Elevated Matrix Metalloproteinase Type 9 (MMP-9) Transcripts After Thymoglobulin Induction in Incident Kidney Transplant Recipients

Matrix metalloproteinase type 9 (MMP-9), which cleaves collagen type IV in basal membranes, has been associated with the progression of chronic kidney disease. The objective of the present study was to evaluate the characteristics of donors, recipients, induction therapies, and allograft function on MMP-9 transcripts from mononuclear cells in kidney transplant recipients. Transcripts were determined in peripheral blood mononuclear cells from 67 incident renal transplant recipients eight days post-transplant using quantitative real-time PCR and quantified using the ΔΔCq method. Median MMP-9 transcripts were 6.1 (IQR, 1.5 to 66.5, N = 4) in AB0-incompatible donor transplants; 3.2 (IQR, 2.0 to 16.9, N = 17) in living donor transplants; and 4.2 (IQR, 2.3 to 9.2, N = 46) in deceased donor transplants (<i>p</i> = 0.8). Importantly, renal transplant recipients who were treated with thymoglobulin had significantly higher median MMP-9 transcripts compared to all other induction therapies (14.5; IQR, 2.8 to 31.9, N = 10; vs. 3.5, IQR, 2.2 to 8.8, N = 57; <i>p</i> = 0.01). Median MMP-9 transcript levels were similar in recipients with delayed allograft function and immediate allograft function (8.86; IQR, 5.29 to 11.57, N = 7; vs. 3.4; IQR, 2.35 to 9.49, N = 60; <i>p</i> = 0.245). Induction therapy with thymoglobulin causes significantly higher MMP-9 transcripts in peripheral blood mononuclear cells, probably indicating an increased inflammatory response.