[The role of vitamin D in the formation of granuloma and in calcium metabolism].
BACKGROUND
Affection of the abdominal organs with sarcoidosis is a part of the generalized granulomatous diseases with clinical manifestations that vary depending on the affected organ.
Formation of granuloma represents a response of the host immune system to different antigen stimuli and it represents an attempt of the host to block the endogenous or exogenous irritant. The active form of vitamin D-1,25-dihydroxyvitamin-D (1,25-D) has an important function in formation of granuloma.
As for the abdominal region, sarcoidosis is most frequently clinically manifested by liver and/or spleen enlargement (20-30% of the affected patients). However, granulomatous infiltrations may also be present along with normal sized organs. Other abdominal localizations are significantly less frequent.
Calcium metabolism disorder represents a significant problem in patients affected with sarcoidosis, particularly in extrapulmonary, chronic forms of the disease. It develops as a result of complex metabolic processes consequential to increased level of 1,25-D and it is considered to be a parameter of granuloma activity (physiological blood value is up to 45 pq/ml). An increased level of provitamin D initiates osteoclast activity that causes bone resorption, which represents a factor of osteoporosis that results in hypercalcemia and hypercalciuria.
Increased calcium release into blood results in production of calcium deposits in the soft tissues and certain organs and thus calculosis develops. It is clinically most frequently manifested as renal calculosis, which is approximately 20 times more frequent in patients affected with sarcoidosis in comparison to general population.


CONCLUSIONS
Examinations of abdominal organ involvement should be a standard procedure in each patient affected with sarcoidosis.
Skodrić-Trifunović
Vesna
V
Klinicki centar Srbije, Beograd, Institut za plućne bolesti i tuberkulozu.
Vucinić-Mihailović
Violeta
V
D002118:Calcium / Q000378:metabolism*; D006099:Granuloma / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D007669:Kidney Calculi / Q000378:metabolism; D012507:Sarcoidosis / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D014807:Vitamin D / Q000502:physiology*
D014807:Vitamin D; D002118:Calcium