The trial is an observational, multi-center study to determine if a new blood test (Immunobiogram®) done after renal transplant can help predict how well the immune system is working and responding to a new kidney. These blood tests could, in the future, potentially guide how doctors manage patient's anti-rejection medication.

Rejection in renal transplants is a major problem unsolved in the long term, as 30-50% of patients lose their kidney due to rejection, or rejection mechanisms are involved elsewhere. One of the presumed key factors that may deliver such bad outcomes is the difficulties to personalise immunosuppressive treatment; a medical need that currently relies on immunosuppressive levels for some medications (pharmacokinetics), clinical guideline recommendations, adverse events profiles and some expensive biomarkers which are not widely used. Immunobiogram® (IMBG) is a tool that evaluates the sensitivity/resistance profile of patients to each of the most widely used and representative immunosuppressant drugs (IM). Thus, IMBG offers information that could become pivotal in clinical management of renal transplanted patients, if its potential benefits are proven. In this clinical study, a technology validation will be performed in which the robustness of the bioassay will be evaluated; and a correlation between the current clinical prognoses of each patient and resistance patterns will be explored.

Inclusion Criteria:

• Age > 25 years and < 70 years.
• Male and Female.
• Renal transplant performed at least 1 year before inclusion.

ARM 1:

• Bad clinical evolution: patients with renal dysfunction and positive biopsy to rejection OR significant increase in strength of DSA expressed as Luminex MFI. Specifically, the following two criteria must comply:

  • Renal function progressive deterioration, with significant creatinine increase of at least 15% for 18 months and/or proteinuria over > 500 mg/day or ratio protein/creatinine> 500 mg/g DE NOVO or increase in 50%.
  • Biopsy in the last 12 months that shows positive signs attributable to any kind of immunological response compatible with any type of rejection AND/OR at least 50% increase in strength of DSA expressed as Luminex MFI in comparison with previous determination and always at titers more than 3000UI.

• Good clinical evolution: patients without rejection episodes, negative DSA, stable renal function and no changes in treatment in the past 12 months. ALL the following criteria must apply

  • Stable renal function in the past 12 months
  • NO DSA titers
  • No history of previous rejection episodes
  • Stable immunosuppressive medication (No change in prednisone or MPA dose and tacrolimus dose with changes <20% of the dose) in the past 12 months

ARM 2:

• Stable renal function
• No DSA titers
• No history of previous rejection episodes
• Stable immunosuppressive medication (No change in prednisone or MPA dose and tacrolimus dose with changes <20% of the dose) at least in the past 18 months

Exclusion Criteria:

• Rejection of informed consent
• Active systemic infections that needed antimicrobial treatment in the past two months
• Active immune-based diseases with acute outbreaks in the past 12 months, despite immunosuppressive treatment
• Severe ischemia-reperfusion injury of current renal transplant with delayed graft function objectively evident at more than 20 days after transplant AND/OR kidney transplanted from a deceased, very elderly donor (>80 years)
• Double transplant (renal + another organ)
• HIV, HBV, HCV infection or other severe infectious diseases that prevent blood samples from being processed in a conventional laboratory
• Chronic Allograft Injury (CAI) unlikely related to immune processes, by the Investigator´s judgement
• Recurrent primary kidney disease

Male and female subjects <25 to < 70 years in age who have had a renal transplant performed at least one year before inclusion in the study