Anti-B-Cell-Activating Factor (BAFF) Therapy: A Novel Addition to Autoimmune Disease Management and Potential for Immunomodulatory Therapy in Warm Autoimmune Hemolytic Anemia.

Although rituximab is not specifically approved for the treatment of warm autoimmune hemolytic anemia (WAIHA), the First International Consensus Group recommends considering its use as part of the initial therapy for patients with severe disease and as a second-line therapy for primary WAIHA. Some patients do not respond to rituximab, and relapses are common. These relapses are associated with elevated B-cell-activating factor (BAFF) levels and the presence of quiescent long-lived plasma cells (LLPCs) in the spleen. A new group of immunomodulatory drugs, B-cell-activating factor inhibitors (BAFF-i), demonstrated efficacy in multiple autoimmune diseases and have the potential to improve WAIHA treatment outcomes by targeting B-cells and LLPCs. This article reviews the role of BAFF in autoimmune disorders and the currently available literature on the use of BAFF-directed therapies in various immunologic disorders, including WAIHA. Collectively, the clinical data thus far shows robust potential for targeting BAFF in WAIHA therapy.

Management of paroxysmal nocturnal hemoglobinuria in CALR mutated post-essential thrombocythemia myelofibrosis: A case report.

Paroxysmal nocturnal hemoglobinuria (PNH) results from the loss of erythrocyte surface proteins, leading to complement activation and its spectrum of effects. We explore this case of a 57-year-old man with post-essential thrombocythemia (ET) myelofibrosis (MF) who developed symptomatic anemia with evidence of hemolysis on lab work. While hemolysis was localized to be intramedullary based on workup, the exact diagnosis was undetermined, leading to a prolonged course of steroid therapy to control anemia. The hemolysis was eventually attributed to PNH diagnosed on flow cytometry and the patient was treated with complement inhibitors with eventual failure of therapy. He ultimately underwent a successful hematopoietic cell transplant (HCT) with post-transplantation flow cytometry showing complete resolution of PNH. While PNH has been identified as a progression of myelodysplastic syndromes, the mechanisms of its rare development in myeloproliferative neoplasms are poorly elucidated. Furthermore, its rarity and often vague symptoms make diagnosis and treatment a challenge. This is the second reported case of a JAK2-negative, CALR-positive post-ET MF and the first reported case to be treated with HCT. This case probes for further insight into the clinical significance between MF and PNH, its impact on management, and further consideration for HCT as curative therapy in such patients who fail complement inhibitor therapy.