The Effects of Diurnal Rhythms on Immune Parameters in New Hampshire Chickens

Abstract

The influence of diurnal rhythms on several immune parameters was studied. When thymic-derived lymphocytes were collected 4 times during a 24-hour period, a variation occurred in the migration ability of these ceils. The migration of T cells at 2:00 a.m. was markedly lower than at other time periods. Similar results were noted employing other T-cell tests: phytohemagglutinin wattle responsiveness and the graft vs. host assay.

Macrophage migration inhibitory factor exhibits a pronounced circadian rhythm relevant to its role as a glucocorticoid counter‐regulator

“…This is consistent with the fact that delayed‐type hypersensitivity responses in humans are increased at night 2 and that symptoms of chronic inflammatory disorders including rheumatoid arthritis 3 and asthma 4 are worst during the night and early morning. Circadian immune rhythms are not unique to man as immune rhythms have also been described in mice, 5 rats, 6 fish 7 and birds 8 . Although circadian cytokine rhythms are principally entrained by plasma cortisol, there is also influence by other neuroendocrine factors including melatonin, growth hormone and prolactin 9 …”