To determine the relationship between the antiinflammatory molecule interleukin 10 (IL-10) and disease symptoms, IL-1beta, tumor necrosis factor (TNF), and IL-1 receptor antagonist (IL-1ra) in patients with polymyalgia rheumatica (PMR).
In 102 patients with PMR, we determined the severity of the disease by the presence of typical clinical symptoms (symptom score with a maximum of 10 points). IL-10, IL-1beta, TNF, and IL-1ra were measured in all patients and 31 age matched healthy controls by enzyme immunometric assays.
Compared to patients with elevated serum levels, patients with normal serum levels of IL-10 (below the mean + 3 SD of controls, 7.79 pg/ml) more often had adynamia (p = 0.045), bilateral muscular pain in shoulders, upper arms or neck (p = 0.045), bilateral muscular pain in the pelvic girdle (p < 0.001), headache (p = 0.014), morning stiffness (p < 0.001), symptoms of depression (p = 0.013), and initial weight loss (p = 0.011), and had a higher symptom score (5.5+/-0.4 vs 3.7+/-0.3; p < 0.001). The overall symptom score correlated negatively with IL-10 serum levels (Rrank = -0.421, p < 0.001). IL-10 correlated negatively with IL-1beta (p = 0.013) and TNF-alpha (p = 0.039). The association between elevated serum levels of IL-10 and low serum levels of IL-1beta and TNF was observed only in patients with corticosteroid treatment. In these patients, elevated serum levels of IL-10 were positively associated with an increased ratio of IL-1ra to IL-1beta.
Elevated serum levels of IL-10 were associated with a more mild form of PMR. This study indicates a favorable role of IL-10 in patients with PMR.