Spontaneous release of leucocyte migration-inhibitory factor by mononuclear cells eluted from rheumatoid synovial tissue.

Spontaneous leucocyte migration-inhibitory factor (LIF) was assayed by an indirect system in which mononuclear cells (MNC) eluted from rheumatoid synovial tissues or isolated from peripheral blood of normal donors were cultured without antigen. The supernatants from these cultures and control supernatants, heated to 80 degrees C for 30 min to destroy the LIF activity, were used in the test. In seven out of eleven rheumatoid arthritis patients the eluted synovial MNC produced LIF spontaneously, whereas none of the twelve normal blood donors showed any such production. The ability to show spontaneous LIF production was primarily seen in the joint tissues from sero-negative patients.