COGNITION AND IMMUNE FUNCTION IN HIV-1 INFECTION

Objectives: To determine (1) whether there were differences in cognition between HIV-1-seropositive and HIV-1-seronegative homosexual men and (2), if so, whether these differences could be explained by the degree of immunosuppression [i.e., CD4 cell count and immunoglobulin A (IgA) levels]. Design: A cross-sectional design was used to compare 66 HIV-1-seropositives (Centers for Disease Control stages II and III, n = 56; stages IVA and IVC-2, n = 10) and 37 HIV-1-seronegatives. The HIV-1-seropositives were classified into three immune groups based on their CD4 cell count (x 10(6)/l) and serum IgA level (mg/dl): (1) moderate [(n = 35) CD4 > 400, IgA < 300]; (2) mixed [(n = 22) either CD4 > 400 and IgA > 300 or CD4 < 400 and IgA < 3001 and (3) poor [(n = 9) CD4 < 400, IgA > 300]. HIV-1-seronegatives formed the 'good' immune group (CD4 > 400 and IgA < 300). Methods: The four groups were compared on tests of verbal and visual memory, information-processing speeds, visuospatial skills, language processes, attention, psychomotor reaction time, and mental status. Factors other than HIV-1 serostatus that can influence cognitive performance were tested as covariates. Results: HIV-1-seropositives had slower information-processing speeds and decreased verbal and visual memory, compared with HIV-1-seronegatives. These differences in cognition were not due to differential immunosuppression or to clinical status among the HIV-1-seropositives. Conclusions: Cognitive alterations occur in HIV-1-infected individuals before AIDS and- appear to be independent of clinical status and degree of immunosuppression as measured by CD4 cell count and IgA levels.