Lymphoblastic Leukaemia in Infants
Starý J.1 ,Gajdoš P.2 ,Trka J.1 ,Vávra V.1 ,Hak J.3 ,Mihál V.4 ,Blažek B.5 ,Hrstková H.6 , Hrušák O.7 ,Michalová K.8 ,Jarošová M.9 ,Jabali Y.10
1 II.dětská klinika UK 2.LF a FN Motol,Praha, 2 Státní zdravotní ústav Praha, 3 Dětská klinika FN Hradec Králové, 4 Dětská klinika FN Olomouc, 5 Dětská klinika FN Ostrava, 6 I.dětská interní klinika FN Brno, 7 Ústav imunologie UK 2.LF a FN Motol,Praha, 8 Centrum nádorové cytogenetiky UK 1. LF VFN Praha, 9 Hemato-onkologická klinika FN Olomouc, 10Dětská klinika NsP České Budějovice |
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Summary:
The therapeutic results in children with acute lymphoblastic leukaemia (ALL)are improving continu-
ously with modern treatment protocols of combined chemotherapy.Approximately 75 %children and
adolescents can be cured from their leukaemia.Among infants younger than one year ALL is a rare
disease.Typical infant ALL originates from very early precursors of B cells with a specific genotype,
large leukaemic mass on diagnosis and high risk of early relapse.Between 1990 –2000,671 children and
adolescents 0 –18 years old were diagnosed with ALL in the Czech Republic.Only 24 (3.6 %)of them were
infants.Boys (n 16)predominated over girls (n 8)and 10 infants were younger than 6 months.ALL
developed from very early precursors of B cells (pro-B ALL)in 16 children,cALL was diagnosed in 7
and T-ALL in one child,respectively.Cytogenetic and molecular genetic investigation revealed trans-
location t(4;11)/fusion gene MLL-AF4 in 11 (45.8 %)patients.Fifteen children were treated according to
the protocol ALL-BFM 90,ALL-BFM 95 was used in one child and age-tailored schedules POG 9407 and
Interfant 99 were used in 5 and 3 children,respectively.Therapeutic results were analyzed in 21 children
because the follow-up of 3 children on the Interfant 99 protocol was too short.The 5-year event-free-
survival (EFS)was 33 %(SE 10 %)with a median follow-up of 7.9 years.Children with ALL and
t(4;11)/MLL-AF4 had a significantly inferior outcome (EFS 10 %)in comparison to children without this
translocation (EFS 55 %;p 0,01).Boys achieved better therapeutic results (EFS 45 %)than girls (EFS
12 %;p 0,007).The explanation of this difference is the higher incidence of t(4;11)in girls.Another
important risk factor in our group was a slow early treatment response in 33 %infants.Poor response
to early therapy is found only in 10 %older children.Infant ALL is a rare disease with a worse prognosis
than ALL in older children due to the different biological properties of the leukaemic cells.
Key words:
acute lymphoblastic leukaemia,infants,t(4;11),fusion gene MLL-AF4
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