TCR alpha beta+/CD4+ T-large granular lymphocyte (LGL) lymphocytosis is a subgroup of monoclonal T-LGL lymphoproliferative disorders that are different from the CD8+ TCR alpha beta T-LGL.
A diagnosis of T cell large granular lymphocyte (T-LGL) leukemia was made, based on cytomorphology, the typical CD3+/CD4-/CD8+/CD16+/CD56-/CD57-/HLA-DR(+/-) immunophenotype of the lymphocytosis (9 x 10(9)/l), and biallelic clonally rearranged T cell receptor beta (TCR beta) genes.
92% of peripheral blood mononuclear cells from a patient with chronic lymphocytosis (WBC 22 x 10(9)/l) were recognized by pan-gamma delta monoclonal antibody (mAb) TCR delta 1.
The structures of rearranged gamma-chain T-cell antigen receptor (TCR) genes were analyzed in 5 cases of T-cell acute lymphoblastic leukemia (T-ALL), in 15 cases of peripheral T-cell non-Hodgkin's lymphoma (T-NHL), in 1 case with large granular CD8 lymphocytosis, 1 case with CD8 lymphocytosis after autologous bone marrow transplantation for Hodgkin's disease, and in 2 cases with nonneoplastic diseases.
T cell receptor (TcR) gene rearrangements were observed in six out of nine cases of CD3+ CD8+ lymphocytoses and provided clear evidence for clonality in this group.
Nine patients had acute lymphoblastic leukaemia (T-ALL), nine patients had prolymphocytic leukaemia (PLL), six patients presented with a T-CLL/T-lymphocytosis syndrome, two patients had Sezary syndrome (SS) and one patient had HTLV-I positive T-cell leukaemia/lymphoma (ATLL). alpha TCR gene rearrangement could be demonstrated by the use of three available probes in only one case.