Association between peripheral blood WBCs C3aR mRNA level and plasma C3a, C3aR, IL-1β concentrations and acute exacerbation of chronic obstructive pulmonary disease

Background: The relationship between C3a-C3aR, IL-1 beta, and the acute exacerbation of chronic obstructive pulmonary disease is still unclear. This study aims to explore the expression levels of C3aR in peripheral blood WBCs and the concentrations of C3a, C3aR, and IL-1 beta in plasma in healthy controls and patients with chronic obstructive pulmonary disease (COPD). Methods: WBCs C3aR level in the peripheral blood, the concentrations of C3a, C3aR, and IL-1 beta in plasma were measured in 60 patients with acute exacerbation of COPD (AECOPD), 30 patients with stable COPD (SCOPD), and 30 healthy controls. The baseline characteristics and clinical data collected from enrolled patients, including age, gender, laboratory indicators, and lung function. We analyzed the correlation between C3a, C3aR, IL-1 beta, and lung function indicators (forced expiratory volume in the first second as a percentage of predicted value, FEV1% pred) in the AECOPD group. Results: The white blood cell count (WBC), neutrophil/lymphocyte ratio (NLR), and C-reactive protein (CRP) of patients in COPD were higher than in healthy controls (P < 0.05). The peripheral blood WBCs C3aR mRNA and plasma C3a, C3aR, and IL-1 beta in AECOPD were higher than in SCOPD and healthy controls (P < 0.05). The peripheral blood WBCs C3aR mRNA and plasma C3aR, and IL-1 beta in AECOPD combined with respiratory failure were higher than in the non-respiratory failure group (P < 0.05). The peripheral blood WBCs C3aR mRNA and plasma C3a, C3aR, and IL-1 beta in AECOPD with high-risk were higher than in the low-risk group (P < 0.05). The peripheral blood WBCs C3aR mRNA and plasma C3a, C3aR, and IL-1 beta in AECOPD were negatively correlated with FEV1pred%. The peripheral blood WBCs C3aR mRNA, the plasma C3a and C3aR in AECOPD were positively correlated with IL-1 beta. Conclusion: The peripheral blood WBCs C3aR mRNA and plasma C3a, C3aR, and IL-1 beta in COPD patients were significantly related to the risk of disease deterioration. The C3a-C3aR axis may be involved in airway inflammation in patients with COPD.