Assessment of Humoral Immune Function in Chronic Obstructive Pulmonary Disease (COPD)

Abstract

Chronic obstructive pulmonary disease (COPD) is an irreversible lung disease, characterized by chronic inflammation which compromises immune responses and facilitates acute exacerbations of COPD (AECOPD). One notable issue is that some patients continue to experience frequent AECOPD despite receiving the maximum available therapies. Although there is a substantial gap in our understanding of the underlying factors contributing to AECOPD, it is well-established that patients with AECOPD and humoral immunodeficiency are predisposed to similar recurrent, respiratory infections; indicating that humoral immune (HI) dysfunction may underlie AECOPD. We hypothesize that HI dysfunction, defined by impaired antibody production to a polysaccharide vaccine, is present in a subset of COPD patients and associated with higher AECOPD frequency.

This thesis aimed to assess the relationship between HI dysfunction in patients with COPD and mean rate of AECOPD in the past year, using a Typhim Vi (polysaccharide) vaccine response test to measure HI function. A prospective cohort study of COPD patients with at least moderate airflow obstruction (FEV1<80% predicted) was conducted. Pre- and post-immunization anti-Typhi Vi IgG titers were quantified in serum samples by the VaccZyme™ Salmonella anti-Typhi Vi IgG ELISA kit in 44 patients.

HI dysfunction was observed in a subset of COPD patients, specifically those with frequent AECOPD in the past year. Age, quality of life scores, smoking history, cellular components and immunoglobulin levels were not associated with HI dysfunction in COPD. Overall, the findings suggest that the presence of HI dysfunction, defined by Typhoid vaccine response, may be an innovative biomarker in clinical practice to phenotype individuals at high-risk of AECOPD.