Transplant rejection may occur by both acute and chronic routes, the former involving the recipient's reaction towards non-self, termed allo-reactivity, which manifests itself in an auto-immune-like inflammatory reaction. Untreated, such an inflammatory reaction leads to damage to the implanted tissue, eventually resulting in its rejection.

In current medical practice, acute rejection is initially mitigated by optimizing tissue matching between donor and recipient, combined with administration of aggressive immunosuppressive therapy that inhibits the host's immune response mainly by targeting T cell reactivity.

Transplanted tissues include kidney, liver, heart, lung and pancreas. The most common transplantation procedure is that of kidney, with around 16,000 new procedures performed in the US annually. While prevention of acute kidney rejection has in recent years been dramatically improved, chronic rejection remains a challenge as kidney failure occurs in about 5% of patients annually, extending as long as ten years post transplantation. The main reasons for chronic transplant rejection include nephrotoxicity of immunosuppressive drugs (e.g. calcineurin inhibitors), delayed graft-targeted cytotoxicity, and overall poor kidney function. Chronic graft rejection may be diagnosed by measuring the glomerular filtration rate (GFR) and through kidney biopsy. Though these tests quite accurately predict graft failure, they usually detect it at a relatively late stage when extensive tissue damage has already occurred. Early detection of chronic graft failure before tissue damage has occurred may help physicians administer therapeutics more effectively, minimizing their side effects while prolonging graft survival rates.

ImmunArray's platform technology provides physicians with tools to answer specific questions regarding the patient's condition and monitor his/her response to specific treatment regimens. Moreover, using the iCHIP the physician will be able to detect the graft rejection process prior to the appearance of clinical signs, and monitor this process in individual patients in order to make therapeutic decisions.