Declining cell-mediated immunity and increased chronic disease burden

The effects of chronic disease have been proposed as an explanation for conflicting results in studies of age effects on cell-mediated immunity.

To examine the hypothesis that declining cell-mediated immunity is more closely linked to chronic disease burden than to chronological age.

Fifty-eight elderly individuals were tested for delayed-type hypersensitivity (DTH) responses to Candida and tetanus antigens. Disease burden was quantified using the Cumulative Illness Rating Scale (CIRS). Higher CIRS scores reflect greater disease burden. Mean DTH response by age group (<71, 71-78, and >78 years) was compared with mean DTH response by CIRS score (<11, 11-15, >15). Total serum IgE levels were measured and similarly stratified by age and CIRS score.

Mean Candida DTH responsiveness declined progressively with increasing disease burden (increasing CIRS score). Mean DTH responses were 7.78, 3.05, and 0.0 mm for CIRS scores less than 11, 11 to 15, and greater than 15, respectively. Candida DTH responses showed no progressive decline with advancing age. Mean DTH responses were 4.7, 3.5, and 5.0 mm in participants younger than 71, 71 to 78, and older than 78 years, respectively. Total serum IgE levels increased with advancing age. Mean total IgE levels were 182, 249, and 342 IU/mL in participants younger than 71, 71 to 78, and older than 78 years, respectively. No correlation was observed between mean total IgE levels and CIRS scores.

An inverse relationship between Candida DTH response and CIRS score suggests that increased chronic disease burden is associated with diminished cell-mediated immune response. Advancing age did not predict a diminished DTH response in our patients. No relationship was observed between chronic disease burden and total serum IgE level.