RACIAL-DIFFERENCES IN SERUM IMMUNOGLOBULIN LEVELS - RELATIONSHIP TO CIGARETTE-SMOKING, T-CELL SUBSETS, AND SOLUBLE INTERLEUKIN-2 RECEPTORS

To investigate the influence of race, cigarette smoking, and immunolog ic parameters on serum immunoglobulins, we analyzed serum IgG, IgA, an d IgM levels in 455 healthy adults. The study population ranged in age from 20 to 69 years, including 282 whites and 173 blacks, 181 never-s mokers, 93 ex-smokers, and 181 current smokers. Race and smoking were independently associated with alterations in serum IgG levels. Blacks had Significantly higher IgG levels than whites (1,587 vs. 1.209 mg/dl ; P<0.001), and never smokers had significantly higher levels than cur rent smokers (1,426 vs. 1,287 vs, mg/dl; P<0.001). IgA and IgM levels were unrelated to race or smoking. Serum IgG was also found to be dire ctly related to the proportion of HLA-DR(+) cells and the level of sol uble interleukin-2 receptors (slL-2R) and inversely related to the pro portion of CD4(+) cells. Investigation of this racial heterogeneity ma y provide insights into the pathogenesis of immunologic diseases that exhibit unexplained racial variation. (C) 1995 Wiley-Liss. Inc.