Low levels of anti-histone antibodies in north Indian children with juvenile rheumatoid arthritis.

BACKGROUND & OBJECTIVES Early onset pauciarticular disease with uveitis is distinctly uncommon in Indian children with juvenile rheumatoid arthritis (JRA). The occurrence of anti-histone antibodies (AHA) in serum is strongly associated with presence of uveitis. There is a paucity of information from India on the levels of AHA in patients of JRA. In this study, an attempt was made to evaluate the levels of IgG and IgM antibodies to histones in children with JRA in north India. METHODS Serum samples of 148 children with JRA (84 boys, 64 girls) were collected. Clinical details including onset, symptoms and course of the disease in each patient were recorded. Detailed eye examination including slit lamp examination was done in all patients at presentation and yearly thereafter to rule out uveitis. The presence of antihistone IgG and IgM antibodies was studied by ELISA. Antinuclear antibodies (ANA) were measured by indirect immunofluorescence using HEP-2 cells as substrate at a screening dilution of 1:40. RESULTS Of the 148 children, 54 had pauciarticular (12 early onset and 42 late onset), 64 polyarticular and 30 systemic onset disease respectively. ANA were present in two children. AHA were raised in 15 (10%) children, of whom 10 had IgM antibodies, 3 had IgG and 2 had both isotypes. None of the children with early onset pauciarticular disease had uveitis, ANA or AHA. INTERPRETATION & CONCLUSION The low occurrence of AHA and uveitis in our subset of patients with JRA is in contrast to that reported from Western countries. The low occurrence is unlikely due to technical reasons as the antigen that has been used consistently showed significant binding to serum from patients with systemic lupus erythematosus (SLE). This is in accordance with the rarity of early onset pauciarticular disease and chronic uveitis in these patients. More studies from other parts of the country are required to validate this observation.