Thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS): treatment outcome, relapses, prognostic factors. A single-center experience of 48 cases. Dervenoulas J, Tsirigotis P, Bollas G, Pappa V, Xiros N, Economopoulos T, Pappa M, Mellou S, Kostourou A, Papageorgiou E, Raptis SA. Annals of Hematology 2000;79(2):66-72.

The thrombotic thrombocytopenic purpura/ hemolytic uremic syndrome (TTP/HUS) is a rare disorder characterized by microangiopathic hemolysis and thrombocytopenia. The authors present a retrospective analysis of the clinical characteristics, treatment outcome, and prognosis of 48 patients diagnosed and treated in an Athens, Greece institution during a 13-year period. The patients ranged in age from 18 to 85 years (mean age=40 years) and 58% were female. Among the 48 patients, 22 (46%) had fever, 35 (73%) neurological abnormalities, and 22 (46%) renal impairment at presentation of the syndrome. The cultures of blood, stool, and urine were negative except for one patient positive for Salmonella. One patient had a concurrent medical problem. All patients were treated with a multimodality regimen including plasma exchange, steroids, antiplatelet agents, and immune globulin G infusion. Of the 48 patients, 41 achieved complete remission, two had a partial response, and five had no response and died of progressive disease. Within a median follow-up period of 40 months, ten of the 41 patients who had achieved remission relapsed, most of them within the first two years, and nine of these responded promptly to plasma exchange therapy. Eight deaths were observed, seven of refractory disease and one in the fourth relapse. The overall survival was 84%. The analysis of prognostic factors revealed advanced age and severe renal impairment (creatinine levels above 2 mg%) as the only parameters associated with treatment failure and poor outcome. However, none of the pretreatment characteristics proved to be of prognostic value regarding the probability of relapse. In conclusion, TTP/HUS represents a syndrome of variable clinical expression and aggressiveness. The use of a multimodality regimen in this series produced a high response rate. Nevertheless, the early identification of poor-prognosis cases, based on clinical characteristics, which probably need more or alternative forms of treatment, is an issue that remains to be elucidated in prospective trials.