The early diagnosis of kidney graft rejection with radioactive autologous bloodplatelets; importance of cell viability

This study concerns the possible suitability of gamma camera scintigraphy after injection of 111In-labelled autologous thrombocytes as an early diagnostic method for the initial events of kidney graft rejection. The maintenance of cell function and viability after cell labelling appeared to be essential for the adequate interpretation of the results of subsequent in vivo measurements. Thrombocytes labelled according to the described procedure showed a normal collagen induced aggregation pattern and normal behaviour in vivo. A small group of individuals with well functioning kidneys, transplanted 4 - 6 months before, served as a control group. The transplanted kidneys could always be located on the scintigram taken 24 hours after 111In-thrombocyte injection. Increased accumulation of radioactive thrombocytes in the graft was observed in patients with clinical and biochemical signs of graft rejection. After adequate therapy, this accumulation decreased towards normal values. Concomitantly a reduced survival of circulating labelled platelets was found in periods with high kidney radioactivity and vice versa. However, in order to assess the value of the technique as an early indication of graft rejection more frequent measurements (i.e. 2 - 3 times a day) are necessary. A method using a portable crystal detector is now under investigation. Finally, it might be possible with this method to discriminate between various clinical courses (i.e. the type of rejection) after transplantation. (author)