Mean daily nasal, throat, general, complication, and total symptom scores and mean daily concentration of interleukin 6 (IL-6) for groups defined by the low-production (white circles) and high-production (black circles) IL-6 −174 phenotypes. The upper horizontal bars indicate the mean value of the low-production IL-6 phenotype plus its standard error, and the lower horizontal bars indicate the mean value of the high-production IL-6 phenotype minus its standard error.