Unexpectedly High Prevalence of Common Variable Immunodeficiency in Finland

Limitations in the clinical utility of vaccine challenge responses in the evaluation of primary antibody deficiency including Common Variable Immunodeficiency Disorders

Vaccine challenge responses are an integral component in the diagnostic evaluation of patients with primary antibody deficiency, including Common Variable Immunodeficiency Disorders (CVID). There are no studies of vaccine challenge responses in primary hypogammaglobulinemia patients not accepted for subcutaneous/intravenous immunoglobulin (SCIG/IVIG) replacement compared to those accepted for such treatment. Vaccine challenge responses in patients enrolled in two long-term prospective cohorts, the New Zealand Hypogammaglobulinemia Study (NZHS) and the New Zealand CVID study (NZCS), were compared in this analysis. Almost all patients in the more severely affected SCIG/IVIG treatment group achieved protective antibody levels to tetanus toxoid and H. influenzae type B (HIB). Although there was a highly significant statistical difference in vaccine responses to HIB, tetanus and diphtheria toxoids, there was substantial overlap in both groups. In contrast, there was no significant difference in Pneumococcal Polysaccharide antibody responses to Pneumovax® (PPV23). This analysis illustrates the limitations of evaluating vaccine challenge responses in patients with primary hypogammaglobulinemia to establish the diagnosis of CVID and in making decisions to treat with SCIG/IVIG. The conclusion from this study is that patients with symptoms attributable to primary hypogammaglobulinemia with reduced IgG should not be denied SCIG/IVIG if they have normal vaccine responses.

A Nationwide Study of the Delayed Diagnosis and the Clinical Manifestations of Predominantly Antibody Deficiencies and CTLA4-Mediated Immune Dysregulation Syndrome in Greece

Background and Objectives: Predominantly antibody deficiencies (PAD) represent the most common type of primary immunodeficiencies in humans, characterized by a wide variation in disease onset, clinical manifestations, and outcome. Considering that the prevalence of PAD in Greece is unknown, and there is limited knowledge on the clinical and laboratory characteristics of affected patients, we conducted a nationwide study. Materials and Methods: 153 patients (male/female: 66/87; median age: 43.0 years; range: 7.0-77.0) diagnosed, and followed-up between August 1979 to September 2023. Furthermore, we classified our cohort into five groups according to their medical history, immunoglobulin levels, and CTLA4-mutational status: 123 had common variable immunodeficiency (CVID), 12 patients with "secondary" hypogammaglobulinemia due to a previous B-cell depletion immunotherapy for autoimmune or malignant disease several years ago (median: 9 years, range 6-14) displaying a typical CVID phenotype, 7 with combined IgA and IgG subclass deficiencies, 5 patients with CVID-like disease due to CTLA4-mediated immune dysregulation syndrome, and 6 patients with unclassified hypogammaglobulinemia. Results: We demonstrated a remarkable delay in PAD diagnosis, several years after the onset of related symptoms (median: 9.0 years, range: 0-43.0). A family history of PAD was only present in 11.8%, with the majority of patients considered sporadic cases. Most patients were diagnosed in the context of a diagnostic work-up for recurrent infections, or recurrent/resistant autoimmune cytopenias. Interestingly, 10 patients (5.6%) had no history of infection, diagnosed due to either recurrent/resistant autoimmunity, or during a work-up of their medical/family history. Remarkable findings included an increased prevalence of lymphoproliferation (60.1%), while 39 patients (25.5%) developed bronchiectasis, and 16 (10.5%) granulomatous disease. Cancer was a common complication in our cohort (25 patients, 16.3%), with B-cell malignancies representing the most common neoplasms (56.7%). Conclusion: Our findings indicate the necessity of awareness about PAD and their complications, aiming for early diagnosis and the appropriate management of affected patients.

Challenges for gene editing in common variable immunodeficiency disorders: Current and future prospects

The original CRISPR Cas9 gene editing system and subsequent innovations offers unprecedented opportunities to correct severe genetic defects including those causing Primary Immunodeficiencies (PIDs). Common Variable Immunodeficiency Disorders (CVID) are the most frequent symptomatic PID in adults and children. Unlike many other PIDs, patients meeting CVID criteria do not have a definable genetic defect and cannot be considered to have an inborn error of immunity (IEI). Patients with a CVID phenotype carrying a causative mutation are deemed to have a CVID-like disorder consequent to an IEI. Patients from consanguineous families often have highly penetrant early-onset autosomal recessive forms of CVID-like disorders. Individuals from non-consanguineous families may have autosomal dominant CVID-like disorders with variable penetrance and expressivity. This essay explores the potential clinical utility as well as the current limitations and risks of gene editing including collateral genotoxicity. In the immediate future the main application of this technology is likely to be the in vitro investigation of epigenetic and polygenic mechanisms, which are likely to underlie many cases of CVID and CVID-like disorders. In the longer-term, the CRISPR Cas9 system and other gene-based therapies could be utilized to treat CVID-like disorders, where the underlying IEI is known.

Common variable immunodeficiency-an independent risk factor for atherosclerotic cardiovascular diseases

Atherosclerosis, a disease of chronic inflammation of the arterial wall, is the main cause of most cardiovascular diseases (CVDs). Common variable immunodeficiency (CVID), a group of diseases characterized by frequent infections due to defective antibody production and lack of human immunoglobulins, plays a role in immune activation and inflammation. Thus, it can be hypothesized that CVID increases the risk for atherosclerotic CVDs. On the other hand, it is also possible that CVID patients are protected from atherosclerotic CVDs based on their life-long immunoglobulin therapy. Here, we examined whether patients with CVID have an increased risk for atherosclerotic CVDs or whether they are protected from these diseases. Using an electronic patient database registry search of a population of 83 CVID patients and their age- and sex-matched, tenfold larger control population we demonstrate that CVID patients have a statistically significantly higher risk for coronary heart disease (OR 2.4, p = 0.015) and peripheral vascular disease (OR 12.5, p < 0.001). Regarding cerebrovascular disease, there was a trend towards CVID patients having more strokes or ischemic attacks, but the difference was not statistically significant (OR 2.0, p = 0.133). The combined OR for CVID patients for atherosclerotic CVDs was 2.6 (p = 0.001). CVID population had more hypertension, but smoking was more seldom. There were no statistically significant differences in the incidence of diabetes or levels of serum total, HDL or LDL cholesterol, or glycosylated hemoglobin A1c between CVID patients and their controls. CVID patients had infections more frequently and the OR for autoimmune diseases was 3.8 (p < 0.001). Finally, a multivariate logistic analysis showed that CVID is an independent risk factor for atherosclerotic CVDs (p = 0.002). The present study demonstrates for the first time that CVID is an independent risk factor for atherosclerotic CVDs. Further studies are required to fully understand the exact mechanisms behind this.

Evaluating Drug Prescription Patterns in Undiagnosed Common Variable Immunodeficiency Patients

OBJECTIVE

To compare the consumption of antibiotics (AB), systemic steroids, and inhaled bronchodilators/glucocorticoids in the 3 years preceding the diagnosis of common variable immunodeficiency (CVID) among CVID patients and matched controls and to estimate whether the level of consumption was associated with the risk of a subsequent CVID diagnosis.

METHODS

We conducted a nested case-control study, identifying all individuals (n=130 cases) diagnosed with CVID in Denmark (1994-2014) and 45 age- and sex-matched population controls per case (n=5850 controls) from national registers. Drug consumption was estimated as defined daily doses per person-year. We used conditional logistic regression to compute odds ratios and 95% confidence intervals.

RESULTS

In the 3 years preceding a CVID diagnosis, we observed more frequent and higher consumption of all three drug classes. The association between consumption and risk of subsequent CVID diagnosis was statistically significant for all drug classes. The association was stronger with higher consumption and shorter time to CVID diagnosis. The fraction of cases compared to the controls redeeming ≥1 prescription of the included drugs during the study period was higher for AB (97% vs 52%), systemic steroids (35% vs 7.4%), and inhaled bronchodilators/glucocorticoids (46% vs 11.7%) (p<0.001).

CONCLUSION

CVID patients have significantly higher use of AB, systemic steroids, and inhaled bronchodilators/glucocorticoids in the 3 years preceding CVID diagnosis than controls. Prescribing these drugs in primary healthcare could be an opportunity to consider (proactive) screening for CVID. Further studies are needed to identify optimal prescription cutoffs that could endorse its inclusion in public health policies.

Common variable immunodeficiency disorder (CVID)-related liver disease: assessment of the main histological aspects using novel semiquantitative scoring systems, image analysis and correlation with clinical parameters of liver stiffness and portal hypertension

AIMS

We aimed to investigate the relationship between T-cell-mediated sinusoidal injury, nodular regenerative hyperplasia like changes (NRH-LC) and fibrosis, clinical measures of fibrosis and portal hypertension, and progression rate in common variable immunodeficiency disorder (CVID)-related liver disease.

METHODS

This is a retrospective single-centre study. Liver biopsies from CVID patients with liver disease were reviewed to assess for NRH-LC, fibrosis and elastosis, including collagen and elastin proportionate areas. CD3 positive T-cells infiltration and sinusoidal endothelial changes by CD34 expression were quantified by image analysis and a semiquantitative method, respectively. These findings were correlated with liver stiffness measurements (LSM) and hepatic venous pressure gradient (HVPG).

RESULTS

NRH-LC and pericellular elastosis were present in most biopsies (32/40 and 38/40, respectively). All biopsies showed fibrosis, which was limited to pericellular in 21/40 (52.5%) and included bridging fibrous septa in 19/40 (47.5%). 28/40 liver biopsies showed enhanced sinusoidal expression of CD34. There were more CD3 positive cells in biopsies with NRH-LC compared with those without. There was no significant correlation between LSM, HVPG and fibrosis/elastosis scores. Five of seven patients with at least two biopsies showed progression in fibrosis stage.

CONCLUSIONS

NRH-LC and fibrosis in CVID patients often coexist along with the presence of sinusoidal endothelial changes and sinusoidal lymphocytic infiltration. Fibrosis progresses over time, and significant fibrosis can be observed in young patients (<30 years old), potentially reflecting a more aggressive form of CVID-related liver disease. Further studies are necessary to investigate the relationship between histological findings, clinical measures of fibrosis and portal hypertension and outcome.

Low and high serum IgG associates with respiratory infections in a young and working age population

BACKGROUND

We investigated health consequences and genetic properties associated with serum IgG concentration in a young and working age general population.

METHODS

Northern Finland Birth Cohort 1966 (NFBC1966, n = 12,231) health data have been collected from birth to 52 years of age. Relationships between life-long health events, medications, chronic conditions, lifestyle, and serum IgG concentration measured at age 46 years (n = 5430) were analysed. Regulatory mechanisms of serum IgG concentration were considered.

FINDINGS

Smoking and genetic variation (FCGR2B and TNFRSF13B) were the most important determinants of serum IgG concentration. Laboratory findings suggestive of common variable immunodeficiency (CVID) were 10-fold higher compared to previous reports (73.7 per 100,000 vs 0.6-6.9 per 100,000). Low IgG was associated with antibiotic use (relative risk 1.285, 95% CI 1.001-1.648; p = 0.049) and sinus surgery (relative risk 2.257, 95% CI 1.163-4.379; p = 0.016). High serum IgG was associated with at least one pneumonia episode (relative risk 1.737, 95% CI 1.032-2.922; p = 0.038) and with total number of pneumonia episodes (relative risk 2.167, 95% CI 1.443-3.254; p < 0.001).

INTERPRETATION

CVID-like laboratory findings are surprisingly common in our unselected study population. Any deviation of serum IgG from normal values can be harmful; both low and high serum IgG may indicate immunological insufficiency. Critical evaluation of clinical presentation must accompany immunological laboratory parameters.

FUNDING

Oulu University Hospital VTR, CSL Behring, Foundation for Pediatric Research.

Dysregulated Lymphocyte Antigen Receptor Signaling in Common Variable Immunodeficiency with Granulomatous Lymphocytic Interstitial Lung Disease

PURPOSE

A subset of common variable immunodeficiency (CVID) patients either presents with or develops autoimmune and lymphoproliferative complications, such as granulomatous lymphocytic interstitial lung disease (GLILD), a major cause of morbidity and mortality in CVID. While a myriad of phenotypic lymphocyte derangements has been associated with and described in GLILD, defects in T and B cell antigen receptor (TCR/BCR) signaling in CVID and CVID with GLILD (CVID/GLILD) remain undefined, hindering discovery of biomarkers for disease monitoring, prognostic prediction, and personalized medicine approaches.

METHODS

To identify perturbations of immune cell subsets and TCR/BCR signal transduction, we applied mass cytometry analysis to peripheral blood mononuclear cells (PBMCs) from healthy control participants (HC), CVID, and CVID/GLILD patients.

RESULTS

Patients with CVID, regardless of GLILD status, had increased frequency of HLADR+CD4+ T cells, CD57+CD8+ T cells, and CD21lo B cells when compared to healthy controls. Within these cellular populations in CVID/GLILD patients only, engagement of T or B cell antigen receptors resulted in discordant downstream signaling responses compared to CVID. In CVID/GLILD patients, CD21lo B cells showed perturbed BCR-mediated phospholipase C gamma and extracellular signal-regulated kinase activation, while HLADR+CD4+ T cells and CD57+CD8+ T cells displayed disrupted TCR-mediated activation of kinases most proximal to the receptor.

CONCLUSION

Both CVID and CVID/GLILD patients demonstrate an activated T and B cell phenotype compared to HC. However, only CVID/GLILD patients exhibit altered TCR/BCR signaling in the activated lymphocyte subsets. These findings contribute to our understanding of the mechanisms of immune dysregulation in CVID with GLILD.

The Rapidly Expanding Genetic Spectrum of Common Variable Immunodeficiency-Like Disorders

The understanding of common variable immunodeficiency disorders (CVID) is in evolution. CVID was previously a diagnosis of exclusion. New diagnostic criteria have allowed the disorder to be identified with greater precision. With the advent of next-generation sequencing (NGS), it has become apparent that an increasing number of patients with a CVID phenotype have a causative genetic variant. If a pathogenic variant is identified, these patients are removed from the overarching diagnosis of CVID and are deemed to have a CVID-like disorder. In populations where consanguinity is more prevalent, the majority of patients with severe primary hypogammaglobulinemia will have an underlying inborn error of immunity, usually an early-onset autosomal recessive disorder. In nonconsanguineous societies, pathogenic variants are identified in approximately 20% to 30% of patients. These are often autosomal dominant mutations with variable penetrance and expressivity. To add to the complexity of CVID and CVID-like disorders, some genetic variants such as those in TNFSF13B (transmembrane activator calcium modulator cyclophilin ligand interactor) predispose to, or enhance, disease severity. These variants are not causative but can have epistatic (synergistic) interactions with more deleterious mutations to worsen disease severity. This review is a description of the current understanding of genes associated with CVID and CVID-like disorders. This information will assist clinicians in interpreting NGS reports when investigating the genetic basis of disease in patients with a CVID phenotype.

Heterozygous premature termination in zinc-finger domain of Krüppel-like factor 2 gene associates with dysregulated immunity

Krüppel-like factor 2 (KLF2) is a transcription factor with significant roles in development, maturation, differentiation, and proliferation of several cell types. In immune cells, KLF2 regulates maturation and trafficking of lymphocytes and monocytes. KLF2 participates in regulation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. Although pulmonary arterial hypertension (PAH) related to KLF2 genetic variant has been suggested, genetic role of KLF2 associated with immune dysregulation has not been described. We identified a family whose members suffered from lymphopenia, autoimmunity, and malignancy. Whole exome sequencing revealed a KLF2 p.(Glu318Argfs*87) mutation disrupting the highly conserved zinc finger domain. We show a reduced amount of KLF2 protein, defective nuclear localization and altered protein-protein interactome. The phenotypically variable positive cases presented with B and T cell lymphopenia and abnormalities in B and T cell maturation including low naive T cell counts and low CD27+IgD-IgM- switched memory B cells. KLF2 target gene (CD62L) expression was affected. Although the percentage of (CD25+FOXP3+, CD25+CD127-) regulatory T cells (Treg) was high, the naive Treg cells (CD45RA+) were absent. Serum IgG1 levels were low and findings in one case were consistent with common variable immunodeficiency (CVID). Transcription of NF-κβ pathway genes and p65/RelA phosphorylation were not significantly affected. Inflammasome activity, transcription of genes related with JAK/STAT pathway and interferon signature were also comparable to controls. Evidence of PAH was not found. In conclusion, KLF2 variant may be associated with familial immune dysregulation. Although the KLF2 deficient family members in our study suffered from lymphopenia, autoimmunity or malignancy, additional study cohorts are required to confirm our observations.

Are we forgetting to carry out serum protein electrophoresis as part of diagnosis workup?

Background

Common variable immunodeficiency (CVID) is a rare disease that affects children and adults and is often difficult to diagnose. Despite being one of the most frequent causes of immunodeficiency, involving gastrointestinal (GI), respiratory, and hematological systems, the disease onset can have heterogeneous and intermittent symptoms, frequently leading to diagnostic delay. GI symptoms are common and can include diarrhea, but the asymptomatic periods lead to overlooking the recurrent pattern. The same can occur with respiratory infections, thus delaying CVID suspicion. The starting point for CVID diagnosis is the decreased gamma globulin levels in serum protein electrophoresis (SPE), also observed through direct immunoglobulin’s dosage.

Case presentation

The patient is a 38 years-old man who had intermittent diarrhea and recurrent airway infections for 19 years, but the CVID diagnosis was achieved only after SPE was carried out. At that time, he was already malnourished, and developed other complications related to CVID in a short period.

Conclusions

SPE is readily available and inexpensive, but is not part of the laboratory approach in diarrhea. According to the case presented herein, it can be useful for patients with recurrent infections or other clues of the disease.

"Common variable immunodeficiency: Challenges for diagnosis"

Common variable immunodeficiency is a heterogeneous condition characterized by B cell dysfunction with reduced serum immunoglobulin levels and a highly variable spectrum of clinical manifestations ranging from recurrent infections to autoimmune disease. The diagnosis of CVID is often challenging due to the diverse clinical presentation of patients and the existence of multiple diagnostic criteria without a universally adopted consensus. Laboratory evaluation to assist with diagnosis currently includes serum immunoglobulin testing, immunophenotyping, assessment of vaccine response, and genetic testing. Additional emerging techniques include investigation of the B cell repertoire and the use of machine learning algorithms. Advances in our understanding of common variable immunodeficiency will ultimately contribute to earlier diagnosis and novel interventions with the goal of improving prognosis for these patients.

Implementation of Early Next-Generation Sequencing for Inborn Errors of Immunity: A Prospective Observational Cohort Study of Diagnostic Yield and Clinical Implications in Dutch Genome Diagnostic Centers

Objective

Inborn errors of immunity (IEI) are a heterogeneous group of disorders, affecting different components of the immune system. Over 450 IEI related genes have been identified, with new genes continually being recognized. This makes the early application of next-generation sequencing (NGS) as a diagnostic method in the evaluation of IEI a promising development. We aimed to provide an overview of the diagnostic yield and time to diagnosis in a cohort of patients suspected of IEI and evaluated by an NGS based IEI panel early in the diagnostic trajectory in a multicenter setting in the Netherlands.

Study Design

We performed a prospective observational cohort study. We collected data of 165 patients with a clinical suspicion of IEI without prior NGS based panel evaluation that were referred for early NGS using a uniform IEI gene panel. The diagnostic yield was assessed in terms of definitive genetic diagnoses, inconclusive diagnoses and patients without abnormalities in the IEI gene panel. We also assessed time to diagnosis and clinical implications.

Results

For children, the median time from first consultation to diagnosis was 119 days versus 124 days for adult patients (U=2323; p=0.644). The median turn-around time (TAT) of genetic testing was 56 days in pediatric patients and 60 days in adult patients (U=1892; p=0.191). A definitive molecular diagnosis was made in 25/65 (24.6%) of pediatric patients and 9/100 (9%) of adults. Most diagnosed disorders were identified in the categories of immune dysregulation (n=10/25; 40%), antibody deficiencies (n=5/25; 20%), and phagocyte diseases (n=5/25; 20%). Inconclusive outcomes were found in 76/165 (46.1%) patients. Within the patient group with a genetic diagnosis, a change in disease management occurred in 76% of patients.

Conclusion

In this cohort, the highest yields of NGS based evaluation for IEI early in the diagnostic trajectory were found in pediatric patients, and in the disease categories immune dysregulation and phagocyte diseases. In cases where a definitive diagnosis was made, this led to important disease management implications in a large majority of patients. More research is needed to establish a uniform diagnostic pathway for cases with inconclusive diagnoses, including variants of unknown significance.

Impaired Memory B-Cell Response to Influenza Immunization in Patients With Common Variable Immunodeficiency (CVID)

Background:

Common variable immunodeficiency (CVID) is a heterogeneous primary immunodeficiency characterized by low serum antibody levels and recurrent infections. The cellular response to immunization in patients with CVID has not been fully investigated. In this study, we aimed to characterize vaccination-induced influenza-specific memory B-cell responses in CVID.

Methods:

Eleven individuals affected with CVID and 9 unaffected control individuals were immunized with the 2010-2011 non-adjuvanted seasonal influenza vaccine. Blood samples were collected on the day of vaccination and at week 8 and week 16 after vaccination, and PBMCs were immunophenotyped by flow cytometry. Influenza specific serology was determined using hemagglutination inhibition and microneutralization against vaccine antigens. Influenza-specific memory B-cell responses were determined by ELISpot.

Results:

Individuals with CVID showed wide variability in the frequency of CD19+ B cells in blood. The CVID group had significantly reduced frequencies of CD19+CD27+ memory B cells. Frequencies of circulating T follicular helper (CD4+CXCR5+) cells were similar between those with CVID and healthy controls. In terms of serology, compared to healthy controls, the CVID group overall showed significantly reduced boosting to vaccine antigens by hemagglutination inhibition and microneutralization assays at 8 weeks compared to controls and failed to maintain responses by 16 weeks compared to controls, resulting in a post-vaccination geometric mean titer (GMT) ≥ 40 to strain A/H1N1 in only 27% at 8 weeks, and 22% at 12 weeks for patients with CVID vs 78% and 75%, respectively for healthy controls. In addition, there was a GMT ≥ 40 to A/H3N2 in only 9% at 8 weeks and 22% at 12 weeks for patients with CVID vs 56% and 50%, respectively for healthy controls. Healthy participants showed significant increases in flu-specific IgM-secreting memory B cells after vaccination, whereas patients with CVID showed non-signifi-cant mild increases. Before vaccination, patients with CVID had significantly lower frequencies of background level influenza-specific IgG and IgA memory B cells. Half of the patients with CVID showed an increase in influenza-specific IgG-secreting memory B cells post vaccination, whereas the other half showed none. All control participants exhibited an increase in influenza-specific IgG-secreting B cells. None of the patients with CVID developed influenza-specific IgA memory B-cell response post vaccination, compared to 5/8 in healthy controls. At week 16, the frequency of influenza-specific memory B-cell responses decayed but to non-zero baseline in healthy controls and to zero baseline in patients with CVID.

Conclusions:

Together, these data demonstrate that patients with CVID respond heterogeneously, but as a group poorly, to non-adjuvanted influenza vaccine, with a subgroup unable to generate influenza-specific memory B-cell responses. No patient with CVID was able to maintain memory response for prolonged periods. Together, our results suggest a defect in Ig class switching and memory B-cell maintenance in patients with CVID during a de novo vaccine immune response.

Clinical and laboratory parameter analysis in patients with common Variable Immunodeficiency

Introduction: Common Variable Immunodeficiency (CVID) is the most prevalent primary immunodeficiency in adult population. The diagnosis is based on low concentration of at least 2 immunoglobulin classes, mostly IgG, with low IgA and/or IgM. Beside recurrent infections, patients with CVID usually suffer from different respiratory, gastrointestinal, autoimmune and malignant diseases. Leading therapeutic approach to managing CVID is regular intravenous (IVIG) and subcutaneous (SCIG) immunoglobulin replacement therapy. Aim: The aim of the study was to analyze clinical and laboratory parameters in patients with CVID. Material and methods: The present study included 24 patients with CVID who were treated at Clinic of Allergy and Immunology, University Clinical Center of Serbia from 2012 to 2022. Demographic data, clinical and laboratory parameters were obtained from the patients' medical records. The concentrations of IgG, IgM and IgA were measured by nephelometry. Statistical analysis was performed using descriptive methods, Student t test for independent samples and Fisher exact test. Results: Respiratory manifestations were found in 70.8% of patients, gastrointestinal in 45.8%, autoimmune in 29.2% and malignancies in 20.8%. The presence of autoimmune diseases was the most common within the patients aged between 20 to 30 years, and it was statistically significantly higher comparing to other age groups (p = 0.014). Serum IgG concentration of 7.6 ± 2.7 g/l was measured. Statistically significantly higher IgG concentrations were observed in patients receiving SCIG (10.2 ± 1.6), compared to those receiving IVIG (6.7 ± 2.4) (t = -3.3, p = 0.003). Premedication was required in 44.4% of patients receiving IVIG. Conclusion: The most common complication of CVID are chronic lung diseases. Autoimmune diseases are the most frequently diagnosed in patients between the ages of 20 and 30. The use of SCIG is identified as better form of immunoglobulin replacement therapy. Total immunoglobulin serum concentration measuring in patients with recurrent infections and autoimmune diseases can contribute to timely diagnosis.

Global systematic review of primary immunodeficiency registries

INTRODUCTION

During the last 4 decades, registration of patients with primary immunodeficiencies (PID) has played an essential role in different aspects of these diseases worldwide including epidemiological indexes, policymaking, quality controls of care/life, facilitation of genetic studies and clinical trials as well as improving our understanding about the natural history of the disease and the immune system function. However, due to the limitation of sustainable resources supporting these registries, inconsistency in diagnostic criteria and lack of molecular diagnosis as well as difficulties in the documentation and designing any universal platform, the global perspective of these diseases remains unclear.

AREAS COVERED

Published and unpublished studies from January 1981 to June 2020 were systematically reviewed on PubMed, Web of Science and Scopus. Additionally, the reference list of all studies was hand-searched for additional studies. This effort identified a total of 104614 registered patients and suggests identification of at least 10590 additional PID patients, mainly from countries located in Asia and Africa. Molecular defects in genes known to cause PID were identified and reported in 13852 (13.2% of all registered) patients.

EXPERT OPINION

Although these data suggest some progress in the identification and documentation of PID patients worldwide, achieving the basic requirement for the global PID burden estimation and registration of undiagnosed patients will require more reinforcement of the progress, involving both improved diagnostic facilities and neonatal screening.

Comparison of Diagnostic Criteria for Common Variable Immunodeficiency Disorders (CVID) in the New Zealand CVID Cohort Study

Common variable immunodeficiency disorders (CVID) are the most frequent symptomatic primary immune deficiencies in adults and children. In addition to recurrent and severe infections, patients with CVID are susceptible to autoimmune and inflammatory complications. The aetiologies of these uncommon conditions are, by definition, unknown. When the causes of complex disorders are uncertain, diagnostic criteria may offer valuable guidance to the management of patients. Over the last two decades, there have been four sets of diagnostic criteria for CVID in use. The original 1999 European Society for Immunodeficiencies and Pan-American Society for Immunodeficiency (ESID/PAGID) criteria are less commonly used than the three newer criteria: Ameratunga et al (Clin Exp Immunol 174:203-211, 2013), ESID (J Allergy Clin Immunol Pract, 2019) and ICON (J Allergy Clin Immunol Pract 4:38-59, 2016) criteria. The primary aim of the present study was to compare the utility of diagnostic criteria in a well-characterised cohort of CVID patients. The New Zealand CVID cohort study (NZCS) commenced in 2006 and currently comprises one hundred and thirteen patients, which represents approximately 70% of all known CVID patients in NZ. Many patients have been on subcutaneous or intravenous (SCIG/IVIG) immunoglobulin treatment for decades. Patients were given a clinical diagnosis of CVID as most were diagnosed before the advent of newer diagnostic criteria. Application of the three commonly used CVID diagnostic criteria to the NZCS showed relative sensitivities as follows: Ameratunga et al (Clin Exp Immunol 174:203-211, 2013), possible and probable CVID, 88.7%; ESID (J Allergy Clin Immunol Pract, 2019), 48.3%; and ICON (J Allergy Clin Immunol Pract 4:38-59, 2016), 47.1%. These differences were mostly due to the low rates of diagnostic vaccination challenges in patients prior to commencing SCIG/IVIG treatment and mirror similar findings in CVID cohorts from Denmark and Finland. Application of the Ameratunga et al (Clin Exp Immunol 174:203-211, 2013) CVID diagnostic criteria to patients on SCIG/IVIG may obviate the need to stop treatment for vaccine studies, to confirm the diagnosis.

Common Variable Immunodeficiency and Autoimmune Diseases: A Retrospective Study of 95 Adult Patients in a Single Tertiary Care Center

Common variable immunodeficiency (CVID) is the most common clinically significant primary immunodeficiency in adulthood, which presents a broad spectrum of clinical manifestations, often including non-infectious complications in addition to heightened susceptibility to infections. These protean manifestations may significantly complicate the differential diagnosis resulting in diagnostic delay and under-treatment with increased mortality and morbidity. Autoimmunity occurs in up to 30% of CVID patients, and it is an emerging cause of morbidity and mortality in this type of patients. 95 patients (42 males and 53 females) diagnosed with CVID, basing on ESID diagnostic criteria, were enrolled in this retrospective cohort study. Clinical phenotypes were established according to Chapel 2012: i) no other disease-related complications, ii) cytopenias (thrombocytopenia/autoimmune hemolytic anemia/neutropenia), iii) polyclonal lymphoproliferation (granuloma/lymphoid interstitial pneumonitis/persistent unexplained lymphadenopathy), and iv) unexplained persistent enteropathy. Clinical items in the analysis were age, gender, and clinical features. Laboratory data included immunoglobulin (Ig)G, IgM and IgA levels at diagnosis, flow-cytometric analysis of peripheral lymphocytes (CD3+, CD3+CD4+, CD3+CD8+, CD19+, CD4+CD25highCD127low, CD19hiCD21loCD38lo, and follicular T helper cell counts). Comparisons of continuous variables between groups were performed with unpaired t-test, when applicable. 39 patients (41%) showed autoimmune complications. Among them, there were 21 females (53.8%) and 18 males (46.2%). The most prevalent autoimmune manifestations were cytopenias (17.8%), followed by arthritis (11.5%), psoriasis (9.4%), and vitiligo (6.3%). The most common cytopenia was immune thrombocytopenia, reported in 10 out of 95 patients (10.5%), followed by autoimmune hemolytic anemia (n=3, 3.1%) and autoimmune neutropenia (n=3, 3.1%). Other autoimmune complications included thyroiditis, coeliac disease, erythema nodosum, Raynaud’s phenomenon, alopecia, recurring oral ulcers, autoimmune gastritis, and primary biliary cholangitis. There were no statistically significant differences comparing immunoglobulin levels between CVID patients with or without autoimmune manifestations. There was no statistical difference in CD3+, CD8+, CD4+CD25highCD127low T, CD19, CD19hiCD21loCD38lo, and follicular T helper cell counts in CVID patients with or without autoimmune disorders. In conclusion, autoimmune manifestations often affect patients with CVID. Early recognition and tailored treatment of these conditions are pivotal to ensure a better quality of life and the reduction of CVID associated complications.

Pulmonary granulomatosis of genetic origin

Granulomatous inflammation of the lung can be a manifestation of different conditions and can be caused by endogenous inflammation or external triggers. A multitude of different genetic mutations can either predispose patients to infections with granuloma-forming pathogens or cause autoinflammatory disorders, both leading to the phenotype of pulmonary granulomatosis. Based on a detailed patient history, physical examination and a diagnostic approach including laboratory workup, pulmonary function tests (PFTs), computed tomography (CT) scans, bronchoscopy with bronchoalveolar lavage (BAL), lung biopsies and specialised microbiological and immunological diagnostics, a correct diagnosis of an underlying cause of pulmonary granulomatosis of genetic origin can be made and appropriate therapy can be initiated. Depending on the underlying disorder, treatment approaches can include antimicrobial therapy, immunosuppression and even haematopoietic stem cell transplantation (HSCT). Patients with immunodeficiencies and autoinflammatory conditions are at the highest risk of developing pulmonary granulomatosis of genetic origin. Here we provide a review on these disorders and discuss pathogenesis, clinical presentation, diagnostic approach and treatment.

Pulmonary granulomatosis of genetic origin mostly occurs in immunodeficiency disorders and autoinflammatory conditions. In addition to specific approaches in this regard, the diagnostic workup needs to cover environmental and occupational aspects.https://bit.ly/31SqdHW

Bronchiectasis is associated with delayed diagnosis and adverse outcomes in the New Zealand Common Variable Immunodeficiency Disorders cohort study

Common variable immunodeficiency disorders (CVID) are multi-system disorders where target organ damage is mediated by infective, autoimmune and inflammatory processes. Bronchiectasis is probably the most common disabling complication of CVID. The risk factors for bronchiectasis in CVID patients are incompletely understood. The New Zealand CVID study (NZCS) is a nationwide longitudinal observational study of adults, which commenced in 2006. In this analysis, the prevalence and risk factors for bronchiectasis were examined in the NZCS. After informed consent, clinical and demographic data were obtained with an interviewer-assisted questionnaire. Linked electronic clinical records and laboratory results were also reviewed. Statistical methods were applied to determine if variables such as early-onset disease, delay in diagnosis and increased numbers of infections were associated with greater risk of bronchiectasis. One hundred and seven adult patients with a diagnosis of CVID are currently enrolled in the NZCS, comprising approximately 70% of patients known to have CVID in New Zealand. Fifty patients (46·7%) had radiologically proven bronchiectasis. This study has shown that patients with compared to those without bronchiectasis have an increased mortality at a younger age. CVID patients with bronchiectasis had a greater number of severe infections consequent to early-onset disease and delayed diagnosis. Indigenous Māori have a high prevalence of CVID and a much greater burden of bronchiectasis compared to New Zealand Europeans. Diagnostic latency has not improved during the study period. Exposure to large numbers of infections because of early-onset disease and delayed diagnosis was associated with an increased risk of bronchiectasis. Earlier diagnosis and treatment of CVID may reduce the risk of bronchiectasis and premature death in some patients.

Perspective: Application of the American College of Medical Genetics Variant Interpretation Criteria to Common Variable Immunodeficiency Disorders

Common variable immunodeficiency disorders (CVIDs) are rare primary immunodeficiency diseases (PIDs) mostly associated with late onset antibody failure leading to immune system failure. Patients with CVID are predisposed to disabling complications such as bronchiectasis and systemic autoimmunity. In recent years a large number of genetic defects have become associated with these disorders. Patients with a causative mutation are deemed to have CVID-like disorders, while those with mutations predisposing to or modifying disease severity remain within the spectrum of CVID as defined by current diagnostic criteria. Next-generation sequencing (NGS) allows simultaneous analysis of multiple genes. Potential mutations identified from NGS are commonly evaluated with the American College of Medical Genetics (ACMG) variant interpretation criteria to determine their pathogenicity (causality). Patients with CVID and CVID-like disorders have marked genetic, allelic, and phenotypic heterogeneity. Although all patients with a CVID phenotype should undergo genetic testing, the complexity of the genetics associated with these disorders is challenging. Variants of unknown significance (VUS) remain a significant barrier to realising the full potential of NGS in CVID and CVID-like disorders. Here we explore the nuances of applying the ACMG criteria to patients with CVID and CVID-like disorders. Close collaboration between the clinician, bioinformatics, and genetics professionals will improve the diagnostic yield from genetic testing and reduce the frequency of VUS.

Lessons Learned From the Clinical Presentation of Common Variable Immunodeficiency Disorders: A Systematic Review and Meta-Analysis

Background

Diagnostic delay in common variable immunodeficiency disorders (CVID) is considerable. There is no generally accepted symptom-recognition framework for its early detection.

Objective

To systematically review all existing data on the clinical presentation of CVID.

Methods

PubMed, EMBASE and Cochrane were searched for cohort studies, published January/1999-December/2019, detailing the clinical manifestations before, at and after the CVID-diagnosis.

Results

In 51 studies (n=8521 patients) 134 presenting and 270 total clinical manifestations were identified. Recurrent upper and/or lower respiratory infections were present at diagnosis in 75%. Many patients had suffered severe bacterial infections (osteomyelitis 4%, meningitis 6%, septicemia 8%, mastoiditis 8%). Bronchiectasis (28%), lymphadenopathy (27%), splenomegaly (13%), inflammatory bowel disease (11%), autoimmune cytopenia (10%) and idiopathic thrombocytopenia (6%) were also frequently reported. A bimodal sex distribution was found, with male predominance in children (62%) and female predominance in adults (58%). 25% of CVID-patients developed other manifestations besides infections in childhood, this percentage was much higher in adults (62%). Immune-dysregulation features, such as granulomatous-lymphocytic interstitial lung disease and inflammatory bowel disease, were more prominent in adults.

Conclusions

The shift from male predominance in childhood to female predominance in adults suggests differences in genetic and environmental etiology in CVID and has consequences for pathophysiologic studies. We confirm the high frequency of respiratory infections at presentation, but also show a high incidence of severe bacterial infections such as sepsis and meningitis, and immune dysregulation features including lymphoproliferative, gastrointestinal and autoimmune manifestations. Early detection of CVID may be improved by screening for antibody deficiency in patients with these manifestations.

Population pharmacokinetic modelling of intravenous immunoglobulin in patients with predominantly antibody deficiencies

AIMS

There is considerable interpatient variability in the pharmacokinetics (PK) of intravenous immunoglobulin G (IVIG), causing difficulty in optimizing individual dosage regimen. This study aims to estimate the population PK parameters of IVIG and to investigate the impact of genetic polymorphism of the FcRn gene and clinical variability on the PK of IVIG in patients with predominantly antibody deficiencies.

METHODS

Patients were recruited from four hospitals. Clinical data were recorded and blood samples were taken for PK and genetic studies. Population PK parameters were estimated by nonlinear mixed-effects modelling in Monolix®. Models were evaluated using the difference in objective function value, goodness-of-fit plots, visual predictive check and bootstrap analysis. Monte Carlo simulation was conducted to evaluate different dosing regimens for IVIG.

RESULTS

A total of 30 blood samples were analysed from 10 patients. The immunoglobulin G concentration data were best described by a one-compartment model with linear elimination. The final model included both volume of distribution (Vd) and clearance (CL) based on patient's individual weight. Goodness-of-fit plots indicated that the model fit the data adequately, with minor model mis-specification. Genetic polymorphism of the FcRn gene and the presence of bronchiectasis did not affect the PK of IVIG. Simulation showed that 3-4-weekly dosing intervals were sufficient to maintain IgG levels of 5 g L^-1 , with more frequent intervals needed to achieve higher trough levels.

CONCLUSIONS

Body weight significantly affects the PK parameters of IVIG. Genetic and other clinical factors investigated did not affect the disposition of IVIG.

Perspective: Evolving Concepts in the Diagnosis and Understanding of Common Variable Immunodeficiency Disorders (CVID)

Common variable immunodeficiency disorders (CVID) are the most frequent symptomatic primary immune deficiency in adults. At this time, the causes of these conditions are unknown. Patients with CVID experience immune system failure consequent to late onset antibody failure. They have increased susceptibility to infections and are also at risk of severe autoimmune and inflammatory disorders as a result of immune dysregulation. An increasing number of monogenic causes as well as a digenic disorder have been described in patients with a CVID phenotype. If a causative mutation is identified, patients are removed from the umbrella diagnosis of CVID and are reclassified as having a CVID-like disorder, resulting from a specific mutation. In non-consanguineous populations, next-generation sequencing (NGS) identifies a genetic cause in approximately 25% of patients with a CVID phenotype. It is six years since we published our diagnostic criteria for CVID. There is ongoing debate about diagnostic criteria, the role of vaccine responses and genetic analysis in the diagnosis of CVID. There have been several recent studies, which have addressed some of these uncertainties. Here we review this new evidence from the perspective of our CVID diagnostic criteria and speculate on future approaches, which may assist in identifying and assessing this group of enigmatic disorders.

Somatic mutations and T-cell clonality in patients with immunodeficiency

Common variable immunodeficiency and other late-onset immunodeficiencies often co-manifest with autoimmunity and lymphoproliferation. The pathogenesis of most cases is elusive, as only a minor subset harbors known monogenic germline causes. The involvement of both B and T cells is however implicated. To study whether somatic mutations in CD4+ and CD8+ T cells associate with immunodeficiency, we recruited 17 patients and 21 healthy controls. Eight patients had late-onset common variable immunodeficiency and nine patients other immunodeficiency and/or severe autoimmunity. In total, autoimmunity occurred in 94% and lymphoproliferation in 65%. We performed deep sequencing of 2533 immune-associated genes from CD4+ and CD8+ cells. Deep T-cell receptor beta sequencing was used to characterize CD4+ and CD8+ T-cell receptor repertoires. The prevalence of somatic mutations was 65% in all immunodeficiency patients, 75% in common variable immunodeficiency and 48% in controls. Clonal hematopoiesis-associated variants in both CD4+ and CD8+ cells occurred in 24% of immunodeficiency patients. Results demonstrated mutations in known tumor suppressors, oncogenes, and genes that are critical for immune- and proliferative functions, such as STAT5B (two patients), C5AR1 (two patients), KRAS (one patient), and NOD2 (one patient). Additionally, as a marker of T-cell receptor repertoire perturbation, common variable immunodeficiency patients harbored increased frequencies of clones with identical complementarity determining region 3 sequences despite unique nucleotide sequences when compared to controls. In conclusion, somatic mutations in genes implicated for autoimmunity and lymphoproliferation are common in CD4+ and CD8+ cells of patients with immunodeficiency. They may contribute to immune dysregulation in a subset of immunodeficiency patients.

From infections to autoimmunity: Diagnostic challenges in common variable immunodeficiency

Common variable immunodeficiency (CVID) is the most common clinically significant primary antibody deficiency diagnosed in adults. The early symptoms are not specific. They include common infections, mainly of the respiratory tract, caused by typical microorganisms, so cases can be missed in primary care. In the majority of patients increased susceptibility to infections coexists with signs or symptoms of autoimmunity, inflammation or polyclonal lymphoproliferation, which can divert diagnosis from immune deficiency. The overall incidence of malignancy is increased in CVID and certain cancers are significantly more common. Lymphomas and gastric carcinoma are the most frequently reported malignancies in CVID, so a high index of suspicion is recommended. Diagnostic delay in CVID is seen worldwide. The main goal of this paper is to increase the awareness about CVID among health care professionals. We aim to present features which can be helpful in CVID diagnosis in order to shorten the “latency” of proper management of CVID patients. We review clinical symptoms, complications and laboratory abnormalities of CVID. Immunoglobulin replacement therapy is regarded as the cornerstone of pharmacological intervention. New modes of Ig application, mainly subcutaneously and via the hyaluronidase-facilitated subcutaneous route, help to adjust therapy to patients’ needs and preferences. Still there remain unmet needs. It remains to be seen whether CVID complications can be avoided by earlier diagnosis, treatment and thorough monitoring in the context of increased risk of malignancy. Development of patient tailored protocols depending on the clinical phenotype and risk factors might be more appropriate. The most important consideration is to diagnose suspected cases and stratify patients in a precise and timely way. Work is needed to define features predictive of unfavorable prognosis.

Global Distribution of Common Variable Immunodeficiency (CVID) in the Light of the UNDP Human Development Index (HDI): A Preliminary Perspective of a Rare Disease

Common variable immunodeficiency (CVID), although the most common primary immunodeficiency in humans, is a rare disease. We explored the spatial global distribution and country-wise prevalence of CVID, based on published data and those available from databases. As a country's medical progress is linked to its technological and socio-economic developmental status, we expected that observed CVID prevalence was linked to human wellbeing. To assess this, we examined the correlation of observed CVID prevalence and the UNDP Human Development Index (HDI), which is a key measure of human development. Seventy-four data sets from 47 countries were available (most of them no older than 10 years). Analyses revealed that observed CVID prevalence ranged from 0.001 to 3.374 per 100,000 (mean 0.676 ± 0.83) and was highest in “high” HDI countries (Spearman′s rho = 0.757). Observed prevalence was particularly high in countries where immunodeficiencies are systematically documented in registers. In “low” and “middle” HDI countries, CVID awareness is extremely poor. Assuming that true CVID prevalence does not differ among countries, this study, though preliminary, provides evidence that the discrepancy between observed and (unknown) true prevalence can be clearly linked to the countries' developmental status. As a potential alternative explanation, we briefly discuss the possibility that variation in CVID prevalence is related to human genetic lineage.

Infectious Complications Reporting in Common Variable Immunodeficiency: A Systematic Review and Meta-analysis

Objectives

Common variable immunodeficiency (CVID) is a heterogeneous disorder characterized by hypogammaglobulinemia and increased susceptibility to recurrent infections.

Methods

We searched PubMed, Web of Science, and Scopus databases to find eligible studies from the earliest available date to January 2018 with standard keywords. Pooled estimates of the infection prevalence and the corresponding 95% confidence intervals were calculated using random-effects models.

Results

We found that pneumonia (67.7%) was the most prevalent infection followed by upper respiratory tract (59.0%) and gastrointestinal infections (36.3%). Furthermore, bacterial complications (41.7%) were higher in CVID patients compared to viral (25.4%), parasitic (18.8%), or fungal (3.4%) infections. Patients with longer age at diagnosis presented with fewer disease comorbidities. There was an inverse correlation between T lymphocyte count and viral infections. Moreover, we found that immunoglobulin M (IgM) serum level was inversely correlated with hepatitis C and gastrointestinal infections, and IgG serum level was inversely correlated with infectious arthritis. Higher numbers of CD4 and CD8 T cells were associated with the lower frequencies of otitis media. CVID patients with infections had significantly lower percentages of CD3 T cells. In contrast, higher percentages of CD19 lymphocytes were found in CVID patients who had a history of infections.

Conclusions

Our findings demonstrated that in addition to hypogammaglobulinemia, patients with CVID have an imbalance in the frequency of T lymphocytes, which is in parallel with the higher frequency of infectious complications.

Variable immunodeficiency study: Evaluation of two European cohorts within a variety of clinical phenotypes

INTRODUCTION

Given the wide heterogeneity of common variable immunodeficiency (CVID), several groups have proposed clinical and immunological classifications to better define follow-up and prognostic algorithms. The present study aims to validate recent clinical and laboratory algorithms, based on different combinations of CVID biomarkers, to provide more personalized treatment and follow-up strategies.

METHODS

We analysed clinical and immunological features of 80 patients with suspected or diagnosed CVID, in two reference centres of Portugal and Spain. Clinical manifestations were categorized into clinical phenotyping proposed by Chapel et al. [1] that included cytopenia; polyclonal lymphocytic infiltration; unexplained enteropathy; and no disease-related complications.

RESULTS

76% of patients in our cohort entered one of the four categories of clinical phenotyping, without overlap (cytopenia; polyclonal lymphocytic infiltration; unexplained enteropathy; and no disease-related complications). The most prominent phenotype was "cytopenia" (40%) followed by "polyclonal lymphocytic infiltration" (19%). The remaining 24% patients of our cohort had overlap of 2 clinical phenotypes (cytopenia and unexplained enteropathy mainly). A delay of CVID diagnosis in more than 6 years presented 3.7-fold higher risk of developing lymphoproliferation and/or malignancy (p < 0.05), and was associated with increased CD8⁺CD45RO ⁺ T-lymphocytes (p < 0.05). An association between decreased switched-memory B cells with lymphoproliferation and malignancy was observed (p < 0.03 and p < 0.05, respectively). CD4 ⁺ T-lymphocytopenia correlated with autoimmune phenotype, with 30% prevalence (p < 0.05). HLA-DR7 expression was related to CVID onset in early life in our patients (13 vs 25 years), and DQ2.5 or DQ2.2 with unexplained enteropathy (p < 0.05).

CONCLUSIONS

The phenotypic and genetic study is crucial for an adequate clinical orientation of CVID patients. In these two independent cohorts of patients, classification based in clinical and laboratory algorithms, provides more personalized treatment and follow-up strategies.

Whole exome sequencing identifies compound heterozygous variants of CR2 gene in monozygotic twin patients with common variable immunodeficiency

Objectives:

A pair of female Malay monozygotic twins who presented with recurrent upper respiratory tract infections, hepatosplenomegaly, bronchiectasis and bicytopenia were recruited in this study. Both patients were suspected with primary immunodeficiency diseases. However, the definite diagnosis was not clear due to complex disease phenotypes. The objective of this study was to identify the causative gene mutation in these patients.

Methods:

Lymphocyte subset enumeration test and whole exome sequencing were performed.

Results:

We identified a compound heterozygous CR2 mutation (c.1916G>A and c.2012G>A) in both patients. These variants were then confirmed using Sanger sequencing.

Conclusion:

Whole exome sequencing analysis of the monozygotic twins revealed compound heterozygous missense mutations in CR2.

Defining Common Variable Immunodeficiency Disorders in 2020

Common variable immunodeficiency disorders (CVID) are the most frequent symptomatic primary immune deficiency in adults. Because there is no known cause for these conditions, there is no single clinical feature or laboratory test that can confirm the diagnosis with certainty. If a causative mutation is identified, patients are deemed to have a CVID-like disorder caused by a specific primary immunodeficiency/inborn error of immunity. In the remaining patients, the explanation for these disorders remains unclear. The understanding of CVID continues to evolve and the authors review recent studies, which have addressed some of these uncertainties.

A Systematic Review and Meta-regression Analysis on the Impact of Increasing IgG Trough Level on Infection Rates in Primary Immunodeficiency Patients on Intravenous IgG Therapy

PURPOSE

We conducted a systematic review and meta-regression analysis to evaluate the impact of increasing immunoglobulin G (IgG) trough levels on the clinical outcomes in patients with PID receiving intravenous immunoglobulin G (IVIG) treatment.

METHODS

Systematic search was conducted in PubMed and Cochrane. Other relevant articles were searched by reviewing the references of the reviewed article. All clinical trials with documented IgG trough levels and clinical outcome of interest in patients receiving IVIG treatment were eligible to be included in this review. Meta-regression analysis was conducted using Comprehensive Meta-analysis Software. Additional sensitivity analyses were undertaken to evaluate the robustness of the overall results.

RESULTS

Twenty-eight clinical studies with 1218 patients reported from year 2001 to 2018 were included. The mean IVIG dose used ranges from 387 to 560 mg/kg every 3 to 4 weekly, and mean IgG trough obtained ranges from 660 to 1280 mg/dL. Random-effects meta-regression slope shows that IgG trough level increases significantly by 73 mg/dL with every increase of 100 mg/kg dose of IVIG (p < 0.05). Overall infection rates reduced significantly by 13% with every increment of 100 mg/dL of IgG trough up to 960 mg/dL (p < 0.05).

CONCLUSION

This meta-analysis concludes that titrating the IgG trough levels up to 960 mg/dL progressively reduces the rate of infections, and there is less additional benefit beyond that. Further studies to validate this result are required before it can be used in clinical practice.

Chemical chaperones reverse early suppression of regulatory circuits during unfolded protein response in B cells from common variable immunodeficiency patients

B cells orchestrate pro-survival and pro-apoptotic inputs during unfolded protein response (UPR) to translate, fold, sort, secrete and recycle immunoglobulins. In common variable immunodeficiency (CVID) patients, activated B cells are predisposed to an overload of abnormally processed, misfolded immunoglobulins. Using highly accurate transcript measurements, we show that expression of UPR genes and immunoglobulin chains differs qualitatively and quantitatively during the first 4 h of chemically induced UPR in B cells from CVID patients and a healthy subject. We tested thapsigargin or tunicamycin as stressors and 4-phenylbutyrate, dimethyl sulfoxide and tauroursodeoxycholic acid as chemical chaperones. We found an early and robust decrease of the UPR upon endoplasmic reticulum (ER) stress in CVID patient cells compared to the healthy control consistent with the disease phenotype. The chemical chaperones increased the UPR in the CVID patient cells in response to the stressors, suggesting that misfolded immunoglobulins were stabilized. We suggest that the AMP-dependent transcription factor alpha branch of the UPR is disturbed in CVID patients, underlying the observed expression behavior.

Common Variable Immunodeficiency: A Standardized Patient Case for Second-Year Medical Students

INTRODUCTION

Common variable immunodeficiency (CVID) is the most common symptomatic antibody deficiency, with a prevalence of 0.6-6.9 depending on the population studied. In contrast to other primary immunodeficiency diseases (PIDDs), symptoms may not appear until the third decade of life. Lack of recognition of CVID is a persistent problem. Myriad confounding clinical phenotypes and frequent infections, including autoimmunity, malignancy, chronic lung disease, granulomatous disease, and gastrointestinal disease, complicate the diagnosis. Often it is years before a diagnosis is made, leading to irreversible morbidities and mortality.

METHODS

Second-year medical students are introduced to CVID during their session on PIDDs that occurs during the immunology/rheumatology course. To assess students' recognition of CVID, a 15-minute OSCE encounter was created that included a simulation of lung sounds (rhonchi), physical exam cards (clubbing, otitis media with effusion), and moulage of skin (petechiae). A standardized patient (SP) portrayed a patient requesting antibiotics for a sinus infection. Students were tasked to both interview the patient and perform a hypothesis-driven physical exam. A postencounter exercise queried the students on their differential diagnosis and their rationale.

RESULTS

Item analysis of the case showed high levels of difficulty and strong discrimination between high- and low-performing students in both communication skills and clinical reasoning in CVID.

DISCUSSION

This SP encounter can be used in both formative and summative assessments to measure the recognition of CVID.

Novel Developments in Primary Immunodeficiencies (PID)-a Rheumatological Perspective

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of the most relevant new disorders, disease entities, or disease phenotypes of primary immune deficiency disorders (PID) for the interested rheumatologist, using the new phenotypic classification by the IUIS (International Union of Immunological Societies) as practical guide.

RECENT FINDINGS

Newly recognized disorders of immune dysregulation with underlying mutations in genes pertaining to the function of regulatory T cells (e.g., CTLA-4, LRBA, or BACH2) are characterized by multiple autoimmune diseases-mostly autoimmune cytopenia-combined with an increased susceptibility to infections due to hypogammaglobulinemia. On the other hand, new mutations (e.g., in NF-kB1, PI3Kδ, PI3KR1, PKCδ) leading to the clinical picture of CVID (common variable immmune deficiency) have been shown to increasingly associate with autoimmune diseases. The mutual association of autoimmune diseases with PID warrants increased awareness of immunodeficiencies when diagnosing autoimmune diseases with a possible need to initiate appropriate genetic tests.

How to Identify Common Variable Immunodeficiency Patients Earlier: General Practice Patterns

PURPOSE

Diagnostic delay is a major problem concerning common variable immunodeficiency (CVID). We aimed to determine the pattern of general practitioner (GP) consultations in individuals diagnosed with CVID within 3 years before the diagnosis and whether the risk of diagnosis was associated with the frequency of consultations or character of examinations.

METHODS

We conducted a nested case-control study, identifying 132 adult CVID patients and 5940 age- and gender-matched controls from national registers during 1997-2013. We used conditional logistic regression to calculate the odds ratios (OR) and 95% confidence intervals (95%CI).

RESULTS

The median number of consultations among individuals with CVID was more than twice that of the controls in all 3 years (3rd, 10; 2nd, 11.5; and 1st, 15.4 vs. 4). We found a statistically significant association between the number of consultations and the risk of a subsequent CVID diagnosis, independent of age and gender, but strongest in the individuals < 40 years. In the 3rd year before diagnosis, having 9-15 consultations compared with 1-4 was associated with an OR (95%CI) of 5.0 (2.3-10.9), 2.4 (1.1-5.4), and 1.3 (0.3-5.3) for those aged 18-40, 41-60, and > 60, respectively. Several examinations (i.e., blood tests for inflammation/infection and pulmonary function test) were associated with increased odds of a subsequent CVID diagnosis.

CONCLUSION

The risk of a CVID diagnosis was highly related to both the number of consultations and the character of examinations performed by the GP. CVID should be a differential diagnosis among patients with multiple consultations, especially in patients < 40 years old.

Measuring quantity and function of pneumococcal antibodies in immunoglobulin products

BACKGROUND

Immunoglobulin replacement therapy is a cornerstone of the treatment of primary immunodeficiencies. Preparations used for replacement therapy are processed by purifying immunoglobulins from large pools of plasma, which were obtained from healthy donors. The constituent antibodies in these products depend on the immune history of the donor pool as well as manufacturing processes that differ among manufacturers. For these reasons various methods have been proposed to examine the levels and function of antibodies to organisms such as Streptococcus pneumoniae, which frequently causes infections in patients with immunodeficiencies. Pneumococcal antibody levels or antibody function can be measured with enzyme-linked immunosorbent assay (ELISA) or multiplexed opsonophagocytosis assay (MOPA). Although these assays were developed initially to assess the immunogenicity of pneumococcal vaccines, the techniques have been adapted to evaluate immunoglobulin products as well.

STUDY DESIGN AND METHODS

This article provides a concise review of the analytic techniques for measuring pneumococcal antibodies and prior studies of immunoglobulin products utilizing these methods.

RESULTS

Studies utilizing these assays have demonstrated that antibody levels of immunoglobulin products can vary with time, location, and manufacturer.

CONCLUSIONS

We highlight current issues and future considerations concerning measurement of pneumococcal antibodies in immunoglobulin products, and the assays used for this purpose.

A High Prevalence of Gastrointestinal Manifestations in Common Variable Immunodeficiency

OBJECTIVES

Common variable immunodeficiency (CVID) is associated with a spectrum of autoimmune complications. We studied the prevalence of gastrointestinal (GI) manifestations and infections in patients with CVID.

METHODS

Complete clinical data of 132 Finnish patients with CVID (106 probable and 26 possible CVID) followed up between 2007 and 2016 were collected to a structured database. Data on endoscopies, histology, and laboratory studies were retrieved from patient files.

RESULTS

Most common referral indications were diarrhea and/or weight loss (47%-67%). Patients with probable CVID had higher fecal calprotectin and α1-antitrypsin and lower blood vitamin B12 than patients with possible CVID. Gastroscopy and colonoscopy were done to 71 (67%) and 63 (59%) patients with probable CVID, respectively. Endoscopies showed that 15% of them had chronic active gastritis and 17% atrophic gastritis and 3% had gastric adenocarcinoma. A celiac sprue-like condition was found in 7 patients (10%), of whom 3 responded to a gluten-free diet. Colonoscopies demonstrated unspecific colitis (14%), ulcerative colitis (8%), microscopic colitis (10%), and Crohn's disease (2%). Colonic polyps were noted in 30% of patients, and 3% had lower GI malignancies. Thirty-five patients with CVID had bacterial or parasitic gastroenteritis; chronic norovirus was detected in 4 patients with probable CVID. Patients with GI inflammation had higher levels of fecal calprotectin and blood CD8 T lymphocytes but lower counts of CD19CD27 memory B cells and/or CD19 B cells. Immunophenotype with low B-cell counts was associated with higher fecal calprotectin levels.

DISCUSSION

Patients with CVID had a high prevalence of GI manifestations and infections of the GI tract. GI inflammation was associated with a distinct immunophenotype and elevated fecal calprotectin.

Keeping it in the family: the case for considering late-onset combined immunodeficiency a subset of common variable immunodeficiency disorders

INTRODUCTION

Common variable immunodeficiency disorders (CVID) are the most frequent symptomatic primary immune defect in adults. Within the broad spectrum of CVID, a proportion of patients present with a predominant T cell phenotype associated with increased mortality. These patients are termed late-onset combined immunodeficiency (LOCID) and are currently separated from patients suffering from CVID. Areas covered: We have recently codiscovered a new CVID-like disorder caused by mutations of the NFKB1 gene. Members of this non-consanguineous New Zealand kindred have a very diverse spectrum of phenotypes in spite of carrying the identical mutation. The proband appears to have the autoimmune variant. The proband's recently deceased sister best matched LOCID while other family members are less severely affected, including one asymptomatic adult brother, who has an affected daughter. Differences in genetics was one of the main arguments for separating these disorders in the past. Expert commentary: Given the recent advances in the understanding of the genetic basis of these conditions, we present the case that LOCID should now be considered a subset of CVID, rather than a separate disorder. At a clinical level, this distinction is less important but it is imperative these patients are carefully evaluated, the relevant complications are treated, and they are offered prognostic information.

Delayed Diagnosis and Complications of Predominantly Antibody Deficiencies in a Cohort of Australian Adults

Background

Predominantly antibody deficiencies (PADs) are the most common type of primary immunodeficiency in adults. PADs frequently pass undetected leading to delayed diagnosis, delayed treatment, and the potential for end-organ damage including bronchiectasis. In addition, PADs are frequently accompanied by comorbid autoimmune disease, and an increased risk of malignancy.

Objectives

To characterize the diagnostic and clinical features of adult PAD patients in Victoria, Australia.

Methods

We identified adult patients receiving, or having previously received immunoglobulin replacement therapy for a PAD at four hospitals in metropolitan Melbourne, and retrospectively characterized their clinical and diagnostic features.

Results

179 patients from The Royal Melbourne, Alfred and Austin Hospitals, and Monash Medical Centre were included in the study with a median age of 49.7 years (range: 16–87 years), of whom 98 (54.7%) were female. The majority of patients (116; 64.8%) met diagnostic criteria for common variable immunodeficiency (CVID), and 21 (11.7%) were diagnosed with X-linked agammaglobulinemia (XLA). Unclassified hypogammaglobulinemia (HGG) was described in 22 patients (12.3%), IgG subclass deficiency (IGSCD) in 12 (6.7%), and specific antibody deficiency (SpAD) in 4 individuals (2.2%). The remaining four patients had a diagnosis of Good syndrome (thymoma with immunodeficiency). There was no significant difference between the age at diagnosis of the disorders, with the exception of XLA, with a median age at diagnosis of less than 1 year. The median age of reported symptom onset was 20 years for those with a diagnosis of CVID, with a median age at diagnosis of 35 years. CVID patients experienced significantly more non-infectious complications, such as autoimmune cytopenias and lymphoproliferative disease, than the other antibody deficiency disorders. The presence of non-infectious complications was associated with significantly reduced survival in the cohort.

Conclusion

Our data are largely consistent with the experience of other centers internationally, with clear areas for improvement, including reducing diagnostic delay for patients with PADs. It is likely that these challenges will be in part overcome by continued advances in implementation of genomic sequencing for diagnosis of PADs, and with that opportunities for targeted treatment of non-infectious complications.