Results showed that rosacea patients had higher frequencies of classical monocytes than healthy controls (p < 0.001), elevated CCR2 expression on classical and intermediate monocytes (p < 0.001), and increased plasma levels of HMGB 1 (p = 0.001), CCL2 (p = 0.0023), IL 1β (p = 0.0393), and TNF α (p = 0.0069), suggesting a key role of monocyte-driven inflammation in rosacea pathogenesis. The gene discussed is CCR2; the disease is rosacea.