Current status of ABO-incompatible kidney transplantation in children

Incidence of malignancy after pediatric kidney transplantation: a single-center experience over the past three decades in Japan

BACKGROUND

Malignancy after kidney transplantation (KT) is one of the most serious post-transplant complications. This study aimed to investigate the incidence, type, and outcomes of malignancy after pediatric KT.

METHODS

We performed a retrospective cohort study on pediatric kidney transplant recipients aged 18 years or younger who received their first transplant between 1975 and 2009.

RESULTS

Among the 375 children who underwent KT, 212 were male (56.5%) and 163 were female (43.5%) (median age at KT, 9.6 years [interquartile range {IQR}] 5.8-12.9 years). The incidence of malignancy was 5.6% (n = 21). The cumulative incidences of cancer were 0.8%, 2.5%, 2.8%, 4.2%, 5.5%, and 15.6% at 1, 5, 10, 15, 20, and 30 years post-transplantation, respectively. Of 375 patients, 12 (3.2%) had solid cancer and nine (2.4%) had lymphoproliferative malignancy. The median age at the first malignancy was 21.3 years (IQR 11.5-33.3 years). The median times from transplant to diagnosis were 22.3 years (IQR 12.3-26.6 years) for solid cancer and 2.2 years (IQR 0.6-2.8) for lymphoproliferative malignancies. During follow-up, five recipients died due to malignancy. The causes of death were hepatocellular carcinoma in one patient, squamous cell carcinoma in the transplanted kidney in one patient, malignant schwannoma in one patient, and Epstein-Barr virus-related lymphoma in two patients. The mortality rate was 0.79 per 1000 person-years (95% confidence interval 0.38, 1.85).

CONCLUSIONS

Early diagnosis and treatment of malignancies in transplant recipients is an important challenge. Therefore, enhanced surveillance and continued vigilance for malignancy following KT are necessary.

ABO-incompatible pediatric kidney transplantation without antibody removal

BACKGROUND

Because of the severe shortage of suitable deceased donors, ABO-incompatible living donor kidney transplantation (ABOi LDKT) is performed even in pediatric recipients in Japan. We performed pediatric ABOi LDKT using rituximab without anti-A/B antibody removal.

METHODS

Thirteen pediatric recipients (mean age 7.4, range 3.4-15.7, four females) whose baseline anti-A/B IgG titers were ≤ × 64 underwent ABOi LDKT without antibody removal and splenectomy between July 2013 and April 2017 at Toho University. Mycophenolate mofetil (MMF) was initiated on day - 10. Rituximab (100 mg) was administered twice. Basiliximab and triple maintenance immunosuppression (calcineurin inhibitor, MMF, and steroids) were administered. Protocol biopsy was performed at 3 months and 1 year after transplantation. We retrospectively compared the clinical outcomes between these recipients and 37 children (mean age 9.0, range 2.6-18.9, 15 female) who underwent ABO-compatible (ABOc) LDKT during the same period.

RESULTS

The mean follow-up periods of ABOi and ABOc groups were 31.9 ± 13.5 and 28.8 ± 14.4 months, respectively. In the ABOi group, no clinical acute rejection (AR) was noted and subclinical AR was observed in four patients without evidence of acute antibody-mediated rejection. In the ABOc group, clinical and subclinical AR developed in 3 and 10 patients, respectively. No significant difference was identified for the mean eGFR between the ABOi and ABOc groups (98.3 ± 48.8 vs. 86.9 ± 39.4, P = 0.452 at 3 months; 78.2 ± 21.2 vs. 79.7 ± 21.3, at 1 year, P = 0.830). Death-censored graft survival at follow-up was 100% in the ABOi group and 94.6% in the ABOc group. Patient survival during the follow-up period in both the groups was 100%. Late-onset neutropenia (LON) requiring granulocyte colony-stimulating factor occurred more frequently in the ABOi group than in the ABOc group (4 vs. 0 patients) (P < 0.001).

CONCLUSIONS

Pre- and post-transplantation antibody removal is not a prerequisite for successful pediatric ABOi LDKT, at least in patients with a low anti-A/B IgG antibody titer. However, LON caused by rituximab should be monitored.

Outcomes of pediatric ABO-incompatible kidney transplantations are equivalent to ABO-compatible controls

BACKGROUND

Due to the profound shortage of suitable deceased allografts, much effort has been made to investigate whether successful kidney transplantation (KT) is possible across the ABO blood group barrier even for pediatric recipients.

METHODS

We reviewed 52 consecutive ABO incompatible (ABOic) transplantation performed between September 1989 and March 2011. The mean age at transplantation was 10.6 ± 3.9 years (range, 4.4-19.7), with 35 boys and 17 girls. The donor-to-recipient ABO blood antigen incompatibility was as follows: A1/O (n = 17); B/O (n = 13); A1/B (n = 6); B/A1 (n = 1); A1B/B (n = 9); and A1B/A (n = 6). As a control group, data were collected from 271 pediatric ABO compatible (ABOc) living donor KT in the same period.

RESULTS

Overall acute rejection episodes (ARE) among the ABOic group were significantly higher than those of the ABOc group (44% vs 26%; P < .02). However, there was no difference in glomerular filtration rate (GFR) at 1 year after transplantation: 86 ± 31 mL/min for ABOic vs 99 ± 37 mL/min for ABOic, respectively. The 1-y, 5-y, and 10-year patient survival rates were 98%, 92%, and 92% in the ABOic group, respectively, and 99%, 98%, and 97% in the ABOc group, respectively (P = not significant [NS]). The overall 1-, 5-, 10-, and 15-year graft survival rates were 94%, 88%, 86%, and 86% in the ABOic group, respectively, and 95%, 92%, 88%, and 78% in the ABOc group, respectively.

CONCLUSION

ABOic KT provided long-term allograft and patient survivals equivalent to ABOc live donor transplantations.

ABO incompatible kidney transplantation

PURPOSE OF REVIEW

Although ABO incompatible kidney transplantation is increasingly recognized as effective, the procedure is still evolving. The purpose of this review is to summarize recent advances in this area.

RECENT FINDINGS

Short to intermediate-term outcome appears good, although long-term results are still preliminary. Pretransplant risk stratification based on antidonor antibody titer may be of limited value. Splenectomy, previously reported to be an important component of ABO incompatible transplantation, appears to be avoidable under many circumstances. The wider implementation of A2 blood group incompatible transplantation shortens waiting time for deceased donor transplantation of blood group B recipients without significantly disadvantaging others. The diagnosis of acute humoral rejection has become clearer following the recognition that C4d deposition commonly occurs in well functioning ABO incompatible allografts. The long-term implications of acute humoral rejection appear substantial even following successful acute therapy, with a significant percentage of patients developing chronic humoral rejection manifested as transplant glomerulopathy. Finally, although ABO incompatible transplantation entails increased expense, when compared with maintenance dialysis and taking into account the health related quality of life benefits of a successful transplant, it is clearly cost effective.

SUMMARY

ABO incompatible kidney transplantation is an effective therapy, and will become more widely implemented in the future.

Kidney transplantation in children and adolescents

Worldwide, specific pediatric allocation schemes successfully try to minimize waiting time for children with end-stage renal disease (ESRD). The article is a review of current issues in pediatric kidney transplantation. The procedure is the treatment of choice for children and adolescents with ESRD, with 1- and 3-year graft survival rates of 95% and 90% and recipient survival after 5 and 10 years of 95% and 90%. Preoperative surgery is often necessary to minimize negative effects of congenital anomalies. No minimum age exists for pediatric transplantation, but most often the recipient body weight is ideally above 10 to 15 kg. Technical concepts should include extravesical anastomosis, stenting of the ureter, and potentially intraperitoneal placement of the graft. Immunosuppression has constantly improved. The aim is a tailored regimen to reduce side effects and improve compliance, which necessitates intense counseling of the child and the parents prior to, during, and after transplantation as many adolescents lose their graft due to noncompliance. Intense follow-up must also exclude infections, especially with herpes and polyoma viruses. For the future, age matching may be only one promising concept to improve results. As only a small number of children require the procedure in each country, multinational studies should be initiated to optimize outcomes in children and adolescents.

ABO-incompatible kidney transplantation of an 8-yr-old girl with donor/recipient-constellation A1B/B

BACKGROUND

Antigen-specific immunoadsorption combined with rituximab offers the possibility for ABO-incompatible kidney transplantation without splenectomy.

PATIENT AND METHOD

An 8-year-old mentally retarded girl with steroid-resistant nephrotic syndrome and focal segmental glomerulosclerosis due to mitochondriopathy poorly tolerated hemodialysis. Paternal blood group A1B was incompatible with blood group B of the child. Therefore, we decided to perform the first ABO-incompatible renal transplantation in a child in Germany using antigen-specific immunoadsorption. Rituximab (1 x 375 mg/m2) was administered 2 weeks before the first immunoadsorption (Glycosorb) ABO A-column). Triple-drug immunosuppression (tacrolimus, mycophenolate mofetil and prednisolone) was simultaneously started with immunoadsorption. Initial tacrolimus levels were targeted between 15 and 20 ng/ml. Before transplantation, six immunoadsorptions were applied on days -9, -7, -4, -3, -2 and -1. Intravenous immunoglobulin (0.5 g/kg) was administered preoperatively. After transplantation, three immunoadsorptions were performed on days +4, +6 and +8.

RESULTS

Before transplantation, antibody (Ab) titers against paternal erythrocytes (20 degrees C) were reduced from 1 : 64 to 1 : 4 by six antigen-specific immunoadsorptions. After transplantation, we performed three more immunoadsorptions and the Ab titers were stable between 1 : 1 and 1 : 8. One, 2 and 8 months later we observed increases in the Ab titer up to 1 : 32 requiring no change in immunosuppressive therapy. No side effects of immunoadsorption were observed. The girl had excellent initial graft function with a serum creatinine of 55 to 70 micromol/l. Two weeks after transplantation, graft biopsy showed no signs of rejection; there was focal positivity for C4d only. Twelve months after transplantation, renal function was stable, with a serum creatinine of 117 micromol/l. Episodes of rejection or severe infections were absent.

CONCLUSION

ABO-incompatible transplantation using antigen-specific immunoadsorption and rituximab may serve as a suitable alternative for children urgently needing renal transplantation and missing a blood group-compatible donor.