Utility of peripheral blood B cell subsets analysis in common variable immunodeficiency

Abstract

Abnormalities in peripheral blood B cell subsets have been identified in common variable immunodeficiency (CVID) patients and classification systems based upon their numbers have been proposed to predict the clinical features. We analysed B lymphocyte subsets by multi-colour flow cytometry (MFC) in a cohort of well-characterized CVID patients to look at their clinical relevance and validate the published association of different classification criteria (Freiburg, Paris and Euroclass) with clinical manifestations. CVID patients had a reduced proportion of total and switched memory B cells (MBC, swMBC) compared to normal controls (P < 0·0006). Patients classified in Freiburg Ia had a higher prevalence of granulomatous diseases (P = 0·0034). The previously published associations with autoimmune diseases could not be confirmed. The Euroclass classification was not predictive of clinical phenotypes. The absolute numbers of all B cell subsets were reduced in CVID patients compared to controls. There was a significant linear correlation between low absolute total B cells and MBC with granulomatous disease (P < 0·05) and a trend towards lower B cells in patients with autoimmune diseases (P = 0·07). Absolute number of different B cell subsets may be more meaningful than their relative percentages in assessing the risk of granulomatous diseases and possibly autoimmunity.

Fig. 1

Analysis of B cell subsets in common variable immunodeficiency (CVID) patients (n = 53) and controls (n = 39) as proportion of lymphocytes and B cells (bars show maximum, 3rd quartile, median, 1st quartile and minimum values): the median percentage of B cells, memory B cells, switched MBC, transitional B cells and plasmablasts was reduced in CVID compared to the controls, P < 0·05. The median CD21^lo B cells was comparable in CVID patients to normal controls; P = 0·1113.

Fig. 2

Analysis of B cell subsets in common variable immunodeficiency (CVID) patients (n = 53) and controls (n = 39) as an absolute count (bars show maximum, 3rd quartile, median, 1st quartile and minimum values): there was significant reduction in the absolute number of total B cells, total and switched memory B cells, CD21^lo cells, transitional B cells and plasmablasts in patients with CVID compared to controls, P < 0·05.