Diversity of T-cell receptor Gene Rearrangements in South Indian Patients with Common Acute Lymphoblastic Leukemia

Abstract

<b>Background</b>: Precursor B-Acute Lymphoblastic Leukemia (precursor B-ALL) oc-curs due to the uncontrolled proliferation of B-lymphoid precursors arrested at a par-ticular 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. <br/><b>Objective</b>: 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. <br/><b>Methods</b>: 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 prod-ucts. <br/><b>Results</b>: In pediatric common-ALL, clonal TCRG and TCRD gene rearrange-ments 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 VγII-Jγ1.3/2.3 was significantly high in AYA compared to pediatric (36.3% vs 4.8%; p<0.025). Thus, VγII-Jγ1.3/2.3 was highly diverse in AYA compared to pediatric. That shows the difference in biology of the disease be-tween pediatric and AYA in South Indian population. <br/><b>Conclusion</b>: The reason for the high frequency of VγII-Jγ1.3/2.3 in AYA of common-ALL in South Indian popu-lation in connection with unknown infectious agents or environmental carcinogens needs to be evaluated further.