1. Graduate Program in Medical Science, University of Fortaleza, Fortaleza, Brazil
2. Medical School, University of Fortaleza, Fortaleza, Brazil
3. Hemotherapy and Hematology Center of Ceará, Fortaleza, CE, Brazil
4. Adolfo Lutz Institute, Virology Center, São Paulo, Brazil
5. Santo André AIDS Program, Santo André, São Paulo, Brazil