1. Retrovirus Laboratory, Virology Center, Adolfo Lutz Institute, São Paulo, Brazil.
2. Santo André Aids Program, São Paulo, Brazil.
3. Division of Pediatric Infectious Diseases, Santa Casa de São Paulo Hospital, São Paulo, Brazil.
4. DST/Aids Reference Center, Campinas, Brazil.
5. Emílio Ribas Infectious Diseases Institute, São Paulo, Brazil.