Immunoglobulin- and complement-coated bacteria in effusions obtained during the early course of acute maxillary sinusitis.

Fifty samples of maxillary sinus effusion from 40 patients (median age 29 years; 26 females and 14 males) with acute maxillary sinusitis (AMS) were subjected to quantitative and qualitative bacteriological analysis. Furthermore, bacteria coated with immunoglobulin (IgG, secretory IgA, IgM) or complement (C3b) were evaluated using an immunofluorescence assay. 72% of the samples harboured detectable bacteria, the most common pathogens being Streptococcus pneumoniae and non-typable Haemophilus influenzae. Of the bacteria-positive samples, 28% harboured immunoglobulin-coated bacteria. During the first weeks of an AMS infection, the present immunoglobulins are insufficient to protect the maxillary sinuses.