[Identification of immunoglobulin and T-cell receptor gene rearrangements--prerequisite for monitoring of minimal residual disease in Polish acute lymphoblastic leukemia patients based on European standards. Preliminary results].

OBJECTIVE

Initiation and popularization of routine molecular diagnostics of minimal residual disease (MRD) are currently one of the most urgent challenges in Polish hemato-oncology. The paper is aimed to present preliminary results of identification of immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements and quantitative assessment of MRD levels in Polish children with acute lymphoblastic leukemia (ALL). The results are presented in the context of clinical significance of MRD study, current methodology of MRD assessment and standardization process in Western Europe.

MATERIAL

DNA isolated from bone marrow / bone marrow mononuclear cells obtained at diagnosis from 26 children (25 B-precursor ALL, 1 T-ALL) aged 1.3-16.5 years.

METHODS

PCR-heteroduplex analysis, based on standard BIOMED-1 and BIOMED-2 primer combinations and protocols for detection of rearrangements and clonality assessment; sequencing of clonal PCR products and comparison with germline sequences of Ig/TCR genes for identification of the rearranged genes andjunctional regions; real-time quantitative PCR (RQ-PCR) with the use of TaqMan probes for assessment of follow-up MRD levels (in 11 patients).

RESULTS

Clonal TCRG, incomplete TCRD, Vdelta2-Jalpha, TCRB, IGK-Kde and IGH gene rearrangements were detected in 61, 61, 35, 13, 39 and 83% of patients, respectively, which was generally concordant with published data for patients of other European nations.

CONCLUSIONS

There is an urgent need to broaden the scope of minimal residual disease study in Poland and to develop Polish standards of MRD diagnostics, based on current European experience and standards.