Primary vs. secondary antibody deficiency: clinical features and infection outcomes of immunoglobulin replacement

Subcutaneous immunoglobulin replacement therapy in patients with immunodeficiencies - impact of drug packaging and administration method on patient reported outcomes

BACKGROUND

Here, the perspective of patients with primary and secondary immunodeficiency receiving subcutaneous immunoglobulin (SCIg) via introductory smaller size pre-filled syringes (PFS) or vials were compared.

METHODS

An online survey was conducted in Canada by the Association des Patients Immunodéficients du Québec (APIQ) (10/2020-03/2021). Survey questions included: reasons for choosing SCIg packaging and administration methods, training experiences, infusion characteristics, and switching methods. The survey captured structured patient-reported outcomes: treatment satisfaction and its sub-domains, symptom state, general health perception, and physical and mental function. Respondents using PFS were compared with vial users, overall and stratified by their administration method (pump or manual push).

RESULTS

Of the 132 total respondents, 66 respondents used vials, with 38 using a pump and 28 using manual push. PFS (5 and 10 mL sizes) were being used by 120 respondents, with 38 using a pump and 82 using manual push. PFS users were associated with a 17% lower median (interquartile range) SCIg dose (10 [8, 12] vs. 12 [9, 16] g/week, respectively), a significantly shorter infusion preparation time (15 [10, 20] vs. 15 [10, 30] mins, respectively), and a trend for shorter length of infusion (60 [35, 90] vs. 70 [48, 90] mins, respectively) compared with those on vials. Patient-reported treatment satisfaction scores were overall similar between vial and PFS users (including on the domains of effectiveness and convenience), except for a higher score for vials over PFS on the domain of global satisfaction (p=0.02).

CONCLUSIONS

Consistent with prescribing that reflects a recognition of less wastage, PFS users were associated with a significantly lower SCIg dose compared with vial users. PFS users were also associated with shorter pre-infusion times, reflecting simpler administration mechanics compared with vial users. Higher global satisfaction with treatment among vial users compared with PFS users was consistent with users being limited to smaller PFS size options in Canada during the study period. Patient experience on PFS is expected to improve with the introduction of larger PFS sizes. Overall, treatment satisfaction for SCIg remains consistently high with the introduction of PFS packaging compared with vials.

Access and use of immunoglobulins in supportive cancer care: A thematic analysis of a systematic review data set

Background

Secondary immunodeficiency (SID) disorders are known to occur in patients with haematological malignancies (HM) due to immunosuppressive treatments. Recurring infections causing subsequent morbidity and mortality commonly occur in this patient cohort. Immunoglobulin replacement therapy (IgRT) benefits patients with primary antibody deficiencies. However, evidence supporting their therapeutic role is not as explicit in SID-associated antibody deficiencies, which raises the questions regarding its use in SID and the knock-on effects of this use on its access and availability more generally.

Objectives

This study aimed to learn about the use of immunoglobulins in SID, identify themes concerning its use and access and suggest methods for improving access.

Design

This study included a thematic analysis of a published data set of 43 articles concerning immunoglobulin use and access in SID.

Data Sources and Methods

The data set used to perform the thematic analysis is based on research articles identified from Excerpta Medica Database (EMBASE) and PubMed databases, published as part of a systematic review and part 1 of this two-part publication series.

Results

A thematic synthesis was conducted to identify recurrent themes. The three primary themes included (1) the context for IgRT prescription, which included patient characteristics and cost burden of IgRT administration, and its use in different countries; (2) factors contributing to inappropriate IgRT use, including health care professionals' awareness of IgRT, disparity between guidelines and actual clinical practice, and the effect of shortages on prescription and chemotherapy-induced hypogammaglobulinemia (HGG); and (3) measures identified to improve IgRT use and access, which included multidisciplinary involvement, improved diagnostic tools and safer withdrawal and stewardship protocols.

Conclusions

IgRT use is increasing in HM as a supportive therapy but without comprehensive clinical guidelines and appropriate prescribing recommendations, medication wastage may occur with consequences for immunoglobulin access.

Respiratory infectious burden in a cohort of antibody deficiency patients treated with immunoglobulin replacement therapy: The impact of lung pathology and gastroesophageal reflux disease

Background

Antibody deficiencies result from reduced immunoglobulin levels and function, increasing susceptibility to, primarily, bacterial infection. Primary antibody deficiencies comprise intrinsic defects in B-cell physiology, often due to inherited errors. Hematological malignancies or B-cell suppressive therapy are major causes of secondary antibody deficiency. Although immunoglobulin replacement therapy (IGRT) reduces infectious burden in antibody deficiency patients, respiratory tract infections remain a significant health burden. We hypothesize that lung pathology and gastroesophageal reflux disease (GORD) increase the risk of pneumonia in antibody deficiency patients, as in the general population.

Objective

For our cohort of patients with primary antibody deficiency and secondary antibody deficiency, we reviewed their respiratory infectious burden and the impact of lung pathologies and GORD.

Methods

The medical records of 231 patients on IGRT at a tertiary referral center, from October 26, 2014, to February 19, 2021, were reviewed to determine microbial isolates from sputum samples and prevalence of common lung pathologies and GORD.

Results

Haemophilus and Pseudomonas species represent a large infectious burden, being identified in 30.2% and 21.4% of sputum samples demonstrating growth, respectively; filamentous fungal and mycobacterial infections were rare. Diagnosed lung pathology increased the proportion of patients with Pseudomonas, Klebsiella, Stenotrophomonas, and Candida species isolated in their sputum, and diagnosed GORD increased the proportion with Enterobacter and Candida species isolated.

Conclusions

Bacterial respiratory infectious burden remains in primary antibody deficiency and secondary antibody deficiency despite IGRT. Lung pathologies encourage growth of species less susceptible to IGRT, so specialist respiratory medicine input and additional treatments such as inhaled antibiotics are indicated to optimize respiratory outcomes.

Insights into Facilitated Subcutaneous Immunoglobulin Use in Patients with Secondary Immunodeficiency Diseases: A FIGARO Subgroup Analysis

The Facilitated Immunoglobulin Administration Registry And Outcomes (FIGARO) Study was a European, multicenter, prospective, observational study conducted across Europe designed to provide insights on the clinical use and tolerability of facilitated subcutaneous immunoglobulin (fSCIG). Data herein are reported for the cohort of patients with secondary immunodeficiency (SID), with a subgroup analysis by age. The SID cohort included 31 patients: 1 pediatric, 15 adult, and 15 older adult patients. Over the 36-month observation period, the median monthly dose of fSCIG (30 g) and median monthly infusion volume per patient (300 mL) remained constant in both adult-age cohorts. Serum trough levels tended to increase over time. Most patients required only one infusion site and could receive the full dose every 3-4 weeks. There was a trend toward self-administration at home. In the adult group, infusion site inflammation and headache were reported at the inclusion visit (n = 1 each), with no adverse drug reactions reported at any of the follow-up visits. No acute severe bacterial infections were reported during the study follow-up. These results demonstrate the feasibility and tolerability of fSCIG use in patients with SID and the flexibility of administration settings including self-administration at home in patients aged ≥65 years.

Guardians of Immunity: Advances in Primary Immunodeficiency Disorders and Management

Primary immunodeficiency disorders (PIDs) are a heterogeneous group of genetic conditions profoundly impacting immune function. The investigation spans various PID categories, offering insights into their distinct pathogenic mechanisms and clinical manifestations. Within the adaptive immune system, B-cell, T-cell, and combined immunodeficiencies are dissected, emphasizing their critical roles in orchestrating effective immune responses. In the realm of the innate immune system, focus is directed toward phagocytes and complement deficiencies, underscoring the pivotal roles of these components in initial defense against infections. Furthermore, the review delves into disorders of immune dysregulation, encompassing hemophagocytic lymphohistiocytosis (HLH), autoimmune lymphoproliferative syndrome (ALPS), immune dysregulation, polyendocrinopathy, enteropathy, and X-linked(IPEX), and autoimmunity polyendocrinopathy candidiasis-ectodermal dystrophy(APECED), elucidating the intricate interplay between immune tolerance and autoimmunity prevention. Diagnostic strategies for PIDs are explored, highlighting advancements in genetic and molecular techniques that enable precise identification of underlying genetic mutations and alterations in immune function. We have also outlined treatment modalities for PIDs, which often entail a multidisciplinary approach involving immunoglobulin replacement, antimicrobial prophylaxis, and, in select cases, hematopoietic stem cell transplantation. Emerging therapies, including gene therapy, hold promise for targeted interventions. In essence, this review encapsulates the complexity of PIDs, emphasizing the critical importance of early diagnosis and tailored therapeutic interventions. As research advances, a clearer understanding of these disorders emerges, fostering optimism for enhanced patient care and management in the future.

Steroid-induced secondary immune deficiency

Despite their widespread clinical use, oral corticosteroids (OCSs) are well known to be associated with a myriad of adverse effects, including immunosuppression. By inhibiting transcription factors and affecting leukocyte function, prolonged OCS use leads to significant CD4 lymphopenia and often a decrease in serum immunoglobulin (Ig)G. Conversely, OCS use has minimal impact on circulating B cell, serum IgM, or serum IgA levels. Although there is a paucity of literature, individuals treated with prolonged OCS seem to typically maintain humoral response to various vaccinations despite hypogammaglobinemia, but this area warrants additional research, especially in the setting of the coronavirus disease 2019 pandemic. Individuals treated with prolonged OCS use are most at risk for opportunistic infections, especially those with underlying malignancy and history of bone marrow transplant. Risk mitigation strategies to decrease infectious complication with OCS use include limiting the dose and duration of therapy, appropriately completing a full vaccination series, consideration for passive immunization, and prophylaxis against opportunistic infections.

Should treatment of hypogammaglobulinemia with immunoglobulin replacement therapy (IgRT) become standard of care in patients with chronic lymphocytic leukemia?

Hypogammaglobulinemia (HGG) is a frequent finding in patients with hematological malignancies, and is commonly described in chronic lymphocytic leukemia (CLL) before or after treatment. We reviewed published literature available online in the last thirty years through Medline search of indexed articles focusing on the main differences and advantages of the products now available on the market, namely intravenous Ig (IVIg) and subcutaneous Ig (SCIg) preparations. IgRT is effective and safe in the prophylaxis of infections in a selected group of patients with CLL and hypogammaglobulinemia and is therefore a valuable tool for clinicians in the everyday management of infectious risk. We encourage the use of SCIg formulations as they appear to have similar efficacy but better cost-effectiveness and tolerability.

Immunoglobulin replacement therapy in patients with immunodeficiencies: impact of infusion method on patient-reported outcomes

BACKGROUND

Understanding the impact of different immunoglobulin (Ig) infusion methods (intravenous [IVIg] and subcutaneous [SCIg]) upon treatment experience can potentially facilitate optimization of patient outcomes. Here, the perspective of patients with primary and secondary immunodeficiency diseases (PID and SID, respectively) receiving IVIg and SCIg was evaluated, in terms of treatment satisfaction, accounting for treatment history, using Association des Patients Immunodéficients du Québec (APIQ) survey data.

METHODS

The online APIQ survey (shared October 2020-March 2021) of patients with immunodeficiencies in Canada contained 101 questions on: Ig use, history, and detailed infusion characteristics; as well as structured patient-reported outcomes such as treatment satisfaction (via TSQM-9), symptom state (via PASS), general health perception (via GHP), and physical and mental function (via PROMIS). Adult respondents (≥ 18 years old) currently using Ig were compared by their current Ig infusion method (IVIg or SCIg cohort) overall, and in a sub-analysis, the IVIg cohort was compared with the SCIg cohort after stratification by respondents who started SCIg when naïve to Ig ('SCIg naïve') or with previous IVIg experience ('SCIg switch').

RESULTS

In total, 54 respondents currently used IVIg and 242 used SCIg. The average duration per infusion of a weekly SCIg infusion was significantly shorter compared with the average duration of a 3-4 weekly IVIg infusion (p < 0.001). The SCIg cohort was associated with significantly higher scores for the TSQM-9 effectiveness domain compared with the IVIg cohort. The scores for TSQM-9 convenience and global satisfaction domains were similar in the two cohorts. The SCIg cohort was also associated with a significantly higher proportion of respondents who were in an acceptable symptom state and a lower proportion who reported very poor or poor perception of health compared with the IVIg cohort. Further, the SCIg naïve subgroup was associated with significantly higher TSQM-9 effectiveness and convenience domain scores compared with the IVIg cohort, while there was no significant difference between the SCIg switch subgroup and the IVIg cohort in terms of convenience.

CONCLUSIONS

A better understanding of how different IgRT administration methods impact treatment experience and satisfaction may assist with informed treatment decision making and ultimately further improvements in patient outcomes.

COVID-19-related health outcomes in people with primary immunodeficiency: A systematic review

A better understanding of COVID-19 in people with primary immunodeficiency (PI), rare inherited defects in the immune system, is important for protecting this population, especially as population-wide approaches to mitigation change. COVID-19 outcomes in the PI population could have broader public health implications because some people with PI might be more likely to have extended illnesses, which could lead to increased transmission and emergence of variants. We performed a systematic review on COVID-19-associated morbidity and mortality in people with PI. Of the 1114 articles identified through the literature search, we included 68 articles in the review after removing 1046 articles because they were duplicates, did not involve COVID-19, did not involve PI, were not in English, were commentaries, were gene association or gene discovery studies, or could not be accessed. The 68 articles included outcomes for 459 people with PI and COVID-19. Using data from these 459 people, we calculated a case fatality rate of 9%, hospitalization rate of 49%, and oxygen supplementation rate of 29%. Studies have indicated that a number of people with PI showed at least some immune response to COVID-19 vaccination, with responses varying by type of PI and other factors, although vaccine effectiveness against hospitalization was lower in the PI population than in the general population. In addition to being up-to-date on vaccinations, current strategies for optimizing protection for people with PI can include pre-exposure prophylaxis for those eligible and use of therapeutics. Overall, people with PI, when infected, tested positive and showed symptoms for similar lengths of time as the general population. However, a number of people with X-linked agammaglobulinemia (XLA) or other B-cell pathway defects were reported to have prolonged infections, measured by time from first positive SARS-CoV-2 test to first negative test. As prolonged infections might increase the likelihood of genetic variants emerging, SARS-CoV2 isolates from people with PI and extended illness would be good candidates to prioritize for whole genome sequencing.

Pediatric Prediction Model for Low Immunoglobulin G Level Based on Serum Globulin and Illness Status

Hypogammaglobulinemia is a condition that requires prompt diagnosis and treatment. Unfortunately, serum immunoglobulin (Ig) measurements are not widely accessible in numerous developing countries. Serum globulin is potentially the best candidate for screening of low IgG level (IgGLo) due to its high availability, low cost, and rapid turnover time. However, multiple factors may influence the probability of prediction. Our study aimed to establish a simple prediction model using serum globulin to predict the likelihood of IgGLo in children. For retrospective data of patients who were suspected of having IgGLo, both serum IgG and globulin were simultaneously collected and measured. Potential factors interfering with serum globulin and IgG levels were investigated for their impact using bivariate binary logistic regression. A multivariate binary logistic regression was used to generate a formula and score to predict IgGLo. We obtained 953 samples from 143 pediatric patients. A strong positive correlation between serum globulin and IgG levels was observed (r=0.83, p < 0.001). A screening test model using serum globulin and illness status was constructed to predict IgGLo. The formula for predicting IgGLo was generated as follows; Predicted score = (2 x globulin (g/dl)) – illness condition score (well=0, sick=1). When the score was <4, the patient has the probability of having IgGLo with a sensitivity of 0.78 (0.71, 0.84), a specificity of 0.71 (0.68, 0.74), PPV of 0.34 (0.29, 0.40) and NPV of 0.94 (0.92, 0.96). This formula will be useful as rapid and inexpensive screening tool for early IgGLo detection, particularly in countries/locations where serum IgG measurement is inaccessible.

Overview of subcutaneous immunoglobulin 16.5% in primary and secondary immunodeficiency diseases

Most primary immunodeficiency diseases, and select secondary immunodeficiency diseases, are treated with immunoglobulin (IG) therapy, administered intravenously or subcutaneously (SCIG). The first instance of IG replacement for primary immunodeficiency disease was a 16.5% formulation administered subcutaneously in 1952. While most SCIG products are now a 10 or 20% concentration, this review will focus on SCIG 16.5% products with a historical overview of development, including the early pioneers who initiated and refined IG replacement therapy, as well as key characteristics, manufacturing and clinical studies. In determining an appropriate IG regimen, one must consider specific patient needs, characteristics and preferences. There are advantages to SCIG, such as stable serum immunoglobulin G levels, high tolerability and the flexibility of self-administered home treatment.

Ten-year population trends of immunoglobulin use, burden of adult antibody deficiency and feasibility of subcutaneous immunoglobulin (SCIg) replacement in Hong Kong Chinese

Background

Adult antibody deficiency remains under-recognised and under-studied - especially among Asian populations. Patterns of immunoglobulin use and the feasibility of subcutaneous immunoglobulin (SCIg) replacement among Chinese patients remains unclear.

Objective

To investigate the trends of immunoglobulin use, burden of adult antibody deficiency and the outcomes of patients on SCIg compared to intravenous immunoglobulin (IVIg) replacement in Hong Kong through a retrospective observational study.

Methods

Population-wide data of immunoglobulin recipients in Hong Kong between 2012 and 2021, and longitudinal clinical data of adult immunodeficiency patients at Queen Mary Hospital were collected and analysed.

Results

Total immunoglobulin consumption and recurrent immunoglobulin recipients increased continuously from 175,512g to 298,514g (ρ=0.99, p<0.001) and 886 to 1,508 (ρ=0.89, p=0.001) between 2012-21 in Hong Kong. Among 469 immunoglobulin recipients at Queen Mary Hospital in 2021, 344 (73.3%) were indicated for replacement. Compared to those on IVIg (n=14), patients on SCIg replacement (n=8) had fewer immunodeficiency-related hospitalisations (IRR=0.11) and shorter duration of hospitalisation stay (IRR=0.10) per year, as well as better quality of life (SF-36v2 Health Survey and Life Quality Index). Estimated annual healthcare cost of SCIg replacement per patient was lower than that of IVIg (HKD196,850 [USD25,096] vs HKD222,136 [USD28,319]).

Conclusion

There was a significantly increasing burden of adult antibody deficiency and immunoglobulin consumption in Hong Kong. SCIg was feasible and more cost-effective when compared to IVIg, with SCIg patients experiencing better clinical outcomes and quality of life. Future prospective studies to confirm the long-term efficacy and superiority of SCIg are required.

Identifying Safety Thresholds for Immunosuppressive Drugs: Applying Insights from Primary Antibody Deficiencies to Mitigate Adverse Events in Secondary Antibody Deficiencies Using Mathematical Modeling of Preclinical and Early Clinical Data

Immunosuppressive drugs can alleviate debilitating symptoms of autoimmune diseases, but, by the same token, excessive immune suppression can result in an increased risk of infection. Despite the dangers of a compromised immune system, clear definitions of what constitutes excessive suppression remain elusive. Here we review the most common infections associated with primary antibody deficiencies (PADs), such as agammaglobulinemia, common variable immunodeficiency (CVID), and IgA deficiency, as well as infections that are associated with drug-induced or secondary antibody immunodeficiencies (SADs). We identify a number of bacterial, viral, and fungal infections (e.g., Listeria monocytogenes, Staphylococcus sp., Salmonella spp., Escherichia coli, influenza, varicella zoster virus, and herpes simplex virus) associated with both PADs and SADs, and suggest that diagnostic criteria for PADs could be used as a first-line measure to identify potentially unsafe levels of immune suppression in SADs. Specifically, we suggest that, based on PAD diagnostic criteria, IgG levels should remain above 2-3 g/L, IgA levels should not fall below 0.07 g/L, and IgM levels should remain above 0.4 g/L to prevent immunosuppressive drugs from inducing mimicking PAD-like effects. We suggest that these criteria could be used in the early stages of drug development, and that pharmacokinetic and pharmacodynamic modeling could help guide patient selection to potentially improve drug safety. We illustrate the proposed approach using atacicept as an example and conclude with a discussion of the applicability of this approach for other drugs that may induce excessive immune suppression.

Clostridium difficile septic arthritis and periprosthetic joint infection in a patient with acute lymphoblastic leukaemia, T-/B-lymphocytopenia and hypogammaglobulinemia - a case report and review of the literature

To the best of our knowledge, we report the first Clostridium difficile infection in a native hip joint with subsequent prosthetic joint infection in a patient at a state of hypogammaglobulinemia. The infection developed following chemotherapy for B-cell precursor acute lymphoblastic leukaemia (BCP-ALL). After chemotherapy, hip arthroplasty was performed for destructive septic arthritis. However, infection in the hip persisted with several failing revisions for more than 3 years, until ultimately hypogammaglobulinemia and T-/B-lymphocytopenia were diagnosed, and supplementation with i.v. immunoglobulins was able to achieve infection control.

Rituximab-induced hypogammaglobulinemia and infection risk in pediatric patients

BACKGROUND

Rituximab is a B-cell depleting agent used in B-cell malignancies and autoimmune diseases. A subset of adult patients may develop prolonged and symptomatic hypogammaglobulinemia following rituximab treatment. However, this phenomenon has not been well delineated in the pediatric population.

OBJECTIVES

This study sought to determine the prevalence, risk factors, and clinical significance of hypogammaglobulinemia following rituximab therapy in children.

METHODS

This was a multicenter, retrospective cohort study that extracted clinical and immunological data from pediatric patients who received rituximab.

RESULTS

The cohort comprised 207 patients (median age, 12.0 years). Compared to baseline values, there was a significant increase in hypogammaglobulinemia post-rituximab therapy, with an increase in prevalence of hypo-IgG (28.7%-42.6%; P = .009), hypo-IgA (11.1%-20.4%; P = .02), and hypo-IgM (20.0%-62.0%; P < .0001). Additionally, low IgG levels at any time post-rituximab therapy were associated with a higher risk of serious infections (34.4% vs 18.9%; odds ratio, 2.3; 95% CI, 1.1-4.8; P = .03). Persistent IgG hypogammaglobulinemia was observed in 27 of 101 evaluable patients (26.7%). Significant risk factors for persistent IgG hypogammaglobulinemia included low IgG and IgA levels pre-rituximab therapy. Nine patients (4.3%) within the study were subsequently diagnosed with a primary immunodeficiency, 7 of which received rituximab for autoimmune cytopenias.

CONCLUSIONS

Hypogammaglobulinemia post-rituximab treatment is frequently diagnosed within the pediatric population. Low IgG levels are associated with a significant increase in serious infections, and underlying primary immunodeficiencies are relatively common in children receiving rituximab, thus highlighting the importance of immunologic monitoring both before and after rituximab therapy.

Immunoglobulin levels in systemic lupus erythematosus: A narrative review

Immunoglobulins play a fundamental role in the protection of the human body against internal and external threats. They also contribute to the immune system homeostasis and maintenance of self-tolerance. Hypogammaglobulinemia is occasionally encountered in routine clinical practice by rheumatologists. Low levels of immunoglobulins can occur as primary or secondary issues and may predispose patients to various forms of infection. However, the impact of the low immunoglobulin level abnormality varies with the underlying condition. In this narrative review, we shed light on the overall types and functions of immunoglobulins for clinicians. We discuss important principles of immunoglobulin measurements. We then consider the primary and secondary causes of low immunoglobulins with a special focus on hypogammaglobulinemia in patients with systemic lupus erythematosus (SLE).

Discontinuation of immunoglobulin replacement therapy in patients with secondary antibody deficiency

INTRODUCTION

Secondary immunodeficiency is becoming a greater medical concern as the usage of immunosuppressive and biological treatments has increased. Individuals with certain medical conditions, such as hematological malignancies, can also have secondary immunodeficiency. Immunoglobulin replacement therapy (IGRT), which has been used for decades in inherited or primary immunodeficiency, provides some protection to patients with acquired and predominant antibody deficiency, i.e. secondary antibody deficiency (SAD). However, IGRT is costly, and supplies are limited. Although there are clinical guidelines on when to initiate IGRT, there is no guideline on when to discontinue it.

AREAS COVERED

The authors reviewed existing literature and provided an overview of the current state of knowledge regarding IGRT discontinuation in SAD patients.

EXPERT OPINION

Long-term supplementary immunoglobulin may not be necessary. Although it is possible to successfully transition away from IGRT in individuals with SAD, evidence-based practices are limited. Without clear guidelines and reliable prognostic markers, IGRT discontinuation practices are restricted to clinical judgment. For this reason, additional research should be conducted to identify markers that indicate the recovery of humoral immunity. Furthermore, the derivation and validation of a set of combined clinical and laboratory criteria to allow safe and timely IGRT discontinuation is warranted.

The Use of 20% Subcutaneous Immunoglobulin Replacement Therapy in Patients With B Cell Non-Hodgkin Lymphoma With Humoral Immune Dysfunction After Treatment With Rituximab

BACKGROUND

Rituximab is an anti-CD20 chimeric antibody used to treat autoimmune conditions and B cell neoplasms. We characterized immunoglobulin (Ig) levels and vaccine responses in rituximab-treated B cell non-Hodgkin lymphoma (NHL) patients. Patients with impaired vaccine responses were offered therapy with 20% subcutaneous (subq) Ig.

PATIENTS AND METHODS

Patients with a biopsy-proven diagnosis of B cell NHL who had received rituximab within the past 24 months were eligible for the study and underwent the following immune evaluation: serum IgG, IgM, IgA, IgE, T/B cell lymphocyte panel, and pre/post vaccine IgG titers to diphtheria, tetanus, and streptococcus pneumoniae. Patients were vaccinated with tetanus, diphtheria and pneumococcal polysaccharide vaccine. Patients with abnormal vaccine responses were offered prophylactic subq Ig for 52 weeks.

RESULTS

Fifteen patients with NHL were enrolled in the study. The median IgG was 628 mg/dL [interquartile range, 489-718 mg/dL]. Three (20%) of 15 patients responded to diphtheria vaccination, 1 (6.7%) of 15 responded to tetanus vaccination, and 3 (20%) of 15 responded to vaccination to streptococcus pneumoniae. Thirteen (86.7%) of 15 met criteria for humoral immunodeficiency. Ten patients received subq Ig, and experienced a significant increase in serum IgG (P = .008). There were no serious adverse events, and there was a decrease in nonneutropenic infections while on subq Ig therapy.

CONCLUSIONS

Patients with NHL treated with rituximab may have significant humoral immunodeficiency as defined by abnormal vaccine responses even in the setting of relatively normal IgG levels. For these patients, subq Ig replacement therapy is well-tolerated and efficacious in improving serum IgG, and may decrease reliance on antibiotics for the treatment of nonneutropenic infections.

Use of recombinant human hyaluronidase-facilitated subcutaneous immunoglobulin in elderly patients

Aim: Data on the real-world use of hyaluronidase-facilitated subcutaneous 10% immunoglobulin (fSCIG; HyQvia^®) in elderly patients with primary or secondary immunodeficiencies (PID or SID) are unreported. This study determined real-world patterns from one administration of fSCIG. Materials & methods: In this retrospective, multicenter study, medical records of patients aged ≥65 years with PID or SID were reviewed. Results: The majority of patients (mean age: 69.9 years) with PID (n = 10) or SID (n = 6) self-administered fSCIG (200-350 ml) at home every 3-4 weeks using a single infusion site by infusion pump at rates up to 300 ml/h. Conclusion: This study provides initial real-world evidence supporting home-based, self-administration of large volumes of fSCIG in elderly patients with PID or SID.

[Immunodeficiency in chronic rhinosinusitis : An important and often underestimated cause]

BACKGROUND

Chronic rhinosinusitis (CRS) is one of the most frequent chronic diseases. Among these patients the prevalence of immune defects is higher than in the healthy general population.

METHODS

A selective review of the literature was carried out in PubMed and Medline covering the period between 2008 and 2019. Additionally, recent German publications in journals not listed in the abovementioned databases were analyzed.

RESULTS

The diagnostic workflow with respect to the immunodeficiency consists of a detailed anamnesis and physical examination, laboratory tests and the antibody reaction to polysaccharide vaccines and antigens. Beside antibiotic treatment, vaccinations and immunoglobulin replacement are available. Notwithstanding the above, functional endoscopic surgery of the paranasal sinuses should be performed according to guideline recommendations.

CONCLUSION

Patients with CRS who do not sufficiently respond to conservative and surgical treatment should be checked for underlying immunodeficiencies.

Rituximab Unveils Hypogammaglobulinemia and Immunodeficiency in Children with Autoimmune Cytopenia

BACKGROUND

Rituximab (RTX; anti-CD20 mAb) is a treatment option in children with refractory immune thrombocytopenia, autoimmune hemolytic anemia (AHA), and Evans syndrome (ES). Prevalence and clinical course of RTX-induced hypogammaglobulinemia in these patients are poorly known.

OBJECTIVE

To evaluate the prevalence and risk factors for persistent hypogammaglobulinemia (PH) after RTX use.

METHODS

Clinical and immunologic data from children treated with RTX for immune thrombocytopenia, AHA, and ES were collected from 16 Italian centers and 1 UK center at pre-RTX time point (0), +6 months, and yearly, up to 4 years post-RTX. Patients with previously diagnosed malignancy or primary immune deficiency (PID) were excluded.

RESULTS

We analyzed 53 children treated with RTX for immune thrombocytopenia (n = 36), AHA (n = 13), and ES (n = 4). Median follow-up was 30 months (range, 12-48). Thirty-two percent of patients (17 of 53) experienced PH, defined as IgG levels less than 2 SD for age at last follow-up (>12 months after RTX). Significantly delayed B-cell recovery was observed in children experiencing PH (hazard ratio, 0.55; P < .05), and 6 of 17 (35%) patients had unresolved B-cell lymphopenia at last follow-up. PH was associated with IgA and IgM deficiency, younger age at RTX use (51 vs 116 months; P < .01), a diagnosis of AHA/ES, and better response to RTX. Nine patients with PH (9 of 17 [53%]) were eventually diagnosed with a PID.

CONCLUSIONS

Post-RTX PH is a frequent condition in children with autoimmune cytopenia; a sizable proportion of patients with post-RTX PH were eventually diagnosed with a PID. In-depth investigation for PID is therefore recommended in these patients.

Iatrogenic antibody deficiency from B-cell targeted therapies in autoimmune rheumatic diseases

B-cell targeted therapies (BCTT) are now widely used in autoimmune rheumatic diseases, including SLE, antineutrophil cytoplasmic antibody-associated vasculitis and rheumatoid arthritis. Early studies suggested that rituximab did not influence serum immunoglobulins. However, subsequently, with increased patient numbers, longer follow-up duration and many patients having received multiple BCTT courses, multiple subsequent studies have identified hypogammaglobulinaemia as a potential side effect. Patients developing hypogammaglobulinaemia appear to fit into two principal categories: the majority who develop transient, often mild reduction in immunoglobulins without increased infection and a much smaller but clinically significant group with a more sustained antibody deficiency, who display increased risk of infection. Monitoring immunoglobulin levels represents an opportunity for the early detection of hypogammaglobulinaemia, and the prevention of avoidable morbidity. In the two major studies, approximately 4%-5% of BCTT-treated patients required immunoglobulin replacement due to recurrent infections in the context of hypogammaglobulinaemia. Despite this, monitoring of immunoglobulins is suboptimal, and there remains a lack of awareness of hypogammaglobulinaemia as an important side effect.

Relevant Infections in Inflammatory Bowel Disease, and Their Relationship With Immunosuppressive Therapy and Their Effects on Disease Mortality

BACKGROUND AND AIMS

There is controversy as to whether the risk of relevant infection in IBD is related to immunosuppressants or the disease itself. The aims of this study were to evaluate: [1] the life-long prevalence and types of relevant infections in patients with IBD related to immunosuppressive treatment, and [2] the relationship of both infection and patient comorbidity to mortality.

METHODS

Observational multicentre retrospective study of IBD patients that presented a relevant infection. For each case, four periods of infection exposure were analysed: P1: pre-IBD diagnosis, P2: from IBD diagnosis to immunosuppressant initiation, P3: during immunosuppressant therapy, and P4: after treatment withdrawal.

RESULTS

The life-long prevalence of relevant infection in the total cohort of patients [6914] was 3%, and 5% in immunosuppressed patients [4202]. 366 relevant infections were found in 212 patients [P1: 9, P2: 17, P3: 334, and P4: 6]. Differences between periods were significant [p < 0.0001]. The most frequent types of infection were respiratory, intestinal and urinary. The most frequent opportunistic infections were tuberculosis [prevalence: 2.6/1000] and herpes zoster [prevalence: 3.9/1000]. Herpes zoster infection was associated with thiopurines alone or in combination with anti-TNF in 75% of the cases, whereas tuberculosis was associated with anti-TNF in 94% of patients. The overall mortality was 4.2%. Infection-related mortality was 2.8% and it was not influenced by comorbidity.

CONCLUSIONS

Relevant infections in IBD patients are rare and appear to be related to immunosuppression. Relevant infection is a major cause of death in IBD.

Duration of frequent or severe respiratory tract infection in adults before diagnosis of IgG subclass deficiency

Many adults with IgG subclass deficiency (IgGSD) experience long intervals of frequent/severe respiratory tract infection before IgGSD diagnosis, but reasons for delays in IgGSD diagnoses are incompletely understood. We performed a retrospective study of 300 white adults (ages ≥18 y) with IgGSD including frequency analyses of age at IgGSD diagnosis, duration of frequent/severe respiratory tract infection before IgGSD diagnosis, and age at onset of frequent/severe infection (calculated). We performed multivariable regressions on age at diagnosis, infection duration, and age at infection onset using these variables, as appropriate: sex; age at diagnosis; diabetes; autoimmune condition(s); atopy; allergy; corticosteroid use; body mass index; serum immunoglobulin isotype levels; blood lymphocyte subsets; three IgGSD-associated human leukocyte antigen-A and -B haplotypes; and referring physician specialties. Mean age at diagnosis was 50 ± 12 (standard deviation) y (median 50 y (range 19–79)). There were 247 women (82.3%). Mean infection duration at IgGSD diagnosis was 12 ± 13 y (median 7 y (range 1–66)). Mean age at infection onset was 38 ± 16 y (median 38 y (range 4, 76)). Age at infection onset was ≥18 y in 95.7% of subjects. Regressions on age at diagnosis and infection duration revealed no significant associations. Regression on age at infection onset revealed one positive association: age at diagnosis (p <0.0001). We conclude that the median duration of frequent/severe respiratory tract infection in adults before IgGSD diagnosis was 7 y. Older adults may be diagnosed to have IgGSD after longer intervals of infection than younger adults. Duration of frequent/severe respiratory tract infection before IgGSD diagnosis was not significantly associated with routine clinical and laboratory variables, including referring physician specialties.

Primary immunodeficiency

Primary immunodeficiency disorder (PID) refers to a large heterogeneous group of disorders that result from defects in immune system development and/or function. PIDs are broadly classified as disorders of adaptive immunity (i.e., T cell, B-cell or combined immunodeficiencies) or of innate immunity (e.g., phagocyte and complement disorders). Although the clinical manifestations of PIDs are highly variable, many disorders involve an increased susceptibility to infection. Early consultation with a clinical immunologist is essential, as timely diagnosis and treatment are imperative for preventing significant disease-associated morbidity. PIDs should be suspected in patients with: recurrent sinus or ear infections or pneumonias within a 1 year period; failure to thrive; poor response to prolonged use of antibiotics; persistent thrush or skin abscesses; or a family history of PID. Patients with multiple autoimmune diseases should also be evaluated. Diagnostic testing often involves lymphocyte proliferation assays, flow cytometry, measurement of serum immunoglobulin (Ig) levels, assessment of serum specific antibody titers in response to vaccine antigens, neutrophil function assays, stimulation assays for cytokine responses, and complement studies. The treatment of PIDs is complex and generally requires both supportive and definitive strategies. Ig replacement therapy is the mainstay of therapy for B-cell disorders, and is also an important supportive treatment for many patients with combined immunodeficiency disorders. The disorders affecting the activity of the T-cell arm of the adaptive system, such as severe combined immunodeficiency, require immune reconstitution as soon as possible. The treatment of innate immunodeficiency disorders varies depending on the type of defect, but may involve antifungal and antibiotic prophylaxis, cytokine replacement, vaccinations and bone marrow transplantation. This article provides an overview of the major categories of PIDs and strategies for the appropriate diagnosis and management of these rare disorders.

Consequences of B-cell-depleting therapy: hypogammaglobulinemia and impaired B-cell reconstitution

Rituximab is a chimeric monoclonal antibody used to treat hematologic and autoimmune diseases by depleting CD20-expressing B cells. Patients may develop hypogammaglobulinemia following treatment, with some demonstrating failure of B-cell recovery. The true frequency of hypogammaglobulinemia and/or impaired B-cell reconstitution post rituximab is unknown due to the lack of prospective studies in different patient cohorts. The clinical significance remains controversial; some patients have recurrent infections while others are relatively asymptomatic. The aim of this review is to describe the prevalence of hypogammaglobulinemia and the associated risk for developing severe infection, in patients with differing underlying clinical conditions treated with rituximab. This may facilitate classification and prognostication of patients who develop these conditions and identify patients who may be at high risk of developing these complications, including those who may benefit from immunoglobulin replacement therapy.

Primary immune deficiency diseases as unrecognized causes of chronic respiratory disease

BACKGROUND

More than half of all primary immune deficiency diseases (PIDD) affect antibody production and are well known as causes of recurrent sinusitis and lung infections. Chronic and recurrent infections of the upper and/or lower airways can contribute to inflammatory and obstructive processes in the lower airways which are initially reversible and considered "asthma", but can eventually cause irreversible remodeling and chronic obstructive pulmonary disease (COPD). Conversely, several lines of evidence suggest that many patients who present with a diagnosis of asthma have an increased incidence of infection, suggesting underlying host-defense defects. Asthma and respiratory infections in the first decades of life are recognized as risk factors for development of COPD, but when patients present with COPD as adults, underlying primary immune deficiency disease may be unrecognized.

MAIN FINDINGS AND CONCLUSIONS

Detection of PIDD as a potentially treatable underlying contributor to recurrent/acute exacerbations and morbidity of COPD, and provision of immunoglobulin (Ig) G replacement therapy, when appropriate, may decrease the progression of COPD. Decreasing the severity and rate of exacerbations and admissions should improve the quality of life and longevity of an important subset of patients with COPD, while decreasing costs. Major steps toward achieving these goals include developing a high index of suspicion, more frequent use and appropriate interpretation of screening tests such as quantitative immunoglobulins and vaccine responses, and prompt institution of IgG replacement therapy when antibody deficiency has been diagnosed.

Secondary antibody deficiency and immunoglobulin replacement

Antibody deficiencies can be either primary or secondary, leading to significant morbidity and mortality without appropriate management. Secondary antibody deficiency can be due to various diseases or iatrogenic causes, especially with the use of immunosuppressive agents such as B-cell depleting therapies. Unlike its primary counterpart, little is known regarding the management of secondary antibody deficiency and it remains an underappreciated entity. This is a growing concern with the growing numbers of patients on various immunosuppressant therapies and increasing survivors of autoimmune diseases and haematological malignancies. In this report, we review the diagnosis and management of secondary antibody deficiency, especially after rituximab-induced hypogammaglobulinemia.

Case Report: Renal Transplantation in Patients with Pre-existing Hypogammaglobulinemia

Hypogammaglobulinemia (HGG) is well-characterized as a common phenomenon after kidney transplantation. However, no reports of pre-existing HGG from kidney transplantation seem to be available. We have reviewed three patients who developed HGG prior to kidney transplantation, and all three were treated successfully with immunoglobulin replacement therapy before and after kidney transplantation. The kidney grafts were functioning at follow-up 1.5-8 years (mean: 3.6 years) after transplantation, and there were no diagnosed episodes of clinical rejections and no severe infection complications post-transplantation.

Impact of Low Immunoglobulin G Levels on Disease Outcomes in Patients with Inflammatory Bowel Diseases

BACKGROUND

Inflammatory bowel diseases (IBDs) are considered immune-mediated disorders with dysregulated innate and adaptive immunities. Secondary immunogloblin deficiency can occur in IBD and its impact on the disease course of IBD is not clear.

AIMS

We sought to determine associations between low IgG/G1 levels and poor clinical outcomes in IBD patients.

METHODS

This historic cohort study was performed on IBD patients with obtained IgG/IgG1 levels. The primary outcome was defined as any IBD-related bowel resection surgery and/or hospitalization. Subgroup analyses assessed particular surgical outcomes in Crohn's disease (CD), ulcerative colitis (UC) or indeterminate colitis (IC), and ileal pouch-anal anastomosis (IPAA). The secondary outcomes included IBD drug escalations and C. difficile or cytomegalovirus infections.

RESULTS

A total of 136 IBD patients had IgG/G1 levels checked and adequate follow-up, 58 (42.6 %) with normal IgG/G1 levels and 78 (57.4 %) having low levels. A total of 49 patients (62.8 %) with low immunoglobulin levels had IBD-related surgeries or hospitalizations, compared to 33 patients (56.9 %) with normal levels [odds ratio (OR) 1.28, 95 % confidence interval (CI) 0.64-2.56; p = 0.49]. Low IgG/G1 levels were associated with IBD-related surgery in CD in univariate analysis [hazard ratio (HR) 4.42, 95 % CI 1.02-19.23; p = 0.048] and in Kaplan-Meier survival curve analysis (p = 0.03), with a trend toward significance on multivariate analysis (HR 3.07, 95 % CI 0.67-14.31; p = 0.15). IBD patients with low IgG/G1 levels required more small bowel resections (12.8 vs. 1.7 %, p = 0.024) and 5-aminosalicylate initiations (28.2 vs. 13.8 %, p = 0.045).

CONCLUSIONS

Our study demonstrated a possible association between low IgG/G1 levels and poor outcomes in CD including surgery. Future implications include using immunoglobulin levels in IBD patients as a prognostic indicator or boosting humoral immunity as a treatment in this subset.

Challenges in the Role of Gammaglobulin Replacement Therapy and Vaccination Strategies for Hematological Malignancy

Patients with chronic lymphocytic leukemia (CLL) and multiple myeloma (MM) are prone to present with antibody production deficits associated with recurrent or severe bacterial infections that might benefit from human immunoglobulin (Ig) (IVIg/SCIg) replacement therapy. However, the original IVIg trial data were done before modern therapies were available, and the current indications do not take into account the shift in the immune situation of current treatment combinations and changes in the spectrum of infections. Besides, patients affected by other B cell malignancies present with similar immunodeficiency and manifestations while they are not covered by the current IVIg indications. A potential beneficial strategy could be to vaccinate patients at monoclonal B lymphocytosis and monoclonal gammopathy of undetermined significance stages (for CLL and MM, respectively) or at B-cell malignancy diagnosis, when better antibody responses are attained. We have to re-emphasize the need for assessing and monitoring specific antibody responses; these are warranted to select adequately those patients for whom early intervention with prophylactic anti-infective therapy and/or IVIg is preferred. This review provides an overview of the current scenario, with a focus on prevention of infection in patients with hematological malignancies and the role of Ig replacement therapy.

Immune deficiency in chronic rhinosinusitis: screening and treatment

INTRODUCTION

Chronic rhinosinusitis (CRS) is a prevalent disease with a high annual cost of treatment. Immune deficiencies are more common in individuals with CRS and should be especially considered in those patients who are refractory to medical and surgical therapy. Areas covered: We performed a literature search in PubMed of the terms "immunodeficiency" and "sinusitis" or "rhinosinusitis" from 2006 through March 2016. All abstracts were reviewed to determine if they pertained to human disease; relevant articles were evaluated in their entirety and included in this review. Expert commentary: CRS is a common disease; in those patients with frequent exacerbations or who are refractory to treatment, an immunodeficiency evaluation should be considered. Treatment includes vaccination, antibiotic therapy, immunoglobulin replacement and surgery.

Lymphoma Secondary to Congenital and Acquired Immunodeficiency Syndromes at a Turkish Pediatric Oncology Center

The prevalence of lymphoma in primary immunodeficiency cases and autoimmune diseases, as well as on a background of immunodeficiency following organ transplants, is increasing. The lymphoma treatment success rate is known to be a low prognosis. Our study aimed to emphasize the low survival rates in immunodeficient vs. immunocompetent lymphoma patients and also to investigate the effect of rituximab in patients with ataxia telangiectasia and other immunodeficiencies. We summarized the clinical characteristics and treatment results of 17 cases with primary immunodeficiency that developed non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) retrospectively. Seven patients were diagnosed with ataxia-telangiectasia, two with common variable immunodeficiency, two with selective IgA deficiency, one with X-related lymphoproliferative syndrome, one with Wiskott-Aldrich syndrome, one with Epstein-Barr virus-related lymphoproliferative syndrome, one with interleukin-2-inducible T-cell kinase (ITK) deficiency, and one with lymphoma developing after autoimmune lymphoproliferative syndrome (ALPS). One patient underwent a renal transplant. Of the nine males and eight females (aged 3-12 years, median = 7) that developed lymphoma, seven were diagnosed with HL and ten with NHL (seven B-cell, three T-cell). The NHL patients were started on the Berlin-Frankfurt-Münster, POG9317, LMB-96, or R-CHOP treatment protocols with reduced chemotherapy dosages. HL cases were started on the doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) and/or cyclophosphamide, vincristine, procarbazine, and prednisone (COPP) protocol, also with modified dosages. Importantly, all seven cases of HL are alive and in remission, while six of the ten NHL patients have died. Primary immunodeficiency is a strong predisposing factor for developing lymphoma. Low treatment success rates relative to other lymphomas and difficulties encountered during treatment indicate that new treatment agents are needed. While some success has been achieved by combining rituximab with lymphoma treatment protocols in B-NHL cases with primary immunodeficiency, the need for new treatment approaches for these patients remains critical.

Inversion of the Vδ1 to Vδ2 γδ T cell ratio in CVID is not restored by IVIg and is associated with immune activation and exhaustion

Common variable immunodeficiency (CVID) is defined by low levels of IgG and IgA, but perturbations in T cells are also commonly found. However, there is limited information on γδ T cells in CVID patients. Newly diagnosed CVID patients (n = 15) were enrolled before and after intravenous IgG (IVIg) replacement therapy. Cryopreserved peripheral blood mononuclear cells were then used to study γδ T cells and CVID patients were compared to healthy controls (n = 22). The frequency and absolute count of Vδ1 γδ T cells was found to be increased in CVID (median 0.60% vs 2.64%, P <0.01 and 7.5 vs 39, P <0.01 respectively), while they were decreased for Vδ2 γδ T cells (median, 2.36% vs 0.74%, P <0.01 and 37.8 vs 13.9, P <0.01 respectively) resulting in an inversion of the Vδ1 to Vδ2 ratio (0.24 vs 1.4, P <0.001). Markers of immune activation were elevated on all subsets of γδ T cells, and HLA-DR expression was associated with an expansion of Vδ1 γδ T cells (r = 0.73, P = 0.003). Elevated PD-1 expression was found only on Vδ2 γδ T cells (median 1.15% vs 3.08%, P <0.001) and was associated with the decrease of Vδ2 γδ T cells (r = -0.67, P = 0.007). IVIg had no effect on the frequency of Vδ1 and Vδ2 γδ T cells or HLA-DR expression, but alleviated CD38 expression on Vδ1 γδ T cells (median MFI 965 vs 736, P <0.05). These findings suggest that immunological perturbations of γδ T cells are a general feature associated with CVID and are only partially reversed by IVIg therapy.

Clinical outcomes of immunoglobulin use in solid organ transplant recipients: protocol for a systematic review and meta-analysis

BACKGROUND

Transplantation improves survival and the quality of life of patients with end-stage organ failure. Infection, due to surgical issues, host factors such as diabetes, immunosuppression, and hypogammaglobulinemia, is a major post-transplant complication. Clinical outcomes of prophylaxis or treatment of hypogammaglobulinemia in solid organ transplant recipients are not well established and are in need of further study.

METHODS/DESIGN

We will conduct a systematic review of studies investigating clinically relevant outcomes of immunoglobulin use either as prophylaxis or treatment of hypogammaglobulinemia after solid organ transplantation. Both randomized and non-randomized studies (excluding case reports and case series of less than 20 subjects) will be included. Outcomes of interest will include the overall rate of infection, hospital admission, hospital length of stay, intensive care unit admission, 1-year all-cause mortality, incidence of acute organ rejection, allograft survival within 1 year, and adverse events. We will search MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, Transplant library, and the International Clinical Trials Registry Platform for randomized and non-randomized studies on adult solid organ transplant patients who received prophylactic immunoglobulin or immunoglobulin treatment. Two reviewers will conduct all screening and data collection independently. We will assess study level of risk of bias using the Cochrane Risk of Bias Assessment Tool for randomized controlled trials and for non-randomized studies. If meta-analysis of outcome data is deemed appropriate, we will use random effects models to combine data for continuous and dichotomous measures.

DISCUSSION

The results of this systematic review may inform guideline development for measuring immunoglobulin level and use of immunoglobulin in solid organ transplant patients and highlight areas for further research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015017620.

Immune deficiency: changing spectrum of pathogens

Current UK national standards recommend routine bacteriology surveillance in severe antibody-deficient patients, but less guidance exists on virology screening and viral infections in these patients. In this retrospective audit, we assessed the proportion of positive virology or bacteriology respiratory and stool samples from patients with severe, partial or no immune deficiency during a 2-year period. Medical notes were reviewed to identify symptomatic viral infections and to describe the course of persistent viral infections. During the 2-year period, 31 of 78 (39·7%) severe immune-deficient patients tested had a positive virology result and 89 of 160 (55.6%) had a positive bacteriology result. The most commonly detected pathogens were rhinovirus (12 patients), norovirus (6), Haemophilus influenzae (24), Pseudomonas spp. (22) and Staphylococcus aureus (21). Ninety-seven per cent of positive viral detection samples were from patients who were symptomatic. Low serum immunoglobulin IgA levels were more prevalent in patients with a positive virology sample compared to the total cohort (P = 0·0078). Three patients had persistent norovirus infection with sequential positive isolates for 9, 30 and 16 months. Virology screening of symptomatic antibody-deficient patients may be useful as a guide to anti-microbial treatment. A proportion of these patients may experience persistent viral infections with significant morbidity.

Aetiology and clinical characteristics of patients with bronchiectasis in a Chinese Han population: A prospective study

BACKGROUND AND OBJECTIVE

Bronchiectasis is a chronic respiratory disease with diverse causes that may differ in clinical features and thus treatment options. However, few large-scale studies on the aetiology of bronchiectasis are currently available. This study aims to determine aetiology and clinical features of bronchiectasis in a Chinese Han population.

METHODS

This prospective study enrolled adult patients diagnosed with bronchiectasis as confirmed by high-resolution computed tomography at five general hospitals in Shandong from January 2010 to August 2014. Causes of bronchiectasis were sought by analysis of clinical history and auxiliary examinations (including serum immunoglobulin determination, saccharin test, Aspergillus skin prick test, autoantibody detection and electronic bronchoscopy).

RESULTS

A total of 476 adult patients with bronchiectasis were included, and all patients were of Chinese Han ethnicity. Idiopathic (66.0%) was the most common cause, followed by post-tuberculosis (16.0%). Other uncommon causes included post-infective (3.8%), immunodeficiency (3.8%), allergic bronchopulmonary aspergillosis (4.0%), rheumatic diseases (4.4%) and primary ciliary dyskinesia (0.9%). Patients with post-tuberculosis bronchiectasis had a higher frequency of upper lobe involvement (P < 0.05). Cylindrical bronchiectasis was the most common type of all causes, with varicose bronchiectasis occurring more frequently in post-tuberculosis bronchiectasis and allergic bronchopulmonary aspergillosis (P < 0.05). However, patients with different causes did not differ in lung function and sputum isolation rate of Pseudomonas aeruginosa (P > 0.05).

CONCLUSIONS

In a Chinese Han population in Shandong, idiopathic bronchiectasis is the most common form of bronchiectasis followed by post-tuberculosis bronchiectasis. Patients with different causes differ in distribution and pattern of bronchiectasis on computed tomography.