Selective outgrowth of a posttransplant B-immunoblastic lymphoma expressing a latent membrane protein-1 deletion variant.

BACKGROUND

Posttransplant lymphoproliferative disorders are generally associated with Epstein-Barr virus (EBV) and are of B cell origin. We report the case of a B-immunoblastic lymphoma that developed in a pretransplantation EBV-seronegative woman 4 months after kidney transplant from her HLA-haploidentical brother. The patient successfully underwent immunotoxin therapy for lymphoma and has been in remission for 36 months.

METHODS

Latent EBV genomes were identified by polymerase chain reaction, and the purified amplification products were directly sequenced with [35S]dATP.

RESULTS

Molecular analysis of the latent membrane protein (LMP)1 oncogene of EBV, which was expressed in most tumor cells, revealed a 30-base pair deletion. No wild-type LMP1 sequences were found. Analysis of peripheral blood mononuclear cells from the EBV-seropositive donor showed the presence of both the LMP1 deletion variant and the wild-type sequence. The LMP1 deletion variant and the wild-type sequence were also identified within peripheral blood mononuclear cells of the EBV-seroconverted kidney recipient 20 months after lymphoma therapy.

CONCLUSION

This pattern is consistent with a natural growth advantage of B cells expressing the LMP1 deletion variant in the immunocompromised host.