Prevalence of autoimmune hematologic and non-hematologic conditions in large granular lymphocytic leukemia: exploratory analysis of a series of consecutive patients

Abstract

Large granular lymphocytic (LGL) leukemia is a relatively rare but well-defi ned clonal lymphoproliferative disorder, typically of indolent clinical behavior and associated with certain autoimmune conditions including immune cytopenias. At our institution, we studied a series of consecutive patients with T-LGL leukemia in the outpatient setting and explored the prevalence of autoimmune hematologic and non-hematologic conditions. Th e presence of these conditions in our cohort was compared with their documented prevalence in the general population and was tested for statistical signifi cance using both χ 2 test and Fisher test for a small number of observations (95% confi dence); a p -value 0.05 was considered signifi cant. A total of 22 patients ( n 22) were diagnosed with LGL leukemia at our institution between the years 2004 and 2013. Th e vast majority of patients were originally referred to us for evaluation of asymptomatic peripheral cytopenias. Diagnosis of LGL leukemia was made according to the World Health Organization (WHO) 2008 criteria including the following attributes: persistence of absolute or relative numbers of large granular lymphocytes without a clear etiology; unexplained cytopenias; aberrant T-cell antigen expression by fl ow cytometry; establishment of clonality via T-cell receptor (TCR) gene rearrangement studies; and/or demonstration of bone marrow involvement by LGL cells [1]. Th e clinicolaboratory data, peripheral blood immunophenotyping results, bone marrow morphology and fl ow cytometry, as well as TCR gene rearrangement studies at the time of diagnosis, were retrospectively reviewed. Th e majority of patients in our cohort were men (59%) and the median age was 75 years (range, 48 – 90) at the time of diagnosis. Most patients were asymptomatic at the time of presentation and had at least one peripheral blood abnormality associated with T-LGL leukemia. Leukopenia was present in 73% of cases, with a median leukocyte count of 3.4 10 9 /L (range, 1.7 – 3.9 10 9 /L); neutropenia was identifi ed in 63% of cases, with a median absolute neutrophil count of 1.1 10 9 /L (range, 0.2 – 1.7 10 9 /L). Lymphocyto