Interleukin 12 in Takayasu's arteritis: plasma concentrations and relationship with disease activity

To investigate plasma concentrations of interleukin 12 (IL-12) and their relationship with disease activity in patients with Takayasu's arteritis (TA).

IL-12 levels were determined by quantitative enzyme immunoassay in the plasma of 80 patients with TA, 25 age/sex matched healthy controls, and 15 followup patients with active TA on immunosuppressive therapy.

Significantly increased levels of IL-12 were observed in patients with TA versus controls (90.6 +/- 365.3 vs 6.9 +/- 11.3 pg/ml; p < 0.05) and in patients with active versus inactive TA (168.7 +/- 507.0 vs 12.6 +/- 26.9 pg/ml; p = 0.005). The prevalence of IL-12 (the cytokine levels above cutoff value) was higher in patients than in controls [44% (35/80) vs 12% (3/25); p < 0.01] and in patients with active versus inactive TA [57% (23/40) vs 30% (40); p < 0.05]. Six of the 9 patients who became inactive on followup also had normalized levels of IL-12.

The data indicate that IL-12 might be an important mediator of inflammation in TA.