Acquired amegakaryocytic thrombocytopenia associated with proliferation of gamma/delta TCR T-lymphocytes and a BCR-ABL (p210) fusion transcript.
Acquired amegakaryocytic thrombocytopenia (AATP) in adults is a rare disorder characterized by severe thrombocytopenia and decreased or absent megakaryocytes in an otherwise normal bone marrow. We present a 44-yr-old man in whom the diagnosis of AATP was established in January 2001. Immunophenotyping of the peripheral blood lymphocytes showed a relative increase in the subpopulation of gamma/delta T-cell receptor (TCR) positive (gamma/delta TCR(+)) and (CD4, CD8) negative T lymphocytes, and PCR suggested a monoclonal pattern of TCR gamma chain gene rearrangement. Cytogenetic examination of his bone marrow cells showed a normal male karyotype but RT-PCR analysis revealed a BCR-ABL (p210) fusion transcript. The inhibition of CFU-Mk growth mediated by the patient's T lymphocytes indicated that the pathogenic mechanism for AATP could be an immunological attack on megakaryocyte progenitors where the gamma/delta TCR-positive T lymphocytes are directly involved. The case emphasizes the complex association of T-lymphocyte monoclonal proliferation and AATP.
Colovic
Milica
M
Institute of Hematology, University Clinical Center, Belgrade, Yugoslavia. marcolov@EUnet.yu
Pavlovic
Sonja
S
Kraguljac
Nada
N
Colovic
Natasa
N
Jankovic
Gradimir
G
Sefer
Dijana
D
Tosic
Natasa
N
D000328:Adult; D001854:Bone Marrow Cells / Q000473:pathology; D002999:Clone Cells; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008533:Megakaryocytes / Q000276:immunology / Q000473:pathology*; D012333:RNA, Messenger / Q000032:analysis; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000737:chemistry / Q000276:immunology / Q000473:pathology*; D013921:Thrombocytopenia / Q000235:genetics* / Q000276:immunology / Q000473:pathology*
D012333:RNA, Messenger; D016692:Receptors, Antigen, T-Cell, gamma-delta; D016044:Fusion Proteins, bcr-abl