Seronegative HIV-2 carriers in India.

ABSTRACT

PIP: This paper describes the characteristics of HIV-2 seropositive and seronegative cases in Mumbai, India, and characterizes the differences between HIV-1 and HIV-2. More than 200 outpatients considered to be at high risk of HIV infection were screened for HIV-1 and HIV-2 antibody and proviral DNA. The study found 11 cases that were discordant for antibody test and HIV proviral DNA (i.e., negative for anti-HIV but positive for HIV-2 proviral DNA). The presence of this provirus was further corroborated by the detection of HIV-2 RNA in the culture medium upon HIV isolation, HIV-2 cDNA sequencing, and antigen detection. The sequence of the isolated HIV-2 genomic RNA did not seem to be altered to the extent that the change would affect antibody binding. Moreover, antibody from the same person in whom HIV-2 was detected did not react with the antigen of this strain even 8 months after the initial sampling. These findings indicate that extremely low production or non-production of the antibody may be brought about by suboptimal immune stimulation due to very low HIV-2 replication speed. This low virus load may account for the negative antibody results in the HIV-2 carriers in India.