Increased serum HLA class I molecule levels in elderly human responders to influenza vaccination

Abstract: Increased cell surface expression and serum levels of HLA class I molecules have been shown to occur in normal elderly humans. Elderly subjects (65 years and older) generally also have a poorer response to influenza vaccine than younger adults. Some 30 to 40% of elderly subjects do not respond to influenza vaccination. Sera from 20 elderly subjects with a positive response to influenza vaccine (HAI antibody titer >40) and 20 subjects who did not respond (HAI antibody titer <40) were randomly selected and the levels of soluble HLA class I molecules determined before and after vaccination. The subjects who responded had higher serum HLA class I levels both before and after vaccination than did non‐responders. Two weeks after vaccination non‐responders showed similar serum HLA class I levels (1.78 mg/ml ± 0.62) as compared to pre‐vaccination levels (1.73 mg/ml ± 0.49). The responders showed significantly higher levels of soluble HLA class I molecules following vaccination (2.64 mg/ml ± 0.99) as compared to pre‐vaccination (2.08 mg/ml ± 0.85, p = 0.00001). Our results suggest that measuring soluble HLA class I molecules in the serum may be useful in assessing the adequacy of response to influenza vaccination in the elderly population. 1993 Blackwell Munksgaard