Objective: To evaluate the immunosuppressive effects of job stress in female nurses, an 8-month longitudinal study was conducted at a major university hospital.
Methods: Four groups of ten subjects each were constructed to represent high versus low objective stress and high versus low subjective stress based on their responses to a job stress questionnaire and objective stress ratings of the hospital's work units. Number of white blood cells (i.e., T cells, B cells, and natural killer cells), and lymphocytic proliferation to mitogens (concanavalin A, phytohemagglutinin, and pokeweed) and toxoid (tetanus) were measured by flow cytometry and radioimmunoassay. Serum levels of hydrocortisol, IL-1β, IFN-γ, and TNF-α, and salivary IgA were measured by enzyme-linked immunosorbent assay. The data were analyzed by repeated measures analysis of variance controlling for age and smoking.
Results: The level of white blood cells was lower among high objective stress group (median: 7,170/m(3); range: 5,386-10,057) compared with that among low objective stress group (8,063; 5,888-9,875) (P = 0.03), however, no other cellular blood variables were found to be significant. In terms of humoral immuno-biomarkers, the level of TNF-α was moderately lower among high objective stress group (1.7 ng/ml; 0.3-2.7) compared with that among low objective stress group (2.2; 0.5-3.5) (P = 0.07), whereas the level of total sIgA was significantly higher among higher objective stress group (72.9 end-point titer/mg/ml/min; 14.4-153.4) compared with that among low objective stress group (44.8; 9.9-123.8) (P = 0.02).
Conclusion: The results of the study suggest that psychological job stress affects the levels of some immunological biomarkers in female nurses.