IgA as a marker of clinical progression among HIV-seropositive intravenous drug users.

The recognition of markers of progression towards disease in carriers of HIV is important in order to identify those who will develop AIDS and to start antiviral treatment at the appropriate time. Most studies of potential markers of progression have been made on homosexual men and haemophiliacs. We studied a population of 87 intravenous drug users (IVDUs), recruited between May 1984 and May 1986, in order to determine the usefulness of CD4 and CD8 counts as well as IgG, IgM and IgA values in predicting progression to AIDS. Eight persons developed AIDS during a median period of 44 months. Overall, the mean IgA value was lower in HIV-seropositive IVDUs than in HIV-negative IVDUs and in HIV-negative persons not using IV drugs and who acted as controls. Even so, a concentration of IgA > 2.5 g/l at enrollment was the best predictor of progression to AIDS. This finding suggests that a raised concentration of IgA may be an important early marker of progression towards disease in this population.