INSULIN-LIKE GROWTH FACTORS I AND II IN SYSTEMIC ONSET JUVENILE ARTHRITIS

Systemic onset juvenile arthritis (SJA) has been associated with growth failure in children treated with or without steroids. Growth hormone secretion in SJA is reported to be normal; however, insulin-like growth factor (IGF) has not been examined. To assess the possible role of IGF's in growth failure in SJA, we measured concentrations of IGF-I and II at different stages of activity in patients receiving either steroid or non-steroid therapy. IGF-I and II concentrations were determined in 2 samples from 10 patients who had not received steroids for at least 6 months and 5 patients receiving prednisone. Mean IGF-I and II concentrations in patients receiving steroids were 53% and 61% of normal mean for age.In patients receiving non-steroid therapy; mean IGF-I and II concentrations were 46% and 64% of normal mean for age. Growth failure during periods of active disease was observed in both groups as only 3/11 pre-pubertal patients had growth ≥ 4.5 cm/year. Erythrocyte sedimentation rate (ESR) was compared with concentrations of IGF-I and II in both groups. A statistically significant correlation of IGF-I and II with ESR was observed in those patients receiving non-steroid therapy Rs=.56 and .59 (p=.02, ≤ .01). In the group of patients receiving prednisone at greater than 5 mg/m2/day, ESR showed a statistically significant correlation with IGF-I (Rs=.68, p< .05) but not IGF-II. Thus, low concentrations of IGF-I and II may contribute to growth failure in children with SJA whether or not they receive steroids.