Heterogeneity of T cell lymphoblastic leukaemias.
Twenty eight out of 170 consecutive cases of acute lymphoblastic leukaemia (ALL) were examined. They were of T cell origin, with the following distribution: seven (28%) cases had pre-T or prothymic features; nine (36%) cases showed early thymocytic features, six (24%) had cortical features; and three (12%) had a "mature" phenotype. The remaining three cases could not be sub-classified. A striking finding was that pre-T ALL differed from intrathymic ALL not only in the absence of both E rosettes and intrathymic differentiation antigens, but also in the expression of two non-lineage specific antigens HLA-DR and CD10. Both antigens appear in the bone marrow from the very first stages of lymphoid differentiation, implying that the origin for pre-T ALL is bone marrow. A comparison of the clinical features of pre-T and thymic ALL showed that pre-T ALL disease showed a pattern more similar to non-T ALL disease: a lower incidence of mediastinal mass, absence of extrahaematopoietic disease, lower white cell counts and haemoglobin concentrations, and a higher incidence of bone pain. No obvious difference in response to treatment was apparent. The results show that T-ALL is not only a heterogeneous immunological group but also suggest that it may have different origins: bone marrow for pre-T ALL and the thymus for thymic ALL.
Gómez
E
E
Department of Haematology, Hospital Clinico, Salamanca, Spain.
San Miguel
J F
JF
González
M
M
Orfao
A
A
López-Berges
C
C
Ríos
A
A
López Borrasca
A
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis; D000951:Antigens, Neoplasm / Q000032:analysis; D002454:Cell Differentiation; D002648:Child; D002675:Child, Preschool; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000276:immunology* / Q000401:mortality / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012737:Sex Factors
D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000949:Histocompatibility Antigens Class II