ELEVATED SERUM LEVELS OF SOLUBLE CD23 (SCD23) PRECEDE THE APPEARANCE OF ACQUIRED IMMUNODEFICIENCY SYNDROME-ASSOCIATED NON-HODGKINS-LYMPHOMA

Human immunodeficiency virus (HIV) infection-associated B-cell hyperst imulation. in particular, the chronic stimulation of B cells to underg o isotype switching, may play an important role in the pathogenesis of acquired immunodeficiency syndrome-associated lymphoma (AIDS lymphoma ). Isotype switching can be induced by various immune system factors, including cytokines, cell-surface stimulatory molecule interactions, a nd CD23. CD23 is a B-cell differentiation and activation marker expres sed on mature B cells that is lost after isotype switching; soluble CD 23 (sCD23) also is a B-cell-stimulatory factor. Because sCD23 is assoc iated with lg isotype switching, and because an enhancement of isotype switching may contribute to the genesis of AIDS lymphoma, we examined serum sCD23 levels in a retrospective study of HIV-seropositive subje cts who had gone on to develop lymphomas. Subjects were participants i n the Multicenter AIDS Cohort Study at UCLA, a study of the natural hi story of AIDS. Greatly elevated sCD23 serum levels were seen in subjec ts who developed AIDS lymphoma, when compared with others with AIDS (w ithout lymphoma), or to HIV-seronegative or HIV-seropositive subjects who did not have AIDS. Because the induction of IgE has been tied to t he activity of CD23, serum IgE levels were also examined in this study , and found to be significantly elevated in those who developed AIDS l ymphoma. These findings suggests that serum sCD23 levels potentially m ay serve as a clinical tool for early detection of lymphomas in people who have HIV infection. Also, these observations provide clues on pos sible pathogenetic mechanisms that result in lymphomagenesis in the co ntext of HIV infection and AIDS. (C) 1995 by The American Society of H ematology.