Current classification of childhood leukemia relies on morphologic, immunophenotypic, and molecular characteristics. aBL is rare and poorly understood. We retrospectively evaluated 7 patients diagnosed with aBL according to European Group for Immunological Classification of Leukemias (EGIL) criteria(2 or more lineages with a score greater than 2).

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Among 269 leukemia patients diagnosed in 2001–2004, 7 (2.6%) were classified as having aBL. Clinical characteristics/course and laboratory data are listed below in Tables1&2.

TABLE 1:

CLINICAL CHARACTERISTICS & COURSE

PATIENTAGESEXRACEINITIAL WBCTREATMENTCOURSE
1 12 F AA 5,600 CCG1961-> CCG2891, HDARAC, HSCT IND. FAILURE; R1:CNS,BM R2:BM R3:CNS,BM DOD, 24M 
2 17 F C 81,600 CCG2891 R1:CNS,BM DOD, 10M 
3 2 M C 40,000 CCG1961 RER; CR1, 16M 
4 2 M H 5,630 CCG1991-> CCG1961, HSCT SER; CR1, 14M 
5 6 F H 38,000 CCG1961 RER; CR1, 12M 
6 16 M AA 150,000 CCG1961-> AAML03P1 IND. FAILURE; R1:BM DOD, 9M 
7 11 M C 77,100 AAML03P1, HSCT RER; CR1, 7M 
PATIENTAGESEXRACEINITIAL WBCTREATMENTCOURSE
1 12 F AA 5,600 CCG1961-> CCG2891, HDARAC, HSCT IND. FAILURE; R1:CNS,BM R2:BM R3:CNS,BM DOD, 24M 
2 17 F C 81,600 CCG2891 R1:CNS,BM DOD, 10M 
3 2 M C 40,000 CCG1961 RER; CR1, 16M 
4 2 M H 5,630 CCG1991-> CCG1961, HSCT SER; CR1, 14M 
5 6 F H 38,000 CCG1961 RER; CR1, 12M 
6 16 M AA 150,000 CCG1961-> AAML03P1 IND. FAILURE; R1:BM DOD, 9M 
7 11 M C 77,100 AAML03P1, HSCT RER; CR1, 7M 
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Table 2:

MORPHOLOGY, IMMUNOPHENOTYPE & CYTOGENETICS

PATIENTFAB MORPHOLOGYFLOW CYTOMETRYEGIL SCORE(T/B/M)CYTOGENETICS/FISH
* =Peripheral Blood 
1* L1, M5 CD3, CD7, pCD5, CD33,MPO 3.5/0/3 6,XX,add(1)(p22);t(3;12)(p24;p13),del(6)(q21q22),del(8)(p21),-9,del(13)(q13q14), +22 
2* L1, M2 P1: CD19, CD22, CD33, Tdt P2: CD2,CD14,CD15, CD33, MPO 2/3.5/4 46,XX,der(8)t(8;?;17)(q11.2;?;q21),der(9)t(8;9)(q21.2;p12),del(15)q21), der(17)t(15;?;17)(q21;?;q11.2) 
3 L2 P1: CD33, CD34 P2: CD13, CD15, CD10, CD19, CD22 0/4/2.5 46, XY, del12p-/TEL deletion 
4 L1 CD19,CD22, CD13, CD15, CD33 0/3/2.5 46, XY 
5 L1, M5 CD19, pCD20, CD22, CD13, CD15, pCD33 3.5/0/3.5 46, XY, del(5)(q15q33), dic(7;9)(p11.2;p12),inv(9)c,t(10,11)(p13;q21) 
6 L2 cCD3, pCD5, CD7, CD13, CD15, CD33,pCD117 0/4/3.5 46, XX/Trisomy 10 
7* L1, M5 CD2,CD3,CD7, TdT, pCD22,CD13, CD15, pMPO, CD117 4/1/4.5 46, XY 
PATIENTFAB MORPHOLOGYFLOW CYTOMETRYEGIL SCORE(T/B/M)CYTOGENETICS/FISH
* =Peripheral Blood 
1* L1, M5 CD3, CD7, pCD5, CD33,MPO 3.5/0/3 6,XX,add(1)(p22);t(3;12)(p24;p13),del(6)(q21q22),del(8)(p21),-9,del(13)(q13q14), +22 
2* L1, M2 P1: CD19, CD22, CD33, Tdt P2: CD2,CD14,CD15, CD33, MPO 2/3.5/4 46,XX,der(8)t(8;?;17)(q11.2;?;q21),der(9)t(8;9)(q21.2;p12),del(15)q21), der(17)t(15;?;17)(q21;?;q11.2) 
3 L2 P1: CD33, CD34 P2: CD13, CD15, CD10, CD19, CD22 0/4/2.5 46, XY, del12p-/TEL deletion 
4 L1 CD19,CD22, CD13, CD15, CD33 0/3/2.5 46, XY 
5 L1, M5 CD19, pCD20, CD22, CD13, CD15, pCD33 3.5/0/3.5 46, XY, del(5)(q15q33), dic(7;9)(p11.2;p12),inv(9)c,t(10,11)(p13;q21) 
6 L2 cCD3, pCD5, CD7, CD13, CD15, CD33,pCD117 0/4/3.5 46, XX/Trisomy 10 
7* L1, M5 CD2,CD3,CD7, TdT, pCD22,CD13, CD15, pMPO, CD117 4/1/4.5 46, XY 
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5 patients had abnormal karyotypes and/or FISH studies; none had MLL rearrangements or t(9;22). Induction treatment consisted of AML-type therapy (CCG 2891 /COG AAML03P1) in 2 patients who achieved CR by day 28. Two patients received ALL-type therapy (CCG 1961) and entered CR by Day 28. Three patients required dose intensification due to induction failure: 2 switched from ALL to AML-type therapy. Post induction chemotherapy was given in 4 cases; allogeneic HSCT in 3 cases (2 in CR1; 1 in 2nd relapse). 2/4 and 2/3, respectively, remain alive in 1st CR after chemotherapy or HSCT. All 3 deaths were from relapse of aBL within 2 yrs from diagnosis & occured in adolescents with complex karyotypes. In our experience, pediatric aBL represents a high risk population, especially in adolescents. Intensive induction chemotherapy is necessary in the majority of cases to achieve CR, although it is unclear whether ALL or AML-type therapy is superior. MLL & t(9;22) may not be as common in pediatric aBL as previously described. Collaborative trials and biologic studies are clearly needed for better understanding and outcomes.

Topics:
abetalipoproteinemia, acute biphenotypic leukemia, pediatrics, antigens, cd15, cd33 antigen, alanine aminopeptidase, cd19 antigens, hematopoietic stem cell transplantation, chemotherapy, neoadjuvant, karyotype determination procedure

Author notes

Corresponding author

2005, The American Society of Hematology
2005
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