Temporary seronegativity in a human immunodeficiency virus type 1-infected man.

Over a period of 3 months a human immunodeficiency virus 1 (HIV-1)-infected patient showed a sequence of positive-negative-positive anti-HIV screening test results. During this period the level of HIV p24 antigen declined and the HIV antibody pattern by Western blot gradually became complete, suggesting recent HIV infection. However the patient's weight loss, esophageal candidiasis, and Pneumocystis carinii pneumonia, together with the severely and persistently lowered CD4 cell counts and the absence of an IgM anti-HIV response, suggest late-stage HIV infection. Despite additional and follow-up testing, it was impossible to determine whether the patient suffered from acute, primary HIV infection with severe immunodepression or from advanced HIV infection (AIDS) with hampered HIV antibody production leading to false-negative test results by the anti-HIV enzyme immunoassay and Western blot. This case illustrates that HIV serology does not always follow the rules. The presence of HIV infection should be considered in a patient showing clinical signs of acute or late-stage HIV infection, even if the anti-HIV assay is negative.