Response to pneumococcal vaccination in mannose-binding lectin-deficient adults with recurrent respiratory tract infections

The Role of Mannose-Binding Lectin and Inflammatory Markers in Establishing the Course and Prognosis of Community-Acquired Pneumonia in Children

BACKGROUND

Community-acquired pneumonia (CAP) is one of the most significant childhood diseases worldwide and a leading infectious cause of death in children. This study aimed to evaluate the prognostic value of the inflammatory markers-C-reactive protein (CRP) and procalcitonin (PCT)-and the polymorphic glycoprotein mannose-binding lectin (MBL), deficiency of which is associated with severe infections, in the determination of the optimal type and timing of therapeutic intervention for CAP in childhood.

METHODS

Retrospective evaluation was conducted on a cohort of 204 children aged 4 months-17 years hospitalized with CAP. Their levels of CRP, PCT, and MBL were assessed for their association with a variety of outcomes, including the incidence of local and systemic complications, admission to the ICU, duration of antibiotic treatment and hospital stay, and death.

RESULTS

CRP and PCT proved to be better predictors of complications of CAP than MBL. The area under the curve (AUC) value was highest for PCT as a predictor of systemic complications (AUC = 0.931, 95%CI 0.895-0.967), while CRP (AUC = 0.674, 95%CI 0.586-0.761) performed best as a predictor of local complications (AUC = 0.674, 95%CI 0.586-0.761). Regarding admission to the ICU, CRP was the weakest predictor (AUC = 0.741), while PCT performed the best (AUC = 0.833), followed by MBL (AUC = 0.797). Sensitivity and specificity were calculated for the optimal threshold generated by receiver operating characteristic (ROC) curves, rendering sensitivity of 90% and specificity of 87% for PCT in assessing the risk of systemic complications, compared to sensitivity of 83% and specificity of 90% for CRP. MBL showed relatively high sensitivity (96%) but low specificity (25%) for predicting the need for ICU admission.

CONCLUSIONS

Early measurement of CRP, PCT, and MBL provides clinicians with important information regarding the course and prognosis of children diagnosed with CAP, thus ensuring prompt, optimal therapeutic management.

Immunogenicity of the 13-Valent Pneumococcal Conjugated Vaccine Followed by the 23-Valent Polysaccharide Vaccine in Chronic Lymphocytic Leukemia

Patients with Chronic Lymphocytic Leukemia (CLL) have a 29- to 36-fold increased risk of invasive pneumococcal disease (IPD) compared to healthy adults. Therefore, most guidelines recommend vaccination with the 13-valent pneumococcal conjugated vaccine (PCV13) followed 2 months later by the 23-valent polysaccharide vaccine (PPSV23). Because both CLL as well as immunosuppressive treatment have been identified as major determinants of immunogenicity, we aimed to assess the vaccination schedule in untreated and treated CLL patients. We quantified pneumococcal IgG concentrations against five serotypes shared across both vaccines, and against four serotypes unique to PPSV23, before and eight weeks after vaccination. In this retrospective cohort study, we included 143 CLL patients, either treated (n = 38) or naive to treatment (n = 105). While antibody concentrations increased significantly after vaccination, the overall serologic response was low (10.5%), defined as a ≥4-fold antibody increase against ≥70% of the measured serotypes, and significantly influenced by treatment status and prior lymphocyte number. The serologic protection rate, defined as an antibody concentration of ≥1.3 µg/mL for ≥70% of serotypes, was 13% in untreated and 3% in treated CLL patients. Future research should focus on vaccine regimens with a higher immunogenic potential, such as multi-dose schedules with higher-valent T cell dependent conjugated vaccines.

Respiratory Outcomes at 5-Year Follow-Up in Children with Mannose-Binding Lectin Deficiency: A Retrospective Cohort Study

OBJECTIVE

Mannose-binding lectin deficiency may predispose children to having increased infection susceptibility. However, there is no conclusive evidence that mannose-binding lectin deficiency is associated with adverse respiratory consequences in children. We aimed to evaluate the effects of mannose-binding lectin deficiency (defined as a level of less than 0.6 mg/L) on clinical, radiological, and microbiological characteristics in children presenting with troublesome respiratory symptoms, as compared to those who are mannosebinding lectin-sufficient.

MATERIAL AND METHODS

We conducted a retrospective cohort study to investigate the association between mannose-binding lectin deficiency and respiratory outcomes in children over a period of 10 years in a large teaching hospital. Children presenting with frequent or persistent respiratory symptoms such as a chronic wet cough lasting more than 4 weeks, recurrent lower respiratory tract infections (≥4 infections in a year), or severe respiratory tract infections requiring admission to intensive care or to high dependency unit were included in the study.

RESULTS

The study showed no significant difference in clinical outcomes with mannose-binding lectin deficiency and sufficiency. Thirty-two percent of children with mannose-binding lectin deficiency and 30% of those with mannose-binding lectin sufficiency had positive respiratory microbiology. Twenty-three percent of children with mannose-binding lectin deficiency and 24% of those with mannose-binding lectin sufficiency had radiological changes on plain radiographs; also the prevalence of bronchiectasis was similar in both groups. The rates of admission to pediatric intensive care unit were comparable in the 2 groups.

CONCLUSIONS

Children with mannose-binding lectin deficiency and sufficiency showed similar clinical, radiological, and microbiological characteristics. Our study suggests that there are no childhood adverse respiratory consequences with mannose-binding lectin deficiency.

Immunogenicity of the 13-valent pneumococcal conjugate vaccine followed by the 23-valent pneumococcal polysaccharide in people living with HIV on combination antiretroviral therapy

BACKGROUND

People living with HIV (PLWH) are at increased risk of pneumococcal infections compared with the general population. The objective of this study was to investigate the immunogenicity of the combined pneumococcal vaccination schedule in PLWH.

METHODS

In this prospective cohort study, adult PLWH on antiretroviral therapy and HIV negative controls received the 13-valent pneumococcal conjugate vaccine (PCV13) at baseline followed by the 23-valent polysaccharide vaccine (PPSV23) at month 2. Serotype-specific IgG levels of 24 vaccine serotypes were measured (months 0, 2, 4, 6, 12). The primary outcome was seroprotection at month 4, defined as the proportion of patients with a post-immunization IgG concentration of ≥1.3 µg/mL for ≥70% (17/24) of vaccine serotypes.

FINDINGS

Samples of 120 patients were analysed. Seroprotection at month 4 was 49% (39/80) for PLWH and 82% (28/34) in controls. At month 12, seroprotection had decreased to 23% (18/79) and 63% (22/35), respectively. Nadir CD4 counts ≥ 200 cells/mm³, preserved kidney function and co-administration of the diphtheria-tetanus-polio (DTP) vaccine were associated with better seroprotection among PLWH. IgG levels of both PLWH and controls (all 24 vaccine serotypes) were significantly higher compared with baseline at all timepoints.

INTERPRETATION

Although IgG levels of all 24 vaccine serotypes increased significantly in both PLWH and controls, only a minority of PLWH achieved seroprotection after PCV13 followed by PPSV23. In addition, protective immunity waned rapidly. Further research into alternative vaccinations strategies for PLWH is needed, such as vaccination schedules with higher-valent pneumococcal vaccines. The DTP vaccine may augment pneumococcal vaccination responses.

Immunogenicity of a 5-dose pneumococcal vaccination schedule following allogeneic hematopoietic stem cell transplantation

The optimal schedule of pneumococcal vaccination after allogeneic hematopoietic stem cell transplantation (allo‐HSCT) remains controversial. The objective of this study was to investigate the immunogenicity of a 5‐dose pneumococcal vaccination schedule in adult allo‐HSCT recipients with and without immunosuppressive therapy. In this prospective cohort study, allo‐HSCT recipients received four doses of the 13‐valent pneumococcal conjugate vaccine (PCV13) and one dose of the 23‐valent pneumococcal polysaccharide vaccine (PPSV23) starting 4–6 months after allo‐HSCT. PCV13 was administered at T0, T1, T2, and T8 (T = months from enrollment) and PPSV23 at T10. Serum was collected at T0, T4, T8, T10, and T12, and IgG levels were measured for all 24 vaccine serotypes by immunoassay. The primary outcome was overall seroprotection at T12 defined as an IgG concentration ≥1.3 μg/ml for 17/24 vaccine serotypes in allo‐HCST recipients with and without immunosuppressive therapy at baseline. Secondary outcomes were serotype‐specific seroprotection and dynamics of IgG levels. We included 89 allo‐HSCT recipients in the final analysis. Overall seroprotection was 47% (15/32) for patients without immunosuppressive therapy at baseline versus 24% (11/46) for patients with immunosuppressive therapy (p = .03). Seroprotection was higher for PCV13 serotypes (78% and 54% respectively; p = .03) and lower for PPSV23‐unique serotypes (28% and 13% respectively; p = .1). IgG concentrations increased significantly over time for all 24 serotypes. Concluding, although immunogenicity of PCV13 serotypes was reasonable, the poor response to PPSV23 serotypes resulted in an insufficient overall response to pneumococcal vaccination for allo‐HSCT recipients. Research into vaccination strategies with higher‐valent T‐cell‐dependent pneumococcal vaccines is needed.

Serologic response to a third dose of an mRNA-based SARS-CoV-2 vaccine in lung transplant recipients

Lung transplant recipients have an increased risk for severe coronavirus disease 2019 (COVID-19) due to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A third dose of a SARS-CoV-2 vaccine has been recommended for all solid organ transplant recipients, but data from lung transplant recipients specifically are scarce. In this study, the serologic response to a third dose of an mRNA-based SARS-CoV-2 vaccine was measured in 78 lung transplant recipients. Sixty-two percent (n = 48) had a serological response to vaccination, which was significantly higher than after the second vaccine dose (27 patients (35%); p = 0.0013). A positive serologic response was associated with having had COVID-19 (p = 0.01), and higher serum IgG level and complement mannose binding lectin pathway activity prior to vaccination (p = 0.04 and p = 0.03, respectively). Serologic response was not associated with the dose of mycophenolate mofetil or prednisone or other immune status parameters. Eleven patients (14%) developed COVID-19 after the second or third vaccine dose, but this did not associate with serologic response after the second vaccine dose (9% in patients who developed COVID-19 versus 39% in patients who did not develop COVID-19 (p = 0.09)), or with serologic response above cut-off values associated with clinical protection in previous studies. In conclusion, the response to mRNA-based SARS-CoV-2 vaccines in lung transplant recipients improves significantly after a third vaccine dose. Factors associated with a positive serologic response are having had COVID-19 prior to vaccination, and serum IgG and complement mannose binding lectin pathway activity prior to vaccination. Serologic response did not associate with clinical protection against COVID-19 in this study.

Immunogenicity of the Currently Recommended Pneumococcal Vaccination Schedule in Patients With Inflammatory Bowel Disease

BACKGROUND

Patients with inflammatory bowel disease (IBD) are at increased risk of invasive pneumococcal infections. Therefore, vaccination with the 13-valent pneumococcal conjugate vaccine (PCV13) followed by 23-valent pneumococcal polysaccharide vaccine (PPSV23) 2 months later is recommended. However, the level of immunogenicity induced by this vaccination schedule in IBD patients with and without immunosuppressive medication remains unclear.

METHODS

We prospectively assessed the immunogenicity of PCV13 followed by PPSV23 in IBD patients by measuring serotype-specific pneumococcal immunoglobulin G antibody concentrations at baseline and 4-8 weeks postvaccination. Response to vaccination was defined as a postvaccination antibody concentration ≥1.3 μg/mL for 70% of the measured serotypes. We analyzed the immunogenic effect of 4 different medication regimens: (1) conventional immunomodulators (ie, oral prednisolone >10 mg/day, thiopurines, methotrexate); (2) anti-tumor necrosis factor agents; (3) combination therapy; and (4) no treatment with immunosuppressive agents (control group).

RESULTS

One hundred forty-one IBD patients were included, of whom 37 were controls. Adequate response to vaccination was 59% (61/104) in patients using immunosuppressive agents (groups 1-3) vs 81% (30/37) in controls (odds ratio, 0.33 [95% confidence interval, .13-.82]). A combination of different immunosuppressive drugs most severely impaired the immune response to pneumococcal vaccination (response, 52% [15/29]).

CONCLUSIONS

Although the sequential vaccination schedule of PCV13 followed by PPSV23 is safe, immunogenic, and thus beneficial in the majority of IBD patients, those receiving immunosuppressive agents, and especially those receiving combination therapy, have an impaired immune response compared to controls. Therefore, preferably, vaccinations should be administered before the initiation of immunosuppressive therapy.

CLINICAL TRIALS REGISTRATION

Dutch trial register #6315.

Pneumococcal vaccination responses in adults with subnormal IgG subclass concentrations

BACKGROUND

We sought to compare Pneumovax®23 responses in adults with subnormal IgG subclass concentrations. We studied adults with normal total IgG, frequent/severe respiratory infection, and subnormal IgG1, IgG3, or IgG1 + IgG3 before and after Pneumovax®23. We defined response as serotype-specific IgG > 1.3 μg/mL and aggregate response as IgG > 1.3 μg/mL for ≥70% of all serotypes tested. We compared patients with and without serotype-specific responses and performed logistic regression on aggregate responses using: age; male sex; body mass index; autoimmune condition(s); atopy; other allergies; subnormal IgGSc immunophenotypes; IgA; and IgM.

RESULTS

There were 59 patients (mean age 44 ± 13 (SD) years; 83.1% women). Median days between pre- and post-Pneumovax®23 testing was 33 (range 19-158). The median post-vaccination summated concentration of serotype-specific IgG was higher in patients with subnormal IgG1 than subnormal IgG3 (responders and non-responders). All subnormal IgG1 + IgG3 non-responders responded to serotypes 8, 9 and 26, unlike other non-responders. Subnormal IgG3 responders had lower responses to serotypes 1, 4, 12, 23, 26, and 51. Subnormal IgG3 non-responders had higher responses to serotypes 1, 3, 8, 9, 12, 14, 19, 51, and 56. Response rates decreased with increasing age. Aggregate responders were: subnormal IgG1, 54%; IgG3, 46%; and IgG1 + IgG3, 46%. Regression on aggregate response revealed lower response with male sex (odds ratio 0.09 [95% CI 0.01, 0.77]) and atopy (0.17 [0.03, 0.83]).

CONCLUSIONS

Serotype-specific IgG responses to Pneumovax®23 were greater in patients with subnormal IgG1 than subnormal IgG3. Male sex and atopy were associated with lower aggregate responses.

Clinical and laboratory associations of mannose-binding lectin in 219 adults with IgG subclass deficiency

Background

Mannose-binding lectin (MBL) deficiency may increase risk of respiratory tract infection in adults unselected for IgG or IgG subclass levels. In a retrospective study, we sought to determine associations of serum MBL levels with clinical and laboratory characteristics of unrelated non-Hispanic white adults at diagnosis of IgG subclass deficiency (IgGSD). We computed the correlation of first and second MBL levels expressed as natural logarithms (ln) in a patient subgroup. We compared these characteristics of all adults with and without MBL ≤50 ng/mL: age; sex; body mass index; upper/lower respiratory tract infection; diabetes; autoimmune condition(s); atopy; other allergy; corticosteroid therapy; and subnormal serum IgG subclasses, IgA, and IgM. We performed logistic regression on MBL ≤50 ng/mL (dichotomous) using the three independent variables with the lowest values of p in univariate comparisons.

Results

There were 219 patients (mean age 51 ± 13 y; 82.5% women). Thirty-six patients (16.4%) had MBL ≤50 ng/mL. Two MBL measurements were available in 14 patients. The median interval between the first and second measurements was 125 d (range 18–1031). For ln-transformed data, we observed adjusted r² = 0.9675; Pearson correlation coefficient 0.9849; and p < 0.0001. Characteristics of patients with and without MBL ≤50 ng/mL did not differ significantly in univariate comparisons. We performed a regression on MBL ≤50 ng/mL using: subnormal IgM (p = 0.0565); upper respiratory tract infection (p = 0.1094); and body mass index (p = 0.1865). This regression revealed no significant associations. Conclusions: We conclude that the proportion of the present IgGSD patients with serum MBL ≤50 ng/mL is similar to that of healthy European adults. MBL ≤50 ng/mL was not significantly associated with independent variables we studied.

Long-term Follow-up of Humoral Immune Status in Adult Lung Transplant Recipients

BACKGROUND

Lung transplant recipients have an increased risk for infections in the posttransplant period due to immunosuppressive therapy. Protection against infections can be achieved through vaccination, but the optimal vaccination schedule in lung transplant recipients is unknown. Data on long-term immunological follow up and vaccination responses after lung transplantation are scarce.

METHODS

Here we present long-term immunological follow up of a cohort of 55 lung transplant recipients. This includes detailed antibody responses after 23-valent pneumococcal polysaccharide vaccination (23vPPV).

RESULTS

All patients were vaccinated with 23vPPV before transplantation. Median follow-up after transplantation was 6.6 years (379 patient-years). After transplantation, there is a significant decrease of all immunoglobulins, IgG subclasses and pneumococcal polysaccharide antibodies. After the first year posttransplantation, there is a gradual increase of all immunoglobulins and IgG subclasses, but values were always significantly lower than in the pretransplant period. After a median of 4.4 years posttransplantation, patients were revaccinated with 23vPPV. The pneumococcal polysaccharide antibody response was impaired in 87% of patients (ie, antibody titer above cutoff and twofold increase between pre and postvaccination values for <70% of serotypes).

CONCLUSIONS

We found that impairment of humoral immunity was most outspoken in the first year after lung transplantation. Immunoglobulin levels remain decreased several years after transplantation and the response to pneumococcal polysaccharide vaccine was significantly lower posttransplantation compared to the pretransplantation response. However, most patients did show a partial response to vaccination. Based on our results, revaccination with pneumococcal vaccines after transplantation should be considered 1 year after transplantation.

Long-term Clinical Outcome of Antibody Replacement Therapy in Humoral Immunodeficient Adults With Respiratory Tract Infections

In severe humoral immunodeficiency the indication for antibody replacement therapy (ART) is clear, and supported by several large studies. However, for milder forms of humoral immunodeficiency, the indication for ART is less clear. This is a retrospective cohort study of 87 adults with recurrent respiratory tract infections who received ART. The patients had severe or mild humoral immunodeficiency, and were followed up for a median of 62months. Infection frequency, pharmacy-registered antibiotics use and hospital admissions significantly decreased under ART compared to the year prior to starting ART (median 5.50 (anamnestically)-0.82 (physician-confirmed) infections/year, p<0.001; median 4.00-2.05antibioticscourses/year, p<0.001; mean 0.75-0.44hospitaladmissions/year, p=0.009). These beneficial effects of ART were seen in both severe and mild immunodeficiency. Bronchiectasis was present in 27 patients when ART was started, but was not associated with clinical outcomes. An increase in hospital admissions under ART, observed in some patients, was significantly associated with pulmonary emphysema and current smoking. In conclusion, this study shows that ART is a long-term effective therapy in adults with recurrent respiratory tract infections with severe as well as with milder forms of humoral immunodeficiency.

Mannose-binding lectin protein and its association to clinical outcomes in COPD: a longitudinal study

BACKGROUND

Functional deficiency of mannose-binding lectin (MBL) may contribute to the pathogenesis of chronic obstructive pulmonary disease. We hypothesized that specific MBL2 gene polymorphisms and circulating MBL protein levels are associated with clinically relevant outcomes in the Predicting Outcome using systemic Markers In Severe Exacerbations of COPD PROMISE-COPD cohort.

METHODS

We followed 277 patients with stable COPD GOLD stage II-IV COPD over a median period of 733 days (IQR 641-767) taking survival as the primary outcome parameter. Patients were dichotomized as frequent (≥ 2 AECOPD/year) or infrequent exacerbators. Serum MBL levels and single nucleotide polymorphisms of the MBL2 gene were assessed at baseline.

RESULTS

The MBL2-HYPD haplotype was significantly more prevalent in frequent exacerbators (OR: 3.33; 95% CI, 1.24-7.14, p = 0.01). The median serum MBL concentration was similar in frequent (607 ng/ml, [IQR; 363.0-896.0 ng/ml]) and infrequent exacerbators (615 ng/ml, [IQR; 371.0-942.0 ng/ml]). Serum MBL was not associated with lung function characteristics or bacterial colonization in sputum. However, high serum MBL at stable state was associated with better survival compared to low MBL (p = 0.046, log rank test).

CONCLUSIONS

In COPD, the HYPD haplotype of MBL2 gene is associated with frequent exacerbations and high serum MBL is linked to increased survival. The PROMISE-COPD study was registered at www.controlled-trials.com under the identifier ISRCTN99586989.

Response to pneumococcal polysaccharide vaccination in patients with chronic and allergic aspergillosis

INTRODUCTION

Pneumococcal infection causes significant morbidity in patients with underlying lung disease, and vaccination has been associated with reduced disease rates. Response to vaccination has not been studied in chronic lung conditions characterised by ongoing infection or inflammation like chronic pulmonary aspergillosis (CPA).

METHODS

In a prospective observational study, consecutive patients with CPA, allergic aspergillosis and bronchiectasis attending a national referral centre received pneumococcal 23-valent polysaccharide vaccine (PPV-23) and had pre- and post-vaccination antibody concentrations quantified as part of routine clinical care. Serotype-specific pneumococcal IgG antibodies were quantified for 12 serotypes using a multiplex microsphere assay. A protective response was defined as a level of >1.3μg/mL or a ≥ fourfold rise in concentration for ≥70% of serotypes, pre to post-vaccination. C-reactive protein, Immunoglobulins and mannose binding lectin (MBL) levels were measured and correlated to vaccine response.

RESULTS

A total of 318 patients were enrolled. In vaccine-naïve patients (n=127), the lowest pre-vaccination levels were seen with serotypes 1 and 4 and the highest with serotype 19A. A protective response post-vaccination was seen in 50% of patients. The poorest responses were observed with serotypes 1, 3 and 4. Levels of C-reactive protein did not affect efficacy. Profound MBL deficiency was found in 28.8%; there were no significant differences in response to vaccination in patients with or without MBL deficiency. Post-vaccination serotype-specific concentrations waned gradually, however they were still elevated compared to pre-vaccination after 2-5 years.

CONCLUSIONS

Patients with chronic and allergic aspergillosis exhibited a poor response to PPV-23 vaccination compared to healthy adults. An alternative vaccination strategy or delay of vaccination until their underlying condition is better controlled, e.g. after treatment with antifungals may result in better response.

Mannose-binding lectin and ficolin-2 do not influence humoral immune response to hepatitis B vaccine

BACKGROUND

Host genetics appear to be an important factor in the failure to generate a protective immune response after hepatitis B (HBV) vaccination. Mannose-binding lectin (MBL) and ficolin-2 (FCN2), two pattern recognition receptors of the lectin pathway of complement, influence the clinical outcome of HBV, and MBL deficiency has been shown to augment the humoral response to HBV vaccination in several experimental models. Here, we investigated the association of MBL and FCN2 with the humoral response to HBV vaccination in a candidate gene and functional study.

PATIENTS AND METHODS

A post hoc analysis of a prospective, interventional HBV vaccination study among human immunodeficiency virus type 1 (HIV-1) uninfected individuals in Kenya was conducted. Serum levels and polymorphisms of MBL and FCN2 were analysed in relation to the immune response to HBV vaccination.

RESULTS

Protective hepatitis B surface antibody levels (≥ 10 mI U/mL) were evident in 251/293 (85.7%) individuals. Median MBL and FCN2 levels were similar in responders vs. non-responders with a weak trend towards lower median MBL levels in non-responders (1.0 vs. 1.6μg/mL, p=0.1). Similarly, there was no difference in four MBL and six FCN2 polymorphisms analysed in the two groups with the exception of an increased frequency of a homozygous MBL codon 57 mutation in non-responders (4 (9.5%) vs. 8 (3.2%), p=0.05) corresponding to lower MBL levels. Results were similar after adjusting for age and sex.

CONCLUSIONS

Our study does not support a prominent role of the lectin pathway of complement in general and MBL and FCN2 in particular in the humoral immune response to HBV vaccination in African adults.