The effect of aging and acute illness on delayed hypersensitivity

Area of Science:

• Immunology
• Clinical Medicine
• Dermatology

Background:

• Delayed hypersensitivity skin tests (DHST) are crucial for assessing cell-mediated immunity.
• Impairments in DHST response are observed in various clinical conditions.
• The impact of acute illness and aging on DHST requires further clarification.

Purpose of the Study:

• To evaluate the delayed hypersensitivity skin test response in normal volunteers and hospitalized patients.
• To determine the influence of acute illness and increasing age on DHST reactivity.
• To assess the recovery of DHST response after acute illness resolution.

Main Methods:

• Standard antigens (monilia, mosquito, mumps, PPD, staphylococcus toxoid, SK-SD, trichophyton) were applied to 321 normal volunteers, 60 ward patients, and 41 ICU patients.
• Delayed hypersensitivity skin test reactions were measured by induration size.
• Reactivity was assessed in relation to age, hospitalization status, and post-discharge recovery.

Main Results:

• 88% of normal subjects showed positive DHST reactions, with no age-related decrease in reactivity.
• Only 62% of ward patients and 63% of ICU patients exhibited positive DHST responses.
• All anergic ICU patients tested post-discharge regained normal DHST reactivity.

Conclusions:

• Acute illness significantly impairs delayed hypersensitivity skin test response.
• Increasing age does not affect DHST reactivity in the studied population.
• DHST responsiveness is restored after recovery from acute illness, indicating its utility in monitoring immune status.