Relation between ABO blood type antigen and antibody and acute vascular rejection in ABO incompatible kidney transplantation

ABO incompatible kidney transplantation - an analysis of UNOS Registry data

BACKGROUND

The ABO incompatible kidney transplants have been performed successfully from large numbers of living donors and some blood type A2 deceased donors. However, there are few reports to support the feasibility of ABO incompatible transplants from non-A2 deceased donors. This problem was examined in the United Network for Organ Sharing (UNOS) data file.

PATIENTS AND METHODS

The UNOS Registry data of kidney transplants performed between 1995 and 2003 from 256 centers was utilized for Kaplan-Meier curves and log-rank tests to compare graft and functional graft survival rates.

RESULTS

Deceased donor transplants from all ABO incompatible donors had the same graft survival rates, as that from ABO compatible donors regardless of whether the blood group incompatibility was A (A1), A2 or B. Graft survival from 201 ABO incompatible donors was 66.9% at 5 yr, compared with 66.7% for ABO compatible donors (p = 0.83). Non-A2 incompatible donors also yielded comparable survival rates to ABO compatible donors. From living donors, ABO incompatible donors yielded significantly lower graft survival rates than the ABO compatible group, although long-term graft survival rates of those who survived >1 yr did not differ significantly.

CONCLUSION

Except higher initial graft loss possibility because of insufficient removal of antibodies, non-A2 kidneys yielded equivalent graft survival rates to ABO compatible transplants. In addition to A2 incompatibilities, Blood group A1 and B incompatibilities can also be considered in ABO incompatible transplants.

Characterization of rejection episodes in patients following positive crossmatch and ABO-incompatible live donor renal transplantation

For kidney transplant recipients with donor-specific antibody (DSA) to HLA- (+XM) or ABO-antigens (ABOI), there is a need to improve detection and treatment of antibody-mediated rejection (AMR). The methods included a retrospective review of consecutive patients that received plasmapheresis and immune globulin (PPIVIg) to abrogate +XM or ABOI. Twelve patients were transplanted after PPIVIg (+XM = 9, ABOI = 2, +XM/ABOI = 1). No hyperacute rejections occurred. Rejection occurred in seven patients [four AMR, three acute cellular rejection (ACR)]. In four +XM patients, DSA was detected during graft dysfunction despite lack of histologic and C4d features of AMR. In one patient, DSA preceded the histologic and immunofluorescent features of AMR. In another patient with borderline changes and DSA, graft function improved after PPIVIg, despite lack of histologic or immunofluorescent evidence of AMR. One patient with Banff IIA ACR and DSA treated with antithymocyte antibody but not PPIVIg had recurrent rejections and poor graft function. In +XM and ABOI recipients with graft dysfunction: (i) DSA may represent AMR in the absence of C4d or histologic features of AMR; (ii) DSA can precede C4d or light microscopic features of AMR; (iii) A poor outcome may result if DSA or continued allograft dysfunction is present and not treated despite a negative biopsy.

Reversibility from delayed hyperacute rejection in ABO-incompatible renal transplantation: histopathological findings of renal allograft biopsy

ABO-incompatible renal transplantation (ABOIRTx) tend to lead to blood type antibody-mediated rejection, the so-called delayed hyperacute rejection (DHAR), which results in short-term graft loss. To clarify the accurate incidence and prognostic value of DHAR among ABOIRTx, we reviewed biopsy specimens obtained from ABOKTx allografts with abrupt dysfunction during the early period after transplantation. Among 74 ABOIRTx patients, 34 patients displayed allograft dysfunction within 14 days following transplantation. The biopsy specimens were classified based on the Banff schema. The pathological diagnosis of ABO blood type antibody-mediated humoral rejection (ABO-AMHR) was made by the following 3 findings: Specimens with all of above-mentioned findings were categorized as severe ABO-AMHR; those with at least one findings, were categorized as mild ABO-AMHR. All patients were treated with steroid pulse therapy and/or modification of other immunosuppressants. Group 1 consisted of severe ABO-AMHR (n = 6); group 2 consisted of mild ABO-AMHR (n = 5); group 3 consisted of acute cellular rejection (n = 3); group 4 consisted of recovery phase of ATN (n = 11); group 5 consisted of calcineurin inhibitor toxicity (n = 2); and group 6 consisted of normal histology (n = 5). One of 6 patients (16%) in group 1 lost the graft because of DHAR irreversible by antirejection and anticoagulation therapy. However, there has been no clear definition of histpathological criteria for DHAR after ABO-incompatible kidney transplantation. The definition must prognosticate whether the rejection process is reversible.

Current status of ABO-incompatible kidney transplantation in children

This article reviews the current status of ABO-incompatible kidney transplantation in the pediatric population. ABO blood type incompatibility between a donor and recipient was generally considered a contraindication to kidney transplantation because of the associated high risk for hyperacute rejection. However, due to a severe shortage of suitable cadaveric allografts, much effort has been made over the last decade to investigate whether successful and effective kidney transplantation is possible across the ABO blood group barrier. At present, ABO-incompatible kidney transplantation has been shown to be a valid alternative even for children with end stage renal disease. In this review, we will discuss protocols available for successfully performing ABO-incompatible kidney transplantation in children: (1) pre-transplant extracorporeal immunomodulation with removal of pre-existing anti-A and/or anti-B antibodies; (2) immunosuppressive therapy and anti-rejection therapy; (3) splenectomy and the associated infectious complication in asplenic children. Also, we will speculate regarding the mechanisms underlying accommodation following transplantation.

Successful living donor renal transplantation despite ABO incompatibility and a positive crossmatch

Potential live kidney donors have been rejected when the prospective recipients are blood type or crossmatch incompatible. By utilizing plasmapheresis combined with intravenous immune globulin (PP/IVIg) prior to surgery, donor-specific antibodies against blood group or human leukocyte antigens (HLA) have been removed, thereby allowing successful renal transplantation. A 26-yr-old male with a panel reactive antibody level of 100% and repeated positive crossmatches against deceased donor kidney offers, including zero HLA mismatched donors, successfully underwent ABO-incompatible kidney transplantation from his HLA-identical but nevertheless crossmatch-incompatible sister. The initial anti-A blood group isoagglutinin titers were 128, 256, and 1024 at room temperature, 37 degrees C, and 37 degrees C anti-IgG enhanced, respectively. With an individualized PP/IVIg regimen based on donor-specific antibody titer, however, the relevant antibodies were adequately reduced and hyperacute rejection avoided. Subsequent antibody-mediated rejection, likely directed against a minor histocompatibility antigen, was diagnosed on postoperative day 7 and successfully treated. Neither ABO, or crossmatch incompatibility, or both in combination prohibit kidney transplantation.

Clinical and pathological assessment of acute vascular rejection in the transplant kidney

Acute vascular rejection (AVR) in kidney transplantation is the most important factor influencing graft prognosis. We focus on patients whose grafts were lost because of AVR, and assessed their clinical characteristics and histological findings of biopsied renal grafts. Biopsied specimens exhibited AVR in 43 patients who underwent kidney transplantation in the Kidney Center of Tokyo Women's Medical University from 1995 to 1999. In the follow-up from 1 to 5 yr (median: 2.5 yr) we classified these patients into three groups: favourable prognosis group (FPG), relatively poor prognosis group (RPPG) and poor prognosis group (PPG). Light microscopic study for histological grading of acute rejection according to the Banff scheme and detection of the C4d complement deposition on peritubular capillaries by the immunofluorescence method were performed. Based on the results, the donors of RPPG and PPG were significantly older than those of FPG, and all factors of acute rejection according to the Banff scheme were not statistically significantly different among the three groups. However, an acute tubular injury mimicking acute tubular necrosis (ATN) was observed in the biopsy specimens from PPG. In conclusion, an older donor is a risk factor of poor prognosis of the graft with AVR, and acute tubular injury mimicking ATN is one of the important features that enables the prediction of graft failure originating from AVR in kidney transplantation.

ABO-incompatible living-donor kidney transplantation in children

BACKGROUND

Due to a severe shortage of suitable cadaveric allografts for children awaiting kidney transplants, we have performed a series of ABO-incompatible living kidney transplantations (LKT) at our institution.

METHODS

Between July 1989 and March 2000, 16 pediatric patients (3 female, 13 male) underwent ABO-incompatible LKT. The mean age at transplantation was 10.9+/-4.3 years (range 5.1-15.0 years). The donor to recipient ABO blood antigen incompatibility was as follows: A1-->O, 5 patients; B-->O, 6 patients; A1B-->B, 2 patients; and A1B -->B, A1-->B, or B-->A1, 1 patient each. The median pretransplantation anti-A1 titers of eight A-incompatible recipients were 1:128 (IgM, range 1:16 to 1:512) and 1:32 (IgG, range 1:2 to 1:128). Median anti-B titers of seven B-incompatible recipients were 1:32 (IgM, range 1:4 to 1:128) and 1:8 (IgG, range 1:2 to 1:64). All patients received three or four sessions of plasmapheresis (PP) and/or immunoadsorption (IA) to remove the anti-A and/or anti-B antibodies before transplantation. Immunosuppression initially consisted of cyclosporine, methylprednisolone, cyclophosphamide, and antilymphocyte globulin. Splenectomy was performed on all recipients at the time of transplantation.

RESULTS

The patients were followed for 6 to 122 months with a mean follow-up of 63 months. All 16 recipients who underwent ABO-incompatible LKT achieved a pretransplant isoagglutinin titer less than 1:8 with 3-4 sessions of PP/IA treatment. Of 16 patients, 10 patients had rebound increase in their IgM and/or IgG anti-A/B titers to greater than 1:64 or predepletion levels within 10 days posttransplantation. In addition, nine patients developed renal dysfunction in association with the rebound increase in their anti-A/B. One patient lost his graft because of uncontrolled delayed hyperacute rejection, whereas eight other recipients recovered completely with pulse steroids and PP/IA therapy. After the third week posttransplant, there was no correlation between the occurrence of AR and their isoagglutinin titers. Moreover, no antibody-mediated rejection was observed, even in recipients with continued high titer anti-A and/or anti-B antibodies. Patient survival is 100% to date. The actuarial 1-year and 5-year graft survival rates are 87% and 85%, respectively. No fatal infectious complications occurred despite the combination of splenectomy and immunosuppressive drugs.

CONCLUSIONS

We have demonstrated that with adequate pre- and posttransplant management, successful kidney transplantation across the ABO barrier is possible in the pediatric population. "Accommodation" of the allografts occurred within 2 weeks of transplantation. Subsequently, the long-term graft outcome of ABO-incompatible LKT was comparable to that of ABO-compatible LKT.