A single-center analysis of Henoch-Schonlein purpura nephritis with nephrotic proteinuria in children.

Background: In children with Henoch-Schonlein purpura nephritis (HSPN), the degree of proteinuria has been proven to be not only a sign of kidney damage, but also an accelerator of kidney disease progression. Nephrotic proteinuria at disease onset has been proposed as a predictor of a poor renal outcome. This study aims to assess the clinical and pathological features of HSPN with nephrotic proteinuria in a single center.

Methods: One hundred thirty-seven patients with HSPN who visited Shanghai Children's Hospital from January 2009 to December 2013 were retrospectively reviewed. The patients were divided into 2 groups based on the 24-h urinary protein levels: nephrotic proteinuria group (NP group: 24-h urinary protein ≥50 mg/kg) and non-nephrotic proteinuria group (NNP group: 24-h urinary protein <50 mg/kg). In addition, data regarding their sex, age, clinical features, renal pathology, and prognosis were collected.

Results: (1) There were 34 boys and 20 girls in the NP group with a mean age of 8.39 ± 2.85 years. The peak age of incidence was 6 to 11 years (72.22%). (2) There were 8 cases (14.81%) with joint symptoms and 9 cases (16.67%) with gastrointestinal symptoms in the NP group. According to the analysis of the laboratory test results, the serum albumin and IgG levels of the NP group were significantly lower than that of the NNP group (35.04 ± 8.45 in the NP group vs. 41.55 ± 4.46 in the NNP group, P < 0.0001; 7.68 ± 3.12 in the NP group vs. 9.53 ± 2.74 in the NNP group, P < 0.001, respectively); their blood urea nitrogen and cystatin C levels increased significantly (P < 0.05). (3) The majority of the pathological changes in the NP group were above the International Study of Kidney Disease in Children (ISKDC) grade III (62.97%). The NP group patients with tubulointerstitial injurie with grade 2 and above (50%) were prioritized. Immune complex deposition in the NP group was dominated by IgA. (4) The prognosis of the NP group was in complete remission (A), and their cases did not develop into end-stage renal disease; their prognosis was also associated with clinical classification (P < 0.01) but was not related to pathologic grading and tubulointerstitial injury (P > 0.05).

Conclusion: The serum albumin and IgG levels of the NP group were significantly lower; however, their blood urea nitrogen and cystatin C levels were higher. The ISKDC grades were mainly above grade III. The prognosis of the NP group was associated with clinical classification and improved after a timely and early treatment.