The first reported use of red blood cell exchange to treat hemoglobin Evans with secondary methemoglobinemia

Abstract

This manuscript describes a novel approach for treating patients with long-term sequelae from hemoglobin Evans (Hb Evans). After instituting conservative therapies for approximately 2 years, our patient's symptoms continually worsened. Therefore, we performed red blood cell exchange (RBCx) to reduce his Hb Evans percentage and his co-existing elevation of methemoglobin. Our assumptions of clinical benefit were based on our collective experience performing RBCx for patients with sickle cell disease. After the first exchange, pre- and post-laboratory results supported our approach and the patient experienced marked improvement in his clinical signs and symptoms. This report provides preliminary proof of principle for the use of RBCx to treat Hb Evans and other non-Hb S hemoglobinopathies.

Keywords: hemoglobin Evans; hemoglobinopathy; methemoglobin; red blood cell exchange (RBCx); unstable hemoglobin.