Studies on leukocyte cultures in measles

Summary

Lymphocyte transformation was studied in measles, one to seven days after the appearance of skin rash. Using a combination of phase contrast and stained-smear cytology, giant cells containing many nuclei were seen in PHA-stimulated cultures of leukocytes from 57 out of 68 (84 per cent) measles children. Abnormal blast cells containing two or more nuclei were seen less frequently (29 per cent of cases). It is suggested that both types of abnormal cells represent the two extremes of a continuous spectrum of cells showing the cytopathic effect of measles virus on proliferating lymphoid cells. In most cases, the giant cells appeared between 24 and 48 hours of culture, were most readily seen on the third day of culture, and disappeared by the fifth day.

Formation of giant cells in measles PHA cultures was not associated with depression of lymphocyte transformation. Blast cell counts were generally normal and tritiated thymidine incorporation was not depressed when compared with cultures from healthy controls.

Giant cells were also seen in 2 of 5 sets of mixed lymphocyte cultures from measles cases. However, abnormal cells were not seen in any unstimulated (control) culture or in PHA-stimulated cultures from healthy children. The role of measles virus in the formation of giant cells byproliferating lymphoid cells, and the possible role of the virus in depleting susceptible lymphocyte sub-populationsin vivo with consequent immunodepression is discussed.