Immunological responses of Gambians in relation to clinical stage of HIV-2 disease.

This study describes a broad spectrum of cellular and antibody-mediated immune responses found in 28 asymptomatic and 37 symptomatic Gambian patients with HIV-2 infection. It shows that these responses vary according to the stage of infection as described by three clinical staging systems. The first system was a local one based on the signs used for the WHO Bangui clinical definition of AIDS, the second, suggested by WHO, was based on a performance scale, and the third was that used by the Centre for Disease Control. Asymptomatic patients had significantly lower mean CD4 counts, lymphoproliferative and interferon-gamma (IFN-gamma) responses and lower IgG and IgM antibody responses to keyhole limpet haemocyanin (KLH) than controls. These measurements and the size of the skin test reaction to purified protein derivative (PPD) or Candida antigen declined significantly according to the stage of infection. Mean values of the serological markers beta 2-microglobulin and neopterin and antibody titres to Epstein-Barr virus capsid antigen (EBVCA) rose significantly according to severity of disease. The Gambian or WHO clinical staging systems, which are easy and cheap to apply, may serve as an alternative to sophisticated and expensive immunological measurements when trying to stage disease and predict prognosis.