A 25-year-old man comes to the office due to a 1-month history of increasing abdominal girth and swollen extremities. His BMI is 32 kg/m². Laboratory evaluation shows decreased serum albumin and hypercholesterolemia, and urinalysis reveals heavy proteinuria and fatty casts. A renal biopsy shows findings consistent with focal segmental glomerulosclerosis. Despite aggressive medical management, the patient requires a kidney transplant from his younger sister, who is a 5 out of 6 HLA antigen match. As a part of his posttransplant immunosuppressive regimen, he takes a medication that inhibits lymphocyte proliferation by directly blocking interleukin-2 signal transduction. This mechanism best describes which of the following drugs?

Question

Quizplus · Accepted Answer

Eductional Objective: Sirolimus binds to the immunophilin FK binding protein (FKBP) in the cytoplasm, forming a complex that binds and inhibits mTOR (mammalian target of rapamycin).  Inhibition of mTOR signaling blocks IL-2 signal transduction and prevents cell cycle progression and lymphocyte proliferation.

A 25-Year-Old Man Comes to the Office Due to a 1-Month