In a recent prospective, longitudinal study published in Scientific Reports, researchers evaluated the humoral and cellular immune responses to pertussis vaccination in chronic obstructive pulmonary disease (COPD) patients.
Study: Immune response to pertussis vaccine in COPD patients. Image Credit: VadiFuoco/Shutterstock.com
Background
COPD, characterized by chronic lung inflammation that impairs lung immunity, increases an individual's susceptibility to all pulmonary infections. Exacerbated decline in lung function causes significant morbidity and mortality in COPD patients.
In one of their previous studies, researchers found decreased immunological response to seasonal flu vaccination in COPD patients. It raises the possibility that other vaccines might also be less effective in COPD patients. Thus, disease prevention strategies aimed at infection prevention might be at stake, raising concerns regarding public health.
Pertussis, caused by Bordetella pertussis, is an acute respiratory infection for which acellular pertussis vaccine (aP) is available. Recently, cases of pertussis resurged among adults over 65 years in the United States.
The majority of these cases, i.e., over 26%, occurred in COPD patients, thus, necessitating evaluation of the effectiveness of aP vaccination in COPD patients.
About the study
In the present monocenter study, researchers recruited eight healthy volunteers and 13 patients with stable COPD between September 2018 and May 2019 from a pulmonary outpatient clinic of the Henri Mondor Hospital in France.
The patients had no lung function exacerbation history or respiratory infection in the month before the study initiation. Also, they met the eligibility criteria for receiving diphtheria-tetanus-polio-pertussis vaccine (Tdap).
First, the team administered a single dose of Tdap intramuscularly (day zero). They asked all the participants to come for blood sample donation on days zero (before vaccination), seven, 15, and 30 post-vaccination.
Next, the researchers examined the humoral immune response on days zero and seven, specifically, the T follicular helper cells (Tfh) and plasmablasts. Additionally, they measured antibody titers against pertussis in serum using blood specimens collected on days zero and 30.
The team used intracellular cytokine staining to evaluate T cell-specific responses using specimens collected 15 days post-vaccination. To this end, they ex-vivo stimulated peripheral blood mononuclear cells (PBMCs) with a B. pertussis peptide pool. The team also analyzed supernatants from stimulated cells.
Results
All 13 COPD patients and eight controls had a median age of 68 and 64, respectively. There were six and 12 males in the healthy volunteers and the COPD group, respectively. As expected, COPS patients had lower forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC), i.e., 57% vs. 102% and 77% vs. 101%.
The study data showed that in COPD patients immune response pattern to pertussis vaccination was in striking contrast to influenza vaccination. The researchers quoted a few possible reasons for the observed discrepancy.
First, the prevalence of pertussis infections is lower than influenza infections, possibly because of the success of its vaccination programs, which resulted in lower exposure to pertussis antigens.
Secondly, the Tdap vaccination schedule typically involved fewer doses, reducing opportunities for immune priming and developing original antigenic sin (OAS) effects. Thirdly, it is also possible because of differences in vaccine design and adjuvant composition of the vaccines for the two diseases.
Accordingly, the authors noted no marked differences in circulating B cells, the cluster of differentiation (CD)4+ and CD8+ T cell subsets, and TFH cells. However, they observed a surge in naïve B cells and a dip in the number of memory B cells in COPD patients.
Furthermore, there was a significant increase in TFH and plasmablasts at day seven post-vaccination, suggesting successful induction of humoral response. Also, both groups had comparable pertussis-specific antibody levels 30 days post-vaccination.
Within 15 days of vaccination, pertussis-specific CD4+ T cells were equivalent in both groups, as quantified by staining for interferon-gamma, interleukin-2, and tumor necrosis factor-alpha.
Conclusion
To summarize, the study data confirmed that COPD patients are not less responsive to all vaccinations. Even though generally vulnerable, they mounted a highly efficient immunological response to pertussis vaccination.
Thus, clinicians should consider providing decennial Tdap boosters to COPD patients.
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