The significance of tubulointerstitial lesions in childhood Henoch–Schönlein nephritis

Background: Little information is currently available on the development of tubulointerstitial lesions in children with Henoch–Schönlein nephritis (HSN). To identify the impact of the development of tubulointerstitial changes in HSN, we retrospectively analyzed renal biopsies obtained from children with HSN. Methods: Twenty-eight children with HSN from whom serial renal biopsies had been obtained before and after immunosuppressive therapy were enrolled in the study. The patients were divided into two groups according to the observed change in tubulointerstitial lesion development: group I (n = 15), with stable or improved tubulointerstitial lesions, and group II (n = 13), with worsened tubulointerstitial lesions. Group II patients had longer duration of proteinuria than group I patients (3.7 ± 3.7 years vs. 1.7 ± 1.7 years, p = 0.052). Results: The change in serum albumin level was negatively correlated with the change in tubulointerstitial scores before and after treatment (γ = −0.444, p = 0.018). Group II patients showed a significant decrease in immunoglobulin G (IgG) and IgA deposits after treatment (p = 0.039 and 0.003, respectively), while group II patients did not (p = 0.458 and 0.506, respectively). Conclusions: Although the International Study of Kidney Disease in Children classification of HSN does not include tubulointerstitial lesions, they can progress during treatment and could have significant clinical implications in association with the duration of proteinuria.