Detection of HIV-specific antibodies in infancy by isoelectric focusing and affinity immunoblotting.

Asymptomatic congenital HIV infection cannot be diagnosed in infants less than 15 mo by routine serologic techniques because of the presence of passively acquired maternal antibody in the infants' circulation. Possibly, infants who synthesize antibody to highly conserved HIV proteins may be recognized by the detection in serum of clonally distinct IgG antibodies to HIV. To test this hypothesis, isoelectric focusing in thin-layer agarose gels was combined with affinity immunoblotting to antigen-coated nitrocellulose membranes. In all 10 cases examined, the presence or absence of clonotypically distinct bands of IgG antibodies was concordant with infectious status. Thus, this technique may provide an accurate serologic approach to the diagnosis of congenital HIV infection.