Immunoglobulin genes re-arrangement in Sudanese patients with leukaemias: a lineage marker.

Abstract

In the recent years major advances was carried out in the improvement in the quality of life and survival for patients with leukaemia especially childhood acute lympholastic leukaemia. These advances have been attributed to improvement in supportive care and identification of prognostic factors that helped to categorize patients into favorable prognostic groups that respond to routine chemotherapeutic agents and non-responding group that need intensive treatment and probably bone marrow transplantation. An important prognostic factor that helped to classify patients is identification of the lineage of the leukaemia. Myeloid and lymphoid cells are treated differently by drugs types and duration. Although most of the classification systems of leukaemias depend on morphology of the cell, cytochemsitry, immunophenotyping and cytogenetics which are commonly used in addition to morphology to classify patients. In Sudan the only available method of lineage characterization is morphological identification of the type of cells. The objective of this study was to determine presence of light chain immunoglobulin rearrangement in Sudanese patients with different leukaemias and to show that morphological diagnosis was relatively in-accurate. This was the first time to conduct this type of moleculobiological study in the Sudan for diagnosis of leukaemia. Forty eight patients with morphologically classify leukaemias consented to participate in this study. Demographic and clinical data showed that there was no significant gender difference in different morphological types of leukaemias. ALL leukaemias were common in the young age group, compared to AML and CLL. DNA samples from twenty four patients were analysed using primers for κ light chain gene rearrangement (VKI & VKII). Two samples (2/2) from AML patients showed rearrangement in VKI, but no rearrangement in VKII, while seven samples (7/11) from ALL patients had rearrangement in VKI and no rearrangement in VKII. In the chronic leukaemias 2 patients (2/2) with CLL and 6 patients (6/9) with CML showed rearrangement in VKI, but no sample showed rearrangement in VKII