Generation of cytotoxic T lymphocytes specific for B-cell acute lymphoblastic leukemia family-shared peptides derived from immunoglobulin heavy chain framework region

Background Immunoglobulin heavy chain variable region （IgHV） is a well-characterized tumor antigen for B-cell malignancies. It can function as a target for T cell-mediated immune response. Clinical trials of IgHV protein vaccines against lymphoma have demonstrated induction of tumor-specific cytotoxic T lymphocyte （CTL） responses. However, complementary determining regions-based individual vaccines have disadvantages for wide clinical application. Although a recent study demonstrated that immunogenic peptides are derived from framework regions （FR） shared among patients with B-cell lymphoma, how to choose the appropriate peptides for each patient is still unsolved. The aim of this study was to investigate whether immunoglobulin heavy chain FR-derived peptides shared in each IgHV family are potential CTL epitopes presented by B-cell acute lymphoblastic leukemia （B-ALL）. Such CTL epitopes might be beneficial to shifting vaccination strategies against B-ALL from individual specificity to family specificity.Methods Seven IgHV gene families were amplified respectively by PCR and sequenced directly from 71 childhood B-ALL cases. Bioinformatics was applied in analyzing characteristics of sequences available and predicting HLA-A^＊0201-restricted CTL epitopes for each IgHV family. An antigen-specific T cell expansion system was used to generate peptide-specific CTLs. The cytotoxicity of CTLs against B-ALL cells was assessed in the lactate dehydrogenase release assay. Results Complete IgHV rearrangements were identified in all of the 71 B-ALL cases. All of 40 sequences available showed ≥98% homology with the nearest germline IgHV genes, indicating IgHV genes in B-ALL of germline nature. Twelve nonapeptides of high HLA-A^＊0201-binding scores were obtained from 26 productive IgHV protein sequences. Ten （83%） of the peptides were located in FR1 and FR3 shared among the corresponding IgHV family. CTLs specific for the peptide QLVQSGAEV located in FR1 （3-11） shared among the IgHV1 family could be successfully generated from peripheral blood mononuclear cells of two HLA-A^＊0201＋ healthy donors in vitro and were capable of killing HLA-matched B-ALL cell clones belonging to the IgHV1 family. Conclusion Anti-B-ALL CTLs against immunoglobulin heavy chain FR-derived peptides have family-specific cytotoxicity.

Rearranged Patterns of IgH and TcRγ Genes in Patients with Acute Lymphoblastic Leukemia

The rearrangement of immunoglobulin heavy chain gene(IgH) and T cell receptor γgene (ToRγ)was studied in 30 patients with acute lymphoblastic leukemia(ALL) by the polymerase chain reaction (PCR). 19 cases was found to have rearrangement of IgH gene,12 of TcRγ. Most of IgH rearrangement was characterized by one or two specific bands while some had more than two. Rearrangement of TcRγgene appeared as one specific band. A slight difference in number, size and lightness of bands was found among the patients. 4 different kinds of rearrangement were observed in the detection of IgH rearrangement in combination with TcRγgene. The rearranged patterns of IgH and TcRγgene as well as the clinical significance were discussed.

A study of Hodgkin/Reed-Sternberg cells using single cell polymerase chain reaction

OBJECTIVE: To investigate the characteristics of Hodgkin/Reed-Stemberg (H/R-S) cells found in patients with various types of Hodgkin's disease (HD). METHODS: H/R-S cells were micropicked from frozen sections of tissues affected by HD. The DNA from these cells was amplified by polymerase chain reaction (PCR) using immunoglobulin heavy chain gene FR III a/JH primers and light chain gene family-specific primers. RESULTS: A total of 52/135 (35.8%) isolated cells showed the specific products in the reactions. IgH and V kappa 4 rearrangements were repeatedly found in many cells from a lymphocyte predominance type sample; repeated V kappa 4 and individual IgH/V kappa 2,4 rearrangements and individual IgH, V lambda 3/ V kappa 4 rearrangements were found in two different cases of the nodular sclerosis type; repeated IgH/ V lambda 3 and individual V lambda 2,4 rearrangements, repeated V kappa 2,4 rearrangements, repeated V kappa 4 and individual IgH/ V kappa 3 rearrangements, repeated IgH and individual V kappa 3/ V lambda 4 rearrangements were detected in 3 cases of the mixed cellularity type. Repeated and individual IgH rearrangements were found in other 2 cases. CONCLUSION: The H/R-S cells isolated from the lymphocyte predominance subtypes of HD have IgH and V lambda 4 gene rearrangements. This suggests that the lymphocyte predominance type is a proliferation of neoplastic B cells. The cells isolated from the mixed cellularity and nodular sclerosis types derive from B lineage cells at various stages of differentiation because of the presence of their IgH, kappa and/or lambda gene rearrangements. To our knowledge, this is the first time that the lambda gene rearrangement was detected in H/R-S cells.

Immunogenetic factors driving formation of ultralong VH CDR3 in Bos taurus antibodies

The antibody repertoire of Bos taurus is characterized by a subset of variable heavy(VH)chain regions with ultralong third complementarity determining regions(CDR3)which,compared to other species,can provide a potent response to challenging antigens like HIV env.These unusual CDR3 can range to over seventy highly diverse amino acids in length and form uniqueβ-ribbon‘stalk’and disulfide bonded‘knob’structures,far from the typical antigen binding site.The genetic components and processes for forming these unusual cattle antibody VH CDR3 are not well understood.Here we analyze sequences of Bos taurus antibody VH domains and find that the subset with ultralong CDR3 exclusively uses a single variable gene,IGHV1-7(VHBUL)rearranged to the longest diversity gene,IGHD8-2.An eight nucleotide duplication at the 3′end of IGHV1-7 encodes a longer V-region producing an extended Fβ-strand that contributes to the stalk in a rearranged CDR3.A low amino acid variability was observed in CDR1 and CDR2,suggesting that antigen binding for this subset most likely only depends on the CDR3.Importantly a novel,potentially AID mediated,deletional diversification mechanism of the B.taurus VH ultralong CDR3 knob was discovered,in which interior codons of the IGHD8-2 region are removed while maintaining integral structural components of the knob and descending strand of the stalk in place.These deletions serve to further diversify cysteine positions,and thus disulfide bonded loops.Hence,both germline and somatic genetic factors and processes appear to be involved in diversification of this structurally unusual cattle VH ultralong CDR3 repertoire.

Chronic Lymphocytic Leukemia Prognostic Index： A New Inteorated Scorino System to Predict the Time to First Treatment in Chinese Patients with Chronic Lymphocytic Leukemia

Background： The established clinical staging systems （Rai/Binet） of chronic lymphocytic leukemia （CLL） cannot accurately predict the appropriate treatment of patients in the earlier stages. In the past two decades, several prognostic factors have been identified to predict the outcome of patients with CLL, but only a few studies investigated more markers together, To predict the time to first treatment （TTFT） in patients of early stages, we evaluated the prognostic role of conventional markers as well as cytogenetic abnormalities and combined them together in a new prognostic scoring system, the CLL prognostic index （CLL-PI）. Methods： Taking advantage of a population of 406 untreated Chinese patients with CLL at early and advanced stage of disease, we identified the strongest prognostic markers of TTFT and, subsequently, in a cohort of 173 patients who had complete data for all 3 variables, we integrated the data of traditional staging system, cytogenetic aberrations, and mutational status of immunoglobulin heavy chain variable region （1GI：tV） in CLL-PI. The median follow-up time was 45 months and the end point was TTFT. Results： The median TTFT was 38 months and the 5-year overall survival was 80%. According to univariate analysis, patients of advanced Rai stages （P 〈 0.001） or with 11q- （P = 0.002）, 17p- （P 〈 0.001）, unmutated IGHV （P 〈 0.001）, negative 13q- （P = 0.007） and elevated lactate dehydrogenase levels （P = 0.001 ） tended to have a significantly shorter TTFT. And subsequently, based on multivariate Cox regression analysis, three independent factors for TTFT were identified： advanced clinical stage （P = 0.002）, 17p- （P = 0.050） and unmutated 1GHV （P = 0.049）. Applying weighted grading of these independent factors, a CLL-PI was constructed based on regression parameters, which could categorize tbur different risk groups （low risk [score 0], intermediate low [score 1], intermediate high [score 2] and high risk [score 3-6]） with significantly different TTFT （median TTFT of not reached （NR）, 65.0 months, 36.0 months and 19.0 months, respectively, P 〈 0.001 ）. Conclusions： This study developed a weighted, integrated CLL-PI prognostic system of CLL patients which combines the critical genetic prognostic markers with traditional clinical stage. This novel modified PI system could be used to discriminate among groups and may help predict the TTFT and prognosis of patients with CLL.

Cytogenetic and molecular aberrations of multiple myeloma patients： a single-center study in Singapore

Background Much is known about the cytogenetic lesions that characterize multiple myeloma （MM） patients from the USA, Europe, and East Asia. However, little has been published about the disease among Southeast Asians. The aim of this study was to determine the chromosomal abnormalities of MM patients in our Singapore population. Methods Forty-five newly-diagnosed, morphologically confirmed patients comprising 18 males and 27 females, aged 46-84 years （median 65 years） were investigated by karyotyping and fluorescence in situ hybridization （FISH）. FISH employing standard panel probes and lp36/lq21 and 6q21/15q22 probes was performed on diagnostic bone marrow samples. Results Thirty-four cases （75.6%） had karyotypic abnormalities. Including FISH, a total detection rate of 91.1% was at- tained. Numerical and complex structural aberrations were common to both hyperdiploid and non-hyperdiploid patients. Numerical gains of several recurring chromosomes were frequent among hyperdiploid patients while structural rear- rangements of several chromosomes including 8q24.1 and 14q32 characterized non-hyperdiploid patients. With FISH, immunoglobulin heavy chain （IGH） gene rearrangements, especially fibroblast growth factor receptor 3 （FGFR3）/IGH and RB1 deletion/monosomy 13 were the most common abnormalities （43.4%）. Amplification lq21 was 10 times more frequent （42.5%） than del（1p36） and del（6q21）. Conclusions We have successfully reported the comprehensive cytogenetic profiling of a cohort of newly-diagnosed myeloma patients in our population. This study indicates that the genetic and cytogenetic abnormalities, and their frequencies, in our study group are generally similar to other populations.