Impaired neutrophil function in patients with common variable immunodeficiency (CVID)

Abstract

Introduction: CVID is an antibody deficiency syndrome characterised by recurrent infection, particularly of the respiratory tract. Lung disease may progress despite antibody replacement therapy. As antibodies enhance phagocytosis, we hypothesised that progression of lung disease may reflect impaired neutrophil function. Therefore, the aim of this study was to compare bacterial killing by neutrophils derived from CVID patients with those from healthy volunteers. Methods: Isolated peripheral blood neutrophils from CVID patients (N=4) and healthy controls (N=8) were incubated with Staphylococcus aureus at a ratio of 1:1 (final concentration 1x10 7 /ml) for 40 minutes. Decreases in S. aureus total viable count were calculated relative to control experiments performed without neutrophils. All assays were performed in triplicate, mean values calculated and independent students T tests used for analysis of results. Results: Killing of S. aureus by neutrophils from healthy controls ranged from 51 – 73% with a mean value of 60%. Killing by neutrophils from CVID patients ranging from 25 – 50% with a mean value of 34% was significantly less (P = 0.0008). Conclusion: Impaired neutrophil function may contribute to reduced clearance of bacteria from the lungs of patients with CVID which may result in the development and progression of chronic lung disease in these patients.