Establishment and characterization of a novel Hodgkin lymphoma cell line, AM-HLH, carrying the Epstein-Barr virus genome integrated into the host chromosome.

We describe the establishment and characterization of a cell line, AM-HLH, obtained from a patient with Epstein-Barr virus-positive (EBV+ ) nodular sclerosis-type Hodgkin lymphoma (HL). The cells were positive for CD2 and CD30 and negative for CD15. The immunoglobulin heavy- and κ light-chain genes were rearranged. The karyotype was of the triploid range. Southern blotting using the EBV terminal repeat probe detected 3 hybridizing bands that were identical to those of the parental HL material. The cells expressed EBV-encoded RNAs as well as latent genes (EBNA1, EBNA2, LMP1, and LMP2A) and lytic genes (BZLF1 and BALF2). Fluorescence in situ hybridization (FISH) with the cosmid pJB8 clone containing a fragment of EBV DNA as a probe revealed multiple hybridization signals at a marker chromosome. Additional FISH using whole chromosome painting and centromere probes in combination with multicolor FISH determined that multiple EBV copies were clustered within the chromosome 20 materials of the marker chromosome. Culture supernatants of AM-HLH contained IL-10 as measured by the bead-based immunoassay. It is possible that an integrated EBV genome and cellular genes on chromosome 20 were coamplified, leading to the enhanced expression of genes involved in cell growth control. The AM-HLH cell line will be useful to clarify the role of cytokines in the development of EBV+ HL.

Clinicopathological features of lymphoma/leukemia patients carrying both BCL2 and MYC translocations.

BACKGROUND: Lymphoid neoplasm with 18q21.3/BCL2 and 8q24/MYC translocation to immunoglobulin (IG) genes as dual-hit lymphoma/leukemia is very rare and known to have a poor clinical outcome. DESIGN AND METHODS: To clarify the clinicopathological characteristics of this malignancy, we analyzed 27 cases of cytogenetically proven dual-hit lymphoma/leukemia. RESULTS: Dual-hit lymphoma/leukemia was diagnosed at presentation in 22 cases and at relapse or disease progression in 5 cases. At the time of diagnosis of dual-hit lymphoma/leukemia, extranodal involvement was found in 25 cases (93%) and central nervous system involvement occurred in 15 cases (56%). The median survival and 1-year survival rate of the 27 cases were only 6 months and 22%, respectively, after diagnosis of the dual-hit lymphoma/leukemia. Seven cases of triple-hit lymphoma/leukemia (dual-hit lymphoma/leukemia with 3q27/BCL6 translocation) were included; the median survival of these patients was only 4 months from the diagnosis of the dual-hit lymphoma/leukemia. The duration of survival of the patients with a triple-hit malignancy was shorter than that of the other 20 cases of dual-hit lymphoma/leukemia (p=0.02). The translocation partner of MYC subdivided the dual-hit cases into two groups; 14 cases of IGH and 13 cases of IGK/L. The MIB-1 index was investigated in 14 cases with aggressive B-cell lymphoma, and was higher in the group with MYC-IGH translocation (n=7) than in the MYC-IGK/L group (n=7) (p=0.02). Overall survival was not different between the MYC-IGH translocation group (n=14) and the MYC-IGK or MYC-IGL translocation group (n=13). CONCLUSIONS: Dual-hit lymphoma/leukemia is a rare but distinct mature B-cell neoplasm with an extremely poor prognosis characterized by frequent extranodal involvement and central nervous system progression with either of the translocation partners of MYC.

[The monitoring of residual disease for chronic myelogenous leukemia patients treated with imatinib mesylate: detection of T315I mutation in ATP binding site of BCR/ABL gene].

Imatinib Mesylate, a specific inhibitor of BCR/ABL tyrosine kinase, was developed as a molecularly targeted drug for the treatment of patients with chronic myelogenous leukemia. We evaluated effectiveness of the drug on cytogenetic response for monitoring residual disease using fluorescence in situ hybridization(FISH), reverse transcription-nested-polymerase chain reaction(RT-nested-PCR) and competitive PCR strategy. Of 9 patients in chronic phase, 7 achieved major cytogenetic response(CR) and 2 achieved minor CR by FISH. In 3 out of 6 patients with complete CR, no BCR/ABL gene was detected by RT-nested-PCR in peripheral blood or bone marrow specimens. Of 4 patients in accelerated phase, 1 achieved complete CR but 3 developed blast crisis. Despite high efficacy of Imatinib, 5 out of 13 patients showed resistance to the drug. To clarify the mechanism of resistance, we have newly developed a method for investigating a point mutation of T315I in tyrosine kinase domain of BCR/ABL gene using RT-PCR restriction digested analysis. None of them showed T315I mutation. The sensitivity of the method was as low as 10 copies of mutant gene. The method is useful for screening the mutation when there are many clinical samples or low copy number of BCR/ABL gene. BCR/ABL value obtained by FISH was of use to predict cytogenetic response when residual disease was above 2 to 3%. Below this level, the routine use of RT-nested-PCR was suffices to monitor minimal residual disease.

PD-1-PD-1 ligand interaction contributes to immunosuppressive microenvironment of Hodgkin lymphoma.

Programmed death-1 (PD-1)-PD-1 ligand (PD-L) signaling system is involved in the functional impairment of T cells such as in chronic viral infection or tumor immune evasion. We examined PD-L expression in lymphoid cell lines and found that they were up-regulated on Hodgkin lymphoma (HL) and several T-cell lymphomas but not on B-cell lymphomas. PD-L expression was also demonstrated in primary Hodgkin/Reed-Sternberg (H/RS) cells. On the other hand, PD-1 was elevated markedly in tumor-infiltrating T cells of HL, and was high in the peripheral T cells of HL patients as well. Blockade of the PD-1 signaling pathway inhibited SHP-2 phosphorylation and restored the IFN-gamma-producing function of HL-infiltrating T cells. According to these results, deficient cellular immunity observed in HL patients can be explained by "T-cell exhaustion," which is led by the activation of PD-1-PD-L signaling pathway. Our finding provides a potentially effective immunologic strategy for the treatment of HL.