High prevalence of a 30-base pair deletion and single-base mutations within the carboxy terminal end of the LMP-1 oncogene of Epstein-Barr virus in the Japanese population.

The presence of 30-base pair (bp) deletion mutants within the carboxy terminal end of the LMP-1 oncogene (BNLF-1 gene) of Epstein-Barr virus (EBV) has been reported in EBV-associated neoplasms. We analysed the 30-bp deletion and the single-base mutations of the LMP-1 gene in 13 spontaneously established lymphoblastoid cell lines (LCLs) from peripheral blood mononuclear cells of three healthy children, four patients with EBV-unrelated acute febrile illnesses, three patients with infectious mononucleosis (IM), and three patients with chronic active EBV infection (CEBV), and six frozen samples from four patients with CEBV and two patients with EBV-associated hemophagocytic syndrome (EBV-AHS). For molecular analysis of the carboxy terminal end of the LMP-1 gene, PCR was performed using primers spanning the carboxy terminal region of the LMP-1 gene. Direct sequence analysis of the PCR products revealed identical 30-bp deletion in 14 of 19 samples (74%). Six point mutations at nucleotide positions 168357, 168355, 168320, 168308, 168295, and 168225 were frequently identified regardless of disease status. Our findings revealed the carboxy terminal end of the LMP-1 gene was mutational hot spots. The 30-bp deletion mutant is widely spread in the Japanese population and is not implicated in EBV-associated lymphoproliferative diseases.