Low-Blood Lymphocyte Number and Lymphocyte Decline as Key Factors in COPD Outcomes: A Longitudinal Cohort Study

Abstract

<b><i>Background:</i></b> Smokers with and without chronic obstructive pulmonary disease (COPD) are at risk of severe outcomes like exacerbations, cancer, respiratory failure, and decreased survival. The mechanisms for these outcomes are unclear; however, there is evidence that blood lymphocytes (BL) number might play a role. <b><i>Objective:</i></b> The objective of this study is to investigate the relationship between BL and their possible decline over time with long-term outcomes in smokers with and without COPD. <b><i>Methods:</i></b> In 511 smokers, 302 with COPD (COPD) and 209 without COPD (noCOPD), followed long term, we investigated whether BL number and BL decline over time might be associated with long-term outcomes. Smokers were divided according to BL number in high-BL (≥1,800 cells/µL) and low-BL (<1,800 cells/µL). Clinical features, cancer incidence, and mortality were recorded during follow-up. BL count in multiple samples and BL decline over time were calculated and related to outcomes. <b><i>Results:</i></b> BL count was lower in COPD (1,880 cells/µL) than noCOPD (2,300 cells/µL; <i>p</i> < 0.001). 43% of COPD and 23% of noCOPD had low-BL count (<i>p</i> < 0.001). BL decline over time was higher in COPD than noCOPD (<i>p</i> = 0.040). 22.5% of the whole cohort developed cancer which incidence was higher in low-BL subjects and in BL decliners than high-BL (31 vs. 18%; <i>p</i> = 0.001) and no decliners (32 vs. 19%; <i>p</i> = 0.002). 26% in the cohort died during follow-up. Furthermore, low-BL count, BL decline, and age were independent risk factors for mortality by Cox regression analysis. <b><i>Conclusion:</i></b> BL count and BL decline are related to worse outcomes in smokers with and without COPD, which suggests that BL count and decline might play a mechanistic role in outcomes deterioration. Insights into mechanisms inducing the fall in BL count could improve the understanding of COPD pathogenesis and point toward new therapeutic measures.

Immune cell ratio and coagulation markers in assessing prognosis of asthma: a cross-sectional study from Saudi Arabia

“…Further, our study found levels of LYM to be lower among smokers than non-smokers. This finding is also in line with a study by Semenzato U. et al (2021) (32), who investigated the relationship between blood lymphocyte and its possible decline over time with long-term outcomes in smokers with and without chronic obstructive pulmonary disease. The study found the lymphocyte count to be lower in these patients (1,880 cells/µL) and a decline in the count to be related to the worst outcome among smokers with or without the disease.…”

Symptomatic smokers without COPD have physiological changes heralding the development of COPD

“…All subjects underwent a comprehensive clinical and functional examination including spirometry, maximum mid-expiratory flow at 25–75% of FVC (MMEF), measurement of diffusing capacity of the lung for carbon monoxide ( D LCO ), using the Communauté Européenne du Charbon et de l'Acier (CECA) as predicted values [ 13 ]. The 6-min walk test (6MWT), modified Medical Research Council (mMRC) Dyspnoea Scale and COPD Assessment Test (CAT) [ 14 ] were also obtained.…”

Suppressor of cytokine signaling-3 expression and its regulation in relation to inflammation in Chronic Obstructive Pulmonary Disease

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