Supplementary Material for: Antibodies against Carbonic Anhydrase in Patients with Aplastic Anemia

<b><i>Background/Aims:</i></b> Antibodies against carbonic anhydrase (CA) have been detected in patients with an aplastic anemia (AA)-like syndrome after autologous stem cell transplantation. <b><i>Methods:</i></b> We analyzed sera of 53 bona fide AA patients before and after treatment with anti-thymocyte globulin (ATG) or bone marrow transplantation for the presence of anti-CA antibodies. <b><i>Results:</i></b> Anti-CA antibodies were detected in 20 patients (38%) and were associated with older age at diagnosis of AA. Antibody-positive patients showed poor response to ATG treatment (complete response 14%) and inferior long-term survival (36% at 10 years), when compared to antibody-negative patients (complete response and 10-year survival both 64%). Two thirds of patients with antibodies at diagnosis of AA became antibody negative after treatment with ATG. Clearance of the antibody did not appear to be associated with hematological improvement. <b><i>Conclusion:</i></b> Antibodies against CA are detected frequently at diagnosis of AA, and their presence identifies a subset of patients with poor response to immunosuppressive treatment.