A decreased frequency of regulatory T cells in patients with common variable immunodeficiency

Gene Signature of Regulatory T Cells Isolated from Children with Selective IgA Deficiency and Common Variable Immunodeficiency

Selective IgA deficiency (SIgAD) is the most common form and common variable immunodeficiency (CVID) is the most symptomatic form of predominant antibody deficiency. Despite differences in the clinical picture, a similar genetic background is suggested. A common feature of both disorders is the occurrence of autoimmune conditions. Regulatory T cells (Tregs) are the major immune cell type that maintains autoimmune tolerance. As the different types of abnormalities of Treg cells have been associated with autoimmune disorders in primary immunodeficiency (PID) patients, in our study we aimed to analyze the gene expression profiles of Treg cells in CVID and SIgAD patients compared to age-matched healthy controls. The transcriptome-wide gene profiling was performed by microarray technology. As a result, we analyzed and visualized gene expression patterns of isolated population of Treg cells. We showed the differences at the gene level between patients with and without autoimmunizations. Our findings suggest that the gene signatures of Treg cells isolated from SIgAD and CVID patients differ from age-matched healthy controls and from each other, presenting transcriptional profiles enriched in innate immune or Th response, respectively. The occurrence of autoimmunity in both types of PID is associated with down-regulation of class I IFNs signaling pathways. In summary, our findings improve our understanding of Treg dysfunctions in patients with common PIDs and associated autoimmunity.

Regulatory T cell frequency in peripheral blood of women with advanced cervical Cancer including women living with HIV

BACKGROUND

Persistent high-risk Human papillomavirus (HR-HPV) infections are the main cause of cervical cancer. Cumulative evidence implicates regulatory T cells (Tregs) as a critical factor in the failure to eliminate HPV-induced cancers leading to their persistence and progression to cancer. Also, the WHO recognised cervical cancer as 100% attributable to persistent HR-HPV infection. The province of KwaZulu-Natal (KZN) in South Africa has a high prevalence of cervical cancer and HIV infection.

MATERIALS AND METHODS

We evaluated Treg frequency in dual infection of HR HPV and HIV coinfection using phenotypic markers, CD4, CD25 and intracellular Foxp3, in the peripheral blood of 51 cervical cancer and 46 non-cervical cancer participants and evaluated the effect of HIV on regulatory T cell proportion. Peripheral blood mononuclear cells were surface stained with a cocktail fluorescent labelled CD4 and CD25 and subsequently with APC anti-human FoxP3 (eBioscience). Flow cytometry was performed with FACS analysis. Statistical analysis of results was done using Instat 3 program (GraphpadR). Tregs results were expressed as median ± interquartile range (IQR). Associations of cervical cancer with demographic, clinical and laboratory variables were evaluated by univariate and multivariate logistic regression analysis using SPSS version 27 (IBM).

RESULTS

Tregs frequency was significantly higher in individuals with cervical cancer (11.00 ± 19.79%) compared to controls (1.71 ± 8.91%) (p < 0.0001). HIV infection was associated with an increase in Tregs frequency. In controls a significant difference in Tregs frequency was noted between women living with HIV (6.00 ± 10.57%, n = 9) and those without HIV (1.30 ± 6.10%, n = 37), p = 0.0023. In multivariate logistic regression, Tregs frequency was significantly associated with cervical cancer after controlling for age, smoking, weight loss, presence of STI, HIV and HPV genotype.

DISCUSSION/CONCLUSION

Higher Tregs frequency was significantly associated with cervical cancer highlighting the immunosuppressive role of Tregs in cervical cancer. Treg frequency was more strongly associated with cervical cancer than HIV infection. We provide baseline data for monitoring Treg frequencies in response to new preventive and therapeutic strategies in the management of cervical cancer.

Members of the Regulatory Lymphocyte Club in Common Variable Immunodeficiency

The role of CD4 T regulatory cells is well established in peripheral tolerance and the pathogenesis of the murine model and human autoimmune diseases. CD4 T regulatory cells (CD4 Tregs) have been investigated in common variable immunodeficiency (CVID). Recently, additional members have been added to the club of regulatory lymphocytes. These include CD8 T regulatory (CD8 Tregs), B regulatory (Bregs), and T follicular helper regulatory (T_FR) cells. There are accumulating data to suggest their roles in both human and experimental models of autoimmune disease. Their phenotypic characterization and mechanisms of immunoregulation are evolving. Patients with CVID may present or are associated with an increased frequency of autoimmunity and autoimmune diseases. In this review, we have primarily focused on the characteristics of CD4 Tregs and new players of the regulatory club and their changes in patients with CVID in relation to autoimmunity and emphasized the complexity of interplay among various regulatory lymphocytes. We suggest future careful investigations of phenotypic and functional regulatory lymphocytes in a large cohort of phenotypic and genotypically defined CVID patients to define their role in the pathogenesis of CVID and autoimmunity associated with CVID.

Immunophenotypic and functional analysis of lymphocyte subsets in common variable immunodeficiency patients without monogenic defects

Common variable immunodeficiency (CVID) is accompanied by various lymphocyte abnormalities believed to be mostly responsible for disease features in patients with no diagnosed monogenic defects. Here, we evaluated the association of B and T lymphocyte abnormalities with the incidence of CVID. Twenty-six genetically unsolved CVID patients were examined for B and T lymphocyte subsets by flow cytometry and CD4⁺ T cell proliferation by Carboxyfluorescein succinimidyl ester (CFSE) test. We detected a reduction in total, naive, memory B cells and plasmablasts, and also total, naive, central memory and regulatory CD4⁺ T cells, besides naive CD8⁺ T cells. There were an increase in CD21^low and transitional B cells, effector memory (EM) and terminally differentiated effector memory (T_EMRA ) CD4⁺ T cell subsets as well as total, EM, T_EMRA , activated and cytotoxic CD8⁺ T cells among non-monogenic CVID patients. CD4⁺ T cells proliferation response was reduced regarding both division index and percent divided. In conclusion, regarding the similarity of lymphocyte abnormalities between patients without genetic defects and those with monogenic defects, genetic mutations are not responsible for these specific lymphocyte changes. However, the novel correlations observed between lymphocyte alterations among genetically unsolved CVID patients may serve as a guide to predict the potential of future CVID development for hypogammaglobulinemia children.

Lymphocytes subsets in correlation with clinical profile in CVID patients without monogenic defects

Objectives: Common variable immunodeficiency (CVID) patients experience clinical manifestations rather than recurrent respiratory infections including autoimmunity, enteropathy, and lymphoproliferation. We evaluated the correlation of lymphocyte subpopulations with such manifestations.Methods: Twenty-six genetically unsolved CVID patients were subdivided into four phenotypes: infection only (IO), autoimmunity (AI), chronic enteropathy (CE), and lymphoproliferative disorders (LP) and examined for lymphocyte subsets by flow cytometry and TCD4⁺ proliferation by Carboxyfluorescein succinimidyl ester (CFSE) test.Results: We detected reduced memory B and increased total, effector memory (EM), cytotoxic, and activated TCD8⁺ in IO, AI and CE, decreased plasmablasts, total and naive TCD4⁺, Regulatory TCD4⁺ (Treg) and naive TCD8⁺ in IO and CE, elevated CD21^low B and terminally differentiated effector memory (T_EMRA) TCD8⁺ in IO and AI, increased helper T (Th2) and Th17 in IO, decreased Th1 in AI and defective total and naive B and central memory (CM) TCD4⁺ in CE. IO showed reduced TCD4⁺ proliferation response.Conclusions: In genetically unsolved CVID patients, increased Th2 and Th17 and reduced Treg is associated with IO, increased CD21^low B and T_EMRA TCD8⁺ and reduced Th1 is contributed to AI and reduced total and naive B, CM TCD4⁺ and naive TCD8⁺ and expanded total TCD8⁺ is correlated with CE.

Beyond monogenetic rare variants: tackling the low rate of genetic diagnoses in predominantly antibody deficiency

Predominantly antibody deficiency (PAD) is the most prevalent form of primary immunodeficiency, and is characterized by broad clinical, immunological and genetic heterogeneity. Utilizing the current gold standard of whole exome sequencing for diagnosis, pathogenic gene variants are only identified in less than 20% of patients. While elucidation of the causal genes underlying PAD has provided many insights into the cellular and molecular mechanisms underpinning disease pathogenesis, many other genes may remain as yet undefined to enable definitive diagnosis, prognostic monitoring and targeted therapy of patients. Considering that many patients display a relatively late onset of disease presentation in their 2nd or 3rd decade of life, it is questionable whether a single genetic lesion underlies disease in all patients. Potentially, combined effects of other gene variants and/or non-genetic factors, including specific infections can drive disease presentation. In this review, we define (1) the clinical and immunological variability of PAD, (2) consider how genetic defects identified in PAD have given insight into B-cell immunobiology, (3) address recent technological advances in genomics and the challenges associated with identifying causal variants, and (4) discuss how functional validation of variants of unknown significance could potentially be translated into increased diagnostic rates, improved prognostic monitoring and personalized medicine for PAD patients. A multidisciplinary approach will be the key to curtailing the early mortality and high morbidity rates in this immune disorder.

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.

Preserved Cellular Immunity Upon Influenza Vaccination in Most Patients with Common Variable Immunodeficiency

BACKGROUND

Vaccination against influenza is recommended for patients with common variable immunodeficiency (CVID), although humoral immune responses in these patients are impaired and the evidence of effective T-cell responses in CVID is not well established.

OBJECTIVE

To determine plasmablast and T-cellular vaccination responses against influenza in patients with CVID.

METHODS

Patients with CVID and healthy controls were vaccinated with the quadrivalent vaccine Influsplit Tetra 2018/2019. Before and 1 week after vaccination plasmablasts and circulating inducible costimulator-expressing T follicular helper cells were measured to determine positive vaccine responses in these patients. In addition, antigen-specific T cells were determined by their upregulation of CD25 and OX40 after in vitro restimulation with the vaccine.

RESULTS

Most healthy controls but only 1 patient with CVID mounted a positive humoral immune response, measured by an increase in plasmablasts 1 week after vaccination. In contrast, most patients with CVID showed an increase in inducible costimulator⁺ T follicular helper cells and/or an increase in antigen-specific CD25⁺OX40⁺ T cells 1 week after vaccination, demonstrating a positive T-cellular immune response.

CONCLUSIONS

Despite the remaining challenge of accurately assessing the complexity of T-cell responses, the recommendation of vaccinating patients with CVID against influenza is reasonable.

Predominantly Antibody-Deficient Patients With Non-infectious Complications Have Reduced Naive B, Treg, Th17, and Tfh17 Cells

Background: Patients with predominantly antibody deficiency (PAD) suffer from severe and recurrent infections that require lifelong immunoglobulin replacement and prophylactic antibiotic treatment. Disease incidence is estimated to be 1:25,000 worldwide, and up to 68% of patients develop non-infectious complications (NIC) including autoimmunity, which are difficult to treat, causing high morbidity, and early mortality. Currently, the etiology of NIC is unknown, and there are no diagnostic and prognostic markers to identify patients at risk.

Objectives: To identify immune cell markers that associate with NIC in PAD patients.

Methods: We developed a standardized 11-color flow cytometry panel that was utilized for in-depth analysis of B and T cells in 62 adult PAD patients and 59 age-matched controls.

Results: Nine males had mutations in Bruton's tyrosine kinase (BTK) and were defined as having X-linked agammaglobulinemia. The remaining 53 patients were not genetically defined and were clinically diagnosed with agammaglobulinemia (n = 1), common variable immunodeficiency (CVID) (n = 32), hypogammaglobulinemia (n = 13), IgG subclass deficiency (n = 1), and specific polysaccharide antibody deficiency (n = 6). Of the 53, 30 (57%) had one or more NICs, 24 patients had reduced B-cell numbers, and 17 had reduced T-cell numbers. Both PAD–NIC and PAD+NIC groups had significantly reduced Ig class-switched memory B cells and naive CD4 and CD8 T-cell numbers. Naive and IgM memory B cells, Treg, Th17, and Tfh17 cells were specifically reduced in the PAD+NIC group. CD21^lo B cells and Tfh cells were increased in frequencies, but not in absolute numbers in PAD+NIC.

Conclusion: The previously reported increased frequencies of CD21^lo B cells and Tfh cells are the indirect result of reduced naive B-cell and T-cell numbers. Hence, correct interpretation of immunophenotyping of immunodeficiencies is critically dependent on absolute cell counts. Finally, the defects in naive B- and T-cell numbers suggest a mild combined immunodeficiency in PAD patients with NIC. Together with the reductions in Th17, Treg, and Tfh17 numbers, these key differences could be utilized as biomarkers to support definitive diagnosis and to predict for disease progression.

Differential immunomodulation of T-cells by immunoglobulin replacement therapy in primary and secondary antibody deficiency

Patients with primary or secondary antibody deficiency (PAD or SAD) are at increased risk of recurrent infections that can be alleviated by immunoglobulin replacement therapy (IRT). In addition to replenishing antibody levels, IRT has been suggested to modulate immune response in patients with antibody deficiency. Although both commonly treated with IRT, the underlying causes of PAD and SAD vary greatly, suggesting differential modulation of T-cell function that may lead to different responses to IRT. To explore this, peripheral blood mononuclear cells (PBMCs) were sampled from 17 PAD and 14 SAD patients before and 2–10 months after initiation of IRT, and analyzed for changes in T-cell phenotype and function. Proportions of CD4, CD8, Treg, or memory T-cells did not significantly change post-IRT compared to pre-IRT. However, we report distinct modulation in T-cell function between PAD and SAD patients post-IRT. Upon α-CD3/CD28 stimulation, proportion of IFN-γ+ CD4 and CD8 T-cells increased in SAD (p = 0.005) but not PAD patients post-IRT compared to baseline. Interestingly, total T-cell proliferation was reduced post-IRT in both PAD and SAD patients, although the reduction in proliferation was primarily due to reduced CD4 T-cell proliferation in PAD (p = 0.025) in contrast to CD8 T-cells in SAD (p = 0.042). In summary, even though IRT provides patients with passive humoral immunity-mediated protection in PAD and SAD, our findings suggest that IRT immunomodulation of T-cells is different in T-cell subsets depending on underlying immunodeficiency.

Phenotypic Analysis of CD4+ Treg, CD8+ Treg, and Breg Cells in Adult Common Variable Immunodeficiency Patients

INTRODUCTION

Regulatory lymphocytes (CD4+ T regulatory cells [Treg], CD8+ Treg, and B regulatory cells [Breg]) play a critical role in immune homeostasis and tolerance. Common variable immunodeficiency (CVID) is associated with increased susceptibility to infections and increased frequency of inflammatory and autoimmune diseases. CD4+ Treg cell abnormalities have been reported in CVID; however, CD8+ Treg cells have not been reported in CVID. The objective of this study was to evaluate CD4+ Treg and CD8+ Treg cells in CVID patients.

METHODS

In 25 patients with CVID and age-matched healthy controls, Treg cells, evaluated in freshly isolated peripheral blood mononuclear cells (natural; nCD4+ Treg and nCD8+ Treg) and following in vitro activation with anti-CD3/CD28 monoclonal antibodies (induced; iCD4+ Treg and iCD8+ Treg) as well as Breg cells were analyzed with specific monoclonal antibodies and isotype controls using flow cytometry.

RESULTS

The proportions of nCD4+ Treg (CD4+ CD127low CD25high FoxP3+), iCD4+ Treg (CD4+ CD127low CD25high FoxP3+), iCD8+ Treg (CD8+ CD25high CD183+ FoxP3+), and Breg (CD19+ CD24high CD38high) lymphocytes were significantly lower in patients with CVID than in controls.

CONCLUSIONS

Altered regulatory lymphocytes may play a role in the pathogenesis and autoimmunity and inflammation associated with CVID.

Factors Beyond Lack of Antibody Govern Pulmonary Complications in Primary Antibody Deficiency

PURPOSE

Pulmonary complications occur frequently in primary antibody deficiency (PAD). While the impact of antibody deficiency may appear implicit for certain respiratory infections, immunoglobulin replacement therapy does not completely ameliorate pulmonary complications in PAD. Thus, there may be antibody-independent factors influencing susceptibility to respiratory disease in PAD, but these remain incompletely defined.

METHODS

We harnessed the multicenter US Immunodeficiency Network primary immunodeficiency registry to compare prevalence of asthma, bronchiectasis, interstitial lung disease (ILD), and respiratory infections between two forms of PAD: common variable immunodeficiency (CVID) and x-linked agammaglobulinemia (XLA). We also defined the clinical and immunological characteristics associated with ILD and asthma in CVID.

RESULTS

Asthma, bronchiectasis, ILD, pneumonia, and upper respiratory infections were more prevalent in CVID than XLA. ILD was associated with autoimmunity, bronchiectasis, and pneumonia as well as fewer B and T cells in CVID. Asthma was the most common chronic pulmonary complication and associated with lower IgA and IgM in CVID. Age of symptom onset or CVID diagnosis was unrelated with ILD or asthma.

CONCLUSION

Despite having less severe immunoglobulin deficiency than XLA, respiratory infections, ILD, and asthma were more common in CVID. Among CVID patients, ILD was associated with autoimmunity and reduced lymphocytes and asthma with lower immunoglobulins. Though our results are tempered by registry limitations, they provide evidence that factors beyond lack of antibody promote pulmonary complications in PAD. Efforts to understand how genetic etiology, nature of concurrent T cell deficiency, and propensity for autoimmunity shape pulmonary disease may improve treatment of PAD.

Aberrant Peripheral Immune Function in a Good Syndrome Patient

Good's syndrome (GS) is often accompanied by recurrent respiratory infections and chronic diarrhea. The main purpose was to evaluate the peripheral immune status of a GS patient after thymoma resection. Twenty healthy volunteers were recruited as healthy controls (HCs). Flow cytometry was applied to determine the proportions of circuiting CD4⁺ T cells, CD8⁺ T cells, γδT cells, and regulatory T (Treg) cells in our GS patient. We also examined the proliferation capability of ex vivo CD4⁺ T cells and detected the levels of cytokines interferon- (IFN-) γ and interleukin-17A secreted by ex vivo immune cells from this GS patient. Compared with healthy control subjects, this GS patient had fewer B cells, an inverted ratio of CD4⁺/CD8⁺ cells, and more Treg cells in his peripheral blood. Additionally, the patient's Vδ2 T cell levels were significantly decreased despite having a normal percentage of γδT cells. Ex vivo peripheral CD4⁺ T cells from the patient showed insufficient proliferation and division potential as well as excessive expression of PD-1. Moreover, IFN-γ was predominantly derived from CD8⁺ T cells in this GS patient, rather than from CD4⁺ T cells and γδT cells. This GS patient had impaired T and B cell immunological alternations and cytokine disruptions after thymectomy. Detailed research should focus on therapies that can adjust the immune status in such patients for a better outcome.

Elizabethkingia miricola as an opportunistic oral pathogen associated with superinfectious complications in humoral immunodeficiency: a case report

BACKGROUND

Elizabethkingia miricola is a rare Gram-negative bacterium found in water and clinical specimens. Typical culturing methods often misidentify Elizabethkingia spp. as Flavobacterium or Chryseobacterium. Although diagnosis is based on culturing samples taken from sterile sites, such as blood, a proper identification of this bacterium requires an expertise that goes beyond the capabilities of a typical clinical laboratory.

CASE PRESENTATION

A 35-year-old woman diagnosed with common variable immunodeficiency was admitted to our center. Previous treatment with antibiotics (amoxicillin plus clavulanate, first and third generation of cephalosporins, macrolides) and systemic corticosteroids (up to 120 mg/day of prednisolone) failed to arrest the spread of inflammation. Gingival recession was observed in her oral cavity, resulting in an apparent lengthening of her teeth. In addition to typical commensal bacteria, including streptococci and neisseriae, strains of Rothia mucilaginosa and Elizabethkingia miricola were identified upon a detailed microbiological examination using a MALDI-TOF MS Biotyper system. The presence of the latter strain correlated with severe periodontitis, lack of IgA in her saliva and serum, a very low IgG concentration (< 50 mg/dl), IgM-paraproteinemia, decreases in C3a and C5a and microvascular abnormality. High-dose immunoglobulin (to maintain IgG > 500 mg/dl) and targeted levofloxacin treatment resulted in immune system reconstitution, oral healing, and eradication of the Elizabethkingia infection.

CONCLUSIONS

E. miricola rarely causes disease in healthy individuals. However, the overgrowth of commensal bacteria, lack of IgG/IgA, microvasculopathy and complement cascade activation in patients with humoral immunodeficiency may facilitate Elizabethkingia invasion. Overuse of antibiotics, particularly beta-lactams, may cause mucosal colonization by E. miricola, followed by its multiplication combined with periodontitis that prompts bacterial translocation. MALDI-TOF Biotyper analysis may become a method of choice for identification of Elizabethkingia infections.

Terminally differentiated memory T cells are increased in patients with common variable immunodeficiency and selective IgA deficiency

Introduction

Previous studies showed that several lymphocyte abnormalities seen in the most frequent symptomatic immunoglobulin deficiency, common variable immunodeficiency (CVID), were also observed in a genetically related asymptomatic disorder - selective IgA deficiency (IgAD). In this study we searched for abnormalities in the differentiation stages of T cells as well as for similarities of these abnormalities in CVID and IgAD patients.

Material and methods

Using flow cytometry in 80 patients with IgAD, 48 patients with CVID, and 80 control persons we determined T-lymphocyte subsets: both CD4 and CD8 were divided into the naïve CD45RO^-CD27⁺, early differentiated CD45RO⁺CD27⁺, late differentiated CD45RO⁺CD27^- and fully differentiated effector CD45RO^-CD27^- memory T cells, as well as Treg cells, defined as CD4⁺CD25highCD127low T cells.

Results

An increase of CD4⁺ and CD8⁺ late differentiated memory cells was observed comparing CVID patients to controls, as well as comparing IgAD patients to controls. In CVID patients an increase of CD4⁺ early differentiated memory cells, a decrease of CD8⁺ intermediate memory cells, and CD4⁺ and CD8⁺ naïve cells were found as well. The abnormalities in IgAD patients might be explained by higher CMV seropositivity observed in our IgAD. We confirmed the repeatedly published decrease of Treg cells in CVID patients, while Treg cells in IgAD patients were increased compared to controls.

Conclusions

Our results show T-cell activation not only in CVID, but also in IgAD patients. The increase in IgAD patients may be influenced by a more frequent CMV infection in our group of IgAD patients.

Modulatory Effects of Antibody Replacement Therapy to Innate and Adaptive Immune Cells

Intravenous immunoglobulin administered at replacement dosages modulates innate and adaptive immune cells in primary antibody deficiencies (PAD) in a different manner to what observed when high dosages are used or when their effect is analyzed by in vitro experimental conditions. The effects seem to be beneficial on innate cells in that dendritic cells maturate, pro-inflammatory monocytes decrease, and neutrophil function is preserved. The effects are less clear on adaptive immune cells. IVIg induced a transient increase of Treg and a long-term increase of CD4 cells. More complex and less understood is the interplay of IVIg with defective B cells of PAD patients. The paucity of data underlies the need of more studies on patients with PAD before drawing conclusions on the in vivo mechanisms of action of IVIg based on in vitro investigations.

FDG PET-CT imaging of therapeutic response in granulomatous lymphocytic interstitial lung disease (GLILD) in common variable immunodeficiency (CVID)

Common variable immunodeficiency (CVID) is the most common severe adult primary immunodeficiency and is characterized by a failure to produce antibodies leading to recurrent predominantly sinopulmonary infections. Improvements in the prevention and treatment of infection with immunoglobulin replacement and antibiotics have resulted in malignancy, autoimmune, inflammatory and lymphoproliferative disorders emerging as major clinical challenges in the management of patients who have CVID. In a proportion of CVID patients, inflammation manifests as granulomas that frequently involve the lungs, lymph nodes, spleen and liver and may affect almost any organ. Granulomatous lymphocytic interstitial lung disease (GLILD) is associated with a worse outcome. Its underlying pathogenic mechanisms are poorly understood and there is limited evidence to inform how best to monitor, treat or select patients to treat. We describe the use of combined 2-[(18)F]-fluoro-2-deoxy-d-glucose positron emission tomography and computed tomography (FDG PET-CT) scanning for the assessment and monitoring of response to treatment in a patient with GLILD. This enabled a synergistic combination of functional and anatomical imaging in GLILD and demonstrated a widespread and high level of metabolic activity in the lungs and lymph nodes. Following treatment with rituximab and mycophenolate there was almost complete resolution of the previously identified high metabolic activity alongside significant normalization in lymph node size and lung architecture. The results support the view that GLILD represents one facet of a multi-systemic metabolically highly active lymphoproliferative disorder and suggests potential utility of this imaging modality in this subset of patients with CVID.

IL-10-Producing Regulatory B Cells Are Decreased in Patients with Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is the most prevalent symptomatic primary immunodeficiency in adults. CVID patients often present changes in the frequency and function of B lymphocytes, reduced number of Treg cells, chronic immune activation, recurrent infections, high incidence of autoimmunity and increased risk for malignancies. We hypothesized that the frequency of B10 cells would be diminished in CVID patients because these cells play an important role in the development of Treg cells and in the control of T cell activation and autoimmunity. Therefore, we evaluated the frequency of B10 cells in CVID patients and correlated it with different clinical and immunological characteristics of this disease. Forty-two CVID patients and 17 healthy controls were recruited for this study. Cryopreserved PBMCs were used for analysis of T cell activation, frequency of Treg cells and characterization of B10 cells by flow cytometry. IL-10 production by sorted B cells culture and plasma sCD14 were determined by ELISA. We found that CVID patients presented decreased frequency of IL-10-producing CD24^hiCD38^hi B cells in different cell culture conditions and decreased frequency of IL-10-producing CD24^hiCD27⁺ B cells stimulated with CpG+PIB. Moreover, we found that CVID patients presented lower secretion of IL-10 by sorting-purified B cells when compared to healthy controls. The frequency of B10 cells had no correlation with autoimmunity, immune activation and Treg cells in CVID patients. This work suggests that CVID patients have a compromised regulatory B cell compartment which is not correlated with clinical and immunological characteristics presented by these individuals.

Common variable immunodeficiency associated with microdeletion of chromosome 1q42.1-q42.3 and inositol 1,4,5-trisphosphate kinase B (ITPKB) deficiency

Common variable immunodeficiency (CVID) is a heterogenous disorder characterized by hypogammaglobulinemia and impaired specific antibody response and increased susceptibility to infections, autoimmunity and malignancies. A number of gene mutations, including ICOS, TACI and BAFF-R, and CD19, CD20, CD21, CD81, MSH5 and LRBA have been described; however, they account for approximately 20–25% of total cases of CVID. In this study, we report a patient with CVID with an intrinsic microdeletion of chromosome 1q42.1-42.3, where gene for inositol 1,3,4, trisphosphate kinase β (ITPKB) is localized. ITPKB has an important role in the development, survival and function of B cells. In this subject, the expression of ITPKB mRNA as well as ITKPB protein was significantly reduced. The sequencing of ITPKB gene revealed three variants, two of them were missense variants and third was a synonymous variant; the significance of each of them in relation to CVID is discussed. This case suggests that a deficiency of ITPKB may have a role in CVID.

CD4+CD25+Foxp3+ T regulatory cells, Th1 (CCR5, IL-2, IFN-γ) and Th2 (CCR4, IL-4, Il-13) type chemokine receptors and intracellular cytokines in children with common variable immunodeficiency

Common variable immunodeficiency (CVID) is a heterogeneous group of primary antibody deficiencies characterized by decreased serum immunoglobulin G along with a decrease in serum IgA and/or IgM, defective specific antibody production, and recurrent bacterial infections. Abnormal lymphocyte trafficking, dysregulated cellular responses to chemokines, and uncontrolled T cell polarization may be involved in the pathogenesis and may help to understand the clinical complications. We evaluated T helper cell subsets (chemokine receptors CCR4, CCR5, and CCR7), expressions on T lymphocytes, intracellular cytokines - IL-2, IL-4, IL-13, IFN- γ-on CD4(+) T cells, and expression of CD4(+)CD25(+)Foxp3(+) regulatory T cells of 20 CVID patients and 26 healthy controls. Autoimmune clinical findings and other complications were also determined. Percentages and absolute numbers of CD4(+)CD25(+) Foxp3(+) cells did not show any significant difference between CVID cases and healthy controls nor between severe and moderate disease patients. The only significant difference regarding Th1 and Th2 type intracellular cytokines was the decreased absolute numbers of CD3(+)CD4(+)IL4(+) cells in CVID cases. There were some findings about T helper cell type dominance in CVID patients such as positive correlation between hepatomegaly and high IL-2 and IFN-γ in CD3(+)CD4(+) cells and very high expression of CCR5 (Th1) on CD3(+)CD4(+) cells in patients with granuloma. Th1 (CCR5) and Th2 (CCR4) type chemokine receptors did not show any dominance in CVID cases. However, frequencies of CCR7 expressing CD3(+) T cells, CD3(+)CD4(+) T helper cells and CD3(+)CD8(+) T cytotoxic cells were significantly lower in severe CVID patients. In addition, presence of autoimmune clinical findings was negatively correlated with CCR7(+) cells. As CCR7 is a key mediator balancing immunity and tolerance in the immune system, the abnormality of this mediator may contribute to the profound immune dysregulation seen in CVID. In addition, Th1 cells seem to be more involved in the disease pathogenesis than Th2 cells.

Common Variable Immunodeficiency: Diagnosis, Management, and Treatment

Common variable immunodeficiency (CVID) refers to a grouping of antibody deficiencies that lack a more specific genetic or phenotypic classification. It is the immunodeficiency classification with the greatest number of constituents, likely because of the numerous ways in which antibody production can be impaired and the frequency in which antibody production becomes impaired in human beings. CVID comprises a heterogeneous group of rare diseases. Consequently, CVID presents a significant challenge for researchers and clinicians. Despite these difficulties, both our understanding of and ability to manage this grouping of complex immune diseases has advanced significantly over the past 60 years.

Differences in Anti-Inflammatory Actions of Intravenous Immunoglobulin between Mice and Men: More than Meets the Eye

Intravenous immunoglobulin (IVIg) is a therapeutic preparation of polyspecific human IgGs purified from plasma pooled from thousands of individuals. When administered at a high dose, IVIg inhibits inflammation and has proven efficacy in the treatment of various autoimmune and systemic inflammatory diseases. Importantly, IVIg therapy can ameliorate both auto-antibody-mediated and T-cell mediated immune pathologies. In the last few decades, extensive research in murine disease models has resulted in the elucidation of two novel anti-inflammatory mechanisms-of-action of IVIg: induction of FcγRIIB expression by sialylated Fc, and stimulation of regulatory T cells. Whereas controversial findings in mice studies have recently inspired intense scientific debate regarding the validity of the sialylated Fc-FcγRIIB model, the most fundamental question is whether these anti-inflammatory mechanisms of IVIg are operational in humans treated with IVIg. In this review, we examine the evidence for the involvement of these anti-inflammatory mechanisms in the therapeutic effects of IVIg in humans. We demonstrate that although several elements of both immune-modulatory pathways of IVIg are activated in humans, incorrect extrapolations from mice to men have been made on the molecular and cellular components involved in these cascades that warrant for critical re-evaluation of these anti-inflammatory mechanisms of IVIg in humans.

Persistent Immune Activation in CVID and the Role of IVIg in Its Suppression

Common variable immunodeficiency (CVID) is one of the most common and clinically important primary immune deficiencies. CVID patients have poor humoral immunity, resulting in recurrent infections of the gastrointestinal and upper respiratory tracts, as well as increased incidence of some forms of cancers and autoimmune diseases. The treatment for CVID is IgG replacement, often given as intravenous immunoglobulins (IVIg). IVIg consists of monomeric IgG purified from pooled plasma from healthy donors and is used to treat an increasing number of conditions including autoimmune diseases. In the case of CVID, IVIg has mainly been seen as reconstitution therapy, providing patients with pathogen-specific antibodies. Recent evidence shows that IVIg has diverse effects on the immune system of CVID patients, and one important component is that IVIg alleviates the state of chronic immune activation. In this review, we will discuss causes and consequences of persistent immune activation in CVID, possible underlying mechanisms for how IVIg treatment reduces immune activation, and implications for our understanding of primary as well as acquired immune deficiencies.

CT screening for pulmonary pathology in common variable immunodeficiency disorders and the correlation with clinical and immunological parameters

BACKGROUND

Pulmonary disease is common in patients with common variable immunodeficiency disorders (CVID) and involves infections, chronic airway disease and interstitial lung disease. Chronic pulmonary disease is associated with excess morbidity and early mortality and therefore early detection and monitoring of progression is essential.

METHODS AND PURPOSE

Thin slice CT scan and pulmonary function were used to determine the prevalence and spectrum of chronic (pre-clinical) pulmonary disease in adult CVID patients regardless of symptoms. CT Scans were scored for airway abnormalities (AD) and interstitial lung disease (ILD). Other CVID related complications and B and T lymphocyte subsets were analyzed to identify patients at risk for pulmonary disease.

RESULTS

Significant pulmonary abnormalities were detected in 24 of the 47 patients (51%) consisting of AD in 30% and ILD in 34% of cases. In only 7 (29%) of these 24 patients pulmonary function test proved abnormal. The presence of AD was correlated to (recurrent) lower respiratory tract infections despite IgG therapy. The presence of ILD was correlated to autoimmune disease and a reduction in the numbers of CD4 + T cells, naïve CD4 + T cells, naïve CD8 + T cells and memory B cells and lower IgG through levels over time.

CONCLUSION

Preclinical signs of AD and ILD are common in CVID patients despite Ig therapy and do not correlate to pulmonary function testing. Patients at risk for ILD might be identified by the presence of autoimmunity or a deranged T cell pattern. Larger studies are needed to confirm these findings and to determine thresholds for the T lymphocyte subsets.

The variable in common variable immunodeficiency: a disease of complex phenotypes

Common variable immunodeficiency (CVID) is the most common and clinically most important severe primary antibody deficiency and is characterized by low levels of IgG, IgA, and/or IgM, with a failure to produce specific antibodies. This diagnostic category represents a heterogeneous group of disorders, which present not only with acute and chronic infections but also with a range of inflammatory and autoimmune disorders as well as an increased incidence of lymphoma and other malignancies. Patients can now be categorized into distinct clinical phenotypes based on analysis of large cohort studies and be further stratified by immunologic laboratory testing. The biologic importance of this categorization is made clear by the 11-fold increase in mortality if even one of these phenotypes (cytopenias, lymphoproliferation, or enteropathy) is present. Limited progress in defining the underlying molecular causes has been made with known causative single gene defects accounting for only 3% of cases, and, for this and the reasons mentioned above, CVID remains resolute in its variability. This review provides a practical approach to risk stratification of these complex phenotypes by using current clinical categories and laboratory biomarkers. The effects of infection as well as inflammatory and autoimmune complications on different organ systems are discussed alongside strategies to reduce diagnostic delay. Recent developments in diagnostics and therapy are also explored.

IVIg immune reconstitution treatment alleviates the state of persistent immune activation and suppressed CD4 T cell counts in CVID

Common variable immunodeficiency (CVID) is characterized by defective B cell function, impaired antibody production, and increased susceptibility to bacterial infections. Here, we addressed the hypothesis that poor antibody-mediated immune control of infections may result in substantial perturbations in the T cell compartment. Newly diagnosed CVID patients were sampled before, and 6-12 months after, initiation of intravenous immunoglobulin (IVIg) therapy. Treatment-naïve CVID patients displayed suppressed CD4 T cell counts and myeloid dendritic cell (mDC) levels, as well as high levels of immune activation in CD8 T cells, CD4 T cells, and invariant natural killer T (iNKT) cells. Expression of co-stimulatory receptors CD80 and CD83 was elevated in mDCs and correlated with T cell activation. Levels of both FoxP3+ T regulatory (Treg) cells and iNKT cells were low, whereas soluble CD14 (sCD14), indicative of monocyte activation, was elevated. Importantly, immune reconstitution treatment with IVIg partially restored the CD4 T cell and mDC compartments. Treatment furthermore reduced the levels of CD8 T cell activation and mDC activation, whereas levels of Treg cells and iNKT cells remained low. Thus, primary deficiency in humoral immunity with impaired control of microbial infections is associated with significant pathological changes in cell-mediated immunity. Furthermore, therapeutic enhancement of humoral immunity with IVIg infusions alleviates several of these defects, indicating a relationship between poor antibody-mediated immune control of infections and the occurrence of abnormalities in the T cell and mDC compartments. These findings help our understanding of the immunopathogenesis of primary immunodeficiency, as well as acquired immunodeficiency caused by HIV-1 infection.

Common variable immunodeficiency and isosporiasis: first report case

We report a severe case of diarrhea in a 62-year-old female HIV-negative patient from whom Giardia lamblia and Isospora belli were isolated. Because unusual and opportunistic infections should be considered as criteria for further analysis of immunological status, laboratory investigations led to a diagnosis of common variable immunodeficiency (CVID). This is the first reported case of isosporiasis in a patient with CVID and illustrates the importance of being aware of a possible link, particularly in relation to primary immunodeficiency.

Frequency and expression of inhibitory markers of CD4(+) CD25(+) FOXP3(+) regulatory T cells in patients with common variable immunodeficiency

Common variable immunodeficiency (CVID) is the most symptomatic primary antibody deficiency associated with recurrent infections and chronic inflammatory diseases as well as autoimmunity. CD4(+) CD25(+) FOXP3(+) regulatory T cells (Tregs) are critical T cell subsets for maintaining self-tolerance and regulation of immune response to antigens thus play a pivotal role in preventing autoimmunity. Thirty-seven CVID patients and 18 age-/sex-matched controls were enrolled. Peripheral blood mononuclear cells (PBMCs) were obtained from both groups, and the percentage of Tregs was calculated using flow cytometry method. The mRNA expression of Tregs' surface markers cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and glucocorticoid-induced tumour necrosis factor receptor (GITR), which are associated with Tregs' inhibitory function, was compared between patients and controls by quantitative real-time PCR TaqMan method. The results revealed that the frequency of Tregs was significantly lower in CVID patients than normal individuals (P < 0.001). In addition, CVID patients with autoimmunity were found to have markedly reduced proportion of Tregs compared to those cases without autoimmune diseases (P = 0.023). A significant difference was seen in factor forkhead box P3 (FOXP3) expression between CVID patients and controls (P < 0.001). The mRNAs of CTLA-4 and GITR genes were expressed at lower levels in CVID patients compared to control group (P = 0.005 and <0.001, respectively). Our findings showed reduced proportion of Tregs in CVID patients together with downregulation of FOXP3 protein and diminished expression of inhibitory Tregs' markers. It could be concluded that all of these changes may be responsible for cellular immune dysregulation observed in these patients especially those with autoimmune manifestation.

CVID patients with autoimmunity have elevated T cell expression of granzyme B and HLA-DR and reduced levels of Treg cells

AIMS

Common variable immunodeficiency (CVID) is a primary antibody immunodeficiency with approximately 20% of patients reporting additional autoimmune symptoms. The primary aim of this study was to compare the levels of activated and regulatory T cells (Treg cells) in CVID patients in an attempt to clarify their possible interactions leading to the generation of autoimmunity.

METHODS

Immunophenotyping of T cells was performed by flow cytometry using a whole blood approach. Surface expression of human leukocyte antigen HLA class II DR and intracellular levels of granzyme B in T cell subsets were assessed; Treg levels were measured using CD4 CD25, FOXp3 and CTLA-4.

RESULTS

CVID patients had higher levels of granzyme B and HLA-DR on CD8(+) T cells compared with control values (mean of 59% vs 30% and 45% vs 21%, respectively). Patients also had reduced levels of Treg cells compared with control values (con mean=3.24% vs pat=2.54%). Patients with autoimmunity (5/23) had a similar level of T cell activation markers to the rest of the patients but with lower Treg cells (mean of 1.1%) and reduced CD25 and CTLA-4 expression. Patients with autoimmunity had a higher ratio of activated to Treg cells compared with patients with no autoimmune symptoms.

CONCLUSIONS

These results highlight that reduced levels of Treg cells were associated with elevated levels of activated T cells, suggesting that reduced Treg cells in these patients may have functional consequences in allowing exaggerated T cell responses.

Common variable immunodeficiency: an update

Common variable immunodeficiency (CVID) describes a heterogeneous subset of hypogammaglobulinemias of unknown etiology. Typically, patients present with recurrent bacterial infections of the respiratory and gastrointestinal tract. A significant proportion of CVID patients develops additional autoimmune, inflammatory or lymphoproliferative complications. CVID is the most frequent symptomatic primary immunodeficiency encountered in adults. Informative monogenetic defects have been found in single patients and families but in most cases the pathogenesis is still elusive. Numerous immunological studies have demonstrated phenotypic and functional abnormalities of T cells, B cells and antigen-presenting cells. A hallmark is the impaired memory B-cell formation that has been taken advantage of for classifying CVID patients. Clinical multi-center studies have demonstrated a correlation between immunological markers and clinical presentation. Long-term outcome is significantly influenced by delay of diagnosis and treatment and the presence of chronic inflammatory complications. While immunoglobulin replacement therapy plus antibiotics can control infections in most cases, patients with non-infectious inflammatory complications such as granulomatous inflammation, interstitial lung disease, inflammatory bowel disease, lymphoproliferation and developing malignancies still represent a therapeutic challenge. In this review we provide a systematic overview of the immunological, clinical, diagnostic and therapeutic aspects of CVID and highlight recent developments in these fields.

Pathogenesis of autoimmunity in common variable immunodeficiency

Common variable immunodeficiency (CVID) presents in up to 25% of patients with autoimmune (AI) manifestations. Given the frequency and early onset in some patients with CVID, AI dysregulation seems to be an integral part of the immunodeficiency. Antibody-mediated AI cytopenias, most often affecting erythrocytes and platelets make up over 50% of these patients. This seems to be distinct from mainly cell-mediated organ-specific autoimmunity. Some patients present like patients with AI lymphoproliferative syndrome. Interestingly, in the majority of patients with AI cytopenias the immunological examination reveals a dysregulated B and T cell homeostasis. These phenotypic changes are associated with altered signaling through the antigen receptor which may well be a potential risk factor for disturbed immune tolerance as has been seen in STIM1 deficiency. In addition, elevated B cell-activating factor serum levels in CVID patients may contribute to survival of autoreactive B cells. Of all genetic defects associated with CVID certain alterations in TACI, CD19, and CD81 deficiency have most often been associated with AI manifestations. In conclusion, autoimmunity in CVID offers opportunities to gain insights into general mechanisms of human autoimmunity.

An overlapping syndrome of allergy and immune deficiency in children

Recurrent airway inflammations in children are an important clinical problem in pediatric practice. An essential challenge is differentiation between allergic background and immune deficiency, which is a difficult task taking into consideration individual predisposition to atopy, immune system maturation in the early childhood, as well as exposition to environmental allergens and microbial antigens. In this paper relationship between selected elements of innate and adaptive immunity, such as pattern-recognition receptors, complement components, dendritic cells, as well as immunoglobulins, and regulatory T lymph cells has been discussed. Particular attention has been paid to these mechanisms of the immune response which, depending on settings and timing of activation, predispose to allergy or contribute to tolerogenic phenotype. In the context of multifactorial conditioning of the innate and adaptive immunity governing the ultimate response and associations between allergy and immune deficiencies, these phenomena should be considered as pathogenetically not precluding, but as an overlapping syndrome.

How I treat common variable immune deficiency

Common variable immunodeficiency is a rare immune deficiency, characterized by low levels of serum immunoglobulin G, A, and/or M with loss of antibody production. The diagnosis is most commonly made in adults between the ages of 20 and 40 years, but both children and older adults can be found to have this immune defect. The range of clinical manifestations is broad, including acute and chronic infections, inflammatory and autoimmune disease, and an increased incidence of cancer and lymphoma. For all these reasons, the disease phenotype is both heterogeneous and complex. Contributing to the complexity is that patient cohorts are generally small, criteria used for diagnosis vary, and the doses of replacement immune globulin differ. In addition, routines for monitoring patients over the years and protocols for the use of other biologic agents for complications have not been clarified or standardized. In the past few years, data from large patient registries have revealed that both selected laboratory markers and clinical phenotyping may aid in dissecting groups of subjects into biologically relevant categories. This review presents my approach to the diagnosis and treatment of patients with common variable immunodeficiency, with suggestions for the use of laboratory biomarkers and means of monitoring patients.