Imlifidase Prior to Kidney Transplant in Highly Sensitised Children

The goal of this clinical trial is to learn about the efficacy and safety of imlifidase in highly sensitized paediatric patients, 1-17 years old, with end stage renal disease (ESRD). The main questions it aims to answer are: * Does imlifidase treatment result in crossmatch conversion that enables transplantation? * How is the function of the transplanted kidney? The participants will be hospitalised in accordance with the normal routines for transplanted patients. The patients will receive medication to prevent rejection of the donor kidney, and because such treatment make the body more vulnerable medications to prevent infections.