1. Clinical Research Unit, Hospital de Especialidades Centro Médico La Raza IMSS, Mexico City, Mexico
2. Universidad Nacional Autónoma de México, Mexico City, Mexico
3. Rheumatology Department, Hospital de Especialidades Centro Médico La Raza IMSS, Mexico City, Mexico
4. Direction of Education and Research, Hospital de Especialidades Centro Médico La Raza IMSS, Mexico City, Mexico
5. Pathology Department, Hospital de Especialidades Centro Médico La Raza IMSS, Mexico City, Mexico