CYP27B1 and Hypercalcemia: Therefore, although immune cell Cyp27b1, in contrast to renal Cyp27b1, is not regulated by the factors controlling calcium and phosphate homeostasis, increased Cyp27b1 expression in macrophages can result in elevated circulating 1,25(OH)2D levels in granulomatous diseases such as sarcoidosis, which may lead to hypercalcemia.(66)