Persistent lymphocytopenia as a diagnostic feature of bronchogenic carcinoma

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

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.

Leukocyte concentrations in discrimination of benign from malignant lung lesions

Malignant lung lesions are associated with significant changes in leukocyte concentrations. However, overlap of values between normal subjects and patients with cancer has limited the clinical utility of this determination. To decrease the overlap, 2,000 cells per differential determination were counted, and replicate automated cell counts were performed in blood samples obtained on different mornings between 7 and 9 A.M. Seventy-five patients who presented with undiagnosed lung lesions were analyzed. Benign and malignant lung lesions could be accurately distinguished by either relative granulocyte or lymphocyte counts. With 65.5 percent granulocytes as the cutoff, 86 percent of patients (38 of 44) proved to have lung cancer had higher values, and 97 percent of patients (30 of 31) with benign lesions had lower values. Likewise, with 28 percent lymphocytes as the cutoff, 87 percent of patients with lung cancer (39 of 44) had lower values, and 94 percent of patients (29 of 31) with benign disease had higher values. Relative monocyte counts were not different. Absolute leukocyte concentrations, although different for each group, had considerable overlap and thus were poor discriminators. These data suggest that precise analytical techniques and the use of relative leukocyte concentrations can improve the clinical utility of the leukocyte count as a discriminator of benign and malignant lung lesions.