The V(D)J recombination in acute lymphoid leukemias: a short review

Antigen recognition by lymphoid cells is mediated by cell surface receptors. Specificity of this recognition is due to somatic gene rearrangements. These recombinations involve gene segments (V, J and in some cases D) which encode the amino terminal part of antigen receptor chains. Surface immunoglobulins (sIg) function as antigen receptors for B cells. Two types of T cell antigen receptors (TCR alpha beta and TCR gamma delta) have been described whose expression at the cell surface of T cells is exclusive. V(D)J rearrangements are clone specific and occur irrespective of antigens during the early stages of lymphoid differentiation. In rare instances, recombination occurs between different Ig/TCR loci or even involve genes distinct of those coding for Ig or TCR. In some cases these genes are activated by the chromosomal rearrangement and could be involved in the transformation of lymphoid cells.