Open AccessLow-Blood Lymphocyte Number and Lymphocyte Decline as Key Factors in COPD Outcomes: A Longitudinal Cohort Study
Author(s) -
Umberto Semenzato,
Davide Biondini,
Erica Bazzan,
Mariaenrica Tinè,
Elisabetta Balestro,
Barbara Buldini,
Santiago J Carizzo,
Pablo Cubero,
Marta Marín-Oto,
Alvise Casara,
Simonetta Baraldo,
Graziella Turato,
Darío Gregori,
J. Marín,
Manuel G. Cosio,
Marina Saetta
Publication year - 2021
Publication title -
respiration
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.264
H-Index - 81
eISSN - 1423-0356
pISSN - 0025-7931
DOI - 10.1159/000515180
Subject(s) - medicine , copd , cohort , incidence (geometry) , cohort study , lymphocyte , lung cancer , immunology , gastroenterology , optics , physics
Background: 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. Objective: 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. Methods: 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. Results: BL count was lower in COPD (1,880 cells/µL) than noCOPD (2,300 cells/µL; p < 0.001). 43% of COPD and 23% of noCOPD had low-BL count ( p < 0.001). BL decline over time was higher in COPD than noCOPD ( p = 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%; p = 0.001) and no decliners (32 vs. 19%; p = 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. Conclusion: 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.