25-Hydroxycholesterol is a potent and selective suppressor of IgA production by B cells wit EC50 about 65 nM.

Dihydrocholesterol is a cholesterol derivative found in human feces, gallstones, eggs and other biological matter, it could reduce plasma cholesterol by inhibiting the cholesterol absorption and increasing the fecal sterol excretion.

Cholesterol is the major sterol in mammals, and its importance in fundamental cellular processes is becoming more appreciated.