Analysis Of IgVH Genetic Constitution And Mutation Status In Patients With Chronic Lymphocytic Leukemia

ObjectiveChronic lymphocytic leukemia(CLL)is a clinically heterogeneous disease.Mutational status of the variable region of the immunoglobulin heavy chain gene(IgVH)is an important prognostic factor in CLL,with improved outcome in mutated patients.The distribution of VH gene family in different ethnic population has been reported in succession.The research about expression and mutation status of VH gene family majorly come from Western countries.As to Asian countries,the data of VH gene only from Japan and Iran has significant statistic difference comparing Western countries.The objective of the present study is to examine the mutational status and VH gene segment location in patients with CLL in China using new multiplex PCR method,and to provide prognostic information.MethodsIgVH mutation was detected by multiplex PCR in 64 CLL patients and purified PCR amplification products were directly sequenced.The segments of VH,DH,JH family and somatic hypermutation status were analyzed by IMGT/V-QUEST and IGBlast.ResultsIn 64 patients,we found the fragment of the most common usage was VH3(31/64,48%),followed by VH4(26/64,41%),VH1(4/64,6%), VH2(2/64,3%)and VH7(1/64,2%).The results also showed that 44 patients(69%)had mutated VH,whereas 20(31%)had unmutated VH, among which six cases had identical sequences with their germlines. Among the 64 sequences of DH segments,DH3 gene family was used most frequently(25/64,39%),among which 11 cases had unmutated VH. The JH segment of the frequent usage was JH6.ConclusionsThe frequency of IgVH gene families indicates significant difference in Chinese CLL patients compared to Western patients,suggesting involvement of antigen selection in different ethnic and/or environmental factors in CLL disease initiation,which maybe one of the most important reasons for significantly different incidence of CLL in different countries. Its prognostic significance need further investigation. ObjectiveMultiple myeloma(MM)is an incurable hematological disorder characterized by the accumulation of malignant plasma cells within the bone marrow(BM).The clinical heterogeneity of MM is dictated by the cytogenetic aberrations presented in the clonal plasma cells.Cytogenetic studies in MM are hampered by the hypoproliferative nature of plasma cells in MM.Therefore,interphase fluorescence in situ hybridization (I-FISH)analysis combined with magnetic-activated cell sorting(MACS) is an attractive alternative for evaluation of numerical and structural chromosomal changes in MM.MethodsInterphase FISH studies with four different specific probes for the regions containing LSI D13S319(13q14),LSI IGH Dual Color(14q32),LSI p53 and CEP 17 were performed in 11 MM patients.Interphase FISH studies with LSI IGH/CCND1,LSI IGH/FGFR3,LSI IGH/MAF and LSI IGH/MYC probes were used to detect t(11;14)(q13;q32), t(4;14)(p16;q32),t(14;16)(q32;q23)and t(8;14)(q24;q32)in patients with 14q32 rearrangement. ResultsMolecular cytogenetic aberrations were found in 7(63.6%)of the 11 MM patients.5 patients(45.5%)had 13q deletion/monosomy 13[del(13q14)], 3 patients(27.3%)had illegitimate IGH rearrangement and 2 patients (18.2%)had p53 deletion.Illegitimate IGH rearrangements include 2 with t(4;14)(p16;q32)and 1 with t(8;14)(q24;q32).None of 11 patients were detected aberrations by conventional cytogenetics.ConclusionThe detection rate of chromosomal aberration by conventional cytogenetics is lower.But interphase FISH technique combined with MACS using CD138-specific antibody is a highly sensitive technique at detecting molecular cytogenetic aberrations in MM.Due to minor sample size and short follow-up,the prognostic value of chromosomal aberration by molecular cytogenetics in MM patients need further research.