CD8+HLA-DR+ T lymphocytes are increased in common variable immunodeficiency patients with impaired memory B-cell differentiation

The recently proposed Piqueras classification of common variable immunodeficiency (CVID) patients is based on flow cytometric quantification of IgD class-switched and CD27 membrane-expressing mature blood B cells. But, many patients also have circulating T cells with immunophenotypic abnormalities, often associated with clinical complications, such as splenomegaly, autoimmune disease, lymphoid proliferation and/or granulomatosis. In 50 unselected CIVD patients, classified according to CD27 and IgD B-cell expression, we analyzed T-lymphocyte subsets according to their expression of HLA-DR and intracellular perforin and/or granzyme B in CD8+ T lymphocytes, CCR7 and CD45RA. CD3+DR+ T-lymphocyte percentages, predominantly CD8+DR+, were significantly higher in patients with clinical complications. MB0 classified patients, characterized by fewer CD27+ B cells, had higher percentages of CD8+DR+ T lymphocytes expressing perforin and/or granzyme with a differentiated effector (CCR7- and CD45RA+) phenotype. In contrast, MB2 patients (with normal CD27+ and IgD- B cells) were free of clinical complications and showed no signs of T-cell activation. MB1 patients (normal CD27+ numbers but fewer IgD- B cells) were either clinically normal or had complications. Combining the set of markers described herein might better define homogeneous groups of patients for etiological studies and clearly segregate patients with clinical complications.

Altered dendritic cell distribution in patients with common variable immunodeficiency

Recent data suggest a critical role for dendritic cells (DCs) in the generation of immunoglobulin-secreting plasma cells. In the work reported herein, we analyzed the frequency of peripheral blood plasmacytoid DCs (pDCs) and myeloid DCs (mDCs) in a cohort of 44 adults with common variable immunodeficiency (CVID) classified according to their CD27 membrane expression status on B cells. A deep alteration in the distribution of DC subsets, especially of pDCs, in the peripheral blood of CVID patients was found. Patients with a reduced number of class-switched CD27+IgD-IgM- memory B cells and patients with granulomatous disease had a dramatic decrease in pDCs (P = 0.00005 and 0.0003 vs controls, respectively) and, to a lesser extent, of mDCs (P = 0.001 and 0.01 vs controls, respectively). In contrast, patients with normal numbers of switched memory B cells had a DC distribution pattern similar to that in controls. Taken together, our results raise the possibility that innate immunity contributes to pathogenesis in CVID.

Le déficit immunitaire commun variable de l’adulte : étude clinique, biologique et immunologique chez 17 patients

PURPOSE

Common variable immunodeficiency (CVID) is an immune defect characterized by primary hypogammaglobulinemia. Most of the time, clinical manifestations that reveal CVID are recurrent bacterial infections, but auto-immune or granulomatous events may occur.

METHODS

This retrospective study was conducted on 17 patients fulfilling the classical CVID definition. Lymphocyte activation level was evaluated in 12 patients through HLA-DR expression on lymphocytes subsets.

RESULTS

This study includes 17 patients, 7 men and 10 women. The mean age at the first clinical manifestation is 23 years and the mean age at diagnosis is 39 years. Recurrent upper and lower bacterial respiratory tract infections are common to all patients. Abdominal infection due to Mycobacterium avium-intracellulare complex is found in one patient. Digestive events are dominated by chronic diarrhea caused by giardiasis, nodular lymphoid hyperplasia or villous atrophy. Seven patients developed auto-immune conditions (insulin dependent diabetes, idiopathic thrombocytopenic purpura (ITP), rheumatoid arthritis) and 7 patients have a splenomegaly. Non caseating granulomas in the spleen or in lymph node biopsies are found in 3 patients. Ten patients have a T lymphopenia, 2 have a B lymphopenia, 5 have a CD4/CD8 ratio <1, and 6 have T CD4(+) lymphocytes <400/mm(3). The study of HLA-DR expression on lymphocytes subsets shows that 7/12 patients have activated T CD4(+) and/or CD8(+) cells and these patients have auto-immune or tumoral manifestations. The other 5 patients do not have activated T lymphocytes but present with infectious events only.

CONCLUSIONS

Our study allows the separation of patients with CVID according to their T lymphocytes activation level. A patient's classification is necessary to define homogeneous groups of patients to perform genetic and functional studies which will probably reveal heterogeneous molecular abnormalities.