Etiopathological mechanisms and clinical characteristics of hyperhemolysis syndrome in Spanish patients with thalassemia.

Hyperhemolysis syndrome (HHS) is characterized by severe intravascular hemolysis with a decrease in the reticulocyte count, which is triggered and aggravated by transfusion and cannot be explained by standard immunohematological studies. A nationwide study was conducted in order to retrospectively identify thalassemia patients with HHS in Spain in order to assess pre-disposing mechanisms for this syndrome. For this, the expression of adhesion (CD49, CD36) and complement-related molecules (C3a, CD59) and the levels of reticulocyte apoptosis and macrophage activation were measured in 4 thalassemia patients with HHS, 14 patients without HHS, and 10 healthy subjects. Five of the six thalassemia patients had δß-thalassemia. The patients were not alloimmunized prior to the syndrome, which was developed after the first transfusion in all but one case. Patients with δß-thalassemia did not respond to corticoids or immunoglobulins; only splenectomy was successful. The expression of CD49 (α4ß1 integrin) was far higher in patients who had experienced HHS (85.07 ± 18.46 vs. 46.28 ± 24.31; p < 0.01), and the difference remained significant after correcting by the number of molecules analyzed (Bonferroni p < 0.05). In our population, δß-thalassemia was the most common hemoglobinopathy in patients with HHS. Furthermore, the risk to develop this syndrome may be associated with an increased expression of α4ß1 integrin.

Oral phosphodiesterase type 5 inhibitors alleviate recurrent priapism complicating thalassemia intermedia: a case report.

INTRODUCTION: Recurrent ischemic priapism still remains a serious and difficult to treat complication of certain hematological disorders. Elucidation of the underlying pathophysiologic mechanisms and application of new effective prophylactic treatments are needed. AIM: To present the efficacy of phosphodiesterase type 5 inhibitors (PDE5is) as a preventive measure against ischemic priapism recurrences complicating thalassemia intermedia. METHODS: We report on the case of a 19-year-old Caucasian man with thalassemia intermedia complicated by recurrent episodes of priapism following therapeutic splenectomy. After failure of conventional measures to control recurrences, a trial of long-term PDE5is use was initiated. MAIN OUTCOME MEASURES: PDE5is efficacy based on clinical patient history. RESULTS: Within 2 months of PDE5i preventive strategy, priapism recurrences nearly resolved. At 6 months, prophylaxis was discontinued. At 12 months, the patient reported clear improvement and satisfaction, experiencing rare episodes of priapism and a physiologic erectile function. CONCLUSIONS: PDE5 dysregulation seems to be an underline pathogenetic mechanism of thalassemia intermedia-associated priapism. It appears that PDE5is might have a role in the clinical management of such patients and their preventive efficacy warrants further testing in clinical trials.