Increased Activity of Some Folic Acid Enzyme Systems in Infectious Mononucleosis

Increased levels of activity for the formate activating enzyme and N⁵,N¹⁰-methylene FH₄ dehydrogenase have been found in the leukocytes from patients with infectious mononucleosis; in addition dihydrofolic reductase, anenzyme not found in mature circulating leukocytes, has been detected in infectious mononucleosis cells. Glucose-6-phosphate dehydrogenase activity isless in infectious mononucleosis leukocytes than in normal leukocytes.

These findings are similar to the results obtained in acute and chronic myelogenous leukemia and indicate that the leukocytes seen in infectious mononucleosis have the enzymatic apparatus associated with synthesis of DNA.

Submitted on November 6, 1961 Accepted on January 12, 1962