Abstract

Objective: We investigated the association between  a presence of  staphylococcal superantigens (SAg) in nasal swabs  and activity of  disease in granulomatosis with polyangiitis (GPA) patients  taking into account correlation with antineutrophil  cytoplasmic antibodies (ANCA) and antimicrobial treatment.

Methods: In a prospective study of all 150 GPA patients hospitalized in the period 2009-2016 nasal swabs were examinated for presence of  Staphylococcus aureus and SAg. Subsequently,  the association with  disease activity was assessed.  

Results: Of 362 Staphylococcus aureus – positive nasal swab culture a presence at least one SAg in 126 samples (34,8%) from 56 patients (48,7%) was found. We did not find the significant correlation between presence of SAg  and  disease activity (p=0,986),  although when individual  SAg were analyzed separatively, SED and TSST-1 were more frequently present in active disease. Additionaly,  the results of the analysis demonstrated a significant correlation between ANCA and activity of GPA (0R 1.42, p=0,0034)  and a protective effect of  trimethoprim/sulfamethoxazole (T/S) treatment (0R 0.52, p<0,0092).   GPA  limited  to SGS appeared as  an unfavorable  factor  associated with disease activity (0R 1.84, p=0.05). 

Conclusion: The association between  staphylococcal SAg in nasal swabs and activity of GPA is not evident. Multiple mechanisms that may lead to disease activation still need to be investigated.