Elevated Granulocyte Colony-stimulating Factor Levels in Patients With Active Phase of Adult-onset Still Disease

Objective Neutrophilia is a hallmark of adult-onset Still disease (AOSD). We aimed to investigate the levels of granulocyte colony-stimulating factor (G-CSF), an essential regulator of neutrophil production and function, in the pathogenesis of AOSD.

Methods Sera were collected from 70 patients with AOSD and 20 healthy controls (HCs). The levels of G-CSF were determined by ELISA. Low-density granulocytes (LDGs) were quantified by flow cytometry. Correlations between G-CSF levels and disease activity, laboratory variables, and LDG levels in patients with AOSD were analyzed by Spearman correlation test.

Results Patients with active AOSD presented significantly higher levels of G-CSF compared to inactive AOSD patients (P < 0.001) and HCs (P < 0.0001). The G-CSF levels were significantly decreased after active AOSD patients achieved disease remission (P = 0.0015). The G-CSF levels were significantly correlated with C-reactive protein, erythrocyte sedimentation rate, ferritin, and systemic score in AOSD (P < 0.0001). Significant correlations between the levels of G-CSF and circulating neutrophils (P < 0.0001), neutrophil-to-lymphocyte ratio (P < 0.0001), percentages of LDGs in the peripheral blood mononuclear cells (P = 0.004), as well as absolute numbers of circulating LDGs (P = 0.018) were identified. Patients with fever, evanescent rash, sore throat, arthralgia, myalgia, lymphadenopathy, or hepatomegaly/elevated liver enzymes displayed significantly higher levels of G-CSF compared to patients without these manifestations (P < 0.05).

Conclusion Our findings indicate that G-CSF is implicated in the pathogenesis of AOSD, and targeting G-CSF may have therapeutic potential for AOSD. In addition, introducing circulating G-CSF levels into the clinical assessment system may help to monitor disease activity.