Sphingosine-1-phosphate receptor modulators are a class of drugs used as immunomodulators, most notably in cases of multiple sclerosis. These drugs have the ability to modulate the G-protein coupled S1P receptors. Drugs that modulate S1P1 receptors bind to those receptors in lymph nodes and prevent certain lymphoid immune cells from being excreted into the blood and reaching the central nervous system (CNS), leading to lymphopenia.
