Increased release of interleukin-12p40 in MS - Association with intracerebral inflammation

Objective: The p40 subunit of interleukin (IL)-12 was recently demonstrated in active lesions in MS. We tested whether the p40 subunit of IL-12 can also be detected in CSF and serum of patients with this disease and, if so, whether release is associated with inflammatory disease activity. Results: This study demonstrates an increased (up to 1,000-fold) compartmentalized release of the p40 subunit but not of the heterodimer p70 in MS. Release of IL-12p40 correlated with classic markers of CNS inflammation (CSF cell counts, immunoglobulin G index) and was significantly increased in patients with gadolinium-enhancing plaques on MRI. Moreover, release of IL-12p40 was associated with CSF levels of myelin basic protein as a measure of myelin degradation, Conclusion: These results suggest a role of IL-12p40 in the pathophysiology of MS.