Immunosuppressive drug-free operational immune tolerance in human kidney transplants recipients. Part II. Non-statistical gene microarray analysis.

Kidney transplant is the reference treatment for patients with end-stage renal disease, but patients may develop long-term rejection of the graft. However, some patients do not reject the transplant, but instead are operationally tolerant state despite withdrawal of immunosuppressive treatment. In this second article we outline a microarray-based identification of key leader genes associated respectively to rejection and to operational tolerance of the kidney transplant in humans by utilizing a non/statistical bioinformatic approach based on the identification of "key genes," either as those mostly changing their expression, or having the strongest interconnections. A uniquely informative picture emerges on the genes controlling the human transplant from the detailed comparison of these findings with the traditional statistical SAM (Tusher et al. 2001 Proc Natl Acad Sci USA 98:5116-5121) analysis of the microarrays and with the clinical study carried out in the accompanying part I article.