[1700] Significance of Isolated Intimal Arteritis (v1) in Kidney Transplants: A Multicenter Observational Study

Banu Sis, Serena Bagnasco, Belinda Lategan, Mark Haas, Parmjeet Randhawa, Lynn Cornell, Alex Magil, Michael Kuperman, Andrew Herzenberg, Kotaro Sasaki, Ian Gibson, Edward Kraus. University of Alberta, Edmonton, Canada

Background: Microarray studies of kidney transplant biopsies identified few isolated v-lesions (intimal arteritis) with no/minimal tubulointerstitial inflammation and low expression of T cell transcripts, questioning whether these cases reflect true rejection (AJT 2007).
We investigated the clinical significance of isolated v1 lesions in 266 kidney transplants performed between 1999 and 2010 in seven transplant centers in North America.
Design: We studied clinical parameters and graft survival (median follow-up after biopsy 44 months) in 100 isolated v1 biopsies (v1 and i<2 and t<2; group 1), in comparison to 90 biopsies with v1 plus high tubulointerstitial inflammation (v1 and i≥2 and t≥2; group 2) and 91 biopsies with v0 with minimal tubulointerstitial inflammation (v0 and i<2 and t<2; group 3). Biopsies with C4d positivity or from ABOi or cross-match positive kidneys were excluded. In selection of controls, no clinical parameter was matched (not to introduce bias). The biopsies were reviewed by a central pathology committee. Biopsies that met the aforementioned histopathology criteria and performed within 2 months of isolated v1 biopsies were selected as controls.
Results: Patient demographics and maintenance immunosuppresion were not different among study groups. The median post transplant time was 29 days in isolated v1, 33 days in group 2, and 21 days in group 3 biopsies (p>0.05). Indication for biopsies differed among groups: delayed or slow graft function triggered biopsies in 24% of isolated v1 group, but was uncommon in control groups (5% in group 2, 11% in group 3) (p<0.05). Acute deterioration of renal function triggered biopsies in 45% of isolated v1 group, 56% of group 2, and 44% of group 3. Serum creatinine at biopsy, 1 month and 6 month post biopsy did not differ among groups. Graft survival also did not differ among groups.

Conclusions: We conclude that, 1) isolated v1 biopsies are seen early and associated with delayed graft function; 2) v1 with or without high tubulointerstitial inflammation is not related to increased graft failure compared to v0. Thus, isolated v1 lesions, after the exclusion of antibody-mediated rejection, are of two types: T cell-mediated rejection and endothelial injury, and have no independent prognostic significance following anti-rejection treatment.
Category: Kidney (does not include tumors)

Tuesday, March 20, 2012 11:15 AM

Platform Session: Section H, Tuesday Morning


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