Recurrence of IgA nephropathy among renal allograft recipients from living donors is greater among those with zero HLA mismatches

BACKGROUND

Risk factors contributing to recurrence of IgA nephropathy (IgAN) after transplantation are unclear. Some (but not all) series have suggested greater degrees of human leukocyte antigen (HLA) matching play a role.

METHODS

Using registry data including all kidney transplants performed in Australia and New Zealand between 1987 and 2004 we examined IgAN recurrence among living donors with zero HLA-mismatches.

RESULTS

Of 1354 grafts performed in recipients with IgAN, live donors (LDs) accounted for 488 including 108 with zero HLA-mismatches. Biopsy-proven IgAN recurrence was reported for 110 (7%) of grafts overall, but 17% of those who received zero HLA-mismatched LD grafts (HR for recurrence free graft survival 2.7 [95% CI 1.5-5.1], P=0.001). There was no significant difference in recurrence rates between zero and >or=1 HLA-mismatched grafts from cadaveric donors (CDs). Recurrence of IgAN was associated with worse graft survival, more so among LD recipients (HR 8.5 [4.8-15.2], P<0.001) than CD recipients (HR 4.5 [2.6-7.5], P<0.001). However, there was no difference in graft survival between zero and >or=1 HLA mismatched LD recipients whose native disease was IgAN. In contrast, zero HLA mismatched recipients of kidneys with other primary renal disease enjoyed a graft survival advantage. No difference in recurrence rates was seen among those with HLA B12, B35 or DR4.

CONCLUSIONS

The increased rates of IgAN-related graft loss among zero HLA-mismatched LD recipients counterbalance the advantage normally seen among zero HLA-mismatched recipients. However, since graft survivals are similar, there is no reason to avoid donor-recipient pairs with zero HLA-mismatches in this setting.

Natural history of idiopathic IgA nephropathy and factors predictive of disease outcome

Among the numerous studies published in the last 20 years that have calculated the actuarial renal survival and tried to individuate the prognostic role of the clinical and histologic features present at the onset of the disease or the time of biopsy, we chose to critically analyze the results of the most valid (23 studies). Actuarial renal survival at 10 years in adults was between 80% and 85% in most of the European, Asian, and Australian studies, but was lower than this in studies from the United States and exceeded 90% in the few studies on children. Concordance existed in this selected literature on the fact that impairment of renal function, severe proteinuria, and arterial hypertension are the strongest and more reliable clinical predictors of an unfavorable outcome. Extent of proteinuria during follow up was an even stronger predictor. In adult patients, a high score of the glomerular and tubulointerstitial lesions predicted a more rapid progression. When the single lesions were analyzed separately, glomerular sclerosis and interstitial fibrosis appeared to be the strongest, most reliable predictors of unfavorable prognosis. More controversial was the role of crescents and capsular adhesions.