[1] Merck Sharp & Dohme Spain, Med Affairs Dept, Josefa Valcarcel 38, Madrid 28027, Spain
[2] Gregorio Maranon Univ Hosp, IBD Unit, Gastroenterol Dept, Clin Res Inst Gregorio Maranon IiSGM, Madrid, Spain
[3] A Coruna Univ Hosp, Rheumatol Dept, La Coruna, Spain
[4] SEISIDA Spanish Aids Multidisciplinary Soc, Madrid, Spain
[5] Miguel Hernandez Univ, Clin Med Dept, Alacant, Spain