Monoclonal IgM gammopathy in adult acquired pure red cell aplasia: culprit or innocent bystander?

Hepatitis C Infection Associated with Acquired Pure Red Cell Aplasia

Acquired pure red cell aplasia is a rare bone marrow failure disorder characterized by many underlying etiologies. The hallmark bone marrow feature is the near absence of erythroid precursors that otherwise exhibit normal cellularity, which has been attributed to both immune- and cellular-mediated mechanisms. Besides being merely speculative and considering the rarity of the disorder, the description of acquired pure red cell aplasia clinical associations represents a unique occasion to improve our current clinical knowledge of the disease, reveal clues on its pathogenesis, and guide therapeutic decisions. The varied clinical scenarios and common acquired pure red cell aplasia associated conditions (i.e., thymoma, T cell/NK-cell large granular lymphocyte leukemia, B cell dyscrasia) suggest a heterogeneity of pathogenic routes. Viral etiologies must always be considered and worked up in the initial assessment of newly diagnosed acquired pure red cell aplasia patients. In this report, we present two cases of hepatitis-C-related acquired pure red cell aplasia and successful use of anti-viral strategies in the achievement of a complete response.

Large Granular Lymphocytic Leukemia: From Immunopathogenesis to Treatment of Refractory Disease

Large Granular Lymphocyte Leukemia (LGLL) is a rare, chronic lymphoproliferative disorder of effector cytotoxic T-cells, and less frequently, natural killer (NK) cells. The disease is characterized by an indolent and often asymptomatic course. However, in roughly 50% of cases, treatment is required due to severe transfusion-dependent anemia, severe neutropenia, or moderate neutropenia with associated recurrent infections. LGLL represents an interesting disease process at the intersection of a physiological immune response, autoimmune disorder, and malignant (clonal) proliferation, resulting from the aberrant activation of cellular pathways promoting survival, proliferation, and evasion of apoptotic signaling. LGLL treatment primarily consists of immunosuppressive agents (methotrexate, cyclosporine, and cyclophosphamide), with a cumulative response rate of about 60% based on longitudinal expertise and retrospective studies. However, refractory cases can result in clinical scenarios characterized by transfusion-dependent anemia and severe neutropenia, which warrant further exploration of other potential targeted treatment modalities. Here, we summarize the current understanding of the immune-genomic profiles of LGLL, its pathogenesis, and current treatment options, and discuss potential novel therapeutic agents, particularly for refractory disease.