MO1002: Two-Step Desensitization Protocol Consisting of High-Dose Intravenous Immunoglobulin, Plasmapheresis and Rituximab in Highly Sensitized Kidney Transplantation

BACKGROUND AND AIMS

High-dose intravenous immunoglobulin (IVIG) therapy has not only immediate effects but also gradual effects via Fc receptors. To optimize IVIG therapy, we adopted a two-step desensitization protocol in kidney transplantation (KTx) with positive flow cytometry crossmatch (FCXM).

METHOD

In the first step, rituximab 200 mg and IVIG 2 g/kg were administered 2 months before KTx. In the second step, patients received additional rituximab 200 mg and IVIG 2g/kg for 2 weeks prior to transplantation in combination with plasmapheresis.

RESULTS

Of the six KTx with positive FCXM, there was no rejection except one (16.7%) subclinical antibody-mediated rejection within 1 month after transplantation. Average graft function was acceptable (serum creatinine level of 1.17 mg/dL).

CONCLUSION

The two-step desensitization protocol is an effective option for achieving successful transplant outcomes in KTx with positive FCXM, which can spare more aggressive and expensive treatments, such as C5 inhibitors, proteasome inhibitors and imlifidase.

MO927IMPACT OF DONOR AGE ON LIVING DONOR KIDNEY TRANSPLANTATION

Background and Aims

Although elderly living donors are recognized as a marginal donor for kidney transplantation, the number of elderly living donors are increasing because of insufficiency. We investigated the impact of donor age on living donor kidney transplantation.

Method

A total 858 adult living donor kidney transplantation (LDKT) between January 2008 and December 2018 was included in this study and followed up until September 2020. LDKTs were stratified into 3 groups according to the donor age; 157 LDKTs from donors aged 30 – 49, 592 LDKTs from donors aged 50 – 69, and 109 LDKTs from donors aged 70 – 89. To investigate the impact of donor age on living donors, postoperative estimated glomerular filtration rates (eGFR), mortality rate and incidence of end stage renal disease were compared between 3 donor age groups. To investigate the impact of donor age on recipients, postoperative eGFR was compared between 3 donor age groups and the risk factors of graft loss were analyzed using Cox regression hazard model.

Results

The eGFRs of donors demonstrated a decline with increased donor age and significant differences at all time points among 3 donor age groups. (Figure 1) Mortality rate and incidence of end stage renal disease of donors were similar among 3 donor age groups. (Figure 2) The eGFRs of recipients demonstrated a decline with increased donor age and significant differences at all time points among 3 donor age groups. (Figure 3) Multivariate analysis using Cox regression hazard model demonstrated donor aged 70 – 89 as a significant risk of graft loss (P = 0.024, hazard ratio 3.053, 95% confidence interval 1.160 – 8.040).

Conclusion

The prognosis of living donors after donation were not affected by the donor age except for the lower eGFR with increased donor age. The eGFRs of recipients and graft loss rates were the worst in the recipients transplanted from donors aged 70 – 89.

P1654INCIDENCE AND RISK FACTORS OF THROMBOTIC MICROANGIOPATHY AFTER KIDNEY TRANSPLANTATION

Background and Aims

Thrombotic microangiopathy (TMA) is characterized by mechanical hemolytic anemia, thrombocytopenia, and renal impairment. TMA that occurs in kidney transplant recipients has multiple etiologies and may be de novo or recurrent. Main causes of TMA among recipients are atypical hemolytic uremic syndrome (aHUS), immunosuppressive drugs, ischemia-reperfusion injury (IRI), viral infections, and antibody-mediated rejection (ABMR). Pathological findings of TMA with thrombosis in glomeruli and arterioles are not rare in graft biopsies, but the clinical signs vary widely by etiologies, and incidence and risk factors for each are uncertain. The purpose of this study is to clarify the current status of TMA after kidney transplantation.

Method

The subjects were 1,336 patients (5,425 biopsy specimens) who underwent kidney transplantation (851 ABO-compatible and 485 ABO-incompatible) at Japanese Red Cross Nagoya Daini Hospital and Masuko Memorial Hospital from January 1, 2000 to June 30, 2018. We investigated patient characteristics and graft survival in 69 patients with pathological findings of TMA (12 with symptomatic TMA and 57 with asymptomatic TMA) and 1,207 patients without findings of TMA. Sixty patients were excluded because of incomplete data or biopsy specimens. TMA patients with acute kidney injury (AKI) were defined as symptomatic TMA in this study.

Results

The incidence of post-transplant TMA was 5.2% (symptomatic TMA : 0.9%, asymptomatic TMA : 4.3%) in our cohort. Multivariate analysis revealed significant risk factors for TMA were presence of donor specific antibodies (DSA) and use of cyclosporine (odds ratio [OR] 3.52; 95% confidence interval [CI] 1.58-7.88; p=0.002 and OR 3.70; 95% CI 1.68-8.11; p=0.001, respectively). Causes of symptomatic TMA were ABMR : 66.7% (5 patients with ABO-incompatibility, 3 with preformed DSA), aHUS : 16.7%, cytomegalovirus and adenovirus infection : 8.3%, and causes of asymptomatic TMA were drug-induced: 40.4% (21 patients with calcineurin inhibitor, 2 with everolimus), ABMR: 31.6% (10 with ABO-incompatibility, 8 with de novo DSA), IRI : 14.0 %. Onset of post-transplant TMA was significantly associated with lower graft survival (Figure A), with a stronger correlation in symptomatic TMA than in asymptomatic TMA (Figure B and C).

Conclusion

TMA with AKI that occurred after kidney transplantation had a poor graft prognosis. Therefore, avoiding transplantation, changing donors or using tacrolimus instead of cyclosporine should be considered for patients with DSA or ABO-incompatibility.

P1647CHANGES IN CAUSES OF EARLY GRAFT LOSS IN LIVING DONOR KIDNEY TRANSPLANT RECIPIENTS, 1972-2018

Background and Aims

In living donor kidney transplantation, the progress of immunosuppressants in recent decades has led to an average graft survival period more than 15 years. However, the rate of graft loss (GL) within 5 years is still about 5%. Since the incidence of early GL is low, clinical evidence of causes and risk factors are limited and it remains unclear whether early GL was predictable before transplantation. Our purposes were to characterize a patient population with GL, to identify risk factors associated with early (<5 years) GL.

Method

The subjects were 1,779 patients who underwent living donor kidney transplantation at Japanese Red Cross Nagoya Daini hospital and Masuko Memorial Hospital from January 1, 1972 to December 31, 2018 (former group (1972-1999) : 503, latter group (2000-2018) : 1,276). We retrospectively examined patient characteristics, timing and causes of GL in 445 cases with GL by December 31, 2019 (GL cases in former group : 335, GL cases in latter group : 110).

Results

The 5- and 10-year graft survival rates were on an increasing trend, with 74.7% and 58.3% in former group and 95.2% and 88.7% in latter group, respectively. In latter group, T cell-mediated rejection and recurrence of primary diseases were significantly more frequent in GL cases within 5 years after transplantation than over 5 years (10% vs 0%, p=0.02 and 6% vs 0%, p=0.04). Although not significant, GL due to antibody-mediated rejection tended to more frequent in over 5 years after transplantation (22% vs 45%). Compared the causes of GL within 5 years after transplantation between GL cases in former group and latter group, rate of allograft rejection significantly reduced (88％ vs 44%, p<0.001), and infections (especially BK polyomavirus infection), medication nonadherence and recurrence of primary diseases tended to increase (0%, 4% and 3% vs 8%, 16% and 8%, respectively).

Conclusion

Our analysis suggests that management of infections, medication nonadherence and recurrence of primary diseases have become more important for living donor kidney transplant recipients in recent years with improved immunosuppressants.

P1636THE IMPACT OF CALCINEURIN INHIBITOR WITHDRAWAL ON DE NOVO DSA PRODUCTION IN LIVING DONOR KIDNEY TRANSPLANTATION

Background and Aims

Chronic antibody mediated rejection caused by de novo donor specific antibody (dnDSA) is one of the biggest reasons for graft failure. At present, because it is difficult to treat CAMR, prevention of de novo DSA production is important. We investigated the risk factor for dnDSA production in living donor kidney transplantation.

Method

807 patients underwent living donor kidney transplantation between January 2008 and December 2016. 159 recipients were excluded because of preformed DSA (58 recipients), pediatric transplantation (35 recipients), pancreas transplantation after kidney transplantation (4 recipients), and insufficient data on DSA after transplantation (62 recipients). 648 recipients were enrolled in this study. In 84 out of 648 recipients, dnDSA were detected until December 2018. With cox regression analysis, the risk factors for de novo DSA production were investigated between dn DSA positive and negative groups. The impact of donor characteristics including age and sex, and recipient characteristics including age, sex, hemodialysis vintage, cold ischemic time, past history of transfusion, pregnancy, and transplantation, HLA mismatch, pre-operative Flow PRA results, ABO incompatibility, rituximab induction, splenectomy, pre-operative plasmapheresis, transplantation from first-degree relatives, conversion of calcineurin inhibitor (CNI), conversion of mycophenolate mofetil, mizoribin, and everolimus, CNI used for induction, induction with mycophenolate mofetil, mizoribin, and everolimus, CNI withdrawal, withdrawal of mycophenolate mofetil, mizoribin, and everolimus, and rejection within 6 months after transplantation were investigated.

Results

In the univariate analysis, male recipient, male donor, and CNI withdrawal were the significant risk factors (P=0.020, HR 1.795, 95%CI 1.095-2.942; P=0.027, HR 0.568, 95%CI 0.344-0.938; P<0.001, HR 6.346, 95%CI 2.560-15.730, respectively). In the multivariate analysis, calcineurin inhibitor withdrawal was significant risk factor with P<0.001, HR 6.374, 95%CI 2.567-15.828.

Conclusion

Calcineurin inhibitor withdrawal was the significant risk factor for de novo DSA production in living donor kidney transplantation