This study revealed that in the Harderian glands of the same birds as used in this study, up-regulated expression of some cytokines and cytokine receptors (CXCL8, CXCL14, CCL20, CSF3R) was present only in the less-tolerant populations that have not yet or only recently experienced epidemics with MG (AZ, HI). The gene discussed is CCL20; the disease is myasthenia gravis.