543 Alteration of Humoral and Cellular Immunity in Patients with Ataxia-Telangiectasia at Reference Center in Sao Paulo, Brazil

BACKGROUND: To analyze the levels of immunoglobulins and the number of T and B lymphocytes in patients with ataxia-telangiectasia (AT) followed in outpatient immunology. METHODS: A descriptive and retrospective study of medical records of patients diagnosed with AT followed at Federal University of Sao Paulo, Brazil. RESULTS: Of 24 patients studied, 5 (21%) had levels of IgG below the age-normal percentile 3 (p3), 3 patients (14%) had values around the 10th percentile. IgA values were below the p3 in 11 (46%) subjects; draws attention to high IgM in 14 (58%) individuals. Anemia was found in only 3 patients (12.5%), in the first case the etiology was probably iron deficiency, the second had a diagnosis of Waldestrom Macroglobulinemia and the third was with sepsis. Seventeen (70.8%) had total lymphocyte count below the p10, marked leukopenia (below p3) was observed in 5 (20.8%). Neutropenia (<1500 cells /mm(3)) was observed in only 2 (8.3%) and eosinophilia (>500 cells /mm(3)) in 6 patients (25%). In 79% (19/24) of patients the lymphocyte subpopulation was analyzed, and 17 (89.5%) of 19 subjects showed low number of CD3+ cells compared with controls of similar age. The number of CD4+ T cells was below the p10 in 21 of 23 evaluated patients (91.3%). Interestingly, in most patients the number of CD4+ T cells was between 200 and 500/mm(3), suggesting severe depression of cellular immunity. Only one patient had a high number of CD8+ T lymphocytes, in 15 (65%) of 23 subjects the number of CD8+ T cells was below p10. Eight patients underwent a CD19+ cell count, and all of them showed low values. NK cells were quantified in 7 individuals, 3 (43%) cases showing high levels. CONCLUSIONS: Most patients treated in our department showed dysgammaglobulinemia, and low number of lymphocytes T and B.