Circadian rhythm of immunoglobulins in aged persons

A circadian rhythm with a high statistical probability was detected for IgA, IgG and IgM in a group of 37 aged subjects. These rhythms have a peak (acrophase) in the early afternoon, around 13h00, with variable confidence interval, which may extend between 8h30 and 17h30. The double amplitude of rhythms is approximately 15% of the mean concentration of antibodies during the day (mesor). No statistical difference was observed in mesor, amplitude or acrophase between males and females or in association with age (below or above 75 years) or in mean concentration of immunoglobulins (inside or outside the adult standard reference value at 8h00).