J.I. Shin

We read with interest the article on Henoch-Schönlein purpura with nephritis in adults by Shrestha et al.1 They point out that there have been no serological markers of prognosis in Henoch-Schönlein nephritis (HSN) in both children and adults. However, a previous report of ours suggested that the serum IgA/C3 ratio could be a useful marker of disease activity in children with severe HSN.2 In this study, the levels of serum IgA or C3 at presentation were variable, but serial assess-ment of the serum IgA/C3 ratio (iIgA/C3) showed a significant correlation with changes in severity of renal pathology and clinical outcome. High circulating levels of IgA did not always correlate with an increase of polymeric IgA1 and mesangial deposition, and levels of serum C3 are not generally decreased in HSN. However, the direction of the changes of IgA and C3 was important, and correlated with clinical outcome. Therefore, IgA and C3 may be an important factor in understanding the pathogenesis of HSN, and the measurement of serum IgA/C3 ratio may be a useful marker of renal progression in HSN patients. However, a large prospective study may be needed to elucidate whether serum IgA/C3 ratio predicts long-term prognosis in children and adults with HSN