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Doctor Office


Why do people need a kidney transplant?

When the kidneys stop working - mostly due to the consequences of high blood pressure and diabetes - a kidney replacement therapy is needed. For patients without uncontrolled infectious disease or oncologic disease who are well enough to take the surgery, kidney transplantation is the treatment of choice.

What are immunosuppressive drugs?

Immunosuppressive drugs reduce the function of your body’s defense system - the immune system. This is called immunosuppression. These drugs are necessary to prevent the immune system to recognize the kidney transplant as foreign and attack it leading to damage (rejection).

What is Torque Teno virus (TTV)?

The Torque Teno Virus is a unique virus. It replicate in human cells and can be found in the blood of almost all humans. In contrast to many other viruses it causes no disease.

How can TTV quantification help patients with a kidney transplant?

TTV levels increased with the amount of the immunosuppression.  Therefore we use it as an indicator how well the immune system is working: an ‘Immunometer’. Low TTV levels would suggest a rather active immune system, whereas high levels would indicate that the immune system is slowed down. Using TTV as an ‘Immunometer’ we try to guide and optimize immunosuppression after kidney transplantation and thus reduce infection and rejection.

How is TTV measured?

TTV is quantified by a simple routine method that is called PCR (polymerase chain reaction). This method allows for the detection of TTV in a very small amount of blood after a simple routine blood draw.

What is a clinical trial?

A clinical trial is performed in a group of patients for whom a novel treatment or intervention is believed to be beneficial. Usually the patients are divided into two groups, one of them receiving the standard and the other the experimental care. After completion of the trial the groups are compared and researchers analyze who performed better.

Why is a clinical trial needed?

We believe that the quantification of TTV in the blood of kidney transplant recipients gives us a better idea of the actual state of the immune system than routine measurements do. A clinical trial is the only and best method to prove our hypothesis that immunosuppression guided by TTV is both useful and safe.

How can I participate in the clinical trial?

If you recently received a kidney transplant and your transplant centre is listed among the recruiting centres you might be eligible for the trial. In this case, you should refer to your treating transplant physician who can provide you with further information.

Can my health care provider use TTV already?

Yes, there are already some laboratories offering TTV quantification and your health care provider can send your samples there to assess the TTV load. However, the benefit of TTV measurement has not been proven yet and TTV has not entered clinical routine.

How can my health care provider learn more about it?

An increasing number of articles, published in scientific journals, address general and specific questions concerning the value of TTV in clinical routine. Our webpage offers additional information. Moreover we will provide all project specific findings on the webpage and on scientific conferences. Details concerning scientific meetings will be announced via the webpage.


How do I learn about the project results?

The results will be distributed via a broad range of media. Communication will include social media, patients’ societies and the project webpage. The results will be posted on a database ( and can be accessed by you under the EU CT number: 2022-500024-30-00.

Who is behind the project?

The project is coordinated by the Medical University of Vienna, Austria and funded by the European Commission. The consortium of the TTV GUIDE TX project includes 19 partners from 7 European countries. Leading European clinical virologists, transplant nephrologists, trial manager and ethicists have teamed up with the healthcare industry. The clinical trial will involve 13 recruiting centres in Austria, Germany, the Netherlands, Spain, the Czech Republic and France.

 for patients transplanted at recruiting centres
Why are there two groups in the trial?

Two groups are needed to assess if Torque Teno virus (TTV)-guided immunosuppression (active group) is safe and effectve compared to the standard treatment (control group). Study particants are randomly assigned to receive either guidance of their immunosuppression by TTV or according to standard of care.


Do I know if I get the TTV guided trial group or in the control group?

No, to avoid potential bias, the participants do not know if they are receiving the TTV-guided treatment or the conventional one. If participants would learn about their assignement they, they might act differently and thus influence the outcome of the trial

Is there any physical intervention?

The only trial specific intervention is the withdrawal of a small amount of blood if routine laboratory test are performed. Therefore no additional vein puncture is necessary.

Do I have to come more often to my transplant centre?

No, the trial does not involve additional visits besides the routine visits.

What do I have to do during the trial?

It is important that you take part at the trial visits and take your immunosuppressive drugs regularly. You should also inform your trial team about any changes in your medications, side effects and infection or organ rejection treated outside the trial centre.​

How am I insured?

As soon as you enter the trial, you will be covered by a specific trial-related insurance.

Do I get any payment?

You can claim travel costs. There will be no additional financial compensation.

Whom can I contact during the trial?

You will be provided with a trial ID card including all contact details of your trial team.

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