Atypical hemolytic uremic syndrome in the Tunisian population

Hemolytic uremic syndrome consists of a triad of acquired hemolytic anemia, thrombocytopenia and renal failure. Our objectives were to determine epidemiology, clinical and laboratory characteristics of patients with atypical hemolytic uremic syndrome (aHUS) to determine the relationship between the complement protein deficit and aHUS in the Tunisian population. We studied retrospectively four cases of atypical HUS in adults admitted in the Nephrology Department of Fattouma Bourguiba Universitary Hospital in Monastir between 2000 and 2008. Three patients had renal failure that required dialysis. One of them received kidney transplantation with no further recurrence of aHUS. Three patients had normal C3, C4, CFH, and FB levels, and in all patients anti-FH autoantibodies were absent. The kidney biopsy of one patient showed in addition to lupus glomerulonephritis histological findings consistent with TMA. A decrease in C3, C4 and CFH levels in this patient was found both before and after the cure. Nephrologists should be aware of autoimmune conditions and genetic abnormalities of the complement regulatory genes as possible pathogenic mechanisms in atypical HUS patients.