B-cell activation in HIV infection: relationship of spontaneous immunoglobulin secretion to various immunological parameters.

Peripheral blood mononuclear cells from HIV-infected individuals spontaneously secrete elevated levels of IgG, IgM and IgD. This increased level of synthesis and secretion is similar in HIV-infected subjects with no or few symptoms, in ARC patients and in AIDS patients. Thus, abnormal B-cell activation is characteristic of patients with mild as well as severe manifestations of HIV infection. The level of spontaneous cellular secretion of IgG, IgM and IgD correlates with serum levels of these isotypes. Levels of spontaneous cellular secretion of IgG and IgM correlate negatively with the percentage but not with the absolute number of T4-positive cells and correlate positively with the percentage but not with the absolute number of T8-positive cells. The data suggest that the proportional distribution of these T-cell subsets is a critical factor in the B-cell dysregulation leading to overproduction of IgG and IgM. On the other hand, spontaneous IgD secretion correlates with neither the percent nor the absolute number of T4 or T8 cells suggesting that the increase of IgD-secretion by B cells is independent of the T-cell defects. The data imply that more than one mechanism underlies the B-cell activation in HIV-infected individuals.