Acquired pure megakaryocytic aplasia report of two cases with long‐term responses to antithymocyte globulin and cyclosporine

Abstract

Acquired pure megakaryocytic aplasia is a rare disorder defined by severe thrombocytopenia with no other hematologic abnormalities and absent, or severely decreased marrow megakaryocytes. The etiology may be immune suppression of megakaryocyte development. Two patients are described who both responded rapidly to a combination of antithymocyte globulin and cyclosporine and who remain in remission 13-20 months after discontinuation of cyclosporine. This regimen is well described for treatment of aplastic anemia and may also be effective for acquired pure megakaryocytic aplasia. Am.

Acquired pure megakaryocytic aplasia successfully treated with cyclosporine

“…Due in part to the heterogeneous nature of the syndrome and the variety of the pathogenic mechanisms, no standard treatment has been established; however, several empirical therapies are used in patients with AATP and include the administration of corticosteroids , IVIG, cyclophosphamide, vincristine, cyclosporine, anti-thymocyte globulin (ATG), splenectomy [15][16][17][18], allogenic bone marrow transplantation [19], and recently, mycophenolate mofetil [20].…”

“…The administration of corticosteroids, IVIG, cyclophosphamide, vincristine, androgens, and mycophenolate mofetil are transiently effective in occasional patients with AATP [1,15,16,20]; however, the administration of cyclosporine alone or in combination with ATG was shown to be very effective in the treatment of AATP [10,15,17,18].…”

Cardiobacterium hominis endocarditis associated with very severe thrombocytopenia and platelet autoantibodies

“…In addition to an immune mechanism, therefore, other factors likely contributed to the severe thrombocytopenia observed in this case including splenic platelet sequestration, sepsis-associated marrow suppression and hemophagocytosis. The marked reduction in bone marrow megakaryocytes may be consistent with an autoimmune syndrome in view of the fact that cytotoxic autoantibodies directed against megakaryocyte precursors have been demonstrated in patients with acquired pure megakaryocytic aplasia [26,27] and immunosuppressive treatment has been successful in this disorder [28]. The lack of response to prednisone and IVIg argues against an immune mediated mechanism; however, up to 30% of ITP patients are refractory to steroids [29] and up to 25% have an inadequate response to IVIg [30,31].…”

Acquired Amegakaryocytic Thrombocytopenic Purpura Progressing into Aplastic Anemia

“…Immunosuppression, however, remains the mainstay of therapy. Treatments shown to be successful include the use of corticoids (Sakurai et al, 1984), intravenous immunglobulins (IVIG) (Leach et al, 1999), cyclosporine (Omri et al, 2010), anti-thymocyte globulin (ATG) (Niparuck et al, 2008), as well as allogeneic stem cell transplantation (Lonial et al, 1999) and anti-CD20 antibodies (Deeren and Dorpe, 2010;Mirzania et al, 2014). While these and other therapeutic agents have shown a wide range of response rates, reports emerged reporting success with thrombopoietin (TPO) receptor agonists recently; a treatment option that has already been theorized earlier (Lown et al, 2010).…”