Serum and urine nitric oxide levels in children with Henoch-Schonlein purpura during activity and remission: a study from North India.

The objective of this study is to compare serum and urine reactive nitrogen intermediates (RNI) and citrulline levels in children with Henoch-Schonlein purpura (HSP) during activity and remission. The study group consisted of 14 children with HSP. We measured serum and urine RNI and citrulline levels by spectrophotometry in the active phase of the disease and then during remission. Serum RNI levels were 303.95 +/- 221.44 nmol/ml in children with active HSP and 72.57 +/- 26.56 nmol/ml during remission, the differences being statistically significant (P = 0.002). Mean urine RNI levels in children with active HSP were significantly higher than that seen during remission (3.25 +/- 1.80 vs. 1.68 +/- 0.65 nmol/ml; P = 0.003). Similarly, serum citrulline levels during disease activity were 790.65 +/- 707.87 nmol/ml as compared to 281.49 +/- 307.29 nmol/ml at the time of remission, the differences being statistically significant (P = 0.002). Mean urine citrulline levels in children with active disease was 1,969.94 +/- 1655.42 nmol/ml as compared to 1,099.34 +/- 955.82 nmol/ml in children with remission, (P = 0.007). Serum and urine RNI and citrulline levels were significantly higher during the acute phase of HSP as compared to the levels obtained during the phase of disease remission. These findings suggest that nitric oxide may perhaps have a role in the pathogenesis of HSP. Further, these laboratory parameters could be of value in monitoring disease activity. To the best of our knowledge, this study is the most comprehensive work published on the subject so far. Our findings, however, need to be confirmed on a larger study sample before firm conclusions can be drawn.