Is administration of rituximab at 375 mg/m without splenectomy appropriate for ABO-incompatible renal transplant?

Beneficial Effects of High-Dose Mizoribine on ABO-Incompatible Living-Related Kidney Transplantation: Two-Year Results by a Japanese Multicenter Study

BACKGROUND

Mizoribine (MZ) has been developed as an immunosuppressive agent in Japan, but it has a less-potent immunosuppressive effect up to 3 mg/kg/d. In the previous study, a Japanese multicenter study, we reported that high-dose MZ, at 6 mg/kg/d, with a calcineurin inhibitor was effective and safe in reducing the frequency of cytomegalovirus (CMV)-related events in ABO-incompatible (ABO-i) living-related kidney transplantation (LKT). In the present study, therefore, we investigated the effects of high-dose MZ with a CNI in ABO-i LKT recipients in a Japanese multicenter study.

METHODS

A total of 37 patients were treated with high-dose MZ (6 mg/kg), a CNI (cyclosporine [CsA] or tacrolimus [Tac]), basiliximab (Bas), rituximab (Rit), and corticosteroids. CsA was started at a dose of 7 mg/kg to maintain blood levels [200 ng/mL (C0), 6000 ng-h/mL (AUC 0-9)]. Tac was started at a dose of 0.2 mg/kg to maintain blood levels [8-10 ng/mL (C0), 100 ng-h/mL (AUC 0-9)]. Bas (20 mg/body) was administrated on day 0 and day 4 after transplantation. Rit (100-200 mg/body) was administrated on day -14 and day -7 before transplantation. MZ was adjusted to maintain target C0 levels of 1.5 to 2.0 μg/mL.

RESULTS

Patient and graft survival rates for 2 years were 100% in the CsA group (n = 22) and 93.3% in the Tac group (n = 15) (not significant, NS). Overall incidence of acute rejection for 2 years was 22.7% in the CsA group and 26.7% in the Tac group. Mean serum creatinine levels at 2 years were 1.29 ± 0.2 mg/dL in the CsA group and 1.21 ± 0.34 mg/dL in the Tac group (NS). The incidence of CMV disease was 0% in both groups, and positive rates of CMV antigenemia were 50.0% and 26.7% in the CsA and Tac groups, respectively (NS). Mean serum uric acid levels were 5.5 ± 1.3 mg/dL and 6.4 ± 1.2 mg/dL at 2 years (NS) in the CsA and Tac groups, respectively.

CONCLUSIONS

A high-dose MZ regimen including calcineurin inhibitor (CsA or Tac), Bas, Rit, and steroids was effective and safe in reducing the frequency of CMV-related events in ABO-i LKT.

How to reduce lethal infectious complications in ABO-incompatible kidney transplantation

BACKGROUND

ABO-incompatible organ transplants are good options for expanding the living donor pool; however, the necessary pre-conditioning to remove ABO antibodies before surgery can evoke critical infectious complications after surgery.

METHODS

Between February 2009 and July 2013, we performed ABO-incompatible kidney transplantation on 182 patients. We analyzed the first 85 patients for post-operative infectious complications in a cross-sectional cohort of patients (group 1, n = 85) who had received an ABO-incompatible kidney transplant and, in light of the results, amended the pre-conditioning (lower dose of rituximab, selective use of calcineurin inhibitors, anti-metabolite reduction, and prophylactic strategy) given to a prospective cohort (group 2, n = 97).

RESULTS

The characteristics of the two groups did not differ significantly. Infectious complications decreased significantly in group 2, including cytomegalovirus (anti-genemia 64.7% vs 27.8%, P < .001) and BK viremia (35.2% vs 18.6%, P = .008). The acute rejection rate and death-censored graft survival were similar in both groups. Notably, with the modified protocol, there were no deaths (8.2% vs 0.0%, P = .03).

CONCLUSIONS

Pre-conditioning for ABO-incompatible kidney transplantation is a prerequisite for successful outcome; its drawbacks can be limited with the use of a modified immunosuppressive strategy. If immunosuppression is modified according to host conditions, ABO-incompatible kidney transplantation can be performed safely with a successful graft outcome.

Late-onset neutropenia and acute rejection in ABO-incompatible kidney transplant recipients receiving rituximab and mycophenolate mofetil

INTRODUCTION

Using rituximab, we have performed successful ABO-incompatible kidney transplantations in recipients without splenectomy as well as in those with high pretransplant anti-A/B antibody titers. A common and increasingly recognized toxicity of rituximab is late-onset neutropenia (LON), defined as unexplained grades III to IV neutropenia occurring at least 4weeks after the last dose of rituximab in the absence of an alternative explanation.

PATIENTS AND METHODS

Between May 2006 and December 2011, 25 patients who received rituximab underwent successful ABO-incompatible kidney transplantation and were enrolled as the subjects in this study. The incidence rate and clinical features of LON as well as the relationship between LON and acute rejection in these patients were studied.

RESULTS

Twelve recipients (48%) experienced LON 2 to 12months after transplantation. Five of the 12 patients (41.6%) who developed LON had an episode of biopsy-confirmed acute cellular rejection, as compared with one of the 13 patients (7.7%) who did not develop LON. Moreover, 3 patients who experienced LON developed steroid and deoxyspergualin-resistant acute cellular rejection requiring OKT-3 administration.

CONCLUSIONS

The frequency of acute cellular rejection was higher in ABO-incompatible kidney transplant recipients with LON than in those without LON. Our findings suggested that these recipients who developed LON after rituximab administration may be at an increased risk for acute cellular rejection.

Successful ABO-incompatible living-donor renal transplant without splenectomy for renal coloboma syndrome: a case report

To our knowledge, this is the first report of an ABO-incompatible living-donor renal transplant without a splenectomy performed in a patient with renal coloboma syndrome, a rare disorder caused by PAX2 gene mutations, and that presents with renal and optic nerve hypodysplasia and disorders of the central nervous system. Many patients with renal coloboma syndrome develop end-stage renal disease requiring renal replacement therapy. Few reports of a well-defined course of renal transplant for coloboma syndrome have been published. We treated a 22-year-old man who had end-stage renal disease from renal coloboma syndrome. We performed an ABO-incompatible living-donor renal transplant with a kidney donated by his father. Two years after the transplant, the patient has good preserved renal function, and his compliance with the immunosuppressive regimen was good.

ABO blood type incompatible kidney transplantation without splenectomy prepared with plasma exchange and rituximab

We have designed a protocol for ABO-incompatible kidney transplantations based on preoperative plasmapheresis with a tacrolimus/mycophenolate mofetil/methylprednisolone/basiliximab protocol using low-dose rituximab (200 mg/body) instead of splenectomy to prevent antibody-mediated acute rejection. Eight patients successfully received transplants with this protocol. The titers of anti-A and -B antibodies as well as the number of CD20(+) cells were readily maintained at a low level posttransplantation. There were no side effects. All patients have renal transplant function with a follow-up of 1-34 months.

Impact of low-dose rituximab on splenic B cells in ABO-incompatible renal transplant recipients

The purpose of this study was to assess the effect of a low-dose rituximab (RIT) at < 375 mg/m(2) on B cells in the spleen and peripheral blood. Five renal transplant recipients received a single dose of RIT at 10, 15, 35, 150, or 300 mg/m(2) 3-13 days before transplantation. One patient who received the same immunosuppressive regimen except for RIT was also enrolled as a control. Splenectomy was performed at the time of transplantation in all patients. The B-cell count in the peripheral blood was analysed with a fluorescence-activated cell sorter using anti-CD19 antibodies, and the B cells in the spleen were analysed by immunohistochemistry using anti-CD20 and -CD79a antibodies. All but one dosage (10 mg/m(2)) of RIT completely eliminated B cells from the circulation within 30 days. Immunohistochemical examination of the spleen showed a marked reduction of B cells in the white pulps in all five recipients compared with that in the control patient. The observations in this study indicated that RIT has a potent effect of depleting B cells in the spleen and peripheral blood at low-doses of < 375 mg/m(2).

B-cell surface marker analysis for improvement of rituximab prophylaxis in ABO-incompatible adult living donor liver transplantation

Although the effectiveness of rituximab has been reported in ABO blood group (ABO)-incompatible (ABO-I) organ transplantation, the protocol is not yet established. We studied the impact of the timing of rituximab prophylaxis and the humoral immune response of patients undergoing ABO-I living donor liver transplantation (LDLT), focusing on clinicopathological findings and the B-cell subset. From July 2003 to December 2005, 30 adult patients were treated with hepatic artery infusion (HAI) protocol without splenectomy for ABO-I LDLT. A total of 17 patients were treated only with HAI (no prophylaxis), and the other 13 were treated with rituximab prophylaxis at various times prior to transplantation. For B-cell study of the spleen, another 4 patients undergoing ABO-I LDLT both with HAI after prophylaxis and eventual splenectomy, and 3 patients with ABO-compatible LDLT with splenectomy were enrolled. The mortality of the 30 patients with HAI, without splenectomy, and with/without rituximab prophylaxis was 33% and the main cause of death was sepsis. Peripheral blood B cells were completely depleted, anti-donor blood-type antibody titer was lower, and clinical and pathological antibody-mediated rejection was not observed in patients with prophylaxis earlier than 7 days before transplantation (early prophylaxis). Early rituximab prophylaxis significantly depleted B cells and memory B cells in the spleen but not in lymph nodes. On the other hand, B cells and memory B cells increased and memory B cells became dominant during antibody-mediated rejection. In conclusion, early prophylaxis with rituximab depletes B cells, including memory B cells, in the spleen and is associated with a trend toward lower humoral rejection rates and lower peak immunoglobulin (Ig)G titers in ABO-I LDLT patients.

The emerging role of rituximab in organ transplantation

Long-term acceptance of solid organ allografts remains a challenge. While many acute rejection episodes can be treated, new mechanisms of allograft damage are now being defined especially in kidney transplantation. Unexpected clusters of CD20(+) cells have been discovered in renal biopsies performed for clinical rejection. C4d deposition is now routinely seen in refractory rejection. Despite the rapid introduction of new immunosuppressive agents in transplantation, the search for an efficacious anti-B-cell agent remains. With novel mechanisms of allograft damage now being defined, it is important to consider how an anti-B-cell agent might fit into an immunosuppressive regimen. Rituximab is a high-affinity CD20 specific antibody that depletes the B-cell compartment by inducing cellular apoptosis. Thus, it is a rational choice for therapy in transplantation to abrogate B-cell mediated events. In this review, we will discuss the mechanisms of action of rituximab, and its use in for a variety of indications in solid organ transplantation. There are emerging case reports that show that rituximab may be an effective agent to treat antibody-mediated rejection, and post-transplant lymphoproliferative disorder. Rituximab has been frequently cited as an important adjunct therapy in desensitization protocols for highly sensitized transplant recipients as well as recipients of ABO incompatible transplants. Rituximab demonstrates promise in this regard and warrants additional consideration in prospective clinical trials.