Table S2: Comparison between patients that had or did not have a change in estimated glomerular-filtration rate ≥ 10 mL/min/1.73 m

(1)

Table S1: Comparison between patients that had or did not have a change in estimated glomerular-filtration rate ≥ 5 mL/min/1.73 m

²

at 3 months post-conversion to belatacept.

Improvement in eGFR ≥5 mL/min/1.73 m² at 3 months post-conversion to belatacept No improvement in eGFR

≥5 mL/min/1.73 m² n = 135

Improvement in eGFR ≥5 mL/min/1.73 m²

n = 84

p- value

Recipients’ gender: male 94 (69.6%) 61 (72.6%) 0.65

Recipients’ age (years) 56.24 ± 12.9 53.7 ± 15.2 0.19

Initial kidney disease Glomerulopathy Interstitial nephropathy Diabetes mellitus and/or nephroangiosclerosis Genetic disease Other

53 (39.3%) 22 (16.3%) 26 (19.3%) 20 (14.8%) 14 (10.4%)

27 (32.1%) 13 (15.5%) 17 (20.2%) 11 (13.1%) 16 (19%)

0.46

Duration of dialysis before kidney

transplantation (months) 40.4 ± 33.4 37.4 ± 35.9 0.52

Rank of transplantation Preemptive transplantation

1.2 ± 0.47 11 (8.1%)

1.2 ± 0.5 14 (16.7%)

0.8 0.08 Donors’ characteristics

Deceased donor

Cause of death: vascular/non-vascular Extended-criteria donor

Gender: male Donor’s age (years) Cold ischemia time (min)

102 (75.6%) 73 (72.3%)/28 (27.7%)

59 (43.7%) 61 (45.2%) 58.3 ± 14.5 874.5 ± 554.6

65 (77.4%) 45 (69.2%)/20 (30.8%)

39 (46.4%) 49 (59.0%) 58.6 ± 16.4 944.7 ± 585.1

0.74 0.72 0.67 0.052

0.89 0.37 Virological status

Recipient EBV seropositive

EBV donor positive/recipient negative Recipient CMV seropositive

CMV donor positive/recipient negative

130 (96.3%) 5 (3.7%) 78 (57.8%) 29 (21.5%)

83 (98.8%) 1 (1.2%) 46 (54.8%)

21 (25%)

0.41 0.41 0.58 0.62 Immunological recipients’ status

Anti-HLA antibodies at KT DSA at KT

DSA at conversion

34 (25.2%) 13 (9.6%) 22 (16.3%)

31 (37.3%) 12 (14.3%) 13 (15.5%)

0.07 0.28

>0.99

Delayed graft function * 30 (22.2%) 26 (31%) 0.33

Immunosuppressive therapy Induction therapy at KT Type of induction therapy

Anti-interleukin-2 receptor blocker Polyclonal antibodies

None Unknown

CNIs before conversion to belatacept Cyclosporine A/ Tacrolimus

129 (95.6%) 103 (76.3%) 26 (19.3%)

6 (4.4%) 0 (0%) 120 (88.9%) 22 (18.3%)/98 (81.7%)

76 (90.5%) 59 (70.2%) 17 (20.2%) 7 (8.3%) 1 (1.2%) 79 (94%) 16 (20.3%)/63 (79.7%)

0.16 0.31

0.23 0.85 Acute-rejection episode before

conversion to belatacept Type of acute rejection

27 (20%) 15 (17.9%) 0.73

0.44

(2)

Abbreviations: eGFR, estimated glomerular-filtration rate; EBV, Epstein--Barr virus; CMV, cytomegalovirus; HLA, human leukocyte antigen; DSA, donor-specific antibodies; KT, kidney transplantation; mTORi, mammalian target of rapamycin inhibitor; IFTA, interstitial fibrosis tubular atrophy.

*Delayed graft function was defined as the need for at least one dialysis session within the first week posttransplantation.

Antibody-mediated rejection Both

3 (11.1%) 4 (14.8%)

4 (26.7%) 2 (13.3%) Kidney biopsy before conversion

Sclerotic glomeruli Glomeruli (g)

Interstitial infiltration (i) Tubulitis (t)

Intimal arteritis (v)

Peritubular capillaritis (ptc) Chronic glomerulopathy (cg) Interstitial fibrosis (ci) Tubular atrophy (ct) Intimal fibrosis (cv)

Arteriolar hyaline thickening (ah) Mesangial matrix thickening (mm) IFTA

Positive C4d staining

1 [0-22]

0 [0-3]

1 [0-3]

0 [0-3]

6 (5.9%)

1 [0-11]

0 [0-2]

0 [0-3]

0 [0-2]

0 [0-3]

1 [0-3]

0 [0-3]

1 [0-3]

9 (13.8%)

0.27 0.52 0.36 0.56 0.67 0.53 0.37 0.48 0.63 0.28 0.85 0.51 0.03 0.1 Conversion to belatacept

Time from KT to conversion (months)

Conversion <3 months posttransplantation

Serum creatinine level at conversion (µmol/L)

eGFR at conversion (mL/min/1.73 m²)

Proteinuria at conversion (g/g of urine creatinine)

Chronic kidney-disease stage at conversion

≥60 mL/min/1.73 m²

45≤ eGFR <60 mL/min/1.73 m² 30≤ eGFR <45 mL/min/1.73 m²

<30 mL/min/1.73 m²

22.2 [0.8-337.1]

13 (9.6%) 228.2 ± 122.5

32.3 ± 16.3 0.2 [0-6.6]

6 (4.4%) 21 (15.6%) 37 (27.4%) 71 (52.6%)

18 [0.1-253.9]

19 (22.6%) 241.7 ± 152.6

31.5 ± 16.5 0.2 [0-5.1]

6 (7.1%) 8 (9.5%) 25 (29.8%) 45 (53.6%)

0.15 0.01 0.47 0.72 0.55 0.52

(3)

Table S2: Comparison between patients that had or did not have a change in estimated glomerular-filtration rate ≥ 10 mL/min/1.73 m

²

at 3 months post-conversion to belatacept.

Improvement in eGFR ≥10 mL/min/1.73 m² at 3 months post-conversion to belatacept No improvement in eGFR

≥10 mL/min/1.73 m² n = 171

Improvement in eGFR

≥10 mL/min/1.73 m² n = 48

p-value

Recipients’ gender: male 121 (70.8%) 34 (70.8%) >0.99

Recipients’ age (years) 56 ± 13.2 52.8 ± 16 0.17

65 (38%) 26 (15.2%) 33 (19.3%) 27 (15.8%) 20 (11.7%)

15 (31.3%) 9 (18.8%) 10 (20.8%)

4 (8.3%) 10 (20.8%)

0.34

Duration of dialysis before kidney

transplantation (months) 38.6 ± 33.3 41.7 ± 38.1 0.57

1.2 ± 0.46 16 (9.4%)

1.25 ± 0.54 9 (18.8%)

Deceased donor

Cause of death: vascular/non- vascular

Extended-criteria donor Gender: male

Donor’s age (years) Cold ischemia time (min)

130 (76%) 88 (51.5%)/41 (24%)

78 (45.6%) 83 (50%) 58.8 ± 14.9 903.7 ± 577.1

37 (77.1%) 30 (62.5%)/7 (14.6%)

20 (41.7%) 27 (57.4%) 57 ± 16.6 893 ± 530.5

0.84 0.15

0.74 0.41 0.47 0.91 Virological status

Recipient EBV seropositive EBV donor positive/recipient negative

Recipient CMV seropositive CMV donor positive/recipient negative

165 (96.5%) 5 (2.9%) 97 (56.7%) 39 (22.8%)

47 (97.9%) 1 (2.1%) 27 (56.3%) 11 (22.9%)

>0.99

>0.99 Immunological recipients’ status

DSA at conversion

47 (27.5%) 19 (11.1%) 29 (17.0%)

18 (38.3%) 6 (12.5%) 6 (12.5%)

0.15 0.79 0.60

Delayed graft function * 42 (24.6%) 14 (29.2%) 0.57

None Unknown

Calcineurin inhibitors before conversion to belatacept Cyclosporine A/ Tacrolimus

162 (94.7%) 129 (75.4%) 33 (19.3%)

9 (5.3%) 0 (0%) 154 (90.1%) 30 (19.5%)/124 (80.5%)

43 (89.6%) 33 (68.8%) 10 (20.8%) 4 (8.3%) 1 (2.1%) 45 (93.8%) 8 (16.7%)/37 (82.2%)

0.19 0.43

0.57

>0.99

Acute-rejection episode before 34 (19.9%) 8 (16.7%) 0.68

(4)

Abbreviations: eGFR, estimated glomerular-filtration rate; EBV, Epstein--Barr virus; CMV, cytomegalovirus; HLA, human leukocyte antigen; DSA, donor-specific antibodies; KT, kidney transplantation; mTORi, mammalian target of rapamycin inhibitor; IFTA, interstitial fibrosis tubular atrophy.

*Delayed graft function was defined as the need for at least one dialysis session within the first week posttransplantation.

Type of acute rejection T-cell mediated rejection Antibody-mediated rejection Both

24 (14%) 5 (2.9%) 5 (2.9%)

5 (10.4%) 2 (4.2%) 1 (2.1%)

0.79

Kidney biopsy before conversion to belatacept

1 [0-22]

0 [0-3]

1 [0-3]

0 [0-3]

10 (7.6%)

0 [0-22]

1 [0-11]

0 [0-3]

0 [0-2]

0 [0-3]

0 [0-0]

1 [0-3]

0 [0-2]

1 [0-3]

5 (14.3%)

0.31 0.78 0.55 0.88 0.60 0.45 0.10 0.83 0.57 0.75 0.85

>0.99 0.39 0.31 Conversion to belatacept

Time from transplantation to conversion (months)

Conversion <3 months post-KT Serum creatinine level at conversion (µmol/L)

Proteinuria at conversion (g/g of creatinuria)

≥60 mL/min/1.73 m²

<30 mL/min/1.73 m²

23.3 [0.8-337.1]

19 (11.1%) 225 ± 117.1

32.7 ± 16.2 0.2 [0-6.6]

8 (4.7%) 26 (15.2%) 48 (28.1%) 89 (52%)

10.6 [0.1-253.9]

13 (27.1%) 263.6 ± 183.1

29.6 ± 17 0.2 [0-1.6]

4 (8.3%) 3 (6.3%) 14 (29.2%) 27 (56.3%)

0.17 0.001

0.08 0.25 0.09 0.3

(5)

Table S3: Comparison between patients that had or did not have a change in estimated glomerular-filtration rate of ≥ 5 mL/min/1.73 m

²

at 12 months post-conversion to belatacept.

Improvement in eGFR ≥5 mL/min/1.73 m² at 12 months post-conversion to belatacept No improvement in

eGFR

≥5 mL/min/1.73 m² n = 115

Improvement in eGFR

≥5 mL/min/1.73 m²n = 91

p-value

Recipients’ age (years) 55± 13.6 55 ± 14.5 0.97

Initial kidney disease Glomerulopathy Interstitial nephropathy Diabetes mellitus and/or nephroangiosclerosis Genetic disease Others

40 (34.8%) 19 (16.5%) 25 (21.7%) 17 (14.8%) 14 (12.2%)

35 (38.5%) 14 (15.4%) 13 (14.3%) 14 (15.4%) 15 (16.5%)

0.65

Duration of dialysis before KT (months)

41.8 ± 35.2 36.2 ± 34.5 0.261

1.19 ± 0.460 11 (9.6%)

1.24 ± 0.52 14 (15.4%)

Deceased donor

Cause of death: Vascular/ Non vascular

Extended criteria donor Gender: male

89 (77.4%) 57 (60.6%)/37 (39.4%)

46 (40%) 58 (50.4%) 56.4 ± 15.9 890.9 ± 555.4

66 (72.5%) 51 (69.9%)/22 (30.1%)

44 (48.4%) 43 (47.8%) 60.4 ± 14.6 890.5 ± 587.3

0.51 0.25

0.31 0.78 0.07 0.99 Virological Status

112 (97.4%) 4 (3.5%) 70 (60.9%) 22 (19.1%)

87 (95.6%) 2 (2.2%) 48 (52.7%) 25 (27.5%)

>0.99 0.69

0.2 0.18 Immunological recipients’ status

Anti-HLA antibodies at KT Donor specific antibodies at KT DSA at conversion

26 (22.6%) 11 (9.6%) 18 (15.7%)

36 (39.6%) 14 (15.6%) 15 (16.5%)

0.009 0.2

>0.99

Anti-interleukin 2 receptor blocker Polyclonal antibodies

None

Calcineurin inhibitors before conversion to belatacept Cyclosporine A/Tacrolimus

91 (79.1%) 21 (18.3%) 3 (2.6%) 101 (87.8%)

20 (17.4%) 81 (70.4%)/14 (12.2%)

63 (70%) 20 (22.2%)

7 (7.8%) 86 (94.5%) 17 (18.7%) 69 (75.8%)/5 (5.5%)

0.15 0.32

>0.99 0.16 Acute-rejection episode before

conversion to belatacept

21 (18.3%) 18 (19.7%) 0.85

(6)

Abbreviations: eGFR, estimated glomerular-filtration rate; EBV, Epstein--Barr virus; CMV, cytomegalovirus; HLA, human leukocyte antigen; DSA, donor-specific antibodies; KT, kidney transplantation; mTORi, mammalian target of rapamycin inhibitor; IFTA, interstitial fibrosis tubular atrophy.

*Delayed graft function was defined as the need for at least one dialysis session within the first week posttransplantation.

T-cell mediated rejection Antibody-mediated rejection Both

15 (13.0%) 3 (2.6%) 3 (2.6%)

13 (14.2%) 3 (3.3%) 2 (2.2%) Kidney biopsy before conversion

to belatacept Sclerotic glomeruli Glomeruli (g)

1 [0-22]

0 [0-3]

0 [0-2]

0 [0-3]

1 [0-3]

0 [0-3]

3 (2.6%)

1 [0-11]

0 [0-2]

0 [0-3]

1 [0-3]

0 [0-3]

1 [0-3]

10 (11%)

Proteinuria at conversion (g/g urine creatinine)

≥60 mL/min/1.73 m²

45 ≤eGFR < 60 mL/min/1.73 m² 30 ≤eGFR < 45 mL/min/1.73 m²

<30 mL/min/1.73 m²

32.6 [1-337.1]

4 (3.5%) 210 ± 92 34.6 ± 17.5

0.2 [0-6.6]

8 (7.0%) 16 (13.9%) 40 (34.8%) 51 (44.3%)

14.1 [0.1-253.9]

19 (20.9%) 236 ± 123 30.3 ± 14.2

0.2 [0-5.1]

3 (3.3%) 13 (14.3%) 21 (23.1%) 54 (59.3%)

0.0002

<0.0001 0.08 0.06 0.09

0.11

(7)

Table S4: Comparison between patients that had or did not have a change in estimated glomerular-filtration rate ≥ 10 mL/min/1.73 m

²

at 12 months post-conversion to belatacept.

Improvement in eGFR ≥10 mL/min/1.73 m² at 12 months post-conversion to belatacept No improvement in

eGFR

≥10 mL/min/1.73 m² n = 151

Improvement in eGFR

≥10 mL/min/1.73 m² n = 55

p-value

Recipients’ age (years) 55.3 ±13.4 54.3 ± 15.6 0.65

55 (36.4%) 24 (15.9%) 29 (19.5%) 24 (15.9%) 19 (12.6%)

20 (36.4%) 9 (16.4%) 9 (16.4%) 7 (12.7%) 10 (18.2%)

0.85

Duration of dialysis before kidney transplantation (months)

40.2 ± 35.1 37.1 ± 34.6 0.57

1.20 ± 0.47 17 (11.3%)

1.26 ± 0.53 8 (14.5%)

Deceased donor

Cause of death: vascular/non- vascular

Extended-criteria donor Gender: male

112 (74.2%) 76 (62.8%)/45 (37.2%)

62 (41.1%) 72 (47.7%) 57.4 ± 15.2 845.5 ± 551.7

43 (78.2%) 32 (69.6%) /14 (30.4%)

28 (50.9%) 29 (53.7%) 60.0 ± 16.0 1016.4 ± 599.3

0.46 0.47

0.25 0.52 0.29 0.58 Virological status

146 (96.7%) 6 (4.0%) 85 (56.3%) 34 (22.5%)

53 (96.4%) 0 (0%) 33 (60%) 13 (23.6%)

>0.99 0.34 0.75 0.85 Immunological recipients’ status

DSA at conversion

39 (25.8%) 14 (9.3%) 23 (15.2%)

23 (41.8%) 11 (20.0%) 10 (18.1%)

0.025 0.05

>0.99

None Unknown

Calcineurin inhibitors before conversion to belatacept Cyclosporine A/ Tacrolimus

145 (96.0%) 117 (77.5%) 28 (18.5%)

6 (4.0%) 0 (0.0%) 135 (89.4%) 26 (17.1%)/109 (72.2%)

50 (9.0%) 37 (67.3%) 13 (23.6%) 4 (7.3%) 1 (1.8%) 52 (94.5%) 11 (20.0%)/41(74.5%)

0.17 0.38

0.41 0.83

(8)

Abbreviations: eGFR, estimated glomerular-filtration rate; EBV, Epstein--Barr virus; CMV, cytomegalovirus; HLA, human leukocyte antigen; DSA, donor-specific antibodies; KT, kidney transplantation; mTORi, mammalian target of rapamycin inhibitor; IFTA, interstitial fibrosis tubular atrophy.

*Delayed graft function was defined as the need for at least one dialysis session within the first week posttransplantation.

Acute-rejection episode before conversion to belatacept Type of acute rejection T-cell-mediated rejection Antibody-mediated rejection Both

29 (19.2%) 21 (13.9%) 5 (3.3%)

3 (2%)

10 (13.5%) 7 (12.7%)

1 (1.8%) 2 (3.6%)

>0.99 0.39

Kidney biopsy before conversion to belatacept

1 [0-22]

0 [0-3]

1 [0-3]

0 [0-3]

5 (4.2%)

1 [0-11]

0 [0-1]

0 [0-3]

0 [0-2]

0 [0-3]

1 [0-3]

0 [0-3]

1 [0-3]

8 (19.5%)

Proteinuria at conversion (g/g urine creatinine)

≥60 mL/min/1.73 m²

<30 mL/min/1.73 m²

25.5 [0.9-337.1]

8 (5.3%) 213.4 ± 92.1

33.5 ± 16.4 0.2 [0-6.6]

9 (6.0%) 20 (13.2%) 50 (33.1%) 72 (47.7%)

11.5 [0.1-253.9]

15 (27.3%) 244.6 ± 141.3

30.7 ± 15.8 0.2 [0-5.1]

2 (3.6%) 9 (16.4%) 11 (20.0%) 33 (60.0%)

0.02

<0.0001 0.067

0.28 0.38

0.22