Grading of Acute and Chronic Renal Lesions in Henoch-Schönlein Purpura

Abstract

The renal outcome of 34 patients with HenochSchönlein purpura nephritis was assessed clinically and by grading acute and chronic renal lesions using a system we applied to primary IgA nephropathy. On a median follow-up period of 65 months, hypertension and the serum levels of creatinine and proteinuria at the time of renal biopsy were correlated with renal survival. Acute glomerular lesions including mesangial hypercellularity, endocapillary proliferation, necrosis, cellular crescents, and leukocytes infiltration were observed, respectively, in 41%, 12%, 50%, 29%, and 32% of the cases. Of these, only glomerular necrotizing lesion and cellular crescent were correlated with the renal survival. Chronic renal lesions based on a grading system applied to primary IgA nephropathy and assessing the extent of glomerular sclerosis (glomerular grading), of tubular loss and interstitial fibrosis (tubulointerstitial grading), and of hyaline arteriolosclerosis demonstrated correlation between these lesions, as well as with renal survival. On follow-up, these chronic renal lesions were predictors of subsequent clinical events associated with disease progression, such as impaired renal function, significant proteinuria, and development of hypertension. Despite some limitations related to the relatively small size, this series indicates that distinction of acute and chronic lesions of Henoch-Schonlein purpura nephritis is important for both the prognosis and management of patients.

Using the Oxford classification of IgA nephropathy to predict long-term outcomes of Henoch–Schönlein purpura nephritis in adults

“…16,17 Crescents are much more often observed in Henoch-Schö nlein purpura nephritis than in IgA nephropathy, and their number has been related to the severity of clinical signs and the prognosis of Henoch-Schö nlein purpura nephritis in previous studies. 5,7,11,26 In our study, crescents in Z50% of glomeruli were more commonly observed in progressors and were significantly associated with reaching the primary end point in an unadjusted model (data not shown), whereas the significance was attenuated in the multivariable model. This finding supports a rationale for the limited utility of crescentic lesioins as a sole prognisticator.…”

“…15,31 In this regard, the predictive value of crescents in Henoch-Schö nlein purpura nephritis does not appear to be potent. Of note, correlation between endocapillary proliferation and crescent formation has been suggested in Henoch-Schö nlein purpura nephritis and IgA nephropathy, 5,26,30 suggesting that these two lesions occur during the active inflammation stage. Whether such acute inflammatory lesions may have long-term impact remains to be further elucidated.…”

“…However, although endocapillary proliferation is considered to be a marker of acute glomerular inflammation, its prognostic value varies with the type of glomerulonephritis. 26 In fact, endocapillary proliferation in lupus nephritis informs physicians that the patient may need urgent intensive immunosuppression because prognosis is poor if left untreated. 27,28 In contrast, endocapillary proliferation in post-streptococcal glomerulonephritis generally does not portend a poor outcome because the kidney function of patients with post-streptococcal glomerulonephritis eventually recovers with little impairment.…”

“…In this regard, the need for a new classification system has been raised. 9,15,26 Considering that Henoch-Schönlein purpura nephritis and IgA nephropathy have common features of pathogenesis and histopathologic findings, we hypothesized that the Oxford classification could also help predict long-term outcomes in HenochSchönlein purpura nephritis. Therefore, in this retrospective study, we evaluated for the first time the usefulness of the Oxford classification for patients with Henoch-Schö nlein purpura nephritis.…”

“…[19][20][21][22] Furthermore, chronic lesions such as tubulointerstitial fibrosis have been identified as portending a poor prognosis in patients with Henoch-Schönlein purpura nephritis. 10,11,26 In light of these data, the extent of tubulointerstitial lesions as a pathologic criterion should be included in future classification systems. We have also shown that endocapillary hypercellularity is associated with adverse renal outcomes.…”