Effect of discontinuation of CsA on reticulocyte counts and RBC transfusion requirements.

Reticulocyte counts increased and RBC transfusion requirements resolved, accompanied by characteristic RBC serologic changes, following discontinuation of CsA in patients with PRCA after major ABO-incompatible NST. Cases are from Table 1; all cases involved group A donors and group O recipients. PRBC transfusions are shown as arrows; strength of forward type for donor RBCs and reverse type for host antidonor isohemagglutinins are shown across top of graph. ⧫, reticulocytes; ○, blood CsA levels. Reticulocyte counts recovered after CsA withdrawal, followed by the appearance of donor RBCs within 7 days. Plasma exchange procedures are indicated with double arrows. (A) UPN 113 with renal cell cancer. (B) UPN 138 with chronic myelogenous leukemia. (C) UPN 149 with paroxysmal nocturnal hemoglobinuria. Plasma exchange to lower markedly increased isohemagglutinins titers of 2048 (256 after DTT treatment) prior to CsA tapering was ineffective, producing transient isohemagglutinin decreases lasting less than 24 hours. Plasma exchange was discontinued after 2 sessions because of an idiosyncratic reaction to albumin replacement fluid. (D) UPN 178 with aplastic anemia. Platelet counts increased and platelet-transfusion independence was achieved by day 14; conversion to full donor myeloid chimerism occurred by day 30. However, reticulocyte counts remained depressed in association with persistently elevated antidonor isohemagglutinin titers for 7 months following transplant. At 6 weeks following discontinuation of CsA, a series of 4 alternate-day plasma exchanges were performed. Isohemagglutinin levels decreased by 50% after each procedure, from a titer of 32 (4 after DTT treatment) to 2, followed by rapid recovery of reticulocyte counts and appearance of donor RBCs.