This is a primary response or a first-set rejection .
Platelets aggregate and blood clots in the vessels, reducing blood flow to the graft.
In transplanted skin, lymphocytes and monocytes accumulate at the base of the graft. I disparate, donor T cells can attack all nucleated cells and cause a wasting syndrome. GVHD and rejection are treated with immunosuppression. Its principal activity is inhibition of helper T cells. Systemic immunosuppression of pregnant female is controversal.