Clonal proliferation of T-Cell large granular lymphocytes

Background T‐cell large granular lymphocyte (T‐LGL) leukemia is a disorder only rarely reported in children. We diagnosed a new case of a clonal T‐LGL proliferation in a 6‐year‐old girl presenting with severe neutropenia and pure red blood cell aplasia (PRCA). Procedure Flow cytometric analysis including TCR‐Vβ repertoire analysis and molecular studies using reverse transcriptase polymerase chain reaction (RT‐PCR), PCR heteroduplex analysis and GeneScan analysis were performed to investigate the clonal nature of the T‐LGL. Results Flow cytometric analysis revealed a Vβ3 clonal nature. Molecular studies identified a clonal Vβ3‐Cβ RT‐PCR product. Both PCR heteroduplex analysis and GeneScan analysis found clonal TCRB and TCRG gene rearrangements. Conclusions An underlying T‐LGL leukemia should be investigated in the diagnostic evaluation of acquired PRCA and neutropenia in young children. Both flow cytometric and molecular analyses can be used to establish the clonal nature of T‐LGL. © 2003 Wiley‐Liss, Inc.