Characteristics of pro-T ALL subgroups: comparison with late T-ALL. The Groupe d'Etude Immunologique des Leucémies.
A group of 30 acute lymphoblastic leukemias (ALL) with the early pro-T phenotype CD7+/cCD3+/CD1-/CD3-/CD4-/CD8-were identified among 103 newly diagnosed ALL with T-lineage markers (T-ALL). Pro T-ALL was more often observed in adults, and showed a lower incidence of hyperleukocytosis than more mature T-ALL. Mediastinal masses and polar acid phosphatase positivity in blast cells were however observed with the same frequency in pro T-ALL and late T-ALL, and rearrangements of both T-cell receptor (TCR) beta and gamma genes were observed in half the pro T-ALL cases tested. The expression of CD34, DR, and myeloid (My) markers was significantly more frequent in pro T-ALL than in late T-ALL, and these three features were strongly linked. TCR gene rearrangements were two to three times more frequent in CD34- and My-pro T-ALL. However, both CD34+ and My+ pro T-ALL showed an incidence of mediastinal masses and polar acid phosphatase positivity similar to this observed in CD34- and My- cases. This supports the assumption that both types of ALL indeed are engaged in the T-lineage, and confirms intracytoplasmic cCD3 as the earliest marker for this lineage. Moreover, CD34 appears to persist up to an early stage of T-cell maturation, where the cells retain myeloid potentiality. Loss of CD34 correlates with TCR-beta gene rearrangement and definitive commitment to the T lineage. Event-free survival analysis suggested a poorer outcome for pro T-ALL in adult patients.
Garand
R
R
Laboratoire d'Hématologie, Hôtel Dieu, Nantes, France.
Voisin
S
S
Papin
S
S
Praloran
V
V
Lenormand
B
B
Favre
M
M
Philip
P
P
Bernier
M
M
Vanhaecke
D
D
Falkenrodt
A
A
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000032:analysis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D015329:Gene Rearrangement, T-Lymphocyte; D006801:Humans; D016130:Immunophenotyping; D007223:Infant; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000276:immunology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D012074:Remission Induction
D015703:Antigens, CD; D014408:Biomarkers, Tumor