IgG avidity to Pseudomonas aeruginosa over the course of chronic lung biofilm infection in cystic fibrosis.
BACKGROUND AND OBJECTIVES
The mechanisms leading to low effectiveness of the humoral immune response against P. aeruginosa in cystic fibrosis (CF) are poorly understood. The aim of the present study was to assess the avidity maturation of specific antipseudomonal IgG before and during the development of chronic lung infection in a cohort of Danish CF patients.


METHODS
Avidity maturation was assessed against a pooled P. aeruginosa antigen (St-Ag) and against P. aeruginosa alginate in 10 CF patients who developed chronic lung infection and 10 patients who developed intermittent lung colonization, using an ELISA technique with the thiocyanate elution method. Avidity was quantitatively determined by calculating the avidity Constant (Kav).


RESULTS
IgG avidity to St-Ag significantly increased at the onset (Median Kav=2.47) and one year after the onset of chronic infection (Median Kav=3.27), but did not significantly changed in patients who developed intermittent colonization. IgG avidity against alginate did not significantly change over the years neither in patients who developed chronic lung infection (Median Kav=3.84 at the onset of chronic infection), nor in patients who developed intermittent colonization.


CONCLUSION
IgG avidity to P. aeruginosa alginate does not significantly enhance as chronic lung infection progresses. This probably plays a role in the difficulty to mount an effective opsonophagocytic killing to clear mucoid P. aeruginosa infection in CF.
['Mauch|Renan Marrichi|RM|', 'Nørregaard|Lena Lingren|LL|', 'Ciofu|Oana|O|', 'Levy|Carlos Emilio|CE|', 'Høiby|Niels|N|']
D000293:Adolescent D000328:Adult D018441:Biofilms D002648:Child D002908:Chronic Disease D003550:Cystic Fibrosis D003718:Denmark D005260:Female D006801:Humans D056724:Immunity, Humoral D007074:Immunoglobulin G D008297:Male D011552:Pseudomonas Infections D011550:Pseudomonas aeruginosa D015203:Reproducibility of Results
IgG avidity Pseudomonas aeruginosa Biofilm Cystic fibrosis Chronic infection Humoral response