Background: Patients with acute exacerbations of COPD (AECOPD) and humoral immunodeficiency are predisposed to similar recurrent, respiratory infections; indicating that antibody dysfunction may underlie AECOPD. Typhim Vi vaccine is a polysaccharide vaccine, and its response can be used to measure humoral immune function.

Aims: We aim (i) to determine the presence and prevalence of humoral dysfunction in COPD with ?1 AECOPD in the past year and (ii) its relationship with AECOPD frequency, using a Typhim vaccine test.

Methods: Pre- and post-immunization anti-typhi IgG titers were quantified by the VaccZyme^TM ELISA from 11 COPD patients (GOLD standard, ?1 AECOPD, no malignancies or immunodeficiencies). Patients were grouped into responders and non-responders (?2-fold post: pre-IgG).

Results: To date, 11 AECOPD patients have been evaluated (mean age 69.18, 5 females). 5 of 11 (45%) patients were non-responders. Mean number of exacerbations per year was 3.20±1.79 for non-responders and 1.33±1.50 for responders. Higher St. George's Respiratory Questionnaire scores (Spearman, ?=-0.52, p<0.05) and older age (?=-0.59, p<0.05) were moderately correlated with lower post: pre-immunization IgG fold change. There were no statistical differences regarding COPD Assessment Test scores (?=0.13), smoking history (?=0.18), and Ig subtypes (IgG ?=0.19, IgA ?=-0.02, IgE ?=0.50, IgM ?=-0.05).

Conclusion: Inadequate antibody response has been observed in some COPD patients (5/11 sample size), specifically those with more exacerbations, lower quality of life, and advanced age. Anti-typhi IgG response may be a biomarker for COPD phenotyping. Further investigation in a larger patient cohort is underway.