Sarcoidosis has paradoxical effects on inflammatory processes; it is characterized by increased macrophage and CD4 helper T-cell activation, resulting in accelerated inflammation, but immune response to antigen challenges such as tuberculin is suppressed. This paradoxic state of simultaneous hyper- and hypoactivity is suggestive of a state of anergy. The anergy may also be responsible for the increased risk of infections and cancer. The regulatory T-lymphocytes in the periphery of sarcoid granulomas appear to suppress IL-2 secretion, which is hypothesized to cause the state of anergy by preventing antigen-specific memory responses.While TNF is widely believed to play an important role in the formation of granulomas (this is further supported by the finding that in animal models of mycobacterial granuloma formation inhibition of either TNF or IFN-γ production inhibits granuloma formation), sarcoidosis can and does still develop in those being treated with TNF antagonists like etanercept. B cells also likely play a role in the pathophysiology of sarcoidosis. Serum levels of soluble human leukocyte antigen (HLA) class I antigens and angiotensin converting enzyme (ACE) are higher in people with sarcoidosis. Likewise the ratio of CD4/CD8 T cells in bronchoalveolar lavage is usually higher in people with pulmonary sarcoidosis (usually >3.5), although it can be normal or even abnormally low in some cases.
The latter can lead to changes in body temperature, mood, and prolactin (see the endocrine and exocrine section for details). Endocrine and exocrine
Prolactin is frequently increased in sarcoidosis, between 3 and 32% of cases have hyperprolactinemia this frequently leads to amenorrhea, galactorrhea, or nonpuerperal mastitis in women. It also frequently causes an increase in 1,25-dihydroxy vitamin D, the active metabolite of vitamin D, which is usually hydroxylated within the kidney, but in sarcoidosis patients, hydroxylation of vitamin D can occur outside the kidneys, namely inside the immune cells found in the granulomas the condition produces. 1,25-dihydroxy vitamin D is the main cause for hypercalcemia in sarcoidosis and is overproduced by sarcoid granulomata. Gamma-interferon produced by activated lymphocytes and macrophages plays a major role in the synthesis of 1 alpha, 25(OH)2D3. Hypercalciuria (excessive secretion of calcium in ones urine) and hypercalcemia (an excessively high amount of calcium in the blood) are seen in <10% of individuals and likely results from the increased 1,25-dihydroxy vitamin D production.Thyroid dysfunction is seen in 4.2–4.6% of cases.Parotid enlargement occurs in about 5–10% of cases. Bilateral involvement is the rule. The gland is usually not tender, but firm and smooth. Dry mouth can occur; other exocrine glands are affected only rarely. The eyes, their glands, or the parotid glands are affected in 20–50% of cases.