Efficacy of measles, mumps and rubella revaccination in children with juvenile idiopathic arthritis treated with methotrexate and etanercept

Objectives. To evaluate the influence of low-dose MTX and etanercept treatment on efficacy of measles, mumps and rubella (MMR) revaccination in children with juvenile idiopathic arthritis. Methods. A prospective nested casecontrol study was performed to investigate markers of MMR revaccination induced humoral and cell-mediated immunity in 15 patients with juvenile idiopathic arthritis (ages 617 yrs), treated with either low-dose MTX therapy alone or in combination with etanercept. The control group consisted of 22 healthy children. Production of IFN- by T memory cells upon in vitro stimulation with measles, mumps and rubella antigens and seroprevalence of virus-specific IgG antibodies were assessed. Medication use, disease activity and patients comments on side-effects were observed during the period of 6 months before and after revaccination. Results. Low-dose MTX therapy following MMR vaccination proved not to hamper T-cell mediated immunity in vitro. Neither low-dose MTX nor etanercept treatment, given simultaneously with revaccination, markedly interfered with generation of long-lived virus-restricted T cells and protective levels of virus-specific IgG antibodies. No increase in disease activity or medication use was seen within 6 months after MMR revaccination, including JIA patients using etanercept. No overt measles, mumps, rubella or secondary severe infections were noted. Conclusions. Low-dose MTX and etanercept treatment do not seem to interfere with intended outcome of MMR revaccination in children with JIA.