Inconclusive presence of adenovirus sequences in human leukemias and lymphomas

Adenoviruses are ubiquitous viruses related to human mild upper tract respiratory infections. Murine cells are semi-permissive to adenovirus replication, and persistent or abortive infections have been associated with tumorigenic potential. Given that only human lymphoid cells are semi-permissive and abortive infections have been described, we hypothesized that adenovirus could be related to the transformation of human haematopoietic cells. We studied 30 lymphomas, 46 leukemias, 10 reactive lymphadenopathies and 40 normal human spleens. The presence of adenovirus sequences and proteins were studied using PCR, southern-blot, slot-blot, in situ hybridization, immunohistochemistry, and western-blot techniques. By using nested PCR, adenovirus sequences were detectable in about 30% of lymphomas, but in less than 10% of leukemias, reactive lymphadenopathies and normal spleens. In no case were we able to demonstrate adenovirus products by in situ hybridization, immunohistochemistry or western-blot. These results indicate that adenovirus sequences are present in a significant number of human lymphomas, but that the number of positive cells is extremely low and no protein expression could be detected. Therefore, we are unable to conclude that persistent infections of human lymphoid cells by adenovirus is related to a higher risk of developing malignant lymphomas or leukemias.