Abstract: Provided herein are methods, compositions, and kits for diagnosing allograft rejection of organ transplants by identifying the presence of anti-endothelial cell antibodies. Such methods and compositions are independent of external confounders such as recipient age, transplant center, assay, cause of end-stage disease, co-morbidities, immunosuppression usage, and the like.

Abstract: In a first aspect, there is provided an isolated polypeptide substrate for a disintegrin-like and metallopeptidase with thrombospondin type-1 motif, 13 (ADAMTS13) that is from 45 to 70 amino acids in length and has an amino acid sequence that is substantially similar to part of the von Willebrand factor A2 domain sequence set forth in SEQ ID NO: 2, with one or more of the following modifications: (i) the amino acid corresponding to position 1599 of SEQ ID NO: 2 is mutated from Q to K; (ii) the amino acid corresponding to position 1610 of SEQ ID NO: 2 is mutated from N to C; and (iii) the amino acids corresponding to Q1624 to R1641 of SEQ ID NO: 2 are deleted.

Abstract: The present invention provides a novel assay for detecting human antibodies specific for a platelet factor 4 (PF4)/heparin complex in a fluid sample. The assay utilizes an immobilized PF4/polyanion complex and an anti-human antibody conjugated to a non-particulate fluorescent dye to capture and detect human PF4/heparin antibodies. Various devices, methods and systems based on the disclosed PF4/heparin assay are also provided.

Abstract: In a first aspect, there is provided an isolated polypeptide substrate for a disintegrin-like and metallopeptidase with thrombospondin type-1 motif, 13 (ADAMTS13) that is from 45 to 70 amino acids in length and has an amino acid sequence that is substantially similar to part of the von Willebrand factor A2 domain sequence set forth in SEQ ID NO:2, with one or more of the following modifications: (i) the amino acid corresponding to position 1599 of SEQ ID NO: 2 is mutated from Q to K; (ii) the amino acid corresponding to position 1610 of SEQ ID NO: 2 is mutated from N to C; and (iii) the amino acids corresponding to Q1624 to R1641 of SEQ ID NO: 2 are deleted.