumococcal immunoglobulin G (IgG) titers and determine whether pneumococcal conjugate vaccine (PCV13) administered after CAR-T develops long-term humoral protection against pneumococcus. A retrospective chart review was performed to identify CAR-T recipients who had serum pneumococcal IgG titers drawn before (baseline) or at days +90, +180, +270, +360, or +540 after CAR-T. We then determined whether they received PCV13 vaccination at these timepoints. IgG concentration ≥1.3 μg/mL was considered protective for that serotype, and patients with ≥6/11 tested vaccine-specific serotypes meeting this threshold were deemed to have humoral protection against pneumococcus. Absolute pneumococcal IgG titers and the proportion of patients with humoral protection, stratified by serotype, and vaccination status were compared by paired nonparametric t-tests. Absolute counts for lymphocyte, CD4 T-cell, and CD19 cell and total IgG level, along with the rate of invasive pneumococcal infections, were measured at these timepoints. A total of 148 CAR-T recipients with pneumococcal IgG titers measured for at least one of the defined time points were identified. At baseline, 25% (19/76) patients with evaluable pneumococcal IgG titers met the definition of humoral protection. Among 44 patients with paired pneumococcal IgG titers at baseline and day+90, absolute IgG titers of all serotypes decreased (geometric mean = 0.41 and 0.32 µg/mL, respectively; P < .001). Thirteen patients were vaccinated following the titer blood draw at day+90 and had paired pneumococcal IgG titers at day+90 and day180. Absolute IgG titers of all vaccine specific serotypes in these vaccinated patients decreased from day+90 to day+180 (geometric mean = 0.36 and 0.29 µg/mL, respectively; P = .03). The proportion of patients meeting the criteria of humoral protection remained the same at day+180 despite vaccination at day+90. The results were similar among 8 patients vaccinated at day+180, as well as 7 patients consecutively vaccinated at day+90 and day+180 with corresponding pneumococcal IgG titers. When all vaccine-specific pneumococcal IgG titers were pooled together by timepoint regardless of vaccination status, the proportion of patients with humoral protection decreased until day+540. Some patients developed humoral protection after vaccination at day+360, maintained seroprotective IgG titers from baseline, or developed protection after receiving intravenous immunoglobulin treatment secondary to recurrent infections. Our study demonstrated that few large B cell lymphoma patients had humoral protection against pneumococcus at baseline, and existing IgG titers decreased after CAR-T. PCV13 vaccination at day+90 or day+180 after CAR-T did not increase humoral protection against pneumococcus. Only at day+540 was there evidence of humoral protection against pneumococcus in a modest proportion of patients. Clinical trials are needed to determine the optimal timing of vaccination, before or after CAR-T, to develop protective immunity against Streptococcus pneumoniae infections.

Antibody response in patients with autoimmune inflammatory rheumatic disease after pneumococcal polysaccharide prime vaccination or revaccination

OBJECTIVE

The aim of the study was to assess the pneumococcal antibody response in autoimmune inflammatory rheumatic disease (AIIRD) patients receiving 23-valent pneumococcal polysaccharide vaccine (PPV23) as a prime vaccination or revaccination.

METHOD

Antibodies to 12 serotypes occurring in the commonly applied pneumococcal vaccines in Denmark were measured in AIIRD patients receiving biological disease-modifying anti-rheumatic drug (bDMARD) treatment for rheumatoid arthritis, spondyloarthritis, or psoriatic arthritis. Patients with a non-protective level of pneumococcal antibodies (geometric mean pneumococcal antibody level < 1 μg/mL) were invited to receive vaccination with PPV23 followed by control of antibody titre 3 months later.

RESULTS

In total, 224 (74%) of 301 patients were included in the analyses, of whom 126 patients had previously received PPV23 vaccination. Post-vaccination antibody measurement revealed that only 80 patients (36%) achieved a protective level of antibodies. In a multivariable logistic regression analysis, significantly more patients without a previous PPV23 vaccination history achieved a protective antibody level compared with patients with a history of PPV23 vaccination less than 5 years ago (p = 0.005). This difference was not seen when comparing the former group with patients vaccinated 5 years ago or more. Methotrexate (MTX) treatment at the time of vaccination was associated with a non-protective antibody level (p < 0.001).

CONCLUSION

Only 36% of patients with a non-protective antibody level achieved a protective level in response to pneumococcal vaccination. Pneumococcal vaccination within the last 5 years and MTX treatment at the time of vaccination were independently associated with a poor antibody response.

Application of vaccine response in the evaluation of patients with suspected B-cell immunodeficiency: Assessment of responses and challenges with interpretation

Diagnostic vaccination is an integral component in the evaluation of patients suspected to have a B cell or humoral deficiency. Evaluation of antibody production in response to both protein- and polysaccharide-based vaccines aids in distinguishing between specific categories of humoral deficiency. Although assessment of pneumococcal polysaccharide responses is widely available and included in diagnostic guidelines, significant variability still exists in the measurement and interpretation of these responses. Interpretation can also be complicated by age, vaccination history and treatment with immunoglobulin replacement therapy. Despite the challenges and limitations of evaluating pneumococcal polysaccharide vaccine responses, it can provide valuable diagnostic and prognostic information to guide therapeutic intervention. Future efforts are needed to further standardize measurement and interpretation of pneumococcal antibody responses to vaccination and to identify and establish other methods and/or vaccines as alternatives to pneumococcal vaccination to address the challenges in certain patient populations.

Methotrexate Treatment Suppresses Monocytes in Nonresponders to Pneumococcal Conjugate Vaccine in Rheumatoid Arthritis Patients

Patients with rheumatoid arthritis (RA) have an increased risk of infections; therefore, immunization against vaccine-preventable diseases is important. Methotrexate (MTX) impairs the antibody response to pneumococcal conjugate vaccine (PCV) in patients with arthritis, and the underlying mechanism is largely unknown. Here, we investigate the potential role of the innate immune system in the faltering antibody response following PCV vaccination in RA patients treated with MTX. Phenotypes of circulating granulocytes and monocytes were analyzed in 11 RA patients treated with MTX, 13 RA patients without disease-modifying antirheumatic drug treatment (0DMARD), and 13 healthy controls (HC). Peripheral blood samples were collected before and 7 days after vaccination. In addition, the MTX group was sampled before initiating treatment. Frequencies of granulocyte and monocyte subsets were determined using flow cytometry. Serotype-specific IgG were quantified using a multiplex bead assay, pre- and 4-6 weeks after vaccination. At baseline, no differences in granulocyte and monocyte frequencies were observed between the groups. Within the MTX group, the frequency of basophils increased during treatment and was higher compared to the HC and 0DMARD groups at the prevaccination time point. MTX patients were categorized into responders and nonresponders according to the antibody response. Before initiation of MTX, there were no differences in granulocyte and monocyte frequencies between the two subgroups. However, following 6-12 weeks of MTX treatment, both the frequency and concentration of monocytes were lower in PCV nonresponders compared to responders, and the difference in monocyte frequency remained after vaccination. In conclusion, the suppressive effect of MTX on monocyte concentration and frequency could act as a biomarker to identify nonresponders to PCV vaccination.

Evaluation of response to 13-valent conjugated pneumococcal vaccination in patients with rheumatoid arthritis receiving upadacitinib: results from a phase 2 open-label extension study

Objective

To assess the immunogenicity of pneumococcal 13-valent conjugate vaccination (PCV-13) in patients with rheumatoid arthritis receiving upadacitinib and background methotrexate (MTX).

Methods

Eligible patients from the phase 2 open-label extension trial BALANCE-EXTEND (NCT02049138) receiving stable dosing of upadacitinib 15 mg or 30 mg once daily plus background MTX were given PCV-13. Antibody titres were collected prevaccination and 4 and 12 weeks postvaccination. The primary endpoint was the proportion of patients with satisfactory humoral response to PCV-13, defined as a ≥2-fold increase in ≥6 of 12 pneumococcal antigens at 4 weeks postvaccination.

Results

Of 111 patients (upadacitinib 15 mg, N=87; 30 mg, N=24), 85.6% were women, 97.3% used concomitant MTX and 44.1% used oral corticosteroids. At 4 weeks, 67.5% (95% CI 57.4 to 77.5) of patients receiving upadacitinib 15 mg and 56.5% (36.3 to 76.8) receiving 30 mg had a satisfactory PCV-13 response. Responses were similar in patients who used or did not use concomitant corticosteroids. No deaths or serious adverse events were reported.

Conclusions

Approximately two-thirds of patients receiving upadacitinib 15 mg once daily achieved a satisfactory humoral response to PCV-13 despite receiving concomitant MTX. Concomitant corticosteroid use did not negatively affect PCV-13 response.

Maintenance of an Immunogenic Response to Pneumococcal Vaccination in Children With Sickle Cell Disease

Patients with sickle cell disease (SCD) are at increased risk for invasive pneumococcal disease because of splenic dysfunction. To mitigate this risk, patients are protected with prophylactic penicillin until completion of pneumococcal vaccination series. The objective of this study was to assess the maintenance of a protective immune response to pneumococcal vaccination in children with SCD. A retrospective review was conducted between June 2019 and June 2020 of all patients with SCD patients for whom it had been 5±1 year since completion of PPSV23 vaccination series. A total of 41 patients were analyzed. The majority of children (68%) were able to maintain an adequate immune response. There was no identifiable disease characteristic associated with maintenance of an appropriate immunogenic response. This study finds that patients with SCD are able to maintain an adequate immune response at the 5±1 year time point from completion of PPSV23 vaccination series. Similarly, patients were not found to have an increased rate of invasive pneumococcal disease even if not meeting criteria for adequate pneumococcal serum titer levels. Maintenance of pneumococcal titers suggests that there may not be a need for revaccination at the 5-year time point in this patient population.

Response to pneumococcal conjugate and polysaccharide vaccination in children with rheumatic disease

Children with rheumatic disease and compromised immune system have an increased risk of infection. Streptococcus pneumoniae is a frequent pathogen, and immunization is recommended. In this study, we investigated whether immunocompromised children with rheumatic disease do respond to pneumococcal immunization with 13-valent pneumococcal conjugate vaccine followed by 23-valent pneumococcal polysaccharide vaccine. The study was conducted at two tertiary referral hospitals in Denmark from 2015 to 2018. Patients with rheumatic disease and compromised immune system aged 2-19 years were eligible. Patients were vaccinated with 13-valent pneumococcal conjugate vaccine followed by 23-valent pneumococcal polysaccharide vaccine. A blood sample was collected before vaccination and after each vaccination. IgG antibodies were quantified for twelve serotypes. Seroprotection for each serotype was defined as IgG ≥0.35 µg/mL. A total of 27 patients were enrolled. After the conjugate vaccine, an increase in antibody titres compared with pre-vaccination was found for all serotypes and 9/12 were significant. After the polysaccharide vaccine, the antibody titres for all serotypes but one was seen to increase but none reached significance. The proportion of patients protected before immunization ranged from 20.8% to 100% for the individual serotypes. Odds ratio for achieving seroprotection after the conjugate vaccine was >1 for 10/12 serotypes but only significant for three serotypes. After the polysaccharide vaccine, the odds ratio was >1 for 9/12 serotypes but none reached significance. In conclusion, children with rheumatic disease and compromised immune system respond to pneumococcal immunization with 13-valent pneumococcal conjugate vaccine and maintain antibody levels upon subsequent immunization with 23-valent pneumococcal polysaccharide vaccine.

Diagnostic Vaccination in Clinical Practice

Testing the antibody response to vaccination (diagnostic vaccination) is crucial in the clinical evaluation of primary immunodeficiency diseases. Guidelines from the American Academy of Allergy, Asthma & Immunology (AAAAI) provide detailed recommendations for diagnostic vaccination with pure pneumococcal polysaccharide vaccines (PPV). However, the degree of compliance with these guidelines and the utility of the guidelines in actual practice are undescribed. To address this, we systematically evaluated diagnostic vaccination in adult patients with suspected primary immunodeficiency diseases in a single tertiary center from 2011 to 2016 (n = 229). We found that full compliance with the AAAAI guidelines was achieved for only 39 patients (17%), suggesting that the guidelines are not easy to follow. Worse, interpretation according to the guidelines was heavily influenced by which serotype-specific antibodies that were used for the evaluation. We found that the arbitrary choices of serotype-specific antibodies could change the fraction of patients deemed to have ‘adequate immunity’ by a factor of four, exposing an inherent flaw in the guidelines. The flaw relates to dichotomous principles for data interpretation under the AAAAI guidelines. We therefore propose a revised protocol for diagnostic vaccination limited to PPV vaccination, subsequent antibody measurements, and data interpretation using Z-scores. The Z-score compiles multiple individual antibody levels, adjusted for different weighting, into one single continuous variable for each patient. In contrast to interpretation according to the AAAAI guidelines, the Z-scores were robust to variations in the choice of serotype-specific antibodies used for interpretation. Moreover, Z-scores revealed reduced immunity after vaccination in the patients with recurrent pneumonia (a typical symptom of antibody deficiency) compared with control patients. Assessment according to the AAAAI guidelines failed to detect this difference. We conclude that our simplified protocol and interpretation with Z-scores provides more robust clinical results and may enhance the value of diagnostic vaccination.

An enzyme-linked immunospot assay to evaluate Pneumovax response when on intravenous immunoglobulin

BACKGROUND

Testing for common variable immunodeficiency (CVID) requires evaluation of specific antibody responses to vaccines. Current practice of evaluating pneumococcal serotype-specific immunoglobulin (Ig)G levels after Pneumovax (P23) has several limitations and is not accurate for patients already on immunoglobulin replacement. In contrast, the enzyme-linked immunospot (ELISPOT) assay can be interpreted in patients on immunoglobulin replacement as ex vivo measurement of specific antibody-secreting cells (ASCs).

OBJECTIVE

To optimize and test an ELISPOT assay to evaluate vaccination response to P23 and compare with P23 serotype-specific IgG for patients on intravenous immunoglobulin (IVIG).

METHODS

We prospectively enrolled a total of 15 adults: normal controls (n = 8), patients with CVID on IVIG replacement (n = 2), patients on IVIG replacement for recurrent infections who did not meet diagnostic criteria for CVID, considered IgG deficiency (n = 2), and patients without immunodeficiency on high-dose IVIG for other diagnosis (n = 3). We measured P23 serotype-specific IgG before and 4 weeks after P23 and ELISPOT ASCs before and 1 week after P23 (with B-cell subpopulation analysis by flow cytometry in patients on IVIG).

RESULTS

Normal controls had a vaccination response by P23 serotype-specific IgG, whereas patients on IVIG did not. Except for true patients with CVID on IVIG, a P23 ELISPOT ASC response was found in normal controls (highest) and most patients on IVIG for recurrent infections or other diagnosis.

CONCLUSION

Our pilot study suggests that an optimized ELISPOT protocol has utility to evaluate the P23-specific antibody response after vaccination. Our ELISPOT assay seemed reliable for patients on IVIG and may help differentiate true patients with CVID from those with a less stringent diagnosis while on IVIG.

Long-term survivors following autologous haematopoetic stem cell transplantation have significant defects in their humoral immunity against vaccine preventable diseases, years on from transplant

Current international guidelines recommend routinely vaccinating haematopoetic stem cell transplant (HSCT) recipients. Despite significant infection-related mortality following autologous HSCT, routine vaccination programmes (RVP) completion is poor. For recovered HSCT recipients, it is uncertain whether catch-up vaccination remains worthwhile years later. To determine potential susceptibility to vaccine preventable infections, we measured antibody titres in 56 patients, a median of 7 years (range 0-29) following autologous HSCT, who had not completed RVP. We found that almost all participants had inadequate titres against diphtheria (98.2%) and pneumococcal infection (100%), and a significant proportion had inadequate titres against measles (34.5%). Of those subsequently vaccinated according to available guidelines, many mounted adequate serological responses. These data suggest a pragmatic catch-up approach for autologous HSCT recipients who have not completed RVP is advisable, with universal vaccination against some pathogens (e.g. Streptococcus pneumoniae and diphtheria) and serologically-guided approaches for others (e.g. measles and varicella zoster virus).

The clinical relevance of IgM and IgA anti-pneumococcal polysaccharide ELISA assays in patients with suspected antibody deficiency

Unlike immunoglobulin (Ig)G pneumococcal polysaccharide (PnPS)‐antibodies, PnPS IgA and IgM‐antibodies are not routinely determined for the assessment of immunocompetence. It is not yet known whether an isolated inability to mount a normal IgM or IgA‐PnPS response should be considered a relevant primary antibody deficiency (PAD). We studied the clinical relevance of anti‐PnPS IgM and IgA‐assays in patients with suspected primary immunodeficiency in a large teaching hospital in ’s‐Hertogenbosch, the Netherlands. Serotype‐specific‐PnPS IgG assays were performed; subsequently, 23‐valent‐PnPS IgG assays (anti‐PnPS IgG assays), and later anti‐PnPS IgA and IgM assays, were performed in archived material (240 patients; 304 samples). Eleven of 65 pre‐ and six of 10 post‐immunization samples from good responders to PnPS serotype‐specific IgG testing had decreased anti‐PnPS IgA and/or IgM titres. Of these, three pre‐ and no post‐immunization samples were from patients previously classified as ‘no PAD’. Determination of anti‐PnPS IgA and IgM in addition to anti‐PnPS IgG did not reduce the need for serotype‐specific PnPS IgG testing to assess immunocompetence [receiver operating characteristic (ROC) analysis of post‐immunization samples: anti‐PnPS IgA + IgG area under the curve (AUC) = 0.80, 95% confidence interval (CI) = 0.63–0.97; anti‐PnPS IgM + IgG AUC 0.80, 95% CI = 0.62–0.98; anti‐PnPS IgA + IgG + IgM AUC = 0.71, 95% CI = 0.51–0.91; anti‐PnPS IgG AUC = 0.93, 95% CI = 0.85–1.00]. Our data show that patients classified as having an intact antibody response based on measurement of serotype‐specific PnPS IgG can still display impaired anti‐PnPS IgM and IgA responses, and that the additional measurement of anti‐PnPS IgA and IgM could not reduce the need for serotype‐specific IgG testing. Future studies are needed to investigate the clinical relevance of potential ‘specific IgA or IgM antibody deficiency’ in patients with recurrent airway infections in whom no PAD could be diagnosed according to the current definitions.

A Toolkit and Framework for Optimal Laboratory Evaluation of Individuals with Suspected Primary Immunodeficiency

Knowledge related to the biology of inborn errors of immunity and associated laboratory testing methods continues to expand at a tremendous rate. Despite this, many patients with inborn errors of immunity suffer for prolonged periods of time before identification of their underlying condition, thereby delaying appropriate care. Understanding that test selection and optimal evaluation for patients with recurrent infections or unusual patterns of inflammation can be unclear, we present a document that distills relevant clinical features of immunologic disease due to inborn errors of immunity and related appropriate and available test options. This document is intended to serve the practicing clinical immunologist and, in turn, patients by describing best available test options for initial and expanded immunologic evaluations across the disease spectrum. Our goal is to demystify the process of evaluating patients with suspected immune dysfunction and to enable more rapid and accurate diagnosis of such individuals.

Pneumococcal immunity and PCV13 vaccine response in SOT-candidates and recipients

BACKGROUND

Solid organ transplantation (SOT) candidates and recipients are highly vulnerable to invasive pneumococcal diseases (IPD). Data on which to base optimal immunization recommendations for this population is scant. The national distribution of IPD serotypes led the Swiss Health Authorities to recommend in 2014 one dose of pneumococcal-13-valent-conjugate-vaccine (PCV13), without any subsequent dose of the 23-valent-polysaccharide-pneumococcal-vaccine (PPV23).

METHODS

This is a retrospective analysis of pneumococcal immunity using a multiplex binding assay, to assess seroprotection rates against a selection of seven PCV13- and seven PPV23-serotypes in SOT-candidates and recipients evaluated and/or transplanted in 2014/2015 in the University Hospitals of Geneva. Seroprotection was defined as serotype-specific antibody concentration greater than 0.5 mg/l and overall seroprotection when this was achieved for ≥ 6/7 serotypes.

RESULTS

Pre-vaccination and at time of transplant sera were available for 35/43 (81%), and 43/43 (100%) SOT-candidates respectively. At listing, 17/35 (49%) SOT-candidates were seroprotected against PCV13 and 21/35 (60%) against PPV23 serotypes. Following one systematic dose of PCV13 at listing, 35/43 (81%) SOT-recipients were seroprotected at day of transplant against PCV13-serotypes and 34/43 (79%) against PPV23 serotypes, compared to 21/41 (51%) and 28/41 (68%) respectively in the controls transplanted in 2013, before the systematic PCV13-vaccination.

CONCLUSIONS

The systematic vaccination with PCV13 of all SOT candidates without additional PPV23 is a good strategy as it confers seroprotection against a wide range of pneumococcal serotypes. Indeed, one of five PCV13-vaccinated SOT-candidates was nevertheless not seroprotected at time of transplant, reflecting their partial immune competence, and indicating the need for additional dose of pneumococcal vaccines before transplant.

A surface plasmon resonance based approach for measuring response to pneumococcal vaccine

Incidence of pneumococcal disease has increased worldwide in recent years. Response to pneumococcal vaccine is usually measured using the multiserotype enzyme-linked immunosorbent assay (ELISA) pneumococcal test. However, this approach presents several limitations. Therefore, the introduction of new and more robust analytical approaches able to provide information on the efficacy of the pneumococcal vaccine would be very beneficial for the clinical management of patients. Surface plasmon resonance (SPR) has been shown to offer a valuable understanding of vaccines' properties over the last years. The aim of this study is to evaluate the reliability of SPR for the anti-pneumococcal capsular polysaccharides (anti-PnPs) IgGs quantification in vaccinated. Fast protein liquid chromatography (FPLC) was used for the isolation of total IgGs from serum samples of vaccinated patients. Binding-SPR assays were performed to study the interaction between anti-PnPs IgGs and PCV13. A robust correlation was found between serum levels of anti-PnPs IgGs, measured by ELISA, and the SPR signal. Moreover, it was possible to correctly classify patients into "non-responder", "responder" and "high-responder" groups according to their specific SPR PCV13 response profiles. SPR technology provides a valuable tool for reliably characterize the interaction between anti-PnPs IgGs and PCV13 in a very short experimental time.

Immunogenicity and safety of the 13-valent pneumococcal conjugate vaccine in 23-valent pneumococcal polysaccharide vaccine-naïve and previously immunized adult patients with severe chronic kidney disease

Individuals with chronic kidney disease (CKD) are at high risk of pneumococcal infections and recommended to receive the 23-valent pneumococcal polysaccharide vaccine (PPV23). Although the 13-valent pneumococcal conjugate vaccine (PCV13) has been found to have higher immunogenicity compared to PPV23 in adults with some immunocompromising conditions, previous PPV23 immunization may decrease the immunogenicity of PCV13. We assessed immunogenicity and safety of PCV13 in 74 PPV23-naïve and 58 previously PPV23-immunized (>1 year ago) patients with severe (stage 4-5) CKD. Serum IgG, IgM, and IgA specific to seven serotypes, i.e. 3, 6B, 9V, 14, 19A, 19F, 23F were quantified pre- and 4 weeks and one year post-immunization. Baseline concentrations for most serotype-specific IgG and IgM, and serotype 3-specific IgA were higher in previously PPV23-immunized compared to PPV23-naïve patients. Immunization with PCV13 significantly increased almost all serotype-specific IgG, all IgA and some IgM; an increase in some serotype-specific IgG and IgM lasted for one year. Fold increases in antibody concentrations and the proportion of individuals with >2-fold increase post-immunization were generally larger in PPV23-naïve than previously immunized patients for most serotype-specific IgG and some IgA. The data show that in patients with CKD who received previous PPV23 immunization over one year ago, the antibody response to PCV13 was inferior compared to pneumococcal vaccine naïve study participants. In both groups, the lowest response to PCV13 was found for serotype 3. Patients of Indigenous ethnic background demonstrated a superior immune response to PCV13 compared to the non-Indigenous counterpart that could partially be related to Indigenous study participants' younger age. Although we found that previous PPV23 immunization could contribute to the more frequent occurrence of systemic adverse events post PCV13 immunization, those did not exceed the mild to moderate range.

Isolating polysaccharide IgG pneumococcal antibody responses by pre-adsorption of conjugate vaccine serotypes: A modified approach for the conjugate vaccine era

BACKGROUND

Assessment of pure polysaccharide response to the 23-valent pneumococcal polysaccharide vaccine (PPV23) can be biased by previous exposure to the conjugate vaccine (PCV). We applied pre-analytical modification to the existing ELISA by pre-incubating serum with PCV.

METHODS

PCV-adsorbed and non-adsorbed sera were prepared before measuring the concentration of anti-pneumococcal capsular polysaccharide (PCP) IgG antibodies by the whole pneumococcal ELISA. Paired pre and post-pneumococcal vaccination sera from 73 subjects were analyzed and the baseline anti-PCP IgG for each sample was subtracted from the post-vaccination value to measure vaccine responses. Absolute change in titers and fold changes were then compared between both methods.

RESULTS

In the PCV-vaccinated group (n = 28), pre-adsorption with PCV significantly reduced the vaccine responses compared to non-adsorbed sera [median increase in anti-PCP titers: 27.55 mg/l and 45.98 mg/l, respectively]. In addition, the median fold change dropped significantly from 3.026 to 2.313. In PPV23-vaccinated immunocompetent subjects (n = 28) there was a significant difference in anti-PCP responses with PCV adsorption [median values: 73.71 mg/l without and 51.04 mg/l with adsorption]. All the antibody deficiency patients (n = 17) displayed poor PPV23 responses. Although PPV23 responsiveness was not statistically different between both methods, we have observed a trend for lower anti-PCP IgG titers in PCV-adsorbed sera compared to non-adsorbed ones. Serotype-specific IgG analysis using a multiplexed bead-based immunoassay performed on 10 paired samples confirmed that the adsorption observed is specific to PCV serotypes.

CONCLUSION

Pre-analytical modification to the conventional ELISA by removing the PCV-specific serotypes may differentiate true polysaccharide response from recall response induced by previous PCV vaccination.

IGA Antibody Induced by Immunization With Pneumococcal Polysaccharides Is a Prognostic Tool in Common Variable Immune Deficiencies

The evaluation of the response to vaccination in patients with inborn errors of immunity is a tool to evaluate T-dependent and T-independent antibody residual function of B lymphocytes and it is part of the diagnostic definition for Common Variable Immune Deficiencies. Currently used classifications for Common Variable Immune Deficiencies patients are based on the frequency of B cell subsets, and have been proven as a valid instrument for identification of patients at higher risk of infectious and non-infectious complications. This 6-years period observational study delineated the measurement of specific IgA antibodies induced by a 23-valent pneumococcal polysaccharides vaccine by a standardized ELISA for the quantification of IgA antibodies to all 23 pneumococcal serotypes as an additional prognostic marker in 74 CVID patients. The inability to mount an IgA-mediated response against the pneumococcal polysaccharide antigens or the inability to maintain the antibody response over time identified poor IgA CVID responders with severe immunological impairment, great risk of co-morbidities, and poor prognosis. The division of CVID patient into specific IgA-non responders and IgA-responders discriminated better than other CVID classifications for infectious risk, while it overlapped for non-infectious complications. Our study suggested to add the evaluation of the antibody response by the 23-valent IgA assay in the clinical monitoring of CVID patients.

Efficacy of immunoglobulin replacement therapy and azithromycin in severe asthma with antibody deficiency

BACKGROUND

Although antibody deficiency (AD) is a well-known cause of recurrent respiratory infections, there are few data on its impact in adults with asthma. The objective of the present study was to assess outcomes in adults with severe asthma and AD after treatment with either azithromycin or subcutaneous immunoglobulins (SCIg).

METHODS

We performed a 5-year, prospective, observational, two-centre study of adults with severe asthma and AD in France. Bronchiectasis was ruled out by high-resolution computed tomography. Patients were treated for one year with either azithromycin (250 mg every other day) or SCIg (0.4-0.6 g/kg/months, weekly). All patients were evaluated for exacerbations, asthma control and lung function at baseline and then one year after treatment initiation.

RESULTS

Thirty-nine patients with severe asthma were included in the study: 14 had been treated with azithromycin and 25 had been treated with SCIg. Before the initiation of treatment for AD, all patients had an Asthma Control Questionnaire (ACQ-7) score > 1.5 (mean ± SD: 2.71 ± 0.53) despite treatment at GINA step 4 or 5, and had a high exacerbation rate requiring oral corticosteroids and/or rescue antibiotics (∼7.2 ± 2.1/patient/year). One year after treatment initiation, we observed a significantly higher FEV1 (mean: 0.18 ± 0.22 L) and ACQ-7 score (1.26 ± 0.68), and a significantly lower exacerbation rate (1.63 ± 1.24/patient/year).

CONCLUSIONS

Treatment of AD dramatically improved asthma outcomes - suggesting that adults with severe asthma and recurrent respiratory infections should be screened and (if appropriate) treated for AD.

The architecture of the IgG anti-carbohydrate repertoire in primary antibody deficiencies

Immune system failure in primary antibody deficiencies (PADs) has been linked to recurrent infections, autoimmunity, and cancer, yet clinical judgment is often based on the reactivity to a restricted panel of antigens. Previously, we demonstrated that the human repertoire of carbohydrate-specific immunoglobulin G (IgG) exhibits modular organization related to glycan epitope structure. The current study compares the glycan-specific IgG repertoires between different PAD entities. Distinct repertoire profiles with extensive qualitative glycan-recognition defects were observed, which are characterized by the common loss of Galα and GalNAc reactivity and disease-specific recognition of microbial antigens, self-antigens, and tumor-associated carbohydrate antigens. Antibody repertoire analysis may provide a useful tool to elucidate the degree and the clinical implications of immune system failure in individual patients.

Humoral response to a 13-valent pneumococcal conjugate vaccine in kidney transplant recipients

BACKGROUND

Vaccination against S. pneumoniae is recommended by national guidelines. Moderate immunogenicity of the 13-valent pneumococcal conjugate vaccine (PCV13) has been reported in adult kidney transplant recipients (KTR). This study further defines the immunogenicity of PCV13 in this cohort.

METHODS

49 KTR were immunized with PCV13. A validated opsonophagocytic killing assay (OPA), a global anti-pneumococcal capsular polysaccharide (anti-PCP) IgG, IgG2, IgM and IgA ELISA, and - for selected patients - a serotype specific anti-PCP WHO reference ELISA were performed pre-vaccination and at month 1 and 12 post-vaccination.

RESULTS

Geometric mean OPA titers increased significantly for 13/13 serotypes at month 1 and for 10/13 serotypes at month 12 post-vaccination. Vaccine response defined as an OPA titer ≥1:8 was reached in 9/13 serotypes (median). 53% reached the vaccine response criteria at month 1 and 45% at month 12. At month 1 after vaccination, the median OPA titer in an age-group matched healthy reference population was 5- to 10-fold higher than in KTR. OPA titers correlated strongly with results to the global and serotype specific anti-PCP IgG ELISA. Lower OPA titers significantly (p < 0.05) correlated with albuminuria, an interval between vaccination and transplantation <12 months, age and treatment with mycophenolate mofetil. Global IgG, IgG2, IgM and IgA, as well as serotype specific anti-PCP antibody concentrations (12/13 serotypes) increased significantly at month 1 and 12 post-vaccination.

CONCLUSIONS

Kidney transplant recipients show a significant humoral response after vaccination with PCV13. Functional antibody response exists, but is not as vigorous as in healthy adults.

Specific Antibody Immunodeficiency Presenting With Streptococcal pneumonia-Induced Spontaneous Bacterial Peritonitis

Specific antibody immunodeficiency (SAD) is a primary immunodeficiency disorder characterized by normal levels of serum immunoglobulins (IgG, IgA, and IgM) associated with a dysfunctional immune response. SAD is associated with recurrent infections in the setting of an insufficient response to polysaccharide vaccinations. Streptococcus pneumoniae is a well-established cause of respiratory infections in SAD. However, there has been a paucity of evidence of pneumococcal peritonitis in SAD patients, being reported as spontaneous in acquired immunodeficiency such as AIDS. We report the first case of S. pneumoniae-induced peritonitis as the presenting sign for SAD.

Defining Polysaccharide Antibody Deficiency: Measurement of Anti-Pneumococcal Antibodies and Anti-Salmonella typhi Antibodies in a Cohort of Patients with Recurrent Infections

BACKGROUND

The correlation between different methods for the detection of pneumococcal polysaccharide vaccine (PPV) responses to diagnose specific polysaccharide antibody deficiency (SAD) is poor and the criteria for defining a normal response lack consensus. We previously proposed fifth percentile (p5) values of PPV responses as a new cutoff for SAD.

OBJECTIVE

To analyze the association of SAD (determined by either World Health Organization (WHO)-standardized ELISA or multiplex bead-based assay) with abnormal response to Salmonella (S.) typhi Vi vaccination in a cohort of patients with recurrent infections.

METHODS

Ninety-four patients with a clinical history suggestive of antibody deficiency received PPV and S. typhi Vi vaccines. Polysaccharide responses to either 3 or 18 pneumococcal serotypes were measured by either the WHO ELISA or a multiplex in-house bead-based assay. Anti-S. typhi Vi IgG were measured by a commercial ELISA kit. Allohemagglutinins (AHA) were measured by agglutination method.

RESULTS

Based on the American Academy of Allergy, Asthma and Immunology (AAAAI) criteria for WHO ELISA, 18/94 patients were diagnosed with SAD and 22/93 based on serotype-specific p5 cutoffs for bead-based assay. The association between the two methods was significant, with 10 subjects showing abnormal response according to both techniques. Abnormal response to S. typhi Vi vaccination was found in 7 patients, 6 of which had SAD. No correlation was found between polysaccharide response and AHA, age, or clinical phenotype.

CONCLUSION

The lack of evidence-based gold standards for the diagnosis of SAD represents a challenge in clinical practice. In our cohort, we confirmed the insufficient correlation between different methods of specific PPV response measurement, and showed that the S. typhi Vi response was not contributive. Caution in the interpretation of results is warranted until more reliable diagnostic methods can be validated.

Focusing on Good Responders to Pneumococcal Polysaccharide Vaccination in General Hospital Patients Suspected for Immunodeficiency. A Decision Tree Based on the 23-Valent Pneumococcal IgG Assay

Background and Aim: Recently, the 23-valent IgG-assay was suggested as screening assay to identify poor responders to pneumococcal polysaccharide (PnPS)-vaccination with the serotype-specific assay as a second-line test. However, in a low pre-test probability general hospital setting predicting good responders could be more valuable to reduce the number of samples needing serotyping. Methods: Serotype-specific PnPS antibody-assays were performed for suspected immunodeficiency in two Dutch general hospitals (Jeroen Bosch Hospital, 's-Hertogenbosch; Elisabeth Tweesteden Hospital, Tilburg). 23-Valent PnPS antibody-assays were subsequently performed in archived material. Data were analyzed using receiver operating characteristic curves (AUC) and agreement indices (ICC). Results: Sera of 284 patients (348 samples) were included; 23-valent IgG-titres and the corresponding sum of PnPS-serotype specific antibodies showed moderate correlation (ICC = 0.63). In 232 conjugated-pneumococcal-vaccine-naïve patients (270 samples), a random 23-valent IgG-titer could discriminate between samples with and without ≥7/11, ≥7/13, or ≥6/9 pneumococcal serotypes when both cut-off values 0.35 and 1.0 μg/ml were used (AUC 0.86 and 0.92, respectively). All patients with a pre-immunization-titer ≥38.2 μg/ml and/or post-immunization-titer ≥96.1 μg/ml and none with a post-immunization-titer ≤38.5 μg/ml exhibited a good response to PnPS vaccination. Using these breakpoints as screening test to predict good responders, only 24% of patients would require further serotyping, as opposed to 68% if breakpoints to predict poor responders would have been used. Conclusion: In a low pre-test probability setting, the 23-valent IgG-assay proved to be a reliable screening test for good responders in conjugated-pneumococcal-vaccine-naïve patients, reducing the overall number of patient samples needing further serotyping, thus reducing overall costs of pneumococcal vaccination response assessment.

Evaluation of pneumococcal and tetanus vaccine responses in patients with rheumatoid arthritis receiving baricitinib: results from a long-term extension trial substudy

Background

Clinical guidelines recommend pneumococcal and tetanus vaccinations in patients with rheumatoid arthritis (RA). Baricitinib is an oral, selective Janus kinase (JAK) 1/JAK 2 inhibitor and is approved for the treatment of moderately to severely active RA in adults in over 50 countries including European countries, the USA, and Japan. This substudy evaluated pneumococcal conjugate and tetanus toxoid vaccine (TTV) responses in patients with RA receiving baricitinib. These vaccines elucidate predominantly T cell-dependent humoral antibody response.

Methods

Eligible RA patients receiving baricitinib 2 mg or 4 mg with or without concomitant methotrexate (MTX) were enrolled in a phase 3 long-term extension trial (RA-BEYOND; ClinicalTrials.gov, NCT01885078) in USA/Puerto Rico. Patients were vaccinated with 13-serotype pneumococcal conjugate vaccine (PCV-13) and TTV. Primary endpoints were the proportion of patients achieving a satisfactory humoral response for PCV-13 (≥ 2-fold increase in anti-pneumococcal antibody concentrations in ≥ 6 serotypes) and TTV (≥ 4-fold increase in anti-tetanus concentrations) at 5 weeks post-vaccination. Secondary endpoints included humoral responses at 12 weeks and functional responses of serotypes 4, 6B, 14, and 23F (twofold and fourfold increases in opsonic indexes at 5 and 12 weeks).

Results

Of 106 patients with a mean duration of RA of approximately 12 years, 80% were female, 30% were taking corticosteroids, and 89% (N = 94) were taking baricitinib plus MTX; most patients (97% PCV-13/96% TTV) completed the evaluations. Overall, 68% (95% CI 58.4, 76.2) of patients achieved a satisfactory response to PCV-13, 43% (34.0, 52.8) achieved a ≥ 4-fold increase in anti-tetanus concentrations, and 74% (64.2, 81.1) achieved a ≥ 2-fold increase. PCV-13 response was similar for patients taking corticosteroids (71%; 53.4, 83.9) vs those not (67%; 55.2, 76.5). The percentage of sera with a ≥ 2-fold increase in post-vaccination opsonic indexes at week 5 ranged from 47% (serotype 14) to 76% (serotype 6B). Through 12 weeks post-vaccination, seven patients (6.6%) reported injection-site events. There were no deaths during the substudy, and three patients experienced a serious adverse event.

Conclusions

Approximately two thirds of patients on long-term baricitinib achieved satisfactory humoral and functional responses to PCV-13 vaccination, while TTV responses were less robust. PCV-13 response was not diminished in those taking concomitant corticosteroids.

Trial registration

ClinicalTrials.gov, NCT01885078. Registered on 24 June 2013.

Specific Antibody Deficiencies in Clinical Practice

Specific antibody deficiency (SAD) is defined as the inability to mount an antibody response to purified Streptococcus pneumoniae capsular polysaccharide antigens in the presence of normal immunoglobulin concentrations and normal antibody responses to protein antigens. In this review, we discuss the difficulties in using presently available testing methods to adequately define SAD. The fact that there are different forms of SADs to pneumococcal surface polysaccharides is detailed. The diagnostic and therapeutic implications of recognizing that, in addition to SAD, there are other forms of SAD in the response to S. pneumoniae polysaccharides are described in detail. The conclusion of this review is that assessment of immunity and therapeutic actions to deal with SADs need to be based on clinical evidence rather than solely on arbitrarily defined antibody responses.

Should Pneumococcal Serotype 3 Be Included in Serotype-Specific Immunoassays?

Since the introduction of the 13-valent pneumococcal conjugate vaccine, a number of studies have demonstrated the limited efficacy of the pneumococcal serotype 3 component of this vaccine. Evidence from seven countries (Denmark, France, Greece, Portugal, Sweden, UK, US) shows limited or no effectiveness of the 13-valent pneumococcal conjugate vaccine against serotype 3 invasive pneumococcal disease and carriage. The serotype 3 capsule has some unique characteristics that may serve to explain this lack of efficacy—capsular polysaccharide is abundantly expressed, leading to a greater thickness of capsule, and free capsular polysaccharide may be released during growth. The serotype 3 component of the Luminex multiplex assay demonstrates inferior inter-laboratory reproducibility than other components and results may not be reliable. This communication outlines this evidence and discusses whether it is necessary to include serotype 3 in the assay in the future.

Immunogenicity of sequential 13-valent conjugated and 23-valent unconjugated pneumococcal vaccines in a population of children with lupus

Pneumococcal vaccination is recommended as a quality indicator for management of children with systemic lupus erythematosus. Literature on the immunogenicity of pneumococcal vaccines (PCVs) in children is scant. We sought to prospectively evaluate via an observational study, the immunogenicity to sequential children with lupus. Out of a cohort of 26 patients, approximately 65% achieved > 70% vaccinated serotype antibody levels of > 1.3 mcg/dL following PCV13, and of 22 patients followed through PPSV23 vaccination, 59% achieved the same. Patients with rituximab exposure in the 6 months prior to a vaccination were more likely to not achieve protective serotype levels ( p < 0.01 for PCV13, trend p = 0.07 for PPSV23). Three of 22 patients with no apparent risk factors did not achieve protective serotype levels. Non-responders to PCV13 generally did not respond to PPSV23. Retrospective healthy controls achieved 100% protective levels in response to PPSV23 vaccination, with 95% of serotypes being > 1.3 mcg/dL. Thus, sequential 13- and 23-valent pneumococcal vaccines achieve protective status for approximately two thirds of pediatric lupus patients in our population. Lack of response to vaccine may be secondary to induced or inherent functional impairments in the patient.

Serologic response to pneumococcal vaccination in children experiencing recurrent invasive pneumococcal disease

Background

Some children are prone to recurrent invasive pneumococcal disease (rIPD) and of these, some respond insufficiently to standard pneumococcal vaccination. Little is known about how to handle these children and if they benefit from additional vaccination. Here, we present results from a nationwide study of pediatric rIPD including data on serotype-specific vaccination response to pneumococcal polysaccharide vaccination (PPV23) and pneumococcal conjugate vaccination (PCV7/13).

Methods

A retrospective, population-based study was conducted using The National Streptococcus pneumoniae Registry, which contains laboratory-confirmed data from all cases of IPD in Denmark. From January 1980–June 2013 all children aged 0–15 years with rIPD were identified. Clinical data and data on serotype-specific pneumococcal antibody response were collected. Over the years quantification of pneumococcal antibodies varied from being presented in arbitrary units (ELISA), in μg/ml (WHO ELISA) and lately in μg/ml based on Luminex technology.

Results

2482 children were diagnosed with IPD and 75 episodes of rIPD were documented in 59 children. An underlying disease was documented in 45 (76%) children. Vaccination data were available for 26 children; 11 were vaccinated solely with PPV23, 8 with a combination of PPV23 + PCV7, 5 with PCV7 and 2 with PCV13. In total, nine responded to PPV23 vaccination and ten were PPV23 non-responders. Of the 15 PCV vaccinated children, two children responded subnormal to PCV7. Among PPV23 non-responders, five responded to subsequent PCV vaccination.

Conclusions

In our population-based study of children with rIPD 53% of the children responded insufficiently to PPV23 vaccination. PPV23 non-responders benefitted from PCV vaccination.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3267-6) contains supplementary material, which is available to authorized users.

Response to Tetanus and Pneumococcal Vaccination Following Administration of Ixekizumab in Healthy Participants

Background

Ixekizumab (IXE) is an interleukin (IL)-17A antagonist approved for the treatment of adults with moderate-to-severe psoriasis.

Objective

The objective of this study was to determine if the immune response to tetanus and pneumococcal vaccines in healthy subjects administered IXE was noninferior to control.

Methods

In a randomized, open-label, parallel-group study, adult subjects received vaccinations alone (N = 42, control) or in combination with 160 mg IXE subcutaneously 2 weeks prior to vaccination and 80 mg IXE on the day of vaccination (N = 41, IXE). Response to tetanus vaccination was defined as anti-tetanus antibodies ≥ 1.0 IU and a ≥ 1.5-fold increase if baseline was ≤ 1.0 IU or a ≥ 2.5-fold increase if baseline was > 1.0 IU. Response to pneumococcal vaccination was defined as a ≥ 2-fold increase from baseline in anti-pneumococcal antibodies against > 50% of the 23 serotypes. The primary outcomes were the percentages of patients with a response to the tetanus and pneumococcal vaccines 4 weeks after vaccination. A noninferiority analysis of IXE to control using a 40% margin was evaluated for the primary outcomes. Safety and pharmacokinetics were also assessed.

Results

IXE (38 completers) was noninferior to control (41 completers) based on the difference in the proportion of responders to tetanus [1.4%; 90% confidence interval (CI) − 16.6 to 19.2] and pneumococcal (− 0.8%; 90% CI − 12.9 to 11.0) vaccines. Twenty subjects (14 IXE, six control) reported 43 mild treatment-emergent adverse events.

Conclusion

IXE does not suppress the humoral immune response to non-live vaccines and was well tolerated in healthy subjects.

ClinicalTrial.gov identifier: NCT02543918.

Electronic supplementary material

The online version of this article (doi:10.1007/s40259-017-0249-y) contains supplementary material, which is available to authorized users.

Divergent humoral responses to 23-valent pneumococcal polysaccharide vaccine in critically-ill burn and neurosurgical patients

INTRODUCTION

Critically ill hospitalized patients are at increased risk of infection so we assessed the immunogenicity of 23-valent pneumococcal polysaccharide vaccine (PPSV23) administered within six days of injury.

METHODS

This prospective observational study compared the immunogenicity of PPSV23 among critically ill burn and neurosurgical patients at a tertiary, academic medical center. Patients received PPSV23 vaccination within six days of ICU admission per standard of care. Consent was obtained to measure concentrations of vaccine-specific IgG to 14 of 23 serotype capsule-specific IgG in serum prior to and 14-35 days following PPSV23. A successful immunologic response was defined as both a ≥2-fold rise in capsule-specific IgG from baseline and concentrations of >1 mcg/mL to 10 of 14 measured vaccine serotypes. Immunologic response was compared between burn and neurosurgical patients. Multiple variable regression methods were used to explore associations of clinical and laboratory parameters to immunologic responses.

RESULTS

Among the 16 burn and 27 neurosurgical patients enrolled, 87.5% and 40.7% generated a successful response to the vaccine, respectively (p = 0.004). Both median post-PPSV23 IgG concentrations (7.79 [4.56-18.1] versus 2.93 [1.49-8.01] mcg/mL; p = 0.006) and fold rises (10.66 [7.44-14.56] versus 3.48 [1.13-6.59]; p<0.001) were significantly greater in burn compared with neurosurgical patients. Presence of burn injury was directly and days from injury to immunization were inversely correlated with successful immunologic response (both p<0.03). Burn injury was associated with both increased median antibody levels post-PPSV23 and fold rise to 14 vaccine serotypes (p<0.03), whereas absolute lymphocyte count was inversely correlated with median antibody concentrations (p = 0.034).

CONCLUSION

Critically ill burn patients can generate successful responses to PPSV23 during acute injury whereas responses among neurosurgical patients is comparatively blunted. Further study is needed to elucidate the mechanisms of differential antigen responsiveness in these populations, including the role of acute stress responses, as well as the durability of these antibody responses.

Value of the Overall Pneumococcal Polysaccharide Response in the Diagnosis of Primary Humoral Immunodeficiencies

Background

An overall response assay [OVA, based on a 23-valent pneumococcal polysaccharide vaccine (PPV23)] is widely used to screen for anti-pneumococcal antibodies. Given the heterogeneity of response from one polysaccharide (PS) to another, a World Health Organization-standardized serotype-specific enzyme-linked immunosorbent assay (SSA) is considered to be the only reliable method for testing anti-PS antibody responses in individuals with suspected primary immunodeficiencies (PIDs).

Objective

To evaluate the OVA relative to the reference SSA.

Methods

Serum samples of adult patients referred for a suspected PID were collected before and then 4–8 weeks after immunization with PPV23. The anti-pneumococcal response was systematically assessed with an SSA (7–16 serotypes) and interpreted according to the American Academy of Asthma, Allergy and Immunology’s current guidelines. We used receiver operating characteristic curves and agreement indices to assess the OVA’s diagnostic value in a first cohort. In order to validate these findings, a second (validation) cohort was then prospectively included.

Results

Sixty-two adult patients were included, and 42 (67.7%) were defined as poor responders according to the SSA. Only the post-immunization titer in the OVA was able to correctly identify poor responders; a titer below 110 mg/L gave a positive predictive value of 100% [identifying 24 (57.1%) of the 42 poor responders], and similar levels of diagnostic performance were observed in the validation cohort. The pre-vaccination antibody titer, the post/pre-vaccination antibody titer ratio and a post-vaccination titer above 110 mg/L in the OVA were not predictive of the response in the SSA.

Conclusion

A post-vaccination antibody titer below 110 mg/L in the OVA was constantly associated with a poor PPV23 response using the SSA. In all other cases, SSA is the only reliable method for assessing diagnostic vaccination with PPV23.

Discrepant serological assays for Pneumococcus in renal transplant recipients - a prospective study

Vaccine immunoprotection for Streptococcus pneumoniae is mediated by opsonizing antibodies targeting serotype-specific capsular polysaccharides. Quantitative antibody levels enzyme-linked immunosorbent assay (ELISA) and antibody-mediated opsonophagocytic assays (OPA) measure vaccine-induced protection; correlation of these assays in transplantation requires investigation. This study examines the laboratory assessment of antibody titers in vaccinated renal recipients. Streptococcus pneumoniae 19A is common in immunocompromised hosts and is represented in protein-conjugate vaccines (PCV) and polysaccharide vaccines (PSV). Antibodies to 19A in serial sera from 30 vaccinated renal transplant recipients were compared using ELISA and OPA assays. Subject titers were classified as protected or not by ELISA (>0.35 μg/ml) and OPA titer (>1:8). Antibody titers analyzed using McNemar's test indicate that protection measured by the two assays are not the same (P = 0.0078); simple linear regression of within-subject geometric means of 19A enzyme-linked immunosorbent assay (ELISA) antibody levels versus 19A opsonophagocytic assays (OPA) titers demonstrates significant correlation between the two assays (P < 0.001). Vaccination is increasingly important given increasing antimicrobial resistance worldwide. OPA and ELISA antibody assays do not correlate well using current values for protective immunity against the Pneumococcus in immunosuppressed transplant recipients. Future studies of vaccination in transplant recipients should evaluate protective antibody levels using both functional antibody assays and standard ELISA antibody titers. (ClinicalTrials.gov: NCT00307125).

Asthma and the Risk of Rheumatoid Arthritis: An Insight into the Heterogeneity and Phenotypes of Asthma

Asthma is traditionally regarded as a chronic airway disease, and recent literature proves its heterogeneity, based on distinctive clusters or phenotypes of asthma. In defining such asthma clusters, the nature of comorbidity among patients with asthma is poorly understood, by assuming no causal relationship between asthma and other comorbid conditions, including both communicable and noncommunicable diseases. However, emerging evidence suggests that the status of asthma significantly affects the increased susceptibility of the patient to both communicable and noncommunicable diseases. Specifically, the impact of asthma on susceptibility to noncommunicable diseases such as chronic systemic inflammatory diseases (e.g., rheumatoid arthritis), may provide an important insight into asthma as a disease with systemic inflammatory features, a conceptual understanding between asthma and asthma-related comorbidity, and the potential implications on the therapeutic and preventive interventions for patients with asthma. This review discusses the currently under-recognized clinical and immunological phenotypes of asthma; specifically, a higher risk of developing a systemic inflammatory disease such as rheumatoid arthritis and their implications, on the conceptual understanding and management of asthma. Our discussion is divided into three parts: literature summary on the relationship between asthma and the risk of rheumatoid arthritis; potential mechanisms underlying the association; and implications on asthma management and research.