Cancer of the gastrointestinal tract results in a restricted T-cell repertoire dependent upon tumor differentiation

The composition and variation of the BCR CDR3s in gastric cancer

Gastric cancer (GC) is the fourth most common type of cancer and the second most common cause of cancer-associated mortality worldwide. B cell-associated autoantibodies against tumor-associated antigens are attractive biomarkers for the development of noninvasive serological tests for the early detection of cancer. This is due to their specificity and stability in the sera. In the present study multiplex polymerase chain reaction and Illumina high-throughput sequencing (HTS) was used to study the composition and variation of the B cell receptor (BCR) complimentary-determining region 3 (CDR3) in GC. The peripheral blood, cancer tissues and peri-cancer tissues were included from 7 patients with GC. On average there was a total of 403,959 CDR3 sequences, with 72,367 unique CDR3 nt sequences and 61,709 unique CDR3 aa sequences per sample identified, which are critical for further understanding the BCR repertoire in GC. The details of GC CDR3s may accelerate the screening process for possible new autoantigens and may provide additional information necessary for generating effective B cell targeted diagnosis and therapeutic strategies.

A NUP98-HOXD13 leukemic fusion gene leads to impaired class switch recombination and antibody production

Myelodysplastic syndrome is a clonal process characterized by ineffective hematopoiesis and progression to acute leukemia. Although many myelodysplastic syndrome and leukemic patients have compromised immunity, the role of underlying mutations in regulating immune function is poorly understood. Recent studies show that NUP98-HOXD13 (NHD13) fusion gene results in myelodysplastic syndrome and impairs lymphocyte differentiation in transgenic mice. In our studies, we sought to elucidate the mechanism by which NHD13 affects B-lymphocyte development and function. Based on our preliminary findings that transgenic mice had increased levels of IgM and reduced IgG1 and IgE, we hypothesized that the fusion gene might impair class switch recombination (CSR). Mice were immunologically challenged with dinitrophenol. NHD13 mice showed a marked reduction in B-lymphocyte differentiation in their bone marrow and spleen following dinitrophenol stimulation and had reduced production of dinitrophenol-specific antibodies. Spleen follicles from these mice were small and hypocellular, indicating failure of clonal expansion. When isolated NHD13 B lymphocytes were stimulated in vitro using Escherichia coli lipopolysaccharide or lipopolysaccharide + interleukin-4, they failed to undergo sufficient CSR and proliferation. Taken together, our findings show that expression of NUP98-HOXD13 impairs CSR and reduces the antibody-mediated immune response, in addition to its role in leukemia. Further delineation of the NUP98-HOXD13 transgene may reveal novel pathways involved in CSR.