WHICH TRANSPLANTED ORGAN HAD THE FIRST EVER CONSENSUS CLASSIFICATION ON ORGAN REJECTION AND PATHOLOGY ?
Most of you said "Kidney". Perhaps we shouldn't be that "nephrocentric". In a recent history related paper in Kidney International, Dr.Kim Solez et al discuss the history of the Banff classification and how it came about.
The need was as early as 1991 when the classification began. Kidney transplant pathology had no mentors and no classifications. The first consensus guidelines that came for any organ was heart allograft rejection and that served as a model for the Banff Kidney transplant classification. There began the history of pathology behind the kidney transplant. So the historically accurate answer is the "heart".