We analyzed the TcR δ rearrangement pattern in 7 B-ALL/LBL and 9 T-ALL/LBL patients with δ rearranged band (s). Blot hybridization analysis of PstI digests did not reveal any Jδ1-rearranged band (s) in all 7 B-ALL/LBL, suggesting DD or VD pattern, whereas all but two cases of T-ALL/LBL showed the rearrangement involved Jδ1 segment. The analysis using 5 different Vδ genes as probes revealed that the majority pattern in B-ALL/LBL corresponded to Vδ2(D)D. There are three pattern (DD, D(D)J, and V(D)DJ) of δ rearrangement but VD in 6 adult patients with CD7+ stem cell leukemia. Therefore, it is suggested that the order of δ rearrangement is DD→(D)DJ→V(D)DJ at the earliest stage of T cell ontogeny. Furthermore, our data indicates that there is the heterogeneity of Vδ gene used at different stage of T-cell development.
