Immunophenotyping of Granzyme-B Expressing Lymphocyte Subset in Renal Allograft Recipients with Chronic Allograft Dysfunction

Background: Granzyme-B is a serine proteinase expressed and released mainly by the cytotoxic T and NK cell. Granules intact Granzyme-B is directly delivered into the target cell, while extracellular Granzyme-B, released in serum leads to nonspecific cleavages of extracellular matrix molecules like vitronectin, collagen, TGF-beta, IL-1 and invites systemic inflammation, tissue remodeling and fibrosis leading to the development of chronic renal allograft dysfunction. Objective: We aimed to immunophenotype the Granzyme-B positive T-lymphocyte subset and Granzyme-B role in the development of chronic renal allograft dysfunction. Methods: We have analyzed the Granzyme-B(+)CD8(+)T/CD8(neg) and Granzyme-B(+)CD3(+)/CD3(neg) cell subset by the flowcytometry and serum Granzyme-B level by the enzyme-linked immunosorbent assay. Results: We have found that the frequency of Granzyme-B+ CD8(neg) CD3+T cell, Granzyme-B+ CD8(low)CD3(+)T cell and Granzyme-B+ CD8(high) CD3+T cell subset was significantly lower and serum Granzyme-B level was significantly higher in CAD group. The frequency of CD3+T, CD3neg lymphocyte, CD8(neg) CD3(+)T, CD8(low)CD3(+)T, CD8(high) CD3+T, Granzyme-B+CD3(neg)CD8(neg) lymphocyte was similar between the group. The frequency of CD3(+)CD8(neg)Gzm-B+ cell was negatively correlated with serum creatinine and CD3(+)CD8(high)Gzm-B+ cell was negatively correlated with serum Granzyme-B level. Similarly, Serum Granzyme-B level was positively correlated with serum creatinine, urine proteinuria and negatively with eGFR. Conclusion: The circulating frequency of Granzyme-B+ CD8(neg) CD3(+)T cell, Granzyme-B+ CD8(low)CD3(+)T cell and Granzyme-B+ CD8(high) CD3(+)T cell subsets were significantly lower and serum Granzyme-B level was significantly higher in renal allograft recipients with CAD.