Blood lymphocytes and measles viraemia.

Previously described giant multinucleated cells were observed in phytohaemagglutinin (PHA) cultures of washed leucocytes from blood samples of seventeen (36%) out of forty-seven children with measles or undiagnosed fever in Ibadan. The giant cells were more readily seen in PHA cultures of purified lymphocyte preparations than in total leucocyte suspensions. It was concluded that the giant cells seen in cultures indicate in-vivo infection of some blood lymphocytes of patients with measles and related infections by syncytium-producing virus. The practical application of lymphocyte cultures to the laboratory diagnosis of measles is stressed, and the concept of circulating lymphocytes acting as vehicles for the systemic spread of measles infection is highlighted.