RACIAL VARIATION IN SERUM-SOLUBLE INTERLEUKIN-2 RECEPTOR LEVELS - A POPULATION-BASED STUDY OF HEALTHY SMOKERS AND NONSMOKERS

To investigate the influence of race and cigarette smoking on serum le vels of soluble interleukin-2 receptors (sIL-2R), we studied a populat ion-based cohort of 282 white and 173 black adults, ages 20-69 years. Serum sIL-2R concentrations in this healthy population ranged from 146 to 2623 U/ml. Whites had significantly higher sIL-2R levels than blac ks (455 versus 365 U/ml; P < 0.001), and cigarette smokers had signifi cantly higher levels than nonsmokers (508 versus 420 U/ml; P = 0.01). White smokers had the highest levels (550 U/ml); white nonsmokers and black smokers had intermediate levels (455 and 450 U/ml, respectively) ; and black nonsmokers had the lowest levels (365 U/ml). Smoking cessa tion appeared to normalize sIL-2R levels; exsmokers who had not smoked for at least 2 years had sIL-2R levels similar to those of never smok ers. These data demonstrate the wide range of serum sIL-2R concentrati ons found in normal healthy adults and the significant influence of ra ce and cigarette smoking. Further investigation of this natural hetero geneity may provide insights into the mechanisms underlying genetic an d environmental influences on this important immunologic parameter. (C ) 1994 Academic Press, Inc.