Fatal fulminant hemolysis-associated pulmonary embolism in mixed-type autoimmune hemolytic anemia: A case report.

Autoimmune hemolytic AQ5 anemia (AIHA) is an immune disorder caused by antibodies directed against unmodified autologous red blood cells. In rare cases, AIHA is comorbid with other immunological disorders; for instance, when AIHA is complicated with immunologic thrombocytopenic purpura (ITP) it is called Evans Syndrome (ES). These multiple autoimmune mechanisms are referred to as "immunological tolerance loss," which is known as a characteristic autoimmunity specific for AIHA. And there are no estimation of the risk for thromboembolism in the "immunological tolerance loss" case.A 66-year-old man was diagnosed with ES after autologous stem cell transplantation for malignant lymphoma. His background immunological status was complicated because AIHA was mixed-type (warm and cold antibody type). The direct/indirect Coombs tests were positive. The anticomplement antibody was positive and his cold hemagglutinin level had increased. Anticardiolipin antibodies were negative: anticardiolipin β2GPI antibody ≤1.2 U/mL (<3.5), anticardiolipin immunoglobulin G antibody ≤8 U/mL (<10), and anticardiolipin immunoglobulin M antibody ≤5 U/mL (<8).ITP and mixed-type AIHA.The patient achieved complete response by initial prednisolone therapy; however, he did not respond to corticosteroid therapy after AIHA recurrence. He required the red blood cell transfusion due to the progression of hemolytic anemia.On the fourth day of refractory treatment following AIHA recurrence, the patient had acute respiratory failure with severe hypoxia and died. The cause of death was identified as pulmonary embolism (PE) based on the laboratory data and echocardiography findings, and a literature search suggested rapidly progressive hemolysis-induced PE.Although infrequent, comorbid thromboembolism to AIHA is well documented; however, a mixed-type AIHA case complicated with thromboembolism has not been previously reported. The combined pathophysiology of AIHA and thromboembolism should be considered in the clinical course of hemolysis. Our case suggested multiple immunological background, ITP, and mixed type AIHA, could be associated to a risk for thromboembolism (TE).