Spontaneous release of leukocyte migration inhibition factor (LMIF) by lymphocytes in chronic lymphatic leukemia patients.

Leukocyte migration inhibition factor (LMIF) activity expressed as a migration index was studied in sera of 13 chronic lymphatic leukemia (CLL) patients and 14 healthy subjects. LMIF activity was present in 92.8% of CLL patients and 14% of controls. The LMIF activity of lymphocyte culture supernatants in the same patients and 7 controls was also studied. A LMIF-like activity was found both, in the sera and phytohemagglutinin (PHA) unstimulated cell supernatants in 9 of 13 patients (69.2%). These results demonstrate the ability of malignant B cells to release LMIF or LMIF-like factors spontaneously.