Multiple autoimmune haemopoietic disorders and insidious clonal proliferation of large granular lymphocytes

We report a patient with clonal proliferation of CD3⁺8⁺TCRαβ⁺ large granular lymphocytes (LGL) presenting multiple episodes of autoimmune cytopenia, including autoimmune neutropenia, idiopathic thrombocytopenic purpura, autoimmune haemolytic anaemia, and pure red cell aplasia. Each disorder appeared separately or as a combination during an 11-year clinical course. The increase of blood CD3⁺8⁺TCRαβ⁺ LGL was detected 6 years after the initial diagnosis of cytopenia, but the absolute number of LGL cells was always <1.0 x 10⁹/1. LGL cells were of monoclonal origin and had a chromosomal abnormality. LGL cells transiently responded to cyclosporine A therapy, which was also effective on all of these autoimmune cytopenias. Accordingly, an undetectable level of proliferation of a clonal LGL population could cause various autoimmune haemopoietic disorders.