Aplastic Anaemia in a Chronic Lymphocytic Leukaemia Patient Treated With Acalabrutinib, a Bruton Tyrosine Kinase Inhibitor—Case Report

ABSTRACT Introduction Although Immune cytopenias such as immune thrombocytopenia (ITP), autoimmune haemolytic anaemia (AIHA) and pure red blood cell aplasia (PRCA) are well documented associations with chronic lymphocytic leukaemia (CLL), aplastic anaemia (AA) is seemingly rare. Case This report describes a case of AA in a CLL patient post commencement of acalabrutinib, a bruton tyrosine kinase inhibitor (BTKi). Discussion We further evaluate the current literature surrounding AA in concurrent lymphoproliferative disorders as well as previous cases in the setting of tyrosine kinase inhibition. Highlighting the potential pathophysiological pathways of T regulatory cell dysfunction resulting in immune targeting of haematopoietic stem progenitor cells, we explore the resultant AA as an aberrant immune response secondary to CLL and/or the inhibition of BTKi. Trial Registration The authors have confirmed clinical trial registration is not needed for this submission.