Common variable immunodeficiency: a new look at an old disease

Airway and interstitial lung disease are distinct entities in paediatric common variable immunodeficiency

Common variable immunodeficiency (CVID) is a common primary immune deficiency, caused by undefined defects in lymphocyte function, and is treated routinely by immunoglobulin substitution. CVID complications include airway disease (AD) and interstitial lung disease (ILD). It was not known if AD and ILD in CVID have a common immunological aetiology and should be considered separate features of the same disease, or as distinct syndromes that require specialized monitoring and treatment. We used high-resolution computed tomography (CT) to diagnose AD or ILD in paediatric CVID patients. Spirometry and body plethysmography did not differentiate between ILD and AD. Patients with AD (n = 11, 20%) developed more pneumonias while children with ILD (n = 8, 15%) showed immune dysregulation characterized by autoimmune complications, more severe memory B cell reduction and expansion of non-naive cytotoxic T cells. In conclusion, ILD and AD in CVID have dissimilar clinical and immunological characteristics, suggesting distinct aetiology requiring tailored monitoring and treatment of these patient subgroups.

Lung MRI as a possible alternative to CT scan for patients with primary immune deficiencies and increased radiosensitivity

BACKGROUND

Patients with common variable immunodeficiency (CVID) suffer from respiratory infections leading over time to permanent lung damage. Increased radiosensitivity has been described, and clinicians should consider a risk-benefit assessment when ordering a CT scan, in that the exact level of "safe" radiation exposure is unknown.

METHODS

Twenty-one patients with CVID were evaluated with chest CT scan, MRI, and pulmonary function tests on the same day. MRI protocol included a T2-weighted rotating blade-like k-space covering sequence (time repetition, 2,000; echo train = 27; field of view, 400 mm; flip angle, 150; slice thickness, 5 mm) on axial and coronal planes. The bronchial and parenchymal abnormalities were compared with those identified by CT scan applying a modified Bhalla scoring system to assess bronchiectasis, bronchial wall thickening, number of bronchial generations involved, mucous plugging, consolidations, emphysema, bullae, and nodules.

RESULTS

CT scan and MRI findings were comparable for moderate to severe degrees of bronchial and parenchymal alterations. A low concordance was found between MRI and CT scan for lower scores of bronchial abnormalities. CT scan allowed a better identification of peripheral airways abnormalities.

CONCLUSIONS

Lung alterations in patients with higher radiation sensitivity, such as patients with CVID, might be evaluated by MRI, a radiation-free technique alternative to CT scan.

T and B lymphocyte abnormalities in bone marrow biopsies of common variable immunodeficiency

In common variable immunodeficiency (CVID) defects in early stages of B-cell development, bone marrow (BM) plasma cells and T lymphocytes have not been studied systematically. Here we report the first morphologic and flow cytometric study of B- and T-cell populations in CVID BM biopsies and aspirates. Whereas the hematopoietic compartment showed no major lineage abnormalities, analysis of the lymphoid compartment exhibited major pathologic alterations. In 94% of the patients, BM plasma cells were either absent or significantly reduced and correlated with serum immunoglobulin G levels. Biopsies from CVID patients had significantly more diffuse and nodular CD3(+) T lymphocyte infiltrates than biopsies from controls. These infiltrates correlated with autoimmune cytopenia but not with other clinical symptoms or with disease duration and peripheral B-cell counts. Nodular T-cell infiltrates correlated significantly with circulating CD4(+)CD45R0(+) memory T cells, elevated soluble IL2-receptor and neopterin serum levels indicating an activated T-cell compartment in most patients. Nine of 25 patients had a partial block in B-cell development at the pre-B-I to pre-B-II stage. Because the developmental block correlates with lower transitional and mature B-cell counts in the periphery, we propose that these patients might form a new subgroup of CVID patients.

Inflammation in common variable immunodeficiency is associated with a distinct CD8(+) response to cytomegalovirus

BACKGROUND

Common variable immunodeficiency is the most common primary immunodeficiency. A subset of patients has debilitating inflammatory complications.

OBJECTIVES

We investigated the role of cytomegalovirus (CMV), and the T-cell response targeted at this virus, in this inflammatory disease.

METHODS

Phenotypic and functional assays were used to profile CMV-specific T cells in patients with common variable immunodeficiency with and without inflammatory complications. Highly sensitive immunohistochemistry was used to detect CMV antigens at sites of inflammation.

RESULTS

Cytomegalovirus was significantly associated with inflammatory disease, which occurred in 31 of 43 (72%) virus-exposed patients and 8 of 31 (26%) naive patients (P = .0001). CMV pp65-NLVPMVATV epitope-specific CD8(+) T-cell frequencies were significantly elevated in inflammatory patients, but these cells did not show evidence of exhaustion, with low levels of programmed death-1 and high T-cell receptor avidity. Rather, they showed features consistent with high in vivo functionality and proliferative activity including reduced levels of the anti-inflammatory marker CD73 (1.67% of NLV(+) cells were CD73(+) vs 42.01% in noninflammatory patients; P = .004) and increased Ki-67 expression (37% vs 2% in noninflammatory patients; P < .0001). In vitro, the CMV-specific T cells showed high antigen-specific proliferative potential compared with cells from noninflammatory patients. By using sensitive immunohistochemistry, we detected for the first time viral antigen at the sites of inflammation, indicative of active viral replication.

CONCLUSION

Our data strongly support a direct role for CMV and a hyperreactive CMV-specific immune response in the debilitating chronic inflammatory complications of common variable immunodeficiency.

Effectiveness of immunoglobulin replacement therapy on clinical outcome in patients with primary antibody deficiencies: results from a multicenter prospective cohort study

A 5-years multicenter prospective study on 201 patients with common variable immunodeficiencies and 101 patients with X-linked agammaglobulinemia over a cumulative follow-up period of 1,365 patient-years was conducted to identify prognostic markers and risk factors for associated clinical co-morbidities, the effects of long-term immunoglobulin treatment and the IgG trough level to be maintained over time required to minimise infection risk. Overall, 21% of the patients with common variable immunodeficiencies and 24% of patients with X-linked agammaglobulinemia remained infection free during the study. A reduction of pneumonia episodes has been observed after initiation of Ig replacement. During the observation time, pneumonia incidence remained low and constant over time. Patients with pneumonia did not have significant lower IgG trough levels than patients without pneumonia, with the exception of patients whose IgG trough levels were persistently <400 mg/dL. In X-linked agammaglobulinemia, the only co-morbidity risk factor identified for pneumonia by the final multivariable model was the presence of bronchiectasis. In common variable immunodeficiencies, our data allowed us to identify a clinical phenotype characterised by a high pneumonia risk: patients with low IgG and IgA levels at diagnosis; patients who had IgA level <7 mg/dL and who had bronchiectasis. The effect of therapy with immunoglobulins at replacement dosage for non-infectious co-morbidities (autoimmunity, lymphocytic hyperplasia and enteropathy) remains to be established. A unique general protective trough IgG level in antibody deficiency patients will remain undefined because of the major role played by the progression of lung disease in X-linked agammaglobulinemia and in a subset of patients with common variable immunodeficiencies.

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.

Diffuse normolipemic plane xanthoma in a child with common variable immunodeficiency

Diffuse plane xanthoma is extremely rare in children. Although it may be associated with systemic disorders, its etiology remains obscure in a number of patients. The case of a boy with common variable immunodeficiency and normal serum lipid levels, who developed diffuse plane xanthoma during treatment with intravenous immunoglobulins, is reported.

Intravenous immunoglobulin induces proliferation and immunoglobulin synthesis from B cells of patients with common variable immunodeficiency: a mechanism underlying the beneficial effect of IVIg in primary immunodeficiencies

Common variable immunodeficiency (CVID) is associated with low serum immunoglobulin concentrations and an increased susceptibility to infections and autoimmune diseases. The treatment of choice for CVID patients is replacement intravenous immunoglobulin (IVIg) therapy. IVIg has been beneficial in preventing or alleviating the severity of infections and autoimmune and inflammatory process in majority of CVID patients. Although the mechanisms of action of IVIg given as 'therapeutic high dose' in patients with autoimmune diseases are well studied, the underlying mechanisms of beneficial effects of IVIg in primary immunodeficiencies are not completely understood. Therefore we investigated the effect of 'replacement dose' of IVIg by probing its action on B cells from CVID patients. We demonstrate that IVIg at low doses induces proliferation and immunoglobulin synthesis from B cells of CVID patients. Interestingly, B cell stimulation by IVIg is not associated with induction of B cell effector cytokine IFN-γ and of transcription factor T-bet. Together, our results indicate that in some CVID patients, IVIg rectifies the defective signaling of B cells normally provided by T cells and delivers T-independent signaling for B cells to proliferate. IVIg 'replacement therapy' in primary immunodeficiencies is therefore not a merepassive transfer of antibodies to prevent exclusively the recurrent infections; rather it has an active role in regulating autoimmune and inflammatory responses through modulating B cell functions and thus imposing dynamic equilibrium of the immune system.

Do ribosomopathies explain some cases of common variable immunodeficiency?

The considerable clinical heterogeneity of patients with common variable immunodeficiency disorders (CVID) shares some similarity with bone-marrow failure disorders such as Diamond-Blackfan anaemia (DBA) and Shwachman-Diamond syndrome (SDS), now recognized as defects in ribosome biogenesis or ribosomopathies. The recognition of a patient with DBA who subsequently developed CVID lends support to our previous finding of a heterozygous mutation in the SBDS gene of SBDS in another CVID patient, suggesting that ribosome biogenesis defects are responsible for a subset of CVID. Genetic defects in the ribosomal translational machinery responsible for various bone marrow failure syndromes are recognized readily when they manifest in children, but diagnosing these in adults presenting with complex phenotypes and hypogammaglobulinaemia can be a challenge. In this perspective paper, we discuss our clinical experience in CVID patients with ribosomopathies, and review the immunological abnormalities in other conditions associated with ribosomal dysfunction. With genetic testing available for various bone marrow failure syndromes, our hypothesis that ribosomal abnormalities may be present in patients with CVID could be proved in future studies by testing for mutations in specific ribosomal genes. New knowledge might then be translated into novel therapeutic strategies for patients in this group of immunodeficiency disorders.

Inflammatory bowel diseases in patients with adaptive and complement immunodeficiency disorders

Crohn's disease and ulcerative colitis are idiopathic chronic inflammatory diseases that primarily affect the gastrointestinal tract. The underlying causes remain poorly understood, but there is a growing body of evidence advocating a likely primary pathogenic role for immunodeficiency in the development of Crohn's lesions. Concordantly, a number of congenital immunodeficiencies disrupting the cellular innate immune system strongly predispose to noninfectious, Crohn's-like inflammatory bowel disease. There are case reports and series suggesting that the same may be true for some of the congenital adaptive and complement immunodeficiencies. This review considers and critiques these potential associations.

High Prevalence of Humoral Immunodeficiency Patients with Refractory Chronic Rhinosinusitis

Background

The purpose of this study was to investigate the prevalence and contribution of humoral immunodeficiency in refractory chronic rhinosinusitis (RCRS). This study was performed at a tertiary care academic referral center.

Methods

RCRS patients who had at least three episodes of documented sinusitis in the previous year despite antibiotic therapy, who had endoscopic sinus surgery performed at University of Iowa Health Care (UIHC), and who were evaluated by the UIHC Adult Immune Disorder Clinic were included. Exclusion criteria included allergic fungal sinusitis, human immunodeficiency virus, and other causes of secondary immunodeficiency. Sixty-seven patients fulfilled the inclusion and exclusion criteria. The results of their immunologic evaluation for atopy and humoral immune function were examined.

Results

The average age of these patients was 50 years (±11.6 years). Twenty-eight (42%) patients had at least one positive result on allergy skin testing. Determination of quantitative immunoglobulins showed low IgG in 9%, low IgA in 3%, and low IgM in 12% of patients. Common variable immunodeficiency was diagnosed in one case. Immunoglobulin G subclasses were tested in 31 cases and found low in 6 patients. Fifty-one patients underwent a dynamic assessment of their antibody response by examining the increase in antibody titer to an unconjugated pneumococcal polysaccharide vaccine. Sixty-seven percent of patients failed to produce more than a fourfold increase in postimmunization antibody titer for >7 of 14 serotypes being tested and were considered to have functional antibody deficiency.

Conclusion

This retrospective review shows an unexpectedly high prevalence of humoral immune dysfunction in patients with RCRS. These findings suggest that assessment of immune function should be undertaken routinely in RCRS. Immune assessment should first include measurement of serum immunoglobulin levels; if these are normal, then functional antibody responses should be evaluated.

Diagnostic strategy for patients with hypogammaglobulinemia in rheumatology

The discovery of hypogammaglobulinemia, which is defined as a plasmatic level of immunoglobulin (Ig) under 5 g/L is rare in clinical practice. However, the management of immunodepressed patients in rheumatology, sometimes due to the use of immunosuppressive treatments such as anti-CD20 in chronic inflammatory rheumatisms, increases the risk of being confronted to this situation. The discovery of hypogammaglobulinemia in clinical practice, sometimes by chance, must never be neglected and requires a rigorous diagnosis approach. First of all, in adults, secondary causes, in particular lymphoid hemopathies or drug-related causes (immunosuppressors, antiepileptics) must be eliminated. A renal (nephrotic syndrome) or digestive (protein-losing enteropathy) leakage of Ig is also possible. More rarely, it is due to an authentic primary immunodeficiency (PID) discovered in adulthood: common variable immunodeficiency (CVID) which is the most frequent form of PID, affects young adults between 20 and 30 years and can sometimes trigger joint symptoms similar to those in rheumatoid arthritis; or Good syndrome, which associates hypogammaglobulinemia, thymoma and recurrent infections around the age of 40 years. In most cases, after confirming hypogammaglobulinemia on a second test, biological examinations and thoracic-abdominal-pelvic CT scan will guide the diagnosis, after which the opinion of a specialist can be sought depending on the findings of the above examinations. At the end of this review, we provide a decision tree to guide the clinician confronted to an adult-onset hypogammaglobulinemia.

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.

A hepatitis C-positive patient with new onset of nephrotic syndrome and systemic amyloidosis secondary to common variable immunodeficiency

Common variable immunodeficiency (CVID) is a heterogenous group of predominantly antibody-deficiency disorders that make up the greatest proportion of patients with symptomatic primary hypogammaglobulinemia. The rare coincidence of amyloidosis and hypogammaglobulinemia has been reported previously. Contrary to the usual insidious, slowly progressive disease following hepatitis C infection, a rapidly progressive cirrhotic form can develop in hypogammaglobulinemic patients. We report a HCV-positive patient with a new onset of nephrotic syndrome and systemic amyloidosis secondary to CVID. Blood analyses showed serum creatinine of 1.8 mg/dL and serum albumin of 3.1 gm/dL; 24-h urinary protein was 11 800 mg/day. Serum immunoglobulin levels were IgG 340 mg/dL, IgM 18 mg/dL, IgA 11 mg/dL. Duodenal biopsy revealed AA-type amyloidosis with potassium permanganate and Congo red staining. After a month of antiproteinuric therapy, the proteinuria was reduced to 3350 mg/day.

Common variable immunodeficiency: computed tomography evaluation of bronchopulmonary changes including nodular lesions in 40 patients. Correlation with clinical and immunological data

BACKGROUND

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency characterized by recurrent respiratory tract infections, mainly sustained by encapsulated bacteria, that may cause irreversible changes in the lungs.

METHODS

Forty patients with CVID were evaluated by computed tomography of the lung; 20 of these underwent computed tomographic follow-up in a 5-year period, during which immunoglobulin replacement therapy was regularly performed.

RESULTS

Pulmonary changes were present in 65% of patients; bronchiectases were present in 65.38%. The incidence of pulmonary nodules was very high (38.46%) and correlated with splenomegaly (70%) and autoimmune phenomena (80%).

CONCLUSIONS

Our study underscores the essential role of imaging, in particular computed tomography, in the identification and monitoring of pulmonary lesions in a large cohort of CVID patients, contributing at the same time to select patients more at risk to develop nodular lesions and potentially to use more appropriate therapeutic strategies.

The French national registry of primary immunodeficiency diseases

The French National Reference Center of Primary Immunodeficiencies (CEREDIH) was established in 2005 and now constitutes a nationwide network of pediatric and adult medicine departments in university medical centers. The registry comprises a total of 3,083 patients (mainly children), with an overall prevalence of 4.4 cases per 100,000 inhabitants. Predominantly B-cell immunodeficiencies are the most common diseases observed (43%). The proportion of common variable immunodeficiencies (CVIDs, 14%) is lower than reported by national registries in other developed countries. The data suggest that although referral to expert centers is fairly adequate for children, this is not yet the case in France for adults. The distribution of primary immunodeficiencies (PIDs) varied significantly across distinct geographical areas and this suggested regional differences in patient care. As the world's largest national registry of PIDs, CEREDIH provides a basis for both further studies and activities aimed at raising the physicians' awareness of PIDs (notably in adults).

Efficacy and safety of a new 20% immunoglobulin preparation for subcutaneous administration, IgPro20, in patients with primary immunodeficiency

Subcutaneous human IgG (SCIG) therapy in primary immunodeficiency (PID) offers sustained IgG levels throughout the dosing cycle and fewer adverse events (AEs) compared to intravenous immunoglobulin (IVIG). A phase I study showed good local tolerability of IgPro20, a new 20% liquid SCIG stabilized with L-proline. A prospective, open-label, multicenter, single-arm, phase III study evaluated the efficacy and safety of IgPro20 in patients with PID over 15 months. Forty-nine patients (5–72 years) previously treated with IVIG received weekly subcutaneous infusions of IgPro20. The mean serum IgG level was 12.5 g/L. No serious bacterial infections were reported. There were 96 nonserious infections (rate 2.76/patient per year). The rate of days missed from work/school was 2.06/patient per year, and the rate of hospitalization was 0.2/patient per year. Ninety-nine percent of AEs were mild or moderate. No serious, IgPro20-related AEs were reported. IgPro20 effectively protected patients with PID against infections and maintained serum IgG levels without causing unexpected AEs.

Patients with humoral primary immunodeficiency do not develop protective anti-influenza antibody titers after vaccination with trivalent subunit influenza vaccine

Yearly influenza vaccination is recommended for patients with humoral primary immunodeficiency (hPID). However, humoral responses following vaccination can be expected to be reduced in these patients. The efficacy of influenza vaccination in patients with hPID, anti-influenza antibody responses was assessed in 26 patients with hPID and 26 matched healthy controls (HC) using hemagglutination inhibition assay. Following vaccination, geometric mean titers (GMT) significantly increased for all influenza strains in the HC group, but only for A/H1N1 in the patient group. Fold increase in anti-influenza titer and seroprotection rates were lower for patients than for HC for A/H3N2 and A/H1N1, leading to postvaccination titer > or =40 in only 29% and 83% vs. 77% and 100%, respectively. Previous vaccination in patients and treatment with IVIg did not result in a higher rate of postvaccination titer > or =40. In conclusion, patients with hPID show hardly any humoral response following influenza vaccination.

A CT scan score for the assessment of lung disease in children with common variable immunodeficiency disorders

BACKGROUND

The prevalence and severity of structural lung disease in children with common variable immunodeficiency (CVID) disorders is not well known, and a dedicated CT scanning protocol and CT scan scoring system have not been described in this category.

METHODS

This was a cohort study of 54 children (34 CVID, 20 CVID-like disorder) in a stable condition who underwent volumetric inspiratory and end-expiratory CT scans. Scans were scored for airway abnormalities, interstitial and parenchymal lung disease, and lymphadenopathy using a newly developed CT scan scoring system. Scores were normalized to a 0% to 100% scale. Observer agreement was assessed using an intraclass correlation coefficient (Ri). Prevalence and severity of CT scan abnormalities were calculated.

RESULTS

Structural lung disease was common (85%-93%), but usually mild as reflected in the relatively low scores (bronchiectasis score 2.8% +/- 6.4%). Moderate-to-severe bronchiectasis was found in three (5%) patients. Expiratory air trapping was the most common finding, found in 71% to 80%, but often in a mild form; application of a cut off level of > 10% reduced its prevalence to 33% to 38%. In 9% to 15% of all patients, air trapping was the only abnormality. Multiple lung nodules were seen in 24% to 25% and could disappear after corticosteroid treatment. Observer agreement was moderate (Ri 0.6-0.79) to good (Ri > 0.8) for all items and the composite scores, except airway wall thickening.

CONCLUSION

In children with CVID disorders, mild structural lung disease is common. Expiratory CT scans show the most frequent abnormality, air trapping. The occurrence of (silent) lung disease progression and the clinical impact of CT scans require further investigations.

CD46-induced human Treg enhance B-cell responses

Regulatory CD4(+) T cells (Treg) are important modulators of the immune response. Different types of Treg have been identified based on whether they are thymically derived (natural Treg) or induced in the periphery (adaptive Treg). We recently reported on an adaptive Treg phenotype that can be induced by the concomitant stimulation of human CD4(+) T cells through CD3 and the membrane complement regulator CD46. These complement (CD46)-induced regulatory T cells (cTreg) potently inhibit bystander T-cell proliferation through high-level secretion of IL-10. In addition, cTreg express granzyme B and exhibit cytotoxic effects toward activated effector T cells. Here, we analyzed the effect of cTreg on B-cell functions in a co-culture system. We found that cTreg enhance B-cell Ab production. This B-cell support is dependent on cell/cell contact as well as cTreg-derived IL-10. In addition, we show that T cells from a CD46-deficient patient are not capable of promoting B-cell responses, whereas CD46-deficient B cells have no intrinsic defect in Ig production. This finding may relate to a subset of CD46-deficient patients, who present with common variable immunodeficiency. Thus, the lack of cTreg function in optimizing B-cell responses could explain why some CD46-deficient patients develop common variable immunodeficiency.

Primary immunodeficiencies

In the last years, advances in molecular genetics and immunology have resulted in the identification of a growing number of genes causing primary immunodeficiencies (PIDs) in human subjects and a better understanding of the pathophysiology of these disorders. Characterization of the molecular mechanisms of PIDs has also facilitated the development of novel diagnostic assays based on analysis of the expression of the protein encoded by the PID-specific gene. Pilot newborn screening programs for the identification of infants with severe combined immunodeficiency have been initiated. Finally, significant advances have been made in the treatment of PIDs based on the use of subcutaneous immunoglobulins, hematopoietic cell transplantation from unrelated donors and cord blood, and gene therapy. In this review we will discuss the pathogenesis, diagnosis, and treatment of PIDs, with special attention to recent advances in the field.

Lymphocyte characteristics in children with common variable immunodeficiency

The diagnosis of common variable immunodeficiency (CVID) is reserved for patients who suffer from undefined B cell dysfunction. Division of the CVID population into subgroups enables research for underlying disease causes. We studied clinical features and lymphocyte characteristics in 38 children with CVID and compared them to 30 children with less severe antibody deficiencies (e.g. specific antibody deficiency combined with IgG subclass deficiency) and with 65 pediatric controls. Most pediatric immune phenotypes were comparable to adult CVID phenotypes, including a selective increase in newly formed B cells and a decrease in memory B cells and CD4(+) T cells. Eighteen percent of pediatric patients had a mutation in the TNFRSF13B gene, which requires further investigation. Finally, pediatric patients with decreased class-switched memory B cells had significantly more complications. A pediatric classification for CVID may enable prediction and early diagnosis of disease related complications and provide a framework for further etiologic research.

Common variable immunodeficiency associated with inflammatory bowel disease and type I diabetes

Common variable immunodeficiency (CVID) is a heterogeneous group of primary immunodeficiency disorders characterized by defective antibody production, low levels of serum immunoglobulins and increased susceptibility to infection. The patient was a 39-year-old male who was admitted to the gastroenterology department with a two week history of diarrhea, blunt abdominal pain below the umbilicus, prolonged febrile state, loss of appetite and loss of body weight of 18 kg during the previous six months. Screening tests of serum immunoglobulins showed decreased concentrations of three types of immunoglobulins: IgA < 0.24 g/L, IgM < 0.18 g/L and IgG < 1.55 g/L. Lymphocytes immunophenotypisation revealed inversed CD4⁺/8⁺ T cells ratio, 0.31 and absence of plasma cells (CD138 negative). Colonoscopy showed a rectal mucosa like cobblestones with multiple longitudinal and serpentinous ulceration, without involvement of other segments of the colon and the small intestine. Histopathology revealed aphtous ulcerative lesions, transmural inflammation with multiple lymphoid aggregates and benign lymphoid nodular hyperplasia of the small intestine. Plasma cells were absent from the lamina propria. Magnetic resonance imaging of a perianal fistula demonstrated a trans-sphicteric type. This case is specific because of the three illnesses associated and only one case of an association of diabetes mellitus type I and immunodeficiency reported thus far.

Reduced immunoglobulin M is associated with sinus mucosal thickening, osteitis and sinus surgery in patients with common variable immunodeficiency

BACKGROUND

Although common variable immunodeficiency (CVID) is associated with sinopulmonary disease, there are no previous systematic evaluations comparing computed tomographic (CT) sinus imaging with immunoglobulin measurements in patients with this condition.

METHODS

We performed a retrospective review by a blinded observer using the Lund-Mackay numerical scoring scale as well as a visual scale for remodeling changes in the paranasal sinus bone on CT scans in CVID patients.

RESULTS

The sinus CT scans of 19 subjects (9 males, 10 females; median age at diagnosis 34 years) are described. There was an inverse relationship between serum IgM and sinus mucosal thickening as described by the Lund-Mackay scale (R = -0.6398; p = 0.0032). Osteitis of the paranasal sinus bone was almost exclusively found in patients with a reduced serum IgM level of less than 25 mg/dl (p = 0.0074).

CONCLUSION

This is the first study to show that sinus mucosal thickening on CT in patients with CVID is inversely related to serum IgM levels.

Dock8 mutations cripple B cell immunological synapses, germinal centers and long-lived antibody production

To identify genes and mechanisms involved in humoral immunity, we did a mouse genetic screen for mutations that do not affect the first wave of antibody to immunization but disrupt response maturation and persistence. The first two mutants identified had loss-of-function mutations in the gene encoding a previously obscure member of a family of Rho-Rac GTP-exchange factors, DOCK8. DOCK8-mutant B cells were unable to form marginal zone B cells or to persist in germinal centers and undergo affinity maturation. Dock8 mutations disrupted accumulation of the integrin ligand ICAM-1 in the B cell immunological synapse but did not alter other aspects of B cell antigen receptor signaling. Humoral immunodeficiency due to Dock8 mutation provides evidence that organization of the immunological synapse is critical for signaling the survival of B cell subsets required for long-lasting immunity.

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.

Therapeutic approaches to secondary immune thrombocytopenic purpura

Secondary thrombocytopenia is similar to primary or idiopathic thrombocytopenia (ITP) in that it is characterized by reduced platelet production or increased platelet destruction resulting in platelet levels<60,000/microL. Thrombocytopenia can occur from secondary causes associated with chronic disorders or with disturbed immune function due to chronic infections, lymphoproliferative and myeloproliferative disorders, pregnancy, or autoimmune disorders. Diagnosis of secondary ITP in some cases is complex, and the thrombocytopenia can often be resolved by treating the underlying disorder to the extent this is possible. In most cases, treatment is focused on reducing platelet destruction, but, in some cases, treatment may also be directed at stimulating platelet production. The most problematic cases of thrombocytopenia may be seen in pregnant women. This review will address various agents and their utility in treating ITP from secondary causes; in addition, thrombocytopenia in pregnancy, ITP in immunodeficiency conditions, and drug-induced thrombocytopenia will be discussed. Unlike primary ITP, treatment often must be tailored to the specific circumstance underlying the secondary ITP, even if the condition itself is incurable.

Serum bactericidal activity against Helicobacter pylori in patients with hypogammaglobulinaemia

The two major primary antibody deficiency disorders are X-linked hypogammaglobulinaemia (XLA) and common variable immunodeficiency (CVID). CVID patients have an elevated risk for gastric cancer and extra-nodal marginal zone lymphoma. Both diseases are associated with Helicobacter pylori infection. We investigated whether antibody deficiency leads to defective serum bactericidal activity against H. pylori. We also investigated the correlation with immunoglobulin (Ig)M levels and observed the terminal complement complex (TCC) activity. Sera of 13 CVID patients (four H. pylori positive), one patient with hyper-IgM syndrome, one patient with Good syndrome (both H. pylori positive), five XLA patients, four H. pylori seropositive controls, four H. pylori seronegative controls and a sample of pooled human serum (PHS) were incubated in vitro with bacterial suspensions of H. pylori for 30 min. After 72 h of culture, colony-forming units were counted. TCC formation was measured by enzyme-linked immunosorbent assay. We found that normal human serum is bactericidal for H. pylori, whereas heat-inactivated serum shows hardly any killing of H. pylori. Serum (1%) of hypogammaglobulinaemia patients has a decreased bactericidal activity against H. pylori. Helicobacter pylori-positive (HP(+)) normal individuals show more than 90% killing of H. pylori, whereas CVID patients show 35% killing (P = 0.007) and XLA patients only 19% (P = 0.003). Serum (1%) of HP(+) volunteers showed significantly better killing compared with serum of H. pylori-negative (HP(-)) volunteers (P = 0.034). No correlation between (substituted) IgG levels and serum bactericidal activity was found, but a weak correlation between total serum IgM and serum bactericidal activity was found. In conclusion, serum bactericidal activity against H. pylori is decreased in patients with hypogammaglobulinaemia. Heat treatment of the serum abolished the bactericidal capacity, indicating that complement activity is essential for the bactericidal effect.

Rituximab as monotherapy and in addition to reduced CHOP in children with primary immunodeficiency and non-Hodgkin lymphoma

Children with primary immunodeficiency or chromosomal breakage syndromes are at increased risk of developing non-Hodgkin lymphomas; they cannot tolerate standard chemotherapy regimens. We report two children with diffuse, large, B-cell lymphoma; one had ataxia telangiectasia and one had common variable immunodeficiency. Both were given rituximab, 1 as monotherapy and 1 in combination with a reduced CHOP regimen. Complete remission was obtained in each patient. Use of rituximab as a first-line monotherapy or in conjunction with reduced chemotherapy should be considered to reduce cytotoxic effects.

Regulatory T cell dysfunction in subjects with common variable immunodeficiency complicated by autoimmune disease

Approximately 25% of subjects with common variable immunodeficiency (CVID) develop autoimmune disease. We analyzed T cell subsets, specifically regulatory T cells along with B cell subsets to determine whether there were changes in regulatory T cells which would correlate with the autoimmune disease clinical phenotype in CVID subjects. We hypothesized that regulatory T cell (CD4+CD25hiCD127lo) suppressive function would be impaired in CVID subjects with autoimmune disease. Using purified, sorted Treg from CVID subjects (n=14) and from healthy controls (HC, n=5) in standard suppression assays, we found the suppressive function of Treg from CVID subjects with autoimmune disease (CVID w/ AI, n=8) to be significantly attenuated compared to CVID subjects with no autoimmune disease (CVID w/o AI, n=6) and to HC (n=5). A number of proteins associated with Treg function were decreased in expression as detected through immunofluorescent antibody via flow cytometry (mean fluorescence intensity (MFI) of FoxP3, Granzyme A, XCL1, pSTAT5, and GITR in Treg was significantly lower (by up to 3 fold) in CVID w/ AI compared to CVID w/o AI and HC. Furthermore, a statistically significant correlation was found between intracellular MFI of FoxP3, Granzyme A, and pSTAT5 in Treg and the degree of Treg dysfunction. These results suggest that attenuation of Treg function is associated with autoimmune disease in CVID subjects and may contribute to autoimmune pathogenesis.