First study of immunoglobulin and T cell receptor gene rearrangements in chronic and acute lymphoblastic leukemias from Tunisia.

We report the first characterization at the immunological and molecular level of 12 cases of chronic lymphocytic leukemia (CLL) and acute lymphoblastic leukemia (ALL) from Tunisia. Our results show biallelic IgH gene rearrangement in B-CLL (6/6). A high ratio of T-ALL (4/6) was observed in Tunisian ALL leukemias. One T-ALL expressed CD10 (common ALL) which has already been found in some other cases of T-ALL. We report the occurrence of T cell receptor (TCR) beta and/or gamma gene rearrangements in two precursor B-ALL patients who had normally rearranged Ig genes. In one precursor B-ALL case, multiple rearranged IgH and TCR gamma bands allowed the identification of three clones. Such an oligoclonal ALL is interesting since only rare biclonal TCR beta or gamma gene rearrangements have been described.