A case of renal icterohaemorrhagic leptospirosis involving a patient with acquired immunodeficiency syndrome (AIDS) is reported. Despite the low levels of CD4+ Tlymphocytes, the clinical course of leptospirosis was similar to that observed in non-immunodepressed patients, and no worsening of AIDS occurred due to the infebtion by the spirochete. Serologic conversion was observed in the microscopic agglutination ...