Histological markers of CNI nephrotoxicity: Specific or not specific? Marion Rabant MD, Renaud Snanoudj MD, Virginie Royal MD, C. Girardin, E.Morelon MD PHD, C. Legendre MD, PHD and Laure Hélène Noël MD Pathology department, NECKER Hospital, Paris, France Renal transplantation department, NECKER Hospital, Paris, France

Cyclosporin and Kidney transplantation Calcineurin inhibitor introduced in late 1970s Considerable improvement in graft survival in the short term Not in the long term Transplant Proc 1993; 25:

Acute and chronic nephrotoxicity Long-term use of CsA in heart transplant recipients associated with irreversible and progressive tubulo-interstitial injury and glomerulosclerosis Chronic CNI nephrotoxicity Myers et al. New Engl J Med 311: , 1984  Vascular effects Arteriolar hyalinosis Pearl Necklace pattern  Tubulo-interstitial effects Striped fibrosis  Glomerular effects FSGS Glomerulosclerosis

N=119 Renal Biopsies=959 Chronic CNI nephrotoxicity 100% after 10 years Nankivell BJ et al. New Engl J Med 2003 …BUT NO CONTROL GROUP WITHOUT CNI And small number of biopsies at 10 years

Material and methods (1) Retrospective analysis N= Renal Biopsies M3, M24, 10 years Updated Banff 97 classification Induction therapy 50% Steroids Azathioprine 2mg/kg/d N=93 CONTROL GROUPCyclosporine (CSA) GROUP N=48 Induction therapy 85% Steroids Azathioprine CsA

Material and methods (2) Demographics Chronic histological parameters IF/TA (0 to III) Arterial fibrous intimal thickening (cv0 to cv3) Arteriolar hyalinosis (ah0 to ah3) Pearl Necklace-like pattern ** Sub-endothelial deposits * Renal function (MDRD) and graft survival CSA doses and blood trough levels * **

Demographics ControlCsAp-value Recipientsn=93n=48 Sex, n (% male)55 (59.1%)36 (75%)0.058 Age, years33.6± ± First transplant93.6%89.6%0.38 CIT, hours21.7 ± ±6.5<0.001 Nephropathy0.9 Glomerulonephritis TI nephritis PKD Other or unknown PRA, mean ±SD20.6 ± ± Donors Deceased/Living donor, n (%) 81(87.1)/12(12.9 ) 47(97.9)/1(2.1)0.018 Age, years28.4 ± ± Total HLA mismatch2.2 ± ±1.8<0.0001

INTERSTITIAL FIBROSIS/TUBULAR ATROPHY 0% 20% 40% 60% 80% 100% p= Months 24.1% 34.1% 0% 20% 40% 60% 80% 100% 24 Months p= % 53.7% 0% 20% 40% 60% 80% 100% CTRL N=98 CsA N=43 10 years p= % 79.2% p=0.013 p=0.016 p< Mean IF/TA CTRLCsA

FIBROUS INTIMAL THICKENING 3 months p=0.34 0% 20% 40% 60% 80% 100% 48.7% 58.3% 24 months p= % 20% 40% 60% 80% 100% 60.5% 79.5% CTRL n=98 CsA n=43 10 years p= % 20% 40% 60% 80% 100% 73.7%88.6% 0.7      1.1 p=0.59 p=0.07 p=  1.0 CTRLCsA No difference Mean cv

CTRL (n=93) CsA (n=48) 3 Months 10 years 0% 20% 40% 60% 80% 100% 48.1%78.0% 24 Months ARTERIOLAR HYALINOSIS 0.4  0.6 p=   0.7 p=   1.0 p< CTRLCsA Mean ah 32.2% 0% 20% 40% 60% 80% 100% 34.1% p=0.8 p=0.001 p= Months 10 years 24 Months 0% 20% 40% 60% 80% 100% 65.5% 92% 35% 8%

% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% CTRL CsA 3 mo.24 mo.10 yr. Sub-endothelial deposits Muscular deposits p<0.01ns Muscular and sub-endothelial deposits ns mo.24 mo.10 yr. CTRL CsA 8.0% (7) 6.8% (3) 13.6% (11) 36.6% (15) 28.0% (26) 68.8 % (33) p<0.005 p<0.001 % of patients with CNI arteriolopathy (n) p=0.8 Muscular deposits 3 mo.24 mo.10 yr. More frequent in hypertension patients

Renal function and graft survival Graft loss CsA Graft loss Control Death CsA Death Control Time post-transplantation in months Cumulative probability of graft loss and death Factors associated with graft loss: CsA Male sex CIT>20 hrs Factors associated with lower eGFR at 10 y: Hypertension Acute rejection CsA No correlation between progression of histological lesion and CsA exposure

In conclusion First study comparing biopsies from CNI and non CNI treated patients in the long term Chronic lesions in the CsA group more frequent and severe…but also present in the control group CNI arteriolopathy (muscular deposits) not specific neither constant after 10y of CsA exposure Use great caution before concluding « CNI nephrotoxicity »