The stimulation of lymphocytes by nucleus pulposus in patients with degenerative disk disease of the lumbar spine.

Being avascular the nucleus pulposus is not normally in contact with the immune mechanisms. Rupture out of its confines may result in an inflammatory reaction and contact with immunocompetent cells. Using the lymphocyte transformation test we incubated lymphocytes of 25 patients and 43 controls with an extract of nucleus pulposus. Ten patients with sequestrated or large herniated disks had a mean transformation index of 16.6 compared to controls whose mean index was 3.6. Nine patients with negative myelograms had an idex similar to controls. These results suggest an auto-immune response to nucleus pulposus in patients with sequestrated disks.