Elevated Serum Levels of Monocyte Chemotactic Protein-1/Chemokine C-C Motif Ligand 2 are Linked to Disease Severity in Patients with Fibromyalgia Syndrome

BACKGROUND: Elevated levels of monocyte chemotactic protein-1/chemokine C-C motif ligand 2 have been identified in fibromyalgia patients. AIMS: To examine the potential association among serum levels of monocyte chemotactic protein-1/chemokine C-C motif ligand 2 with disease severity of fibromyalgia. STUDY DESIGN: Cross-sectional study. METHODS: Seventy-nine female patients with fibromyalgia and 75 healthy normal controls were included in our study. Serum levels of monocyte chemotactic protein-1/chemokine C-C motif ligand 2 were detected by enzyme-linked immune sorbent assays. The existence of tender points was evaluated based on the standardized manual tender point examination. Pressure pain thresholds at the knees, and bilateral trapezius muscles were measured with an algometer. A visual analog scale and the Revised Fibromyalgia Impact Questionnaire were utilized to assess the degree of pain and functional abilities. RESULTS: Serum levels of monocyte chemotactic protein-1/chemokine C-C motif ligand 2 were significantly greater in patients with fibromyalgia compared with healthy controls (151.6±31.9 pg/mL vs 103.3±25.2 pg/mL, p<0.001). Patients with severe fibromyalgia had significantly higher serum levels of chemokine C-C motif ligand 2 than patients with mild and moderate fibromyalgia (173.1±21.9 pg/mL vs 151.0.0±35.1 pg/mL, p=0.01). Patients with moderate fibromyalgia revealed markedly augmented serum levels of chemokine C-C motif ligand 2 compared with patients with mild fibromyalgia (151.0±35.1 pg/mL vs 133.3±23.9 pg/mL, p=0.03). Serum levels of chemokine C-C motif ligand 2 were positively associated with tender point scores (r=0.455, p<0.001). In addition, serum levels of chemokine C-C motif ligand 2 were positively associated with pressure pain thresholds in both knees and bilateral trapezius muscles (knees: r=-0.349, p=0.002; trapezius muscles: r=-0.318, p=0.004). Finally, we found elevated serum levels of chemokine C-C motif ligand were also positively associated with the visual analog scale (r=0.368, p=0.001), and the Fibromyalgia Impact Questionnaire score (r=0.401, p<0.001). CONCLUSION: Elevated serum levels of monocyte chemotactic protein-1/chemokine C-C motif ligand 2 are linked to disease severity of fibromyalgia. Therapeutic interventions inhibiting monocyte chemotactic protein-1/chemokine C-C motif ligand 2 in fibromyalgia deserve additional studies.