[1] Royal Free & Univ Coll Med Sch, Royal Free Ctr HIV, Dept Immunol, Div Infect & Immun, London NW3 2QG, England
[2] Royal Free & Univ Coll Med Sch, Royal Free Ctr HIV Med, Dept HIV Med, Royal Free Hosp, London NW3 2QG, England
[3] Royal Free & Univ Coll Med Sch, Dept Rheumatol, Dept Med, London NW3 2QG, England
[4] Royal Free & Univ Coll Med Sch, Dept Gastroenterol, Dept Med, London NW3 2QG, England