Cyclic eosinophilic leukocytosis in eosinophilic leukemia with observations on transcobalamin I and eosinophils.

A patient with eosinophilic leukemia was noted to have spontaneous fluctuations in his eosinophil and total leukocyte counts over a 3-year period. The range of eosinophil counts observed was from 736/microliters to 401,400/microliters. Sharp fluctuations occurred whether chemotherapy was administered at the nadir or the peak of a cycle or was withheld. A shortening of the cycle length from 44 to 25 days, and a marked increase in amplitude of the cycle occurred in the terminal phase of his illness. Two additional observations merit mention. An abnormal alpha-2 globulin of 40,000 molecular weight was detected in his serum. In addition, cyclic fluctuations of serum transcobalamin I that accompanied his cyclic eosinophil counts were noted, and eosinophils were documented for the first time to be rich sources of this protein.