The role of circulating donor-specific anti-HLA antibodies (DSA) in the development of accelerated arteriosclerosis have been recently reported in kidney transplant recipients. This study investigated the characteristics of DSA that are associated with the severity of allograft arteriosclerosis.

We enrolled 744 consecutive kidney transplantation performed between January 1, 2004 and January 1, 2010 at Necker Hospital (Paris, France), with systematic assessment of injury phenotype and arteriosclerotic lesions using the vascular fibrous intimal thickening (cv) Banff score on allograft biopsies performed at one year after transplantation. We assessed circulating DSA and their characteristics (specificity, HLA class, mean fluorescence intensity [MFI] and C1q-binding) at six months after transplantation.

We identified 281 patients with cv0 score, 213 patients with cv1 score, 189 patients with cv2 score and 61 patients with cv3 score. The distribution of DSA according to cv score was the following: 47/281 (17%) in cv0 patients, 39/213 (18%) in cv1 patients, 63/189 (33%) in cv2 patients and 28/61 (46%) in cv3 patients. Immunodominant DSA (iDSA) MFI level was positively correlated with the severity of arteriosclerosis (Spearman's rho=0.23, p=0.002), with a mean MFI of 3204.0±3725.2 in cv0 patients, 3760±3598 in cv1 patients, 4892±4676 in cv2 patients and 5541±3892 in cv3 patients. C1q-binding DSA prevalence increased with the severity of allograft arteriosclerosis: 8/281 (3%) in cv0 patients, 6/213 (3%) in cv1 patients, 25/189 (13%) in cv2 patients and 9/61 (15%) in cv3 patients (p<0.001). Patients with C1q-binding iDSA had a higher cv score compared with patients with non-C1q-binding DSA (1.7±1.0 versus 1.3±1.1, respectively, p=0.01). The C1q-binding capacity of DSA was associated with increased microvascular inflammation (p<0.001) and C4d deposition in peritubular capillaries or arteries (p<0.001).

This study shows a biological gradient between DSA MFI level and the severity of allograft arteriosclerosis. The complement-binding capacity of DSA is associated with an increased severity of arteriosclerosis and complement deposition in allograft.

CITATION INFORMATION: Loupy A, Viglietti D, Duong Van Huyen J, Glotz D, Legendre C, Zeevi A, Lefaucheur C. Complement-Binding Donor-Specific Anti-HLA Antibodies Are Associated with Severe Kidney Allograft Arteriosclerosis. Am J Transplant. 2016;16 (suppl 3).

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