[Lymphocytic, phenotypic and functional studies in primary immunodeficiencies]

In this report we present the leukocyte phenotypic analysis of 64 cases of primary immune deficiencies (PID). Functional studies related to lymphocyte activation (CD25 (Tac) antigen expression and response to exogenous IL2) as well as immunoregulatory pathways (spontaneous suppressor activities and suppression by soluble factors) were also considered taking immunodeficiency with hyper-IgM (IDHM) as model. The study of mononuclear cell populations with monoclonal antibodies allowed the characterization of defined phenotypes. In common variable immunodeficiency, B cells were present in normal percentages. In sex-linked agammaglobulinemia there was a lack of B lymphocytes and normal distribution of regulatory populations. These results point out the difference between these two entities despite their clinical and infective similarities. Excess of cells expressing CD38 antigen (NV: 4 +/- 2) were found in: predominantly cell mediated immunodeficiency (PCMI): 38 +/- 20; ataxia telangiectasia: 25 +/- 8, hyper-IgE syndrome: 24 +/- 13; Di George syndrome (DGS): 24 +/- 9, chronic mucocutaneous candidiasis: 15 +/- 7. The increased expression of this antigen was correlated with the presence of compromised cellular immunity. The DGS presented the lowest level of CD8 cells (6 +/- 5; NV: 21 +/- 7). In two patients with IDHM, the phenotypic profile was similar to that found in PCMI (low CD3 cells, low CD4/CD8 ratio and elevated CD38 cells). The depressed proliferative response to PHA demonstrates a cellular immune defect. In both patients we found a low expression of CD25 antigen in stimulated cells. Moreover, the addition of exogenous IL2 decreased the proliferative response to PHA in a dose-dependent fashion, suggesting that the cells expressing the CD25 antigen have suppressor capacity.(ABSTRACT TRUNCATED AT 250 WORDS)