APHERESIS IN GRADE-4 BONE-MARROW TRANSPLANT ASSOCIATED THROMBOTIC MICROANGIOPATHY - A CASE SERIES

Bone marrow transplant-associated thrombotic microangiopathy (BMT-TM) ranges in severity from a self-limited to a fatal disorder. There has been no specific therapy for this condition. We have previously descri bed a clinical grading system for BMT-TM, based upon lactate dehydroge nase level (LDH) and percentage fragmented cells (FC) as follows: grad e 0, normal or up arrow LDH and % FC less than or equal to 1.2%; grade 1, normal LDH and FC greater than or equal to 1.3%; grade 2, up arrow LDH and FC = 1.3-4.8%; grade 3, up arrow LDH and FC = 4.9-9.6%; and g rade 4, up arrow LDH and FC greater than or equal to 9.7%. Patients wi th grade 4 BMT-TM usually have fulminant disease and generally succumb . This study summarizes results using a variety of apheresis procedure s in a series of 16 patients with grade 4 BMT-TM. The apheresis proced ures consisted of plasma exchange (with replacement with fresh frozen plasma or cryo-poor plasma), and protein A immunoadsorption (PAI). The PAI exchanges were not done concurrently with plasma exchange procedu res. Fifteen patients had undergone an allogeneic BMT and the 16th pat ient had undergone an autologous peripheral blood stem cell transplant . Half showed hematologic improvement with a downstaging of their TM t o grades 1-3. All non-responders died a median of 11 days following th e onset of grade 4 BMT-TM. The median survival in the responders was s ignificantly (P = 0.001) increased to 218 days with three responders s urviving more than 400 days following the onset of this severe complic ation. These results suggest a role for apheresis in the treatment of this lethal complication. Nevertheless grade 4 BMT-TM represents a maj or complication of BMT; the median survival in this group of 16 patien ts with grade 4 BMT-TM was only 31 days. (C) 1996 Wiley-Liss, Inc.