The Collaborative Transplant Study originated from the need to gain further insight into the complex problems and risks involved in human organ transplantation. It is based on the voluntary cooperation of transplant centers from around the world. The study was initiated in 1982 by Gerhard Opelz in Heidelberg. After his retirement at the end of February 2015, Caner Süsal took over its coordination until September 2021. Since then, Hien Tran and the CTS staff in Heidelberg have been coordinating the CTS.

The study's aims are strictly scientific. The philosophy behind it is that the knowledge-gaining process can be accelerated by combining the experience of many, especially with respect to complex interactions of factors and the analysis of rare events. Aside from maintaining a transplant registry, the CTS conducts various prospective and retrospective studies on particular research topics.


With the active support of more than 400 transplant centers in 42 countries, the CTS is one of the largest international voluntary studies in the field of medicine. Data sets to more than 800,000 for kidney, heart, lung, liver, and pancreas transplants have been collected. This wealth of data has provided invaluable insights into transplantation-related problems.

The study is coordinated from the Institute of Immunology of the Heidelberg University, Germany. The Heidelberg CTS team includes physicians, immunologists, computer scientists, statisticians and laboratory staff.

Research Topics

Research topics within the CTS project include:

Publication of Results

Results are reported in the periodic CTS Newsletters and in scientific publications. As a feature of the website we are providing a collection of graphs showing analysis results based on subsets of CTS data.

Participants are welcome to contact us with ideas for research projects with CTS data.


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