On July 31, 1992, CDC reported five cases of CD4+ T-lymphocytopenia in persons without evident human immunodeficiency virus (HIV) infection in the United States. As of August 5, 1992, CDC has received reports of nine additional persons with similar clinical presentations. All persons who have been reported to CDC meet the three criteria for CD4+ T-lymphocytopenia without evident HIV infection. Another 21 persons suspected to have this condition have been described, 10 of whom reside in the United States. This report summarizes the 14 cases reported to CDC and provides information on the national surveillance system established to determine the prevalence and distribution of this condition.(ABSTRACT TRUNCATED AT 250 WORDS)