Extracellular Ca²⁺ uptake by T cells might help to make a diagnosis of acute rejection

To more non-invasively diagnose acute rejection, we focused on the uptake of extracellular Ca²⁺ by T cells as a result of the activation of Ca²⁺ release activated Ca²⁺ channels. A full thickness of the skin allograft model was established using BN rats as the donors and LEW rats as the recipients, and similar LEW rats as both donors and recipients in the control group. After transplantation, the grafts were staged histopathologically in both rats. The uptake of extaracellular ⁴⁵Ca pre T cell was measured in the macrophage-treated and non-treated groups, and the ratios between the two groups were calculated and the results were compared according to the post-operative day. No histopathological findings of acute rejection were observed in the control group. The allograft model group showed acute rejection histopathologically beginning on day 2 and increased through day 5. The macrophage-treated model/non-treated model ⁴⁵Ca uptake ratio (CAR) was significantly higher in the allograft rats on day 2. No significant difference was observed on day 4. Measuring the uptake of extracellular Ca ²⁺ by recipient T cells using donor macrophages might be useful for making a diagnosis of acute rejection.