[1] IMSS, CMN Siglo 12, Hosp Pediat, Unidad Invest Med Inmunol, Mexico City, DF, Mexico
[2] IMSS, Clin 25, Dept Reumatol, Mexico City, DF, Mexico
[3] Univ Nacl Autonoma Mexico, Dept Bioquim, Mexico City 04510, DF, Mexico
[4] Ctr Med Nacl Siglo XXI, Hosp Especialidades, Dept Reumatol, Mexico City, DF, Mexico
[5] Hosp Gen Mexico City, Serv Reumatol, Mexico City, DF, Mexico