Rescue of IgM, IgG, and IgA production in common varied immunodeficiency by T cell-independent stimulation with Epstein-Barr virus

Measurement of peripheral B cell subpopulations in common variable immunodeficiency (CVID) using a whole blood method

Recent reports have described reduced populations of CD27+ memory B cells and increased percentages of undifferentiated B cells in peripheral blood of patients with common variable immunodeficiency (CVID). This work has prompted two attempts to classify CVID based on rapid flow cytometric quantification of peripheral blood memory B cells and immature B cells. Evidence to support the hypothesis that such in vitro B cell classification systems correlate with clinical subtypes of CVID is being sought. For the classification to be useful in routine diagnosis, it is important that the flow cytometric method can be used without prior separation of peripheral blood mononuclear cells (PBMC). We have examined 23 CVID patients and 24 controls, using both PBMC and whole blood, and find an excellent correlation between these methods. The reproducibility of the method was excellent. We classified the CVID patients by all three of the existing classifications, including secretion of immunoglobulin by B cells in vitro as described by Bryant, as well as the more recent flow cytometric classification methods. Only one patient changed classification as a result of using whole blood.

Severe deficiency of switched memory B cells (CD27(+)IgM(-)IgD(-)) in subgroups of patients with common variable immunodeficiency: a new approach to classify a heterogeneous disease

Hypogammaglobulinemia is the hallmark of common variable immunodeficiency (CVID) syndrome, a heterogeneous disorder predisposing patients to recurrent bacterial infections. In this study, we investigated the peripheral B-cell compartment of 30 well-characterized CVID patients in comparison to 22 healthy controls. Flow cytometric analysis of peripheral blood lymphocytes revealed a reduction of class-switched CD27(+)IgM(-)IgD(-) memory B cells below 0.4% in 77% of our patients (group I), while this B-cell subpopulation exceeded 0.5% in all healthy donors and in 23% of CVID patients (group II). These results correlate well with the capacity of peripheral blood lymphocytes to produce immunoglobulins in vitro upon stimulation with Staphylococcus aureus Cowan I (SAC) plus interleukin-2 because the production of immunoglobulin G in vitro is entirely dependent on the presence of switched memory B cells. The subdivision of group I into patients with an increased proportion of CD21(-) peripheral B cells (> 20%; group Ia) and patients with normal percentages of CD21(-) B cells (< 20%; group Ib) revealed a significant clustering of patients with splenomegaly and autoimmune cytopenias in group Ia. Based on these observations, we propose a fast and reliable new classification for CVID patients by flow cytometric quantification of class-switched memory and immature B cells in the peripheral blood of patients. Our results point toward defects at various stages of B-cell differentiation in CVID subgroups and support the value of a B-cell-oriented classification principle. A consensus on this new classification system will hopefully provide a tool for rapidly defining homogeneous subgroups of CVID for functional studies and genetic linkage analysis.

Common variable immunodeficiency

Common variable immunodeficiency (CVID) is a common primary immnodeficiency disease, the hallmark of which is hypogammaglobulinemia. Due to the lack of antibodies, patients usually have recurrent bacterial infections, but there are a number of other puzzling manifestations, including inflammatory conditions, autoimmune disease, and the development of lymphomas. Most patients are diagnosed as adults, and delay in the recognition of the antibody defect is common. A number of defects of T cell function and deficits in the memory B cell pool have been identified, but the underlying cause of this defect remains unknown.

Classification of patients with common variable immunodeficiency by B cell secretion of IgM and IgG in response to anti-IgM and interleukin-2

We have classified patients with common variable immunodeficiency (CVI) on the basis of the ability of their B cells to respond to anti-IgM and interleukin (IL)-2 in vitro. Group A had cells unable to secrete IgM or IgG, Group B secreted IgM alone, and Group C secreted both IgM and IgG. A separate small group of patients lacked peripheral B cells. Where Ig secretion was present with anti-IgM and IL-2, EBV increased it, but where it was absent, EBV only induced IgM secretion in two out of eight Group A patients and IgG in one out of five Group B patients. These classifications are related to the sex of the patient and may represent different loci of the block in B-cell differentiation in CVI.

Clinical and immunologic analyses of 103 patients with common variable immunodeficiency

Common variable immunodeficiency (CVI) or hypogammaglobulinemia is a heterogeneous primary immunodeficiency disease in which B cells produce little or no antibody. Since the disease is relatively rare and the spectrum of associated illnesses is broad, patients are given care by a variety of specialists. Thus it has been difficult to determine the incidence of specific complications. In these studies we analyzed 103 consecutively referred CVI patients of age range 3-71 years (average, 29 years) who were followed for a period of 1-13 years (total of 750 patient years). The average serum IgG was 174.4 mg/dl for untreated patients and 301 mg/dl for patients treated with intramuscular immunoglobulin at the time of the first visit. The average IgA was 14.5, and the average IgM was 80.7, with no difference between or after immunoglobulin treatment. About one-half of the patients had T-cell dysfunction, but lymphocyte stimulation responses were inversely related to age, which implies worsened T-cell immunity with age. Serum IgG and IgA levels were found to be statistically associated (P = 0.008), and serum IgG was related to lymphocyte stimulation with concanavalin A (P = 0.01). By 1986, 79 patients were alive, 23 had died, and 1 could not be located. Recurrent bacterial illnesses were common to all patients, and 22% had developed chronic lung disease, 22% autoimmune disease, 15% cancer, 13% hepatitis, and 9% malabsorption. Autoimmune disease was more common in females, and cancer was more likely to develop in the fifth and sixth decades. In 11% of the group, other family members were found to be immunodeficient (hypogammaglobulinemic or IgA deficient). Nine patients died of respiratory insufficiency (with or without other complications), and seven patients died of cancer. These data provide valuable information about the immunologic abnormalities and the spectrum and frequency of illnesses associated with hypogammaglobulinemia.