Unusual manifestations of secondary syphilis and abnormal humoral immune response to Treponema pallidum antigens in a homosexual man with asymptomatic human immunodeficiency virus infection.

The case presented here involves a 32-year-old homosexual man with human immunodeficiency virus (HIV) seropositivity and unusual manifestations of secondary syphilis. The patient presented with syphilitic keratoderma and chorioretinitis, and his appearance superficially resembled that of a patient with Reiter's syndrome. Although nontreponemal and treponemal tests for syphilis showed reactivity, the patient's humoral immune response to individual polypeptides of Treponema pallidum, measured by Western blot analysis, was markedly abnormal. The possible relationship between asymptomatic HIV infection and an abnormal humoral immune response to a second pathogen, in this case T. pallidum, is discussed. Our case is one of several recent cases of active syphilis reported in individuals with HIV seropositivity.