Altered CD4⁺ T cell immunity in nurses occupationally exposed to viral pathogens

Area of Science:

• Immunology
• Virology
• Occupational Health

Background:

• Pathogen exposure, particularly herpesviruses, significantly shapes the immune system's basal state and response to challenges.
• The impact of high viral exposure on baseline immune signatures and the mechanisms for maintaining immune balance during repetitive exposures remain largely unknown.

Purpose of the Study:

• To investigate baseline immune signatures, including T cell phenotyping and antigen-specific responses, in pediatric (PED) nurses with high occupational viral exposure.
• To compare immune profiles between PED nurses and neonatal intensive care unit (NICU) nurses (controls with infrequent exposure) to understand occupational exposure effects.

Main Methods:

• Detailed T cell phenotyping was performed.
• Antigen-specific CD4+ and CD8+ T cell responses to varicella zoster virus (VZV) proteins and tetanus toxoid (TT) were measured.
• Cytokine profiles were analyzed in PED nurses and NICU nurses, stratified by cytomegalovirus (CMV) serostatus.

Main Results:

• CMV-seronegative PED nurses showed a reduced CD4+ T cell response to VZV proteins and TT compared to CMV-seronegative NICU nurses, suggesting exposure-related attrition.
• Distinct T cell phenotypes associated with CMV-seropositivity appeared less prominent in PED nurses, indicating a potential attenuating effect of occupational exposure on CMV-associated immunosenescence.
• Sustained occupational exposure may lead to a decline in specific T cell responses within the CD4+ compartment.

Conclusions:

• Occupational exposure to viral pathogens significantly impacts CD4+ T cell immunity.
• Continuous exposure may lead to T cell attrition and potentially alter age-related immune changes.
• Further investigation in larger cohorts is warranted to confirm these findings and elucidate mechanisms.