Hypogammaglobulinaemia Post-Lung Transplant Is Associated with Deficient B Cell Function

Purpose We have recently shown that hypogammaglobulinaemia is common in lung transplant recipients and is a risk factor for both infection and bronchiolitis obliterans syndrome. However, the mechanisms leading to low immunoglobulin (Ig) levels are unknown. Therefore the aim of this study was to better understand B cell biology post-lung transplant. Methods and Materials Peripheral blood mononuclear cells (PBMCs) were collected from lung transplant recipients (n=30) and healthy age-matched controls (n=18). T and B cellular subsets were identified and enumerated by flow cytometry. In vitro stimulated IgG production was measured by ELISA. Results The total number of circulating PBMCs was reduced in lung transplant patients (median 0.9 x 10^6 (IQR 0.6-1.2 x 10^6) PBMCs per mL whole blood) compared to healthy controls (median 1.4 x 10^6 (IQR 1-1.8 x 10^6) PBMCs per mL whole blood, p Conclusions Hypogammaglobulinaemia after lung transplantation is related to both a reduced B cell fraction and a reduced functional capacity for IgG production.