1. Division of International Medicine and Infectious Diseases, Department of Medicine, Weill Medical College of Cornell University, New York, New York 10021.
2. Serviço de Imunologia do Hospital Universitário Prof. Edgard Santos, Universidade Federal da Bahia, Salvador, Bahia, Brazil.
3. Department of Public Health, Weill Medical College of Cornell University, New York, New York 10021.