The autoimmune cytopenias are a group of disorders resulting primarily from 
autoantibody-mediated destruction of blood cells, with variable clinical 
sequelae depending on the severity and lineage affected. Disease presentation 
ranges from an asymptomatic finding on a routine full blood count to an acutely 
unwell patient suffering the clinical consequences of severe anaemia, 
neutropenia or thrombocytopenia. The cytopenia may be primary or secondary to 
underlying infectious, immune or malignant processes. Thrombotic 
thrombocytopenic purpura (TTP) is a distinct, rare but potentially 
life-threatening entity that classically but not invariably presents with a 
pentad of acute onset haemolytic anaemia, thrombocytopenia, neurological 
symptoms, renal impairment and fevers. Autoimmune cytopenias have formed a 
recognised diagnostic entity for over 150 years yet continue to present a 
challenge in medical practice due to heterogeneity in clinical presentation and 
triggering factors, an incomplete understanding of underlying pathophysiology 
and a lack of evidence-based therapeutic approaches.