Information bearing on the prevalence and character of Reiter's syndrome and allied disorders as they occur in a setting of HIV infection was reviewed. Based on the frequency of infections by organisms capable of inducing reactive arthritis and the presence of HLA-B27 in 71% of the individuals, it was concluded that the disorder strongly resembled Reiter's syndrome occurring in the non-HIV infected group. Preliminary evidence suggested an enhanced penetrance of susceptibility among HLA-B27 individuals. In view of the preservation of CD8 lineage T cells and functional loss of CD4 lineage T cells in HIV-infected patients, it was suggested that a specific immune recognition event is at the center of the pathogenesis of this syndrome which involves preservation of an unknown antigen in the context of HLA-B27 to CD8 lineage suppressor/cytotoxic T cells.