[A perinatal diagnostic problem: patients serologically negative but infected with HIV]

Comprehensive HIV diagnosis of 142 patients was done by ELISA, IgG immunoblot, IgA immunoblot (in patients under 24 months), plasma antigen determination, viral isolation by culture and genome detection by polymerase chain reaction (PCR) amplification. Results showed that 14 patients (10%) with negative or indefinite results for anti-HIV-1 IgG antibody were in fact infected by the virus. Eleven of these patients were between 2 and 24 months of age, two between 4 and 6.5 years and one was 30 years old. Diagnosis was obtained by antigen positivity in four of them; by PCR amplification of peripheral mononuclear cells of proviral DNA in five of them; by PCR and immunofluorescence (IF) of cultured cells in four cases, and the last diagnosis was made by IgG immunoblot and IF of the viral culture. These cases pose a problem because of false negative HIV serology, particularly in patients under 24 months of age.