1. Department of Infectious Diseases, Hospital de Infectología “La Raza” National Medical Center, Instituto Mexicano Del Seguro Social, Mexico city, México
2. Center for HIV and Hepatogastroenterology, Duesseldorf, Germany
3. Department of Internal Medicine, General Hospital, “La Raza” National Medical Center, Instituto Mexicano Del Seguro Social, Mexico city, México
4. División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, México city, México