Clinical relevance of membrane attack complex deposition in children with IgA nephropathy and Henoch-Schönlein purpura

BACKGROUND

IgA nephropathy (IgAN) and Henoch-Schönlein purpura are common glomerular disorders in children sharing the same histopathologic pattern of IgA deposits within the mesangium, even if their physiopathology may be different. Repeated exposure to pathogens induces the production of abnormal IgA1. The immune complex deposition in the renal mesangium in IgAN or potentially in small vessels in Henoch-Schönlein purpura induces complement activation via the alternative and lectin pathways. Recent studies suggest that levels of membrane attack complex (MAC) in the urine might be a useful indicator of renal injury. Because of the emerging availability of therapies that selectively block complement activation, the aim of the present study is to investigate whether MAC immunostaining might be a useful marker of IgA-mediated renal injury.

METHODS

We conducted immunohistochemistry analysis of the MAC on renal biopsies from 67 pediatric patients with IgAN and Henoch-Schönlein purpura. We classified their renal biopsies according to the Oxford classification, retrieved symptoms, biological parameters, treatment, and follow-up.

RESULTS

We found MAC expression was significantly related to impaired renal function and patients whose clinical course required therapy. MAC deposits tend to be more abundant in patients with decreased glomerular filtration rate (p = 0.02), patients with proteinuria > 0.750 g/day/1.73 m², and with nephrotic syndrome. No correlation with histological alterations was observed.

CONCLUSIONS

We conclude that MAC deposition could be a useful additional indicator of renal injury in patients with IgAN and Henoch-Schönlein purpura, independent of other indicators.

Vascular access for chronic hemodialysis in children: arteriovenous fistula or central venous catheter?

BACKGROUND

The choice of vascular access (VA) for hemodialysis (HD) in end-stage renal disease (ESRD) is arteriovenous fistula (AVF) or central venous catheter (CVC). Whereas clinical practice guidelines suggest AVF to preserve the vascular bed, pediatric nephrologists tend to favor CVC for shorter-term dialysis. Our objective was to determine whether pediatric priority allocation policies for deceased-donor kidneys affect VA planning.

METHODS

Pediatric priority for deceased-donor kidneys was instituted in Quebec in 2004. We retrospectively compared clinical practice on AVF, CVC, wait time on transplant list, HD duration in pre-policy (group A) and post-policy (group B) from 1997-2011.

RESULTS

We identified 78 patients with a median age of 14.7 years (range, 0.7-20.5 years) and weight of 46 kg (12.5-95 kg); AVF decreased from 76 % in group A to 41 % in group B (p = 0.002). Wait times on transplant list were significantly reduced: median 413.5 days (range, 2-1,910 days) in group A vs. 89 days (range, 18-692 days) in group B (p = 0.003). Time on HD for deceased-donor recipients was shorter: 705 (range, 51-1,965 days) group A vs. 349.5 days (range, 158-1,060 days) group B (p = 0.01).

CONCLUSIONS

This is the first study to document VA changes related to pediatric priority allocation policy. Our fistula-first center saw a shift toward CVC-first.