HLA-A alleles of patients with pyothorax-associated lymphoma: anti-Epstein-Barr virus (EBV) host immune responses during the development of EBV latent antigen-positive lymphomas.

Pyothorax-associated lymphoma (PAL) is an Epstein-Barr virus (EBV) latent antigen-positive lymphoma resembling EBV-transformed lymphoblastoid cell lines (LCLs) and develops in non-immunocompromised patients. Thus, deficient anti-viral-antigen immune responses might be involved in the development of PAL. As MHC class I-restricted cytotoxic T lymphocytes (CTLs) are the major constituent of anti-viral immune responses, the HLA allele type and its expression may affect the development of PAL. Flow-cytometric analyses of PAL cell lines and LCLs using the W6/32 monoclonal antibody revealed that expression of HLA class I varied among cell lines. Although one PAL cell line, OPL-2, exhibited low expression, an LCL and another PAL cell line, OPL-1, strongly expressed HLA class I. Among the EBV latent infection genes, EBV nuclear antigens 2, 3, 4 and 6 and latent membrane proteins can induce efficient CTL responses in combination with HLA-A2 or -A11. HLA-A alleles of PAL patients were determined using low-resolution PCR-based typing with HLA-A locus sequence-specific primer combinations. The antigen frequencies of HLA-A2 and -A11 in PAL patients were not significantly different from those in the normal Japanese population. Although HLA class I antigen should be expressed during the course of lymphomagenesis, no HLA-A alleles influenced the development of overt PALs.