Inhibition of tyrosine kinases by sunitinib associated with focal segmental glomerulosclerosis lesion in addition to thrombotic microangiopathy.

Sunitinib is an orally administered inhibitor of tyrosine kinases and has become the standard of care for many patients with metastatic renal cell carcinoma. Its use has been associated with renal toxicity in some patients. We report a patient with a metastatic clear-cell renal carcinoma who showed arterial hypertension, nephrotic syndrome and azotaemia 10 months after treatment with sunitinib. The renal biopsy revealed focal segmental glomerulosclerosis (FSGS) in addition to thrombotic microangiopathy (TMA), and the complete syndrome disappeared 6 months after sunitinib withdrawal. To our knowledge, this is the first case of FSGS associated to TMA secondary to sunitinib treatment. We discuss the possible glomerular pathomechanism.

High prevalence of anti-C1q antibodies in biopsy-proven active lupus nephritis.

BACKGROUND: Anti-C1q antibodies (anti-C1q) have been shown to correlate positively with systemic lupus erythematosus (SLE) nephritis. Several clinical studies indicated a high negative predictive value, suggesting that active lupus nephritis is rarely seen in patients with no anti-C1q. However, the true prevalence of anti-C1q at the time of active lupus nephritis has not been well established. The aim of this study was to determine prospectively the prevalence of anti-C1q in proven active lupus nephritis at the time of the renal biopsy. METHODS: In this prospective multi-centre study, we investigated adult SLE patients undergoing renal biopsy for suspected active lupus nephritis. Serum samples were taken at the time of the biopsy and analysed for the presence of anti-C1q in a standardized way. The activity of lupus nephritis was classified according to the renal histology. Biopsies were also analysed for the presence of glomerular IgG, C1q and C3 deposition. RESULTS: A total of 38 patients fulfilling at least 4/11 American College of Rheumatology (ACR) criteria for the diagnosis of SLE were included. Out of this, 36 patients had proliferative (class II, III or IV) and two had class V lupus nephritis. All but one patient with proliferative lupus nephritis were positive for anti-C1q (97.2%) compared with the 35% of control SLE patients with inactive lupus nephritis and 25% of SLE patients without lupus nephritis ever. All patients were positive for glomerular C1q (36/36) and 37/38 patients had glomerular IgG deposits. Anti-C1q strongly decreased during successful treatment. CONCLUSIONS: Anti-C1q have a very high prevalence in biopsy-proven active lupus nephritis, thus a negative test result almost excludes active nephritis. The data support the hypothesis of a pathogenic role of anti-C1q in lupus nephritis.

Renal cell carcinoma co-existent with other renal disease: clinico-pathological features in pre-dialysis patients and those receiving dialysis or renal transplantation.

BACKGROUND: Patients on chronic dialysis are prone to developing acquired cystic kidney disease (ACKD), which may lead to the development of renal cell carcinoma (RCC). The risk factors for the development of RCC so far have not been determined in pre-dialysis patients with co-existent renal disease. The aim of this study was to evaluate the clinico-pathological features of RCC in pre-dialysis patients with associated renal diseases or in those undergoing chronic dialysis and renal transplantation. METHODS: We studied 32 kidneys from 31 patients with RCC and associated renal diseases. Of those, 18 kidneys were from 17 patients not on renal replacement therapy (RRT) when diagnosed with RCC; 14 patients received dialysis or dialysis followed by renal transplantation. Several clinico-pathological features were analysed and compared between the two groups. RESULTS: Overall, there was a preponderance of males (75%); nephrosclerosis was the predominant co-existent disease (31%). The median intervals from renal disease to RCC in the dialysis and transplanted groups were significantly longer than in the pre-dialysis group (15.8+/-1.1 vs 2.4+/-0.7 years, P<0.0001). In contrast to pre-dialysis RCC, the dialysis and transplant RCC groups had greater frequency of ACKD (100 vs 28%, P<0.0001), papillary type RCC (43 vs 11%, P<0.05) and multifocal tumours (43 vs 5%, P<0.05). At the end of the study, 71% of dialysis and transplanted patients and 72% of pre-dialysis patients were alive. CONCLUSIONS: ACKD develops in dialysis patients, as it does in those with renal disease prior to RRT. The duration of renal disease, rather than the dialysis procedure itself, appears to be the main determinant of ACKD and RCC. The RCC occurring in patients with ACKD and prolonged RRT is more frequently of the papillary type and multifocal than the RCC occurring in patients with no or few acquired cysts and a short history of renal disease. Long-term outcomes did not differ between the two groups.