IgD production and other lymphocyte functions in HIV infection: immaturity and activation of B cells at different clinical stages.

T and B cell function, in particular IgD production in vitro, were studied across the spectrum of HIV infection in homosexual men and compared with seronegative homosexual and heterosexual male controls. Proliferation to phytohaemagglutinin (PHA) was reduced most strikingly in symptomatic HIV infection; it was also impaired in HIV seronegative homosexual men and there was no difference between these and asymptomatic HIV seropositives or those with persistent generalized lymphadenopathy (PGL). Spontaneous IgG and IgM production were increased in patients with PGL and Kaposi's sarcoma; pokeweed mitogen (PWM)-induced production of IgG and IgM was reduced in all HIV infected subjects. Spontaneous production of IgD was highest in asymptomatic HIV infection, with raised values also seen in PGL and AIDS with opportunist infection; IgD production was suppressed by PWM in the same groups. These data indicate an increase in circulating immature B cells. Markers of B cell immaturity and polyclonal activation are apparent to differing degrees at different stages of HIV infection.