Progressive decrease in VH3 gene family expression in plasma cells of HIV-infected patients.

We have analysed the expression of VH gene families in total peripheral plasma cells of mu and gamma isotypes from a group of HIV-infected patients. CD19- and CD20- cells were separated from B lymphocytes, and anchored RT-PCR products were hybridized with specific VH gene family probes and with a consensus JH region probe. The VH/JH hybridization intensity ratios were taken as a parameter to measure VH expression. In vivo VH3 gene family expression is reduced in plasma cells of all HIV-infected patients compared with adult healthy donors. This decrease is maximal in patients with AIDS: > 90%. This is true for both studied isotypes. Conversely, the two other main VH gene families, VH1 and VH4, show no significant variation in expression. We and others have previously shown that VH3 gene family expression is first expanded and then decreased in peripheral B lymphocytes of HIV-infected patients. The present results extend these observations and show that VH3 gene family expression is also affected in plasma cells. The existence of a B cell superantigen in HIV infection may explain these data. This pronounced reduction in VH3 family expression may participate in the impaired humoral responses against bacterial agents found in HIV-infected patients.