Antimicrobial activity of serum of cystic fibrosis patients before and after lung transplantation

Abstract

Cystic fibrosis (CF) is a systemic congenital disease characterized by chronic bronchopulmonary infection of bacterial and fungal origins. Numerous antimicrobial peptides (AMP) play a special role in humoral immunity in CF patients. Each AMP was characterized in detail earlier. A new method has been developed recently in the Russian Federation for estimation of the cumulative antimicrobial activity of all AMPs in different bioliquids.The aim of the study was the application of this method for the estimation of antimicrobial activity of whole sera and the AMP-containing low molecular serum fractions in patients with CF before and after lung transplantation.Methods. Sera from 11 CF patients of 24 – 33 years old obtained before and after lung transplantation were used in the study. Antimicrobial activities of the whole serum and its fractions with the molecular mass under 100 kDa were estimated by the effect of the specimens on Candida albicans test culture cells and by spectrophotometric assay of dye, which was internalized by the killed cells, as compared to the control untreated cells.Results. The total serum activity and AMP fractions activity in patients with CF were lower than in the healthy volunteers (medians): 82.3% vs 87.8 % (p ≤ 0.01) and 17.2% vs 41.9% (p ≤ 0.01). After the lung transplantation, both activities increased to 84.5% vs 33.3%, respectively. The improvement of AMP fractions activity was observed during 12 months after the transplantation. Serum albumin levels were lower in CF patients as compared to the reference values but normalized after lung transplantation.Conclusion. Obviously, the activity of the serum components of humoral immunity, which are responsible for direct antimicrobial defense, is decreased in CF patients compared to the reference values. The lung transplantation increased their activity considerably.