Radioimmunologic identification and evaluation of local xenogenic graft versus host (GVH) reactions

A radionuclide method was developed to evaluate a local GVH reaction. 5-20x106 mononuclear cells prepared from 15 healthy blood donors were injected into the abdominal skin of 15 partially immunosuppressed rats. 48 hours later, 0.5 mCi of [Tc-99m] sodium pertechnetate was injected and local GVH reactions were evaluated from nodules on inverted skins that were imaged and analyzed by a portable gamma camera interfaced with mini computer. There was an excellent visualization of positive GVH reaction with greater than 5x106 mononuclear cells, and there was also good correlation between inoculated cell numbers and radioactive count density ratios, providing objective standardization for the grading of positive reactions