T-lymphocyte subsets in duodenal, ileal, coecal, colonal, sigmoidal, and rectal lamina propria were determined in order to compare the distribution of CD2+, CD4+, and CD8+ cell subsets as well as the CD4/CD8 ratio in six different compartments of the gastrointestinal tract. In both HIV1-infected and not HIV1-infected patients, no differences in the distribution of T-lymphocyte subsets could be noted between the compartments examined. The HIV1-infected patients showed a decrease of CD4+ helper cells and CD4/CD8 ratio and an increase of CD8+ suppressor/cytotoxic cells in all examined segments. In terms of lamina propria T-lymphocyte subsets, the intestinal immune system seems to react to HIV1-infection homogenously.