Immunological effects of shift work in healthcare workers

Abstract

The immune system potentially plays an important mechanistic role in the relation between shift work and adverse health effects. To better understand the immunological effects of shift work, we compared numbers and functionality of immune cells between night-shift and non-shift workers. Blood samples were collected from 254 night-shift and 57 non-shift workers employed in hospitals. Absolute numbers of monocytes, granulocytes, lymphocytes, and T cell subsets were assessed. As read out of immune function, monocyte cytokine production and proliferative capacity of CD4 and CD8 T cells in response to various stimuli were analysed. The mean number of monocytes was 1.15 (95%-CI = 1.05–1.26) times higher in night-shift than in non-shift workers. Furthermore, night-shift workers who worked night shifts in the past three days had a higher mean number of lymphocytes (B = 1.12 (95%-CI = 1.01–1.26)), T cells (B = 1.16 (95%-CI = 1.03–1.31)), and CD8 T cells (B = 1.23 (95%-CI = 1.05–1.45)) compared to non-shift workers. No differences in functional parameters of monocytes and lymphocytes were observed. The differences in numbers of monocytes and T cells suggest that chronic exposure to night-shift work as well as recent night-shift work may influence the immune status of healthcare workers. This knowledge could be relevant for preventive initiatives in night-shift workers, such as timing of vaccination.

The Association Between Shift Work and Immunological Biomarkers in Nurses

“…Unfortunately, in the present study most IL-6 data were under the LOD and we could not make any clear conclusions as to whether shift workers suffered from a systemic inflammation with regard to IL-6 or whether there was an alteration seen after a night shift. With respect to the previous literature on how shift work and sleep relate to cytokines, our findings are partially in contrast with several previous studies (5,7,8,12,21) but in agreement with others (6,10,11). In a systematic review and meta-analysis on the link between sleep disturbance, sleep duration and inflammation, Irwin et al (3) found 72 studies assessing IL-6, TNF-alpha, and C-reactive protein (CRP).…”

“…Also, in a recent study comparing 254 night shift workers with 57 non-shift workers, no association in relation to work status was detected on a range of cytokines. However, night work was associated with increased number of monocytes and lymphocytes (11). In a clinical review, Faraut et al (12) addressed the issue of shift work and immunity, and suggested several lines of further studies (e.g., use of non-invasive biological markers, conduct more longitudinal studies) to delineate the pathways by which circadian misalignment and short sleep may influence immunological mechanisms.…”

Are night shift workers at an increased risk for COVID-19?

“…In one study, a bimodal rhythmic cytokine secretion was found to phase-shift 4.5–6 hours earlier in peripheral blood mononuclear cells from people who had undergone simulated night shift work conditions than in those collected from people examined following simulated day shift work conditions [22] . Another study found that the average number of monocytes was 1.15 times higher in night-shift workers, and that night-shift workers who had worked night-shifts in the past three days had higher mean numbers of lymphocytes, T cells, and CD8+ T cells [23] . These alterations in immune response and cell subpopulations might also contribute to the increased risk for autoimmune diseases, cardiovascular and metabolic disorders, and cancer reported in night shift workers.…”

Shift work influences the outcomes of Chlamydia infection and pathogenesis

“…Cytokines and chemokines are important mediators of this immune response 28 – 30 . Infected ECD mice had higher secretions of the proinflammatory cytokines TNF-α and IL-1β in the first week of infection tapering off by the second week 15 , 31 . Excessive secretion of proinflammatory cytokines is associated with adverse pathological outcomes in the genital tract 32 – 35 .…”