Frequency of antinuclear antibodies in mestizo Mexican children with morphea.

Morphea is a disease that affects connective tissue and microvessels. Its pathogenesis is unknown, but several autoimmune factors participate. Our objective was to determine the frequency of antinuclear antibodies (ANAs) in pediatric patients with morphea and to establish their relation with the clinical variants and disease activity. A cross-sectional study was carried out from January 1999 to January 2008 in patients with morphea seen at the Instituto Dermatologico de Jalisco. ANAs were determined through an indirect immunoflourescent method, and the immunospecificity was done with a double immunodiffusion technique in agarose gel. A total of 34 children were included in the study, 74% of the female gender. Plaque morphea was the most common variant, present in 44% of the cases, followed by linear morphea in 38%, and generalized morphea in 18%. ANAs were positive in 29%, with homogenous immunoflourescense as the most frequent pattern (70%). Of the ANA-positive patients, 83% had generalized morphea, and in 70% of the cases the disease were considered as active. The frequency of ANA-positive children with morphea was 29%, and seems to be related to more extensive disease. No previous studies exist on this topic in the mestizo Mexican population.