Common variable immunodeficiency: a review

Seronegative autoimmune diseases: A challenging diagnosis

Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren's syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.

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.

Long-term efficacy, safety, and tolerability of recombinant human hyaluronidase-facilitated subcutaneous infusion of immunoglobulin (Ig) (fSCIG; HyQvia(®)) in immunodeficiency diseases: real-life data from a monocentric experience

Humoral immunodeficiency diseases represent a heterogeneous group of disorders that require long-term therapies. Thus, the treatment provided must not only be effective but also safe and well tolerated. In this paper, we report our data on the efficacy, safety, and tolerability of recombinant human hyaluronidase-facilitated subcutaneous infusion of immunoglobulin (Ig) (fSCIG; HyQvia(^®)) in immunodeficiency patients. We collected retrospective data from 30 patients with primary and secondary immunodeficiency diseases in therapy with fSCIG from September 2014 to December 2019. We evaluated the efficacy of the therapy, taking into account serum IgG values during follow-up and the number of annual infectious events and serious bacterial infections reported by patients. Safety was assessed on the basis of the number and intensity of adverse events (AEs) and local reactions reported. Our real-life data suggest that long-term repeated self-administration of recombinant human hyaluronidase-facilitated subcutaneous infusion of immunoglobulins results in a reduced rate of infectious events if compared to the pre-treatment rate. Both AEs and local reactions are mild to moderate and were never reasons for treatment discontinuation. Therapy with HyQvia shows prolonged efficacy and good tolerability; these aspects, together with the possibility of self-administration at home, minimize the impact the illness has on patients.

Epidemiology and pathophysiology of malignancy in common variable immunodeficiency?

Common variable immunodeficiency (CVID) is a diagnostic category of primary immunodeficiency (PID) which may present with heterogeneous disorders including recurrent infections, autoimmunity, granulomatous diseases, lymphoid and other types of malignancies. Generally, the incidence of malignancy in CVID patients is around 1.5-20.7% and usually occurs during the 4th-6th decade of life. Non-Hodgkin lymphoma is the most frequent malignancy, followed by epithelial tumours of stomach, breast, bladder and cervix. The exact pathological mechanisms for cancer development in CVID are not fully determined; however, several mechanisms including impaired genetic stability, genetic predisposition, immune dysregulation, impaired clearance of oncogenic viruses and bacterial infections, and iatrogenic causes have been proposed to contribute to the high susceptibility of these patients to malignancies.

Salivary Immunoglobulins in Individuals with Common Variable Immunodeficiency

Oral manifestations of common variable immunodeficiency (CVID) are rare, have rarely been studied and have given controversial results. There are few data about IgA, IgG, and IgM antibody salivary levels in the literature, and there are few papers about the clinical impact of antibody deficiencies and CVID on the oral health of such patients. The aim of this study was to measure serum and salivary IgA, IgG, and IgM levels in CVID participants and controls, and to associate immunoglobulin levels with caries and periodontal disease. This was a case-control study involving 51 CVID individuals and 50 healthy controls. All participants underwent examination for dental caries and periodontal disease. Blood and whole saliva samples were collected on the same day of the oral examination. Serum IgA, IgM, and IgG levels were measured by turbidimetry and salivary IgA, IgM, and IgG titers were assessed by enzyme-linked immunosorbent assay. Incidences of caries and gingivitis were significantly higher in the CVID group than in the control group (p<0.05). Salivary and blood IgA and IgM titers were significantly reduced in the CVID group, but there was no association of salivary immunoglobulin levels with periodontal disease or with caries incidence (p>0.05 for both). Although CVID was associated with increased susceptibility to caries and gingivitis, it was not associated with low salivary levels of IgA and IgM.

ICOS Co-Stimulation: Friend or Foe?

Over the last 15 years, the inducible T cell co-stimulator (ICOS) has been implicated in various immune outcomes, including the induction and regulation of Th1, Th2, and Th17 immunity. In addition to its role in directing effector T cell differentiation, ICOS has also been consistently linked with the induction of thymus-dependent (TD) antibody (Ab) responses and the germinal center (GC) reaction. ICOS co-stimulation, therefore, appears to play a complex role in dictating the course of adaptive immunity. In this article, we summarize the initial characterization of ICOS and its relationship with the related co-stimulatory molecule CD28. We then address the contribution of ICOS in directing an effector T cell response, and ultimately disease outcome, against various bacterial, viral, and parasitic infections. Next, we assess ICOS in the context of TD Ab responses, connecting ICOS signaling to follicular helper T cell differentiation and its role in the GC reaction. Finally, we address the link between ICOS and human autoimmune disorders and evaluate potential therapies aiming to mitigate disease progression by modulating ICOS signaling.

Phenotyping and follow up of forty-seven Iranian patients with common variable immunodeficiency

BACKGROUND

Common variable immune deficiency (CVID) is a heterogeneous syndrome with a wide variety of signs and symptoms. This study describes the phenotyping and survival of the CVID patients in the allergy and clinical immunology department of Rasol-E-Akram Hospital of Iran University of Medical Sciences in Tehran.

METHOD

We retrospectively reviewed hospital files of CVID patients in our department until January 2014. All patients were diagnosed with standard diagnostic criteria of CVID, treated and visited monthly, during the follow-up period. We divided the patients into four phenotypes; infection only, cytopenia, polyclonal lymphocytic infiltration and unexplained enteropathy. The immunologic, demographic and clinical findings in different phenotypes were analysed.

RESULTS

The study included 47 CVID patients with mean age at onset of symptoms and diagnosis of 11.2 and 20.2 years, respectively. Phenotyping of our patients was: only infection (62%), cytopenia (26%) and PLI (19%) and 94% of cases had only one phenotype. We did not find a significant relation between the clinical phenotypes and immunologic or demographic data. Rate of parental consanguinity in our cases was 47%. Parental consanguinity was related to lower age at onset, lower age at diagnosis and higher baseline IgG levels. Patients with malignancy and autoimmunity had significantly higher age at onset. Our patients were followed-up for 6.9 years and the mortality rate during this time was 6%.

CONCLUSIONS

Parental consanguinity and age at onset of CVID symptoms may have important roles in CVID manifestations.

Investigating the colloidal stability of fluorescent silica nanoparticles under isotonic conditions for biomedical applications

Fluorescent silica nanoparticle (NP) labels are of great interest in biomedical diagnostics, however, when used in bioassays under physiological conditions they rapidly agglomerate and precipitate from solution leading to high levels of non-specific binding. In this work, using size and zeta-potential data obtained from Dynamic and Electrophoretic Light Scattering analysis, the improvement in colloidal stability of silica NPs under physiological conditions was correlated with an increase in the concentration of three additives: (1) a protein, bovine serum albumin (BSA); (2) a neutral surfactant, Tween 20®; and (3) a charged surfactant, sodium dodecyl sulfate (SDS). The number of BSA molecules present in the NP corona at each concentration was calculated using UV-Vis spectroscopy and a bicinchoninic acid protein assay (BCA). The optimal concentration of each additive was also effective in stabilizing antibody labeled fluorescent nanoparticles (αNPs) under physiological conditions. Using a fourth additive, trehalose, the colloidal stability of αNPs after freeze-drying and long-term storage also significantly improved. Both as-prepared and freeze-dried αNPs were tested in a standard fluorescence immunoassay for the detection of human IgG. The as-prepared assay showed a higher sensitivity at low concentration and a lower limit of detection when compared to a free dye assay. Assays performed with freeze dried αNPs after 4 and 22 days also showed good reproducibility.

Lymphoproliferative disease and cancer among patients with common variable immunodeficiency

Innate immune deficiencies are a heterogeneous group of genetically inherited diseases affecting the innate and adaptive immune systems that confer susceptibility to infection, autoimmunity, and cancer. This review discusses the latest insights into the links between common variable immunodeficiency (CVI) and malignancies. Although Ig therapy greatly reduces the number of infections and enhances survival, it does not appear to address the development of cancer, especially lymphoma. The reasons for the increased susceptibility to lymphoid malignancies are unclear. These include genetics, immune dysregulation, radiosensitivity and chronic infections such as Helicobacter pylori, EBV, human herpes virus type 8 and cytomegalovirus. Further studies will allow us to better stratify the risk for cancer in these patients, and teach us to better prevent these complications and to better treat them.

Therapeutic management of primary immunodeficiency in older patients

Primary immunodeficiency disease (PID) has traditionally been viewed as a group of illnesses seen in the paediatric age group. New advances in diagnosis and treatment have led to an increase in the number of elderly PID patients. However, there is lack of research evidence on which to base clinical management in this group of patients. Management decisions often have to be based therefore on extrapolations from other patient cohorts or from younger patients. Data from the European Society for Immunodeficiencies demonstrates that the vast majority of elderly patients suffer from predominantly antibody deficiency syndromes. We review the management of PID disease in the elderly, with a focus on antibody deficiency disease.

Reduced immunoglobulin levels in epilepsy patients treated with levetiracetam, lamotrigine, or carbamazepine

OBJECTIVES

The aim of the study was to investigate immunoglobulin levels in patients with epilepsy using the antiepileptic drugs (AED) levetiracetam (LEV), carbamazepine (CBZ), or lamotrigine (LTG).

METHODS

A total of 211 patients and 80 controls (age: 18-45 years) of both genders were included. The patients had been treated with either LEV (n = 47), CBZ (n = 90), or LTG (n = 74) monotherapy for at least 6 months. Total concentrations of immunoglobulin G (IgG), IgG subclasses (IgG1, IgG2, IgG3, and IgG4), immunoglobulin A (IgA), and immunoglobulin M (IgM) were measured. Smoking, drinking habits, and physical activity were recorded, and body mass index (BMI) was calculated.

RESULTS

A significantly lower total IgG and IgG1 was found in both men and women treated with LTG and in men on CBZ. IgG2 and IgG4 were also lower in LTG-treated women, and IgA and IgM were lower in LTG-treated men. Patients treated with LEV did not differ from the control group.

CONCLUSIONS

Low levels of immunoglobulins were found in patients with epilepsy treated with LTG or CBZ. As our group of patients consisted of otherwise healthy young adults, one should be especially aware of a possible effect of AEDs on immunoglobulin levels when treating selected patient groups, for example immunocompromised patients. Immunoglobulin concentrations should be measured in patients treated with LTG or CBZ who experience recurrent infections, and a change in medication should be considered.

Emergence of a multidrug-resistant Haemophilus influenzae strain causing chronic pneumonia in a patient with common variable immunodeficiency

We report the emergence of a multidrug-resistant Haemophilus influenzae strain in a patient with common variable immunodeficiency suffering from recurrent bronchopneumonia caused by H. influenzae. After the patient had received several antibiotic therapies, a strain was isolated showing resistance to ampicillin, ampicillin/sulbactam, cefazolin, cefuroxime, ciprofloxacin, and clarithromycin. Polymerase chain reaction analyses and sequencing revealed the presence of the beta-lactamase gene bla(TEM-1), two mutations (A502T and R517H) in the ftsI gene encoding the transpeptidase region of the penicillin-binding protein 3, and one mutation in the ribosomal protein gene L4 (G65D) conferring resistance to beta-lactams and macrolides, respectively. Additionally, the plasmid-encoded aac(6')-Ib-cr gene mediating slightly reduced susceptibility to quinolones and two mutations in the DNA gyrase gene gyrA and one mutation in the topoisomerase IV gene parC were identified leading to a high-level fluoroquinolone-resistant phenotype. In conclusion, the treatment of H. influenzae infections accompanied by high bacterial loads such as bronchopneumonia can be complicated by the selection of multidrug-resistant strains. Moreover, the emergence of aac(6')-Ib-cr in H. influenzae causing low fluoroquinolone resistance levels might have contributed to the selection of DNA gyrase and topoisomerase IV mutants.

A case of focal segmental glomerulosclerosis in an adult patient with hypogammaglobulinemia superimposed on membranoproliferative glomerulonephritis in childhood

Background

Common variable immunodeficiency (CVID) is a disorder characterized by hypogammaglobulinemia without a known predisposing cause.

Case presentation

We report a 36-year-old man who had suffered membranoproliferative glomerulonephritis (MPGN) in his childhood, later diagnosed with CVID at 35 years of age. He presented at our hospital with signs of proteinuria. A renal biopsy revealed he suffered from focal segmental glomerulosclerosis (FSGS), possibly due to obesity and hypertension, not CVID - associated MPGN.

Conclusion

This is the first case report of FSGS in a CVID patient. In this case, we have to pay attention not only to the treatment of obesity and hypertension for FSGS but also to the recurrence of immune-complex glomerulonephritis such as MPGN, in case of the restoration of hypogammaglobulinemia.

Oral manifestations in patients with hypogammaglobulinemia

OBJECTIVE

The overall objective of this study was to assess the oral manifestations and their association with immunologic status and health history, of individuals with hypogammaglobulinemia.

STUDY DESIGN

A case-controlled study of 100 subjects with hypogammaglobulinemia and 93 control individuals was performed. All participants were examined for dental caries, periodontal disease, mucosal lesions/infections, and general oral health problems. Decayed, missing, filled teeth and community periodontal index were recorded. Complete blood count, serum immunoglobulins, and lymphocyte immunophenotyping were measured on the same day of the oral health assessment.

RESULTS

Individuals with hypogammaglobulinemia showed higher prevalence of enamel hypoplasia and complaints of dry mouth, and lower prevalence of dental caries and periodontal disease.

CONCLUSIONS

The systemic conditions associated with hypogammaglobulinemia were not associated with enhanced susceptibility to caries, gingivitis, or periodontitis; however, individuals with hypogammaglobulinemia were more likely to report more episodes of recurrent aphthous ulcers compared with control individuals.

Proteomic analysis of sera from common variable immunodeficiency patients undergoing replacement intravenous immunoglobulin therapy

Common variable immunodeficiency is the most common form of symptomatic primary antibody failure in adults and children. Replacement immunoglobulin is the standard treatment of these patients. By using a differential proteomic approach based on 2D-DIGE, we examined serum samples from normal donors and from matched, naive, and immunoglobulin-treated patients. The results highlighted regulated expression of serum proteins in naive patients. Among the identified proteins, clusterin/ApoJ serum levels were lower in naive patients, compared to normal subjects. This finding was validated in a wider collection of samples from newly enrolled patients. The establishment of a cellular system, based on a human hepatocyte cell line HuH7, allowed to ascertain a potential role in the regulation of CLU gene expression by immunoglobulins.

The C104R mutant impairs the function of transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI) through haploinsufficiency

BACKGROUND

TNFRSF13B, which encodes transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), is mutated in 10% of patients with common variable immunodeficiency. One of the 2 most common TACI mutations in common variable immunodeficiency, C104R, abolishes ligand binding and is found predominantly in the heterozygous state. The murine TACI mutant C76R is the equivalent of the human TACI mutant C104R.

OBJECTIVE

We sought to define the consequence of the C76R mutation on TACI function in mice that express both wild-type TACI and the murine C76R mutant.

METHODS

Transgenic mice that express murine TACI C76R, the counterpart of human TACI C104R, on the TACI(+/-) B6/129 background (C76R/TACI(+/-) mice) were constructed. Serum immunoglobulins and antibody responses to the type II T-independent antigen trinitrophenylated (TNP)-Ficoll were determined by means of ELISA. B-cell proliferation in response to a proliferation-inducing ligand was determined based on tritiated thymidine incorporation into DNA. IgG1 secretion by B cells in response to a proliferation-inducing ligand plus IL-4 was determined by means of ELISA.

RESULTS

C76R/TACI(+/-) mice had significantly impaired antibody responses to the type II T-independent antigen TNP-Ficoll compared with TACI(+/+) B6/129 control animals, and their B cells were impaired in their capacity to proliferate and secrete IgG1 in response to TACI ligation. Unexpectedly, TACI(+/-) mice had similarly impaired B-cell function as C76R/TACI(+/-) littermates. Impaired TACI function caused by haploinsufficiency was confirmed in TACI(+/-) mice on the C57BL/6 background.

CONCLUSION

These results suggest that the human TACI mutant C104R might impair TACI function in heterozygotes through haploinsufficiency.

A case of explosive progression of hepatocellular carcinoma in a patient with common variable immunodeficiency (CVID)

OBJECTIVE

While it is well known that patients with common variable immunodeficiency (CVID) are predisposed to various malignancies, primarily non-Hodgkin's lymphoma and gastric carcinomas, to our knowledge no cases of hepatocellular carcinoma have been reported in the absence of preexisting liver disease.

METHOD AND RESULTS

We report a 50-year-old male patient with CVID with a B- and T-cell deficiency. The patient was on prophylactic intravenous gammaglobulin and had received several years earlier a course of rituximab for an autoimmune disorder. He had no history of hepatitis. The patient developed a rapidly progressing hepatocellular carcinoma within 3 to 4 weeks.

CONCLUSIONS

Although patients with CVID are predisposed to malignancies such as lymphoma and adenocarcinoma of the stomach, rapidly progressive hepatocellular carcinoma in the absence of any preexisting liver disease has not been described.

NOD2 polymorphisms in clinical phenotypes of common variable immunodeficiency disorders

Common variable immunodeficiency disorders (CVIDs) are a heterogeneous group of diseases characterized by hypogammaglobulinaemia and consequent susceptibility to infection. CVID patients commonly develop a variety of additional manifestations for which the causative factors are not fully understood. Two such manifestations are granulomatous disease and enteropathy. Because the ability to predict complications would aid clinical management, we continue to search for possible disease modifier genes. NOD2 acts a microbial sensor and is involved in proinflammatory signalling. Particular mutations of the NOD2 gene are associated with Crohn's disease including gly908arg, leu1007finsc and arg702trp polymorphisms. We hypothesized that NOD2 polymorphisms may be a disease modifier gene towards an enteropathic or granulomatous phenotype within CVIDs. Sequence-specific primers returned genotypes for 285 CVID patients from centres across the United Kingdom and Europe. We present the frequencies of the different phenotypes of patients within our international cohort. Arg702trp polymorphisms were significantly less frequent than wild-type (WT) (P = 0·038) among international CVID patients with splenomegaly. Gly908arg polymorphisms were more prevalent than WT in UK patients with autoimmune disorders (P = 0·049) or enteropathy (P = 0·049). NOD2 polymorphisms were not more prevalent than WT in CVID patients with clinical phenotypes of granulomata. UK allele frequencies of 0·014, 0·056 and 0·026 were found for gly908arg, arg702trp and leu1007finsc NOD2 polymorphisms, respectively. These do not differ significantly from UK immunocompetent controls confirming, as expected, that in addition these NOD2 polymorphisms do not confer susceptibility to CVIDs per se.

B cells from common variable immunodeficiency patients fail to differentiate to antibody secreting cells in response to TLR9 ligand (CpG-ODN) or anti-CD40+IL21

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterised by hypogammaglobulinaemia and antibody deficiency to T dependent and independent antigens. Patients suffer from recurrent respiratory infections and poor response to vaccination. Although the underlying molecular defect is unknown, most CVID patients show impaired late B cell differentiation. We investigated B cell differentiation and immunoglobulin secretion induced by two different stimuli: TLR9 specific ligand (CpG-ODN) and anti-CD40 combined with IL21. The contribution of BCR signalling (anti-IgM stimulation) was also evaluated. B cells from CVID patients produced low levels of IgG and IgA in response to both kinds of stimuli that was not restored by anti-IgM. Production of IgM was conserved when cells were stimulated with anti-CD40 and IL21. These results point to a wide signalling defect in B lymphocytes from CVID patients that may be related to their hypogammaglobulinaemia and poor response to vaccination.

Bilateral knee arthrodesis in a patient with common variable immunodeficiency

Patients with common variable immunodeficiency can present with debilitating arthritis. We present the case of a 42-year-old man with bilateral knee arthritis who underwent a right total knee arthroplasty that subsequently became infected. Five months after resection arthroplasty, his right leg spontaneously fused in extension, but his left knee was limited to an arc of motion between 90° and 110°. At the patient's request, he underwent a noninstrumented arthrodesis of the left knee. The patient now has bilateral arthrodeses and ambulates with a cane. While arthroplasty may be attempted in such patients, the increased risk of infection may potentially result in arthrodesis, possibly without instrumentation.

Evaluation of immunoglobulin levels and infection rate in patients with common variable immunodeficiency after immunoglobulin replacement therapy

BACKGROUND/PURPOSE

Common variable immunodeficiency (CVID) is characterized by decreased serum levels of IgG and increased susceptibility to recurrent infections. The aim of this study was to evaluate the IgG subclass levels of CVID patients.

METHODS

Twenty-four CVID patients who had been under regular intravenous immunoglobulin replacement therapy for 96.13 +/- 54.83 months were enrolled in this study. Serum IgG and IgG subclass levels, and clinical outcomes for these patients were evaluated after this period of treatment.

RESULTS

Mean serum IgG levels were significantly increased from 272.91 +/- 185.58 mg/dL at the time of diagnosis to 455.29 +/- 200.23 mg/dL after treatment, while there was no significant difference in the serum levels of IgM and IgA. Decreased serum levels of IgG1 were detected in 75% of the patients studied. Decreased serum levels of IgG2, IgG3 and IgG4 were also detected in 6, 11, and 11 patients, respectively. All patients experienced recurrent infectious diseases either before, or after, diagnosis.

CONCLUSION

Although serum IgG levels in the patients significantly increased after regular intravenous immunoglobulin replacement therapy, serum IgM and IgA levels remained diminished over time. Furthermore, a number of cases had low levels of IgG subclasses, in spite of normal total IgG levels, which could explain why some patients had continued infections, even after immunoglobulin replacement therapy.

Comparison of pulmonary diseases in common variable immunodeficiency and X-linked agammaglobulinaemia

Patients with CVID are at greater risk of developing lung complications than patients with XLA because of delayed diagnosis and possible immune dysregulation. Early diagnosis and appropriate treatment reduces the incidence of pulmonary infections in both groups of patients. However, CVID patients are prone to progressive lung disease despite optimal immunoglobulin therapy.

BACKGROUND AND OBJECTIVE

Pulmonary disease is the most common complication in patients with common variable immunodeficiency (CVID) or X-linked agammaglobulinaemia (XLA). Pulmonary disease may progress despite immunoglobulin replacement therapy. In this study pulmonary complications were compared in patients with CVID or XLA.

METHODS

Pulmonary complications were evaluated in 115 patients (76 with CVID and 39 with XLA) by reviewing hospital records of chest infections, pulmonary function tests and high-resolution CT scans.

RESULTS

Thirty-two patients with XLA (82%) presented with 59 episodes of pneumonia before diagnosis, whereas 15 patients (38.4%) experienced pneumonia after immunoglobulin replacement therapy (1.67 vs 0.45 episodes per patient per year). Among the CVID patients, 196 episodes of pneumonia were documented in 59 patients (77.6%) before diagnosis, while 36 patients (47.3%) experienced pneumonia after therapy (1.11 vs 0.58 episodes of pneumonia per patient per year). Forty-seven (41%) patients (38 with CVID and 9 with XLA) developed chronic lung disease. The CVID patients developed more complications, including bronchiectasis and lymphoid interstitial pneumonitis, than the XLA patients.

CONCLUSIONS

Patients with CVID had a greater likelihood of developing lung disease, possibly due to delayed diagnosis and immune dysregulation, as compared with XLA patients. Early diagnosis of patients with primary antibody deficiencies and adequate i.v. immunoglobulin replacement therapy substantially reduces the number of pulmonary infections. However, CVID patients are prone to progression of lung disease despite optimal immunoglobulin therapy because of the nature of the disease. This important issue should be addressed in further studies.

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

Introduction

Common variable immunodeficiency disorder (CVID) is a heterogeneous syndrome, characterized by deficient antibody production and recurrent bacterial infections in addition abnormalities in T cells. CD4⁺CD25^high regulatory T cells (Treg) are essential modulators of immune responses, including down-modulation of immune response to pathogens, allergens, cancer cells and self-antigens.

Objective

In this study we set out to investigate the frequency of Treg cells in CVID patients and correlate with their immune activation status.

Materials and Methods

Sixteen patients (6 males and 10 females) with CVID who had been treated with regular intravenous immunoglobulin and 14 controls were enrolled. Quantitative analyses of peripheral blood mononuclear cells (PBMC) were performed by multiparametric flow cytometry using the following cell markers: CD38, HLA-DR, CCR5 (immune activation); CD4, CD25, FOXP3, CD127, and OX40 (Treg cells); Ki-67 and IFN-γ (intracellular cytokine).

Results

A significantly lower proportion of CD4⁺CD25^highFOXP3 T cells was observed in CVID patients compared with healthy controls (P<0.05). In addition to a higher proportion of CD8⁺ T cells from CVID patients expressing the activation markers, CD38⁺ and HLA-DR⁺ (P<0.05), we observed no significant correlation between Tregs and immune activation.

Conclusion

Our results demonstrate that a reduction in Treg cells could have impaired immune function in CVID patients.

The murine equivalent of the A181E TACI mutation associated with common variable immunodeficiency severely impairs B-cell function

TNFRSF13B, which encodes TACI (transmembrane activator and calcium-modulator and cyclophilin ligand interactor), is mutated in 10% of patients with common variable immune deficiency (CVID). One of the 2 most common TACI mutations in CVID, A181E, introduces a negative charge into the transmembrane domain. To define the consequence of the A181E mutation on TACI function, we studied the effect of its murine equivalent, mTACI A144E, on TACI signaling in transfected cells and on TACI function in transgenic mice. The mTACI A144E mutant, like its human TACI A181E counterpart, was expressed on the surface of 293T transfectants and was able to bind ligand, but exhibited impaired constitutive and ligand-induced NF kappaB signaling. In addition, constitutive and ligand-induced clustering of the intracellular domain was deficient for A144E as measured by fluorescence resonance energy transfer. Transgenic mice expressing the A144E mutant on TACI(-/-) background had low serum IgA levels and significantly impaired antibody responses to the type II T-independent antigen TNP-Ficoll. B cells from A144E transgenic mice were impaired in their capacity to proliferate and secrete IgG1 and IgA in response to TACI ligation. These results suggest that mTACI A144E mutation and its human counterpart, A181E, disrupt TACI signaling and impair TACI-dependent B-cell functions.

Common variable immunodeficiency: etiological and treatment issues

One of the great advances in clinical medicine was the recognition of the pleomorphism of the immune response and the multiple afferent and efferent limbs of antigen processing and responsiveness. A significant contribution to this understanding was derived from studies of human immunodeficiency states, including both inherited and acquired syndromes. Amongst these syndromes, one of the most common, and least understood, is common variable immune deficiency (CVID). CVID is a syndrome that leads to a reduction in serum immunoglobulins and complications including recurrent infections. Management includes immunoglobulin replacement therapy; however, patients with CVID are at risk for complications of exogenous immunoglobulin administration as well as CVID-associated diseases such as autoimmune processes and malignancies. To assess the current state of knowledge in the field, we performed a literature review of a total of 753 publications covering the period of 1968 until 2008. From this list, 189 publications were selected for discussion. In this review, we demonstrate that while the molecular basis of CVID in many cases remains incompletely understood, significant strides have been made and it is now clear that there is involvement of several pathways of immune activation, with contributions from both T and B cells. Furthermore, despite the current gaps in our knowledge of the molecular pathogenesis of the syndrome, there have been dramatic advances in management that have led to improved survival and significantly reduced morbidity in affected patients.

Transmembrane activator and calcium-modulator and cyclophilin ligand interactor mutations in common variable immunodeficiency

PURPOSE OF REVIEW

TNFRSF13B, the gene which encodes transmembrane activator and calcium-modulator and cyclophilin ligand interactor (TACI), is mutated in nearly 10% of patients with common variable immune deficiency (CVID), an antibody deficiency syndrome characterized by loss of memory B cells and plasma cells. This review discusses the normal function of TACI and the role of TACI mutants in CVID.

RECENT FINDINGS

TACI activates isotype switching, mediates immunoglobulin production in response to type II T-independent antigens, and plays an inhibitory role in B cell homeostasis. Recent evidence indicates that TACI synergizes with CD40 and Toll-like receptors for immunoglobulin secretion and promotion of plasma cell differentiation. The two most common TACI mutants associated with CVID--C104R and A181E--are primarily found as heterozygous mutations suggesting that they either cause haploinsufficiency or exert a dominant negative effect. TACI mutations in CVID are associated with an increased susceptibility to autoimmunity and lymphoproliferation.

SUMMARY

TACI has a dual function in promoting B cell antibody responses and inhibiting B cell proliferation. The observation that TACI mutations are present in healthy participants suggests that modifier genes may play an important role in the development of CVID. The discovery of these genes will help understand the pathogenesis of this disease.

Enhanced levels of urokinase plasminogen activator and its soluble receptor in common variable immunodeficiency

Common variable immunodeficiency (CVID) is a heterogeneous syndrome characterized by defective immunoglobulin production and high frequency of bacterial infections, autoimmunity and manifestations of chronic inflammation. The urokinase plasminogen activator (uPA), its cell bound and soluble receptor (uPAR, suPAR) have complex biological functions involving innate immune defense mechanisms and regulation of inflammation. Based on this dual role, we hypothesized that the uPA system could be affected in CVID, and examined expression of components of the uPA system in subgroups of CVID. All CVID-patients had increased plasma levels of suPAR with particularly high levels in those with splenomegaly and thrombocytopenia. Plasma uPA levels were also raised in these patients, and both suPAR and uPA levels correlated with the monocyte activation marker neopterin. Monocytes from CVID patients had increased expression of uPAR. We show an increased activation of the uPA system possibly contributing to the inflammatory phenotype seen in subgroups of CVID patients.

TACI mutations and disease susceptibility in patients with common variable immunodeficiency

The most prevalent primary immunodeficiency is common variable immunodeficiency (CVID). Mutations have been described in four genes, ICOS, CD19, BAFF-R and TNFRSF13B (encoding TACI), together associated with 10-15% of CVID cases. We investigated a family with CVID and identified the heterozygous C104R TNFRSF13B mutation in two of the three index-children with CVID, a mother with selective immunoglobulin A deficiency, a mother with recurrent infections and a healthy grandfather. Remarkably, we did not find the TNFRSF13B mutation in the third index-child with CVID, despite his hypogammaglobulinaemia and decreased response to unconjugated pneumococcal vaccine. This family illustrates that TNFRSF13B mutations induce disease susceptibility rather than cause disease directly. Apparently, other genetic or environmental factors, still to be identified, contributed to the development of CVID in this family. Consequently, TNFRSF13B mutations must be interpreted with caution in the clinical setting.

Common variable immunodeficiency: a new look at an old disease

Primary immunodeficiencies comprise many diseases caused by genetic defects primarily affecting the immune system. About 150 such diseases have been identified with more than 120 associated genetic defects. Although primary immunodeficiencies are quite rare in incidence, the prevalence can range from one in 500 to one in 500 000 in the general population, depending on the diagnostic skills and medical resources available in different countries. Common variable immunodeficiency (CVID) is the primary immunodeficiency most commonly encountered in clinical practice, and appropriate diagnosis and management of patients will have a significant effect on morbidity and mortality as well as financial aspects of health care. Advances in diagnostic laboratory methods, including B-cell subset analysis and genetic testing, coupled with new insights into the molecular basis of immune dysfunction in some patients with CVID, have enabled advances in the clinical classification of this heterogeneous disease.

Autoimmunity in common variable immunodeficiency

BACKGROUND

Autoimmunity has been increasingly recognized as a major issue in patients with common variable immunodeficiency (CVID), the most common symptomatic primary immunodeficiency in adulthood. Different authors report high prevalences of autoimmune diseases in CVID, and several mechanisms have been proposed to explain this apparent paradox. Genetic predisposition, under current surveillance, innate and adaptive immunity deficiencies leading to persistent/recurrent infections, variable degrees of immune dysregulation, and possible failure in central and peripheral mechanisms of tolerance induction or maintenance may all contribute to increased autoimmunity.

CONCLUSIONS

Data on the clinical/immunological profile of affected patients and treatment are available mostly concerning autoimmune cytopenias, the most common autoimmune diseases in CVID. Treatment is based on conventional alternatives, in association with short experience with new agents, including rituximab and infliximab. Benefits of early immunoglobulin substitutive treatment and hypothetical premature predictors of autoimmunity are discussed as potential improvements to CVID patients' follow-up.

Serum bactericidal antibody responses to meningococcal polysaccharide vaccination as a basis for clinical classification of common variable immunodeficiency

Common variable immunodeficiency (CVID) is a heterogeneous group of disorders characterized by hypogammaglobulinemia and increased susceptibility to recurrent pyogenic infections. This study was performed to subclassify CVID on the basis of the bactericidal antibody responses of patients to polysaccharide meningococcal vaccine. Twenty-five patients with CVID (18 male and 7 female) and 25 healthy volunteers received meningococcal polysaccharide vaccine A + C. Serum bactericidal antibody (SBA) titers were measured at baseline and after 3 weeks. Response was correlated with clinical and immunological manifestations of CVID. Twenty-four (96%) of the 25 normal controls had a protective SBA titer of > or = 8 postvaccination, whereas only 16 (64%) of the 25 CVID patients had a protective titer (P value = 0.013). Among the patients with CVID who were nonresponders, there were significantly increased rates of bronchiectasis (P = 0.008), splenomegaly (P = 0.016), and autoimmunity (P = 0.034) in comparison with patients who had protective SBA titers. A reversed CD4/CD8 ratio was more common in the nonresponder group of patients (P = 0.053). We conclude that individuals with CVID who cannot produce protective postvaccination titers after receiving meningococcal polysaccharide vaccine are more likely to exhibit bronchiectasis, splenomegaly, and autoimmune diseases. Vaccination response may define subgroups of patients with CVID, enabling more effective monitoring and therapeutic strategies.

TACI, isotype switching, CVID and IgAD

Common Variable Immunodeficiency (CVID) is the most prevalent human primary immunodeficiency requiring medical attention. Until recently the only known genetic defect specific to CVID was ICOS deficiency that accounts for about 1% of the patients analyzed. Mutations in the TNFR family member TACI (transmembrane activator and calcium-modulator and cyclophilin ligand interactor), which mediates isotype switching in B cells, were found to be present in 5% of patients with CVID. Mutations in TACI were also found in relatives of patients with CVID who suffered from IgA deficiency (IgAD) as well as in a patient with isolated IgAD. In the majority of patients described to date only one TACI allele is mutated, showing an autosomal dominant transmission of the disease. B cells from individuals with TACI mutations did not produce IgG and IgA in response to the TACI ligand, APRIL (a proliferation-inducing ligand), probably reflecting impaired isotype switching. These results suggest that TACI mutations can lead to CVID.

Translational mini-review series on immunodeficiency: molecular defects in common variable immunodeficiency

Common variable immunodeficiency (CVID) is a primary immunodeficiency that typically affects adults and is characterized by abnormalities of quantative and qualitative humoral function that are heterogeneous in their immunological profile and clinical manifestations. The recent identification of four monogenic defects that result in the CVID phenotype also demonstrates that the genetic basis of CVID is highly variable. Mutations in the genes encoding the tumour necrosis factor (TNF) superfamily receptors transmembrane activator and calcium-modulating ligand interactor (TACI) and B cell activation factor of the TNF family receptor (BAFF-R), CD19 and the co-stimulatory molecule inducible co-stimulator molecule (ICOS) all lead to CVID and illustrate the complex interplay required to co-ordinate an effective humoral immune response. The molecular mechanisms leading to the immune defect are still not understood clearly and particularly in the case of TACI, where a number of heterozygous mutations have been found in affected individuals, the molecular pathogenesis of disease requires further elucidation. Together these defects account for perhaps 10-15% of all cases of CVID and it is highly likely that further genetic defects will be identified.

Grouping of patients with common variable immunodeficiency based on immunoglobulin biosynthesis: comparison with a classification system on CD4-naïve cells

The present study compared two different systems of classification of patients with common variable immunodeficiency (CVID); one based on in vitro immunoglobulin biosynthesis; and another on CD4-naïve cell counts. Peripheral blood mononuclear cells (PBMCs) were isolated from 35 patients with CVID and 20 healthy controls. They were stimulated for the secretion of IgM and IgG after stimulation with Staphylococcus aureus Cowan I (SAC) upon supplementation of interleukin-2 (IL-2) or with pokeweed mitogen. T cell subsets were estimated by flow cytometry. By the first system, patients were classified into group A (n=18) with secretion of neither IgG nor IgM; into group B (n=12) with detectable IgM but no IgG secretion; and into group C (n=5) with IgM and IgG secretion similar to controls. By the second system, patients were classified into group I (n=12) with less than 109 CD4-naïve cells/mul; into group II (n=12) with CD4-naïve cells within 109-225microl(-1); and into group III (n=11) with more than 225 CD4-naïve cells/mul. All groups I-III were defective for in vitro release of IgG and IgM. The likelihood ratio for splenomegaly in patients with <225 CD4-naïve cells/mul was 5.08 (p: 0.024). CD4-naïve cell counts of patients were positively correlated to serum levels of IgG and IgA of patients. The presented results revealed that the former system described adequately the function of B cells and the latter the clinical status of the patient. Our proposal is that both should be used for the characterization of patients with CVID.

Increased serum levels of soluble CD30 in patients with common variable immunodeficiency and its clinical implications

Common variable immunodeficiency (CVID) is a heterogeneous group of disorders, characterized by hypogammaglobulinemia and increased susceptibility to recurrent pyogenic infections, autoimmunity, and malignancies. Twenty-five cases with CVID (18 male and 7 female) and 25 healthy volunteers were investigate in this study. Soluble CD30 (sCD30) serum levels of the subjects were measured and compared. Serum levels of sCD30 in the patients with CVID were significantly increased in comparison with controls (36.93 +/- 32.38 vs 5.27 +/- 1.32 U/ml, P < 0.001). The group of patients with splenomegaly and reversed ratio of CD3+CD4+ T cells/CD3+CD8+ T cells had the highest serum levels of sCD30 (66.01 +/- 43.34 U/ml) in comparison with other patients (P = 0.010). High levels of sCD30 in the CVID patients with splenomegaly and the presence of lymphoma in a patient with the highest level of sCD30 may suggest a soluble form of this marker as a prognostic tool in such diseases.

Genetic defects in common variable immunodeficiency

Common variable immunodeficiency (CVID) is the most frequent clinically manifested primary immunodeficiency. According to clinical and laboratory findings, CVID is a heterogeneous group of diseases. Recently, the defects of molecules regulating activation and terminal differentiation of B lymphocytes have been described in some patients with CVID. In this study, we show the overview of deficiencies of inducible costimulator, transmembrane activator and calcium-modulator and cytophilin ligand interactor, CD19 molecules, their genetic basis, pathogenesis and clinical manifestations.

Autoimmune lymphoproliferative syndrome in a patient with common variable immunodeficiency: dichotomy of apoptosis

BACKGROUND

Autoimmune lymphoproliferative syndrome (ALPS) is a disorder usually associated with hypergammaglobulinemia and defective apoptosis mostly due to Fas or Fas ligand mutation. Common variable immunodeficiency (CVID) is a disorder with hypogammaglobulinemia commonly associated with increased Fas expression and spontaneous apoptosis.

OBJECTIVE

To describe a patient with a unique combination of hypogammaglobulinemia and ALPS with Fas deficiency but high spontaneous apoptosis.

METHODS

Fas expression on freshly isolated lymphocytes was evaluated by means of immunofluorescence using polyclonal rabbit anti-Fas IgG antibody. Apoptosis of cultured lymphocytes was quantitated using acridine orange and ethidium bromide staining.

RESULTS

We describe a male patient diagnosed as having CVID at the age of 10 years receiving monthly intravenous immunoglobulin. The patient developed ALPS at the age of 21 years manifested by persistent lymphadenopathy and hepatosplenomegaly. The percentage of double-negative T lymphocytes was estimated to be 9%. Freshly isolated lymphocytes showed low Fas expression (3.6% for the patient and 11.2% for the control). The spontaneous apoptosis rate was high (15% for the patient and 5% for the control).

CONCLUSIONS

Autoimmune lymphoproliferative syndrome can be associated with hypogammaglobulinemia and should be looked for in chronic nonmalignant lymphoproliferation in CVID. Common variable immunodeficiency might involve Fas-independent pathways or recruitment of Fas downstream molecules for apoptosis. There is a subset of patients with both CVID and ALPS in whom Fas deficiency could be associated with enhanced spontaneous apoptosis.

Successful treatment of common variable immunodeficiency disorder-associated diarrhea with budesonide: a case report

PURPOSE

Common variable immunodeficiency disorder (CVID) is an immunological disease that can present with gastrointestinal (GI) symptoms including chronic diarrhea and abdominal pain. We report a patient with CVID and chronic diarrhea who significantly improved with budesonide.

METHODS

A 47-yr-old woman with CVID-associated diarrhea, steatorrhea, abdominal pain, and bloating for several years had an exhaustive evaluation for secondary causes of her symptoms, which was unrevealing. At the advice of her immunologist, she attempted a course with budesonide that significantly improved her GI symptoms. Given the absence of literature on this treatment in CVID, we attempted to systematically evaluate the clinical benefits after withdrawal of and retreatment with budesonide.

RESULTS

Diarrhea, steatorrhea, abdominal pain, and bloating recurred within 2 days of discontinuing budesonide. All parameters assessed improved upon reinitiating budesonide. Further, serum immunoglobulin G (IgG) levels significantly increased with treatment. No significant side effects were observed with budesonide.

CONCLUSION

This is the first report of a patient with CVID-related chronic diarrhea to be successfully treated with oral budesonide. This observation provides clinicians with an effective and safe treatment option in this difficult group of patients.

Low numbers of regulatory T cells in common variable immunodeficiency: association with chronic inflammation in vivo

Common variable immunodeficiency (CVID) is a heterogeneous syndrome characterized by defective immunoglobulin production and high frequency of bacterial infections, autoimmunity and manifestations of chronic inflammation. Abnormalities of CD4+CD25high forkhead box P3 (FoxP3)+ regulatory T cells (Treg) have been associated with autoimmune and inflammatory disorders, and we hypothesized that CVID might be characterized by Treg abnormalities. CD3+ cells from patients and controls were analysed for the expression of FoxP3 mRNA by real time reverse transcription-polymerase chain reaction (RT-PCR). Peripheral blood mononuclear cells from CVID patients and controls were stained for Treg markers, analysed by flow cytometry and compared to clinical characteristics. The main findings were: (i) CVID patients had significantly decreased expression of FoxP3 mRNA and decreased proportions of CD4+CD25highFoxP3+ cells compared to controls; (ii) CVID patients with splenomegaly had even lower proportions of Treg compared to other patients and controls; (iii) serum levels of the inflammatory marker neopterin were correlated negatively with the proportions of Treg within the CVID population, while there was no significant association with bronchiectasis. We have demonstrated decreased proportions of Treg in CVID patients, particularly in those with signs of chronic inflammation. Decreased proportions of TReg are suggested to be pathogenetically important in autoimmunity, and our results suggest that TReg may have a similar role in CVID.

Common variable immunodeficiency syndrome associated with epidermodysplasia verruciformis

We report the association of common variable immunodeficiency syndrome with epidermodysplasia verruciformis (EV) manifesting as flat warts and squamous cell carcinomas in a 21-year-old Hispanic woman. Human papillomavirus (HPV) typing by polymerase chain reaction using an EV-HPV primer system, cloning, and sequencing detected HPV-8 and HPV-23 DNAs in the biopsy sample. Our case is the second reported case of common variable immunodeficiency syndrome associated with EV.

Linkage of autosomal-dominant common variable immunodeficiency to chromosome 4q

The phenotype of common variable immunodeficiency (CVID) is characterized by recurrent infections owing to hypogammaglobulinemia, with deficiency in immunoglobulin (Ig)G and at least one of IgA or IgM. Family studies have shown a genetic association between CVID and selective IgA deficiency (IgAD), the latter being a milder disorder compatible with normal health. Approximately 20-25% of CVID cases are familial, if one includes families with at least one case of CVID and one of IgAD. Nijenhuis et al described a five-generation family with six cases of CVID, five cases of IgAD, and three cases of dysgammaglobulinemia. We conducted a genome-wide scan on this family seeking genetic linkage. One interval on chromosome 4q gives a peak multipoint LOD score of 2.70 using a strict model that treats only the CVID patients and one obligate carrier with dysgammaglobulinemia as affected. Extending the definition of likely affected to include IgAD boosts the peak multipoint LOD score to 3.38. The linkage interval spans at least from D4S2361 to D4S1572. We extended our study to a collection of 32 families with at least one CVID case and a second case of either CVID or IgAD. We used the same dominant penetrance model and genotyped and analyzed nine markers on 4q. The 32 families have a peak multipoint LOD score under heterogeneity of 0.96 between markers D4S423 and D4S1572 within the suggested linkage interval of the first family, and an estimated proportion of linked families (alpha) of 0.32, supporting the existence of a disease-causing gene for autosomal-dominant CVID/IgAD on chromosome 4q.