Abnormalities of interleukin 2 receptor expression associated with decreased antigen-induced lymphocyte proliferation in patients with AIDS and related disorders.
Several parameters of lymphocyte interleukin 2 receptor (IL-2R) expression in response to tetanus toxoid (TT) were monitored using a receptor-specific monoclonal antibody and flow cytometry in patients with acquired immunodeficiency syndrome (AIDS, n = 6), AIDS-related complex (ARC, n = 8), or lymphadenopathy syndrome (LAS, n = 9). These parameters, measured on days 6 and 7 of culture, included (a) the percentage of recovered lymphocytes expressing IL-2R, (b) the number of IL-2R-positive cells/lymphocyte trigger region (a relative measure of the number of IL-2R-positive cells per culture), and (c) mean fluorescence intensity of IL-2R-positive cells. Data were then assessed in relation to DNA synthesis on day 7 of culture. Normal DNA synthesis was observed in nine patients (Pt-N group), and the mean values for all three IL-2R expression parameters in this group did not significantly differ from those of the healthy control group (n = 20). In contrast, 14 patients exhibited low proliferation (Pt-L group) and mean values for all three parameters were significantly lower in this group compared to both the Pt-N and control groups. When considering individual patient values, day 7 IL-2R+ cell number proved the best predictor of DNA synthesis results: all 14 patients in the Pt-L group exhibited low IL-2R+ cell number, while seven of nine patients in the Pt-N group exhibited normal IL-2R+ cell number. Thus, low TT-induced lymphocyte proliferation in AIDS and related disorders is associated with defective IL-2R expression. Further, assessment of IL-2R+ cell number appears to be a valid alternative assay for monitored antigen-induced T cell proliferation in vitro.