Diversity of T-cell receptor gene rearrangements in South Indian patients with common Acute Lymphoblastic Leukemia

ABSTRACT

Precursor B-Acute Lymphoblastic Leukemia [precursor B-ALL] occurs due to the uncontrolled proliferation of B-lymphoid precursors arrested at a particular stage of B-cell development. Precursor-B-ALL is classified mainly into pro-B-ALL, common-ALL and pre-B-ALL. The Common Acute Lymphoblastic Antigen CD10 is the marker for common-ALL. This study was aimed to examine the diversity of T-cell receptor Gamma [TCRG] and T-cell receptor Delta [TCRD] gene rearrangements in South Indian Common-ALL patients. Clonality of TCRG and TCRD was studied in 52 cases [pediatric=41 and adolescents and young adults=11] of common-ALL. TCRG and TCRD gene rearrangements were amplified by PCR and the clonality was assessed by Heteroduplex analysis of amplified products. In pediatric common-ALL, clonal TCRG and TCRD gene rearrangements were detected in 19 [46.3%] and 18 [43.9%] cases respectively. In adolescents and young adults [AYA], TCRG was rearranged in 8 [72.7%] cases and TCRD was rearranged in 4 [36.3%] cases. In the present study of common-ALL, the frequency of a TCRG rearrangement V gamma II-J gamma 1.3/2.3 was significantly high in AYA compared to pediatric [36.3% vs 4.8%; p<0.025]. Thus, V gamma II-J gamma 1.3/2.3 was highly diverse in AYA compared to pediatric. That shows the difference in biology of the disease between pediatric and AYA in South Indian population. The reason for the high frequency of V gamma II-J gamma 1.3/2.3 in AYA of common-ALL in South Indian population in connection with unknown infectious agents or environmental carcinogens needs to be evaluated further