B cells and immunoglobulin in ABO-incompatible renal transplant patients receiving rituximab and double filtration plasmapheresis

The effects of double-filtration plasmapheresis on coagulation profiles and the risk of bleeding

BACKGROUND/PURPOSE

Double-filtration plasmapheresis (DFPP) can be used to remove circulating pathogenic molecules. By reclaiming filtered albumin, DFPP reduces the need for albumin and plasma replacement. Large proteins, such as fibrinogen, are removed. Our institution adopts a DFPP treatment protocol consisting of active surveillance of coagulation profiles and prophylactic supplementation of blood products containing fibrinogen. This study aims to investigate the effects of consecutive DFPP treatments on serial coagulation profiles and the risk of bleeding under this protocol.

METHODS

Serial laboratory data and bleeding events at a single tertiary medical center were prospectively collected. Prophylactic transfusion of cryoprecipitate or fresh frozen plasma (FFP) was instituted if significant coagulopathy or a clinically evident bleeding event was observed.

RESULTS

After the first treatment session, plasma fibrinogen levels decreased from 332 ± 106 mg/dL to 96 ± 44 mg/dL in the 37 study patients. In the following sessions, plasma fibrinogen levels were maintained at around 100 mg/dL under prophylactic transfusion. No major bleeding events were recorded, but five (14%) patients experienced minor bleeding.

CONCLUSION

DFPP treatment might be performed safely along with active monitoring of coagulation profiles and prophylactic transfusion of cryoprecipitate or FFP.

Advancement in preoperative desensitization therapy for ABO incompatible kidney transplantation recipients

ABO incompatibility has long been considered an absolute contraindication for kidney transplantation. However, with the increasing number of patients with ESRD in recent years, ABO-incompatible kidney transplantation (ABOi-KT) has expanded the types of donors by crossing the blood group barrier through preoperative desensitization therapy. At present, the desensitization protocols consist of removal of preexisting ABO blood group antibody titers and prevention of ABO blood group antibody return. Studies have suggested similar patient and graft survival among ABOi-KT and ABOc-KT recipients. In this review, we will summarize the effective desensitization regimens of ABOi-KT, aiming to explore effective ways to improve the success rate and the long-term survival rate of ABOi-KT recipients.

Effects of perioperative dexmedetomidine infusion on renal function and microcirculation in kidney transplant recipients: a randomised controlled trial

OBJECTIVE

Ischemia-reperfusion injury affects postoperative transplanted kidney function in kidney transplant recipients. Dexmedetomidine was reported to attenuate ischemia-reperfusion injury and improve microcirculation, but its propensity to cause bradycardia and hypotension may adversely affect microcirculation. This study investigated the effect of dexmedetomidine on postoperative renal function and sublingual microcirculation in kidney recipients.

METHODS

The enrolled kidney transplant recipients were randomly allocated to the control group or dexmedetomidine group. After anaesthesia induction, patients in the dexmedetomidine group received dexmedetomidine infusion until 2 h after surgery. Sublingual microcirculation was recorded using an incident dark-field video microscope and analysed. The primary outcomes were the creatinine level on a postoperative day 2 and total vessel density at 2 h after surgery.

RESULTS

A total of 60 kidney recipients were analysed, and the creatinine levels on postoperative day 2 were significantly lower in the dexmedetomidine group than in the control group (1.5 (1.1-2.4) vs. 2.2 (1.7-3.0) mg/dL, median difference -0.6 (95% CI, -0.7 to -0.5) mg/dL, p = .018). On a postoperative day 7, the creatinine levels did not differ significantly between the two groups. Total vessel density at 2 h after surgery did not differ significantly between the two groups.

CONCLUSION

We found that early postoperative renal function was better in kidney transplant recipients receiving dexmedetomidine infusion, but total vessel density was not significantly different between the intervention and control groups. Key messagesIschemia-reperfusion injury affects postoperative transplanted kidney function, and dexmedetomidine was reported to attenuate ischemia-reperfusion injury and improve microcirculation in other clinical conditions.This study showed that early postoperative renal function was better in kidney transplant recipients receiving dexmedetomidine.Dexmedetomidine's side effect of bradycardia and hypotension may affect microcirculation, our results revealed that the perioperative sublingual microcirculation did not differ significantly in kidney transplant recipients receiving dexmedetomidine.

Novel double-filtration plasmapheresis preserves fibrinogen while removing immunoglobulin-G antibodies before ABO blood type-incompatible kidney transplantation

Background

Removal of anti-blood group antibodies is important for successful ABO-incompatible kidney transplantation (ABOi-KTx). Double-filtration plasmapheresis (DFPP) using albumin solution removes antibodies effectively. However, fibrinogen is largely removed resulting in hemostatic failure. Herein, we designed an altered combination of plasma membranes in DFPP (novel DFPP, nDFPP) to retain more fibrinogen while removing IgG, and assessed its efficacy and safety compared with conventional DFPP (cDFPP).

Methods

Consecutive ABOi-KTx recipients (from 2015 to 2018) were enrolled. For the first membrane, we used Cascadeflo EC-50W in nDFPP and Plasmaflo OP-08W in cDFPP, and Cascadeflo EC-20W as the second membrane in both modalities. Removal rates (RR) of IgG, IgM and fibrinogen per DFPP session, and adverse events were compared with historical control patients who underwent cDFPP before ABOi-KTx, between 2006 and 2015.

Results

nDFPP and cDFPP groups included 12 and 23 cases, respectively. nDFPP was inferior to cDFPP in RR of IgG and IgM. nDFPP was also inferior to cDFPP in the decline in anti-blood group IgG and IgM antibody titers. However, fibrinogen was more preserved in nDFPP compared with cDFPP, indicating that nDFPP has more selective removal properties (median RR of IgG, IgM, and fibrinogen: 62.1%, 15.7% and 37.6%, respectively, in nDFPP; and 74.5%, 85.0% and 76.6%, respectively, in cDFPP). In the comparison of hemostatic function among the patients who had arteriovenous fistula for hemodialysis, prolonged hemostasis (> 20 min) at the cannulation site was significantly less frequently observed in nDFPP group (1 in 9 cases, 9.1%) than in cDFPP group (all 18 cases, 10%, p < 0.0001).

Conclusions

nDFPP preserves fibrinogen while removing anti-blood type IgG antibodies before ABOi-KTx.

Latent Tuberculosis Infection Increases in Kidney Transplantation Recipients Compared With Transplantation Candidates: A Neglected Perspective in Tuberculosis Control

Background

The prevalence and incidence of latent tuberculosis infection (LTBI) in patients with kidney transplantation remain unclear.

Methods

In this prospective study, we enrolled kidney transplantation candidates (KTCs) and recipients (KTRs) from 2014 to 2018. We defined LTBI as a positive result of QuantiFERON-TB Gold In-tube (QFT). We analyzed the predictors for LTBI acquisition and followed up on QFT assay test for 2 years among those initially without LTBI.

Results

Of 425 patients enrolled, 305 (71.8%) patients belonged to the KTC group and 120 (28.2%) to the KTR group. The initial QFT showed positive results in 32 (10.5%) and 24 (20.0%) patients in the KTC and KTR groups, respectively (P = .009). The QFT response value in patients with LTBI was higher in the KTR group than in the KTC group (1.85 vs 1.06 IU/mL, P = .046). Multivariate logistic regression showed that old age, absence of bacillus Calmette–Guérin (BCG) scar, presence of donor-specific antibody, and KTR group were independent factors for positive LTBI. For participants with initial negative QFT, positive QFT conversion within a 2-year follow-up was higher after kidney transplantation (20%) than in KTCs (5.5%) (P = .034).

Conclusions

This study is the first cohort to follow up LTBI status in patients with kidney transplantation and shows its higher prevalence and incidence in KTRs. It indicates that surveillance of LTBI after renal transplantation is important. In addition to status of kidney transplantation, old age, no BCG vaccination, and positive donor-specific antibody are also positive predictors for LTBI.

Establishment of calculated panel reactive antibody and its potential benefits in improving the kidney allocation strategy in Taiwan

BACKGROUND/PURPOSE

Renal transplant candidates who are highly sensitized to human leukocyte antigens (HLAs) tend to wait longer to find a matched donor and have poor outcomes. Most organ-sharing programs prioritize highly sensitized patients in the allocation scoring system. The HLA sensitization status is traditionally evaluated by the panel-reactive antibody (PRA) assay. However, this assay is method dependent and does not consider the ethnic differences in HLA frequencies. A calculated PRA (cPRA), based on a population's HLA frequency and patients' unacceptable antigens (UAs), correctly estimates the percentage of donors suitable for candidates. The Taiwan Organ Registry and Sharing Center does not prioritize sensitized patients. We propose that the incorporation of the cPRA and UAs into the renal allocation program will improve the local kidney allocation policy.

METHODS

We established a cPRA calculator using 6146 Taiwanese HLA-A, -B, -C, -DR, and -DQ phenotypes. We performed simulated allocation based on the concept of acceptable mismatch for 76 candidates with cPRA values exceeding 80%.

RESULTS

We analyzed 138 waitlisted renal transplant candidates at our hospital, and we determined that the concordance rate of the cPRA and PRA for highly sensitized (%PRA > 80%) candidates was 92.5%, which decreased to 20% for those with %PRA < 80%. We matched 76 highly sensitized patients based on acceptable mismatch with the HLA phenotypes of 93 cadaver donors. Forty-six patients (61%) found at least one suitable donor.

CONCLUSION

The application of the cPRA and acceptable mismatch can benefit highly sensitized patients and reduce positive lymphocyte cytotoxicity crossmatch.

Repeated cycles of high-dose intravenous immunoglobulin and plasmapheresis for treatment of late antibody-mediated rejection of renal transplants

BACKGROUND/PURPOSE

Intravenous immunoglobulin (IVIG) plays a central role in the treatment of antibody-mediated rejection (AMR) of renal allografts, but the treatment outcomes for late AMR (>6 months after transplantation) are poor.

METHODS

We performed a retrospective study to assess the response patterns of IVIG-based (2 g/kg) desensitization for late AMR. Patients who received desensitization after the pathological diagnosis of late AMR positive for complement component C4d were grouped as the Desensitized Group and compared to a historical Control Group with complement component C4d positivity in retrospective stainings.

RESULTS

The 10-year graft survival of the Desensitized Group (73.9%, n = 35) was significantly better than that of the historical Control Group (35.0%, n = 40) without desensitization. In the Desensitized Group, a subgroup of patients (D2 Subgroup, n = 11), who responded to desensitization initially but deteriorated later, was identified to benefit from repeated cycles of desensitization at 31.1 ± 20.9 months. Patients receiving only one cycle of desensitization were further grouped into D1-good (n = 10) and D1-poor (n = 14) based on their long-term renal function. The D2 Subgroup patients did not exhibit significant improvements in renal function compared to the D1-poor patients, until 30 months after IVIG-based desensitization, suggesting desensitization therapy has a working window of approximately 24 months.

CONCLUSION

Repeated cycles of IVIG-based desensitization help stabilize long-term renal function in patients with persistent AMR.