Leukocytic Response to Measles

The precise nature of the leukocytic reactions during measles still remains a subject concerning which there are surprising differences of opinion. Although it is generally held that a leukocytosis is present during the incubation period, followed as a rule by a leukopenia during the acute febrile stage,1there is a lack of agreement regarding the changes in the differential count. It was early pointed out by several investigators2that the fall in the blood count was due chiefly to a diminution in the number of lymphocytes. Diametrically opposed to this finding, however, have been the reports of a lymphocytosis occurring simultaneously with the rash.3Moreover, it has been maintained4that variations in the number of polymorphonuclear cells principally account for the leukocytosis or the leukopenia observed in the different phases of the disease. More recent workers,5on the other hand, have laid great stress on