Epstein-Barr virus(EBV) is associated with development of various types of lymphoma, especially NK/T cell lymphoma. Recently, its subtypes and LMP-1, major oncoprotein of EBV, have been studied. We investigated the frequency of EBV, its subtypes, and LMP-1 status on the cases diagnosed at Ewha university hospital between 1993 and 2002.

Sixteen cases of NK/T cell lymphomas were studied. In situ hybridization for EBER-1 mRNA and PCR for EBV subtypes and 30 base pair deletion of LMP-1 were done.

All cases showed EBV positivity by EBER in situ hybridization. All cases contained Type A viruses and 10 cases(62.5%) revealed LMP-1 30bp deletion.

EBV act as a causative role in the development of NK/T cell lymphoma. The exact role of LMP-1 30bp deletion variant in the lymphomatogenesis should be studied with larger number of cases.

To investigate the time of rearrangement of the TCR gene in the process of NKT cell differentiation from CD34+ human cord blood cells in vitro.

We isolated the CD34+ human cord blood cells and induced the differentiation of NKT cells by liquid culture including IL-15, FL and SCF for 30 days. In order to detect the time of TCR gene rearrangement in differentiated NKT cell, we performed PCR for TCR-rearrangement excision circles (TRECs) with isolated DNA.

Signal joint TREC first appeared on day 4 or day 8 and continuously existed until day 30. Between day 9 and day 21, cells showed high output of coding joint TRECs after signal joint rearrangement.

In differentiated NKT cells, TCR gene rearrangement started within a week after culture started and mostly occurred in 2 to 3 weeks after culture started.