Sullivan, Luz Y.

ABO incompatibility is frequent in haematopoietic stem cell transplantation (HSCT), yet the clinical impact of non-ABO red blood cell (RBC) alloimmunisation remains less defined. We describe the clinical course of a man in his 50s with chronic eosinophilic leukaemia who underwent a mismatched unrelated donor (MMUD) HSCT. Despite a major ABO mismatch and high-titre pre-existing anti-E antibodies against an E-antigen positive donor, the patient achieved successful trilineage engraftment without haemolysis. Six months after the transplant, he developed severe pancytopenia and a positive direct antiglobulin test (DAT) with anti-E elution. These serologic findings coincided with disease relapse rather than isolated immune-mediated haemolysis. This case illustrates that successful engraftment is possible across RhE-incompatibility and underscores the need to interpret late serologic abnormalities within the broader context of graft function and disease status.

ABSTRACTWe describe a case of a 56‐year‐old male who developed severe, refractory hypotension after an intentional ingestion of clozapine and who became hemodynamically stable after one session of therapeutic plasma exchange (TPE). The patient, who presented after an ingestion of clozapine, was found to have altered mental status and hypotension in the emergency department. Escalating catecholamine vasoactive agents were necessary to maintain adequate hemodynamics. Angiotensin II was added and rapidly up titrated in efforts to maintain adequate blood pressure. Due to persistent hemodynamic instability despite four vasoactive agents, TPE was attempted to enhance the elimination of the highly protein bound medication. Within 2 h of completing TPE, the catecholamines and vasopressin were stopped, and angiotensin II dosing was significantly decreased. This is the first report of utilizing TPE as a method of enhanced elimination of a toxic clozapine ingestion resulting in severe hemodynamic compromise. Further study is necessary to determine if TPE should be incorporated into the care of patients experiencing clozapine toxicity.