Lupus glomerulonephritis in 788 Chinese children: a multi-centre clinical and histopathological analysis based on 549 renal biopsies.

BACKGROUND: System lupus erythematosus (SLE) is a severe multisystem autoimmune disease.

OBJECTIVE: To describe the clinical and pathological features, treatment, and renal outcome in children under 18 years with lupus nephritis (LN).

METHODS: The study was undertaken by a questionnaire completed in 26 Grade 3A hospitals' paediatric renal units in China. The study comprised 788 children (619 girls, 169 boys) diagnosed with SLE by the American College of Rheumatology criteria (1997) during 2005-2010. Results of renal biopsies were classified according to the guidelines of The International Association of Nephrology and the Renal Pathology Society (2003). Guidelines by the Chinese Society of Paediatric Nephrology were applied for the diagnosis and treatment (for trial implementation) in 2010 to determine inclusion. The data included the prevalence of acute kidney injury (AKI), SLE disease activity index (SLEDAI), renal histopathology and the induction of therapy mode.

RESULTS: The mean (SD) age of onset of SLE was 10.9 (2.90) years (range 1-18) and at diagnosis was 11.3 (2.9) years. The mean (SD) SLEDAI score was 13.5 (5.53). The clinical classification was as follows: about 36 (4.6%) patients had isolated haematuria, 99 (12.6%) isolated proteinuria, 60 (7.6%) isolated haematuria and proteinuria, 157 (19.9%) acute glomerulonephritis, 392 (49.7%) nephrotic syndrome, 20 (2.5%) rapidly progressive glomerulonephritis, 15 (1.9%) chronic nephritis, 2 (0.3%) tubule-interstitial damage and 7 (0.9%) subclinical LN. A total of 549 children (69.7%) underwent renal biopsy. The most frequent renal histopathological findings of LN were Class IV, followed by Class II and Class V + IV. There were no significant differences between the age groups in either renal pathological types or prognosis. In 242 (30.7%) patients, LN was complicated by AKI. Those with AKI had an older mean (SD) age at onset than the non-AKI patients [11.5 (2.8) years vs 10.7 (2.9) years, respectively, p < 0.0001] and a higher SLEDAI score [14.3 (5.8) vs 13.1 (5.4), respectively, p = 0.003]. In the induction phase, cyclophosphamide (CTX) and mycophenolate mofetil (MMF) were equally effective in the patients with the same pathological type. Follow-up records were only available for 482 (61.2%) patients, with a mean (SD) follow-up time of 21.5 (18.4) months. Six of the 35 patients who deteriorated required dialysis and seven died.

CONCLUSION: In LN, AKI is a risk factor for poor outcome. Owing to different times of onset and remission, the pathological types of LN cannot be estimated by clinical manifestation alone, and therefore renal biopsy should be undertaken in all LN children with AKI. In the induction phase, there was no significant difference in efficacy between CTX and MMF. Follow-up of children with LN in China needs to be improved.