Which of the following statements best explain why mycophenolate mofetil is currently substituted for azathioprine to prevent rejection in solid organ transplantation?
A 42-year-old woman undergoing heart transplant received mycophenolate mofetil, cyclosporine, and prednisone before surgery.
A. Its immunosuppressant activity is definitely superior to that of azathioprine B. It has significantly less adverse effects than azathioprine C. It has drastically reduced the risk of graft versus host disease D. It selectively inhibits macrophage-mediated production of several interleukins E. It selectively inhibits antigen recognition by antigen presenting cells
It has significantly less adverse effects than azathioprine-answer: b(hardman, pp 1471, koda-kimble, pp 35-7)mycophenolate mofetil is a prodrug which is biotransformed into mycophenolic acid.this active metabolite inhibits inosine monophosphate dehydrogenase, an enzyme involved in the denovo pathway of purine biosynthesis. however, unlike azathioprine, it does not inhibit enzymes involvedin the salvage pathway of purine or pyrimidine biosynthesis and, therefore, it selectively inhibit theproliferation of lymphocytes (including b and t lymphocytes) because these cells lack the enzymes ofthe alternative salvage pathway. because of this, mycophenolate mofetil is cytotoxic only forlymphocytes, whereas azathioprine is cytotoxic for all rapidly growing cells. this explains why the drughas significantly less adverse effects than azathioprine.a) the immunosuppressant activity of mycophenolate and azathioprine is roughly the same since bothdrugs are able to kill b and t lymphocytes.c) graft versus host disease is a disease that occurs after stem cell transplantation, not after solid organtransplantation.d) mycophenolate mofetil has negligible effects on macrophages since these cells can utilize thesalvage pathway for purine biosynthesis.e) mycophenolate mofetil has no effect on antigen presenting cells.