The leukocyte aggregation test (LAT) detects the in vitro adhesion of sensitized, but not nonimmune, recipient leukocytes onto donor kidney cell monolayers. The test specifically detects cell-mediated homograft immunity up to 15 days prior to the appearance of clinical signs or alteration of chemical indexes. The presence of a positive reaction always signified incipient homograft rejection, which was usually controlled by intravenously administered, high-dose methylprednisolone sodium succinate (Solu-Medrol) therapy. There was no instance in which methylprednisolone treatment effectively reversed rejection in the presence of a negative leukocyte aggregation test. One common form of homograft rejection may be characterized by positive LAT results, a cellular infiltrate on the renal biopsy specimen, and sensitivity to methylprednisolone therapy.
Kahan BD, Krumlovsky F, Ivanovitch P, Greenwald J, Firlit C, Bergan J, Tom BH. The Leukocyte Aggregation TestImmunodiagnostic Applications and Immunotherapeutic Implications for Clinical Renal Transplantation. Arch Surg. 1975;110(8):984-990. doi:10.1001/archsurg.1975.01360140128025