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54
ICCS 2012
P43
PRECURSOR B-CELL LYMPHOBLASTIC LEUKEMIA
WITH SURFACE IMMUNOGLOBULIN LIGHT CHAIN
RESTRICTION: 2 CASES REPORT
Ya-ping Zhai
1
, Yan-hui Liu
1
, Yin Zhang
1
, Wei Cheng
1
, Yu-long
Li
1
1
The Institute of Hematology,Henan Provincial People’s
Hospital
Introduction:
B-cell acute lymphoblastic leukemia (ALL) can
be classified into two major subtypes: precursor B (pB)-ALL
and mature B-cell ALL. Mature B ALLs are typically TdT
negative and sIg positive, while pB-ALL characteristically
express TdT and are sIg negative. Therefore, pB- ALL
with sIg light chain restriction is extremely rare.
Methods:
Immunophenotic and cytogenetic features of the leukemic
blast cells were reviewed.
Results:
The 2 patients (1 male
adult aged 22 years and 1infant aged 18 months) presented
with non-specific symptoms. The leukemic blast cells in
both cases showed characteristic of FAB L2 lymphoblasts
and co-expressed CD34/CD19/CD10/CD22/cCD79a/CD9/
HLA-DR/CD38/ TdT / CD123/CD13 (partial) and unexpected
single surface immunoglobulin lambda (sIg lambda) light
chains restriction by flow cytometry. As expected, they were
negative for surface immunoglobulin kappa (sIg kappa)
light chains, CD7,CD5, CD117,CD33,CD56, CD23,FMC7,
MPO. In addition, the leukemic blast cells from the infant
patient were positive for CD20 while the lymphoblasts from
the adult patient were negative for CD20. Cytogenetic
analysis revealed the adult with t(9;22)(q34;q11) and the
infant with normal karyotype. Karyotypic analysis in both
cases was negative for 8q24(myc) translocation. Both cases
were diagnosed and managed as pB ALL and the patients
had good response to therapy for pB ALL, the patient with
t(9;22)(q34;q11) also received imatinib therapy.
Conclusion:
sIg light chain restriction does not necessarily represent
a mature B-cell ALL phenotype. As different treatment
regimens are used separately for pB ALL and mature B
ALL, attention must be paid to such a rare ALL for avoiding
inadequate therapy or overtreatment.
POSTER ABSTRACTS