Thymic aging begins early, accelerates with puberty and continues at an individual pace. If the thymus shows accelerated aging, its biological age is ahead of chronological age. Thymic aging may be accelerated by various factors including toxic substances, steroid hormones, infections. These can significantly decrease fresh naive T-cell output leading to increased incidence of infections, cancers and autoimmune diseases. Our long-term goal is to establish artificial personalised 3D thymus tissue from peripheral blood that is suitable for both immunology research and medical autologous reimplantation to support immune functions. For this first 3D PCL scaffold is printed then colonised by thymic epithelial cells trans-differentiated from peripheral blood monocytes. This is then seeded with peripheral blood hemopoetic stem cells (CD34+ HSC) differentiated towards T-lineage thus constructing a thymus lobe.