Immunoglobulins and complement factor C4 in adult rhinosinusitis

Area of Science:

• Immunology
• Otolaryngology

Background:

• Chronic or recurrent rhinosinusitis (CRS/RRS) affects a significant population, with underlying immune dysregulation suspected.
• The role of the complement system and immunoglobulin levels in CRS/RRS pathogenesis remains incompletely understood.

Purpose of the Study:

• To investigate the association between complement system factors (C3, C4, classical pathway activity) and immunoglobulin levels with CRS/RRS.
• To identify specific immune parameters that differentiate CRS/RRS from acute rhinosinusitis (ARS) and healthy controls.

Main Methods:

• Analysis of immunoglobulins (IgA, IgG subclasses) and complement components (C3, C4, C4A/C4B null alleles) in patient cohorts.
• Comparison of CRS/RRS patients, ARS patients, and healthy controls using logistic regression analysis.
• Assessment of clinical factors including nasal polyposis and bronchial asthma.

Main Results:

• Complement was found to be up-regulated in rhinosinusitis patients.
• C4A null alleles and reduced levels of IgA, IgG, IgG1, IgG2, IgG3, and IgG4 were more prevalent in CRS/RRS patients.
• Nasal polyposis, bronchial asthma, C4A null alleles, and combined low IgG1/IgG4 or IgG2/IgG4 were significantly associated with CRS/RRS compared to ARS.

Conclusions:

• C4A null alleles are associated with CRS/RRS, potentially affecting immune defense and inflammation.
• A combination of clinical and immunological factors, including specific immunoglobulin subclass deficiencies, may serve as prognostic variables for CRS/RRS.