D1.481 - Prevalence of Immunoglobulin Deficiency in Patients with Chronic Rhinosinusitis Followed in a Tertiary Referral Center

Chronic rhinosinusitis (CRS) is frequently associated with defects in humoral immunity, but the prevalence of quantitative immunoglobulin abnormalities in CRS populations from tertiary centers remains underrecognized. Identifying these abnormalities may guide targeted investigation and management in patients with difficult-to-treat or recurrent disease.

We aim assess the prevalence and patterns of serum immunoglobulin (IgG, IgA, IgM) deficiency in patients with CRS followed in immunology and otorhinolaryngology tertiary referral services in Brazil.

This retrospective cross-sectional chart review included consecutive patients aged ≥15 years with a diagnosis of CRS and at least one recent measurement of serum IgG, IgA and IgM performed in two tertiary referral centers. Immunoglobulin levels were interpreted according to age-adjusted reference ranges established for the Brazilian population, and Ig deficiency was defined as values below the lower limit of normal for each isotype.

A total of 242 patients with CRS were evaluated (median age 63 years, range 15–94; 53.7% female). Overall, 125 patients (51.7%) had at least one immunoglobulin deficiency, with a prevalence of IgG, IgA and IgM deficiency of 48.9%, 3.4% and 6.0%, respectively. Isolated IgM deficiency was observed in 105 patients (43.4%), isolated IgA deficiency in 4 patients (1.7%) and isolated IgG deficiency in 6 patients (2.5%), while combined IgG with IgA or IgM deficiency occurred in 3.9% of cases.

More than half of this CRS cohort from tertiary referral centers presented quantitative immunoglobulin abnormalities, predominantly involving IgM and IgG. These findings support routine screening of serum immunoglobulin levels in patients with CRS, particularly in those with refractory or recurrent disease, to identify underlying humoral immune defects that may influence clinical management.