The effects of shift work on the functional alteration in immune cells on hospital female nurses engaged in the morning and night shifts: Correlating with psychological stress and immune functions

Shift work has been increasingly associated with alterations in immune regulation and stress responses. Circadian alteration, sleep disruption, and occupational stressors collectively impair immune status. However, the specific association between shift work, psychological stress, and the immune function of monocytes, neutrophils and lymphocytes among female nurses is still not clear. The aim of our study is to evaluate the association between shift work, psychological stress, and immune cell functions in female nurses using a within-subject design. A cross-sectional, repeated-measures observational study with a within-subject design was conducted at a tertiary care hospital from March to July 2025 among eight female nurses aged 22-32 y. Blood sampling and psychological stress assessments (Perceived Stress Scale and Copenhagen Psychosocial Questionnaire) were conducted within 2 h after completion of each shift. Monocytes, neutrophils, lymphocytes, and plasma were isolated from the blood of the same participants after each shift for immune marker assessment. Stress scores were significantly higher after night shifts. Night shift samples showed increased oxidative stress and stress-related markers, reduced nitric oxide levels, decreased phagocytic activity, leads towards the pro-inflammatory state along with altered chemokine receptor expression. This study highlights the association between shift work, psychological stress, and altered immune function in female nurses. Lack of sleep data is a limitation, as sleep variability may influence stress and immune responses. Future studies with larger, more diverse cohorts and detailed sleep assessments are needed to confirm these findings across different healthcare settings.