ABO desensitization affects cellular immunity and infection control after renal transplantation

Efficacy of valganciclovir prophylaxis in kidney transplant recipients following low-dose rituximab induction therapy: a multicenter retrospective study

BACKGROUND

Rituximab (RIT) induction therapy is widely used for desensitization against ABO-incompatible living-donor kidney transplants (KT). However, the efficacy of valganciclovir (VGCV) prophylaxis against cytomegalovirus (CMV) disease and infection in KT recipients (KTRs) following RIT induction remains unclear.

METHODS

The current multicenter retrospective study included 213 KTRs who received low-dose RIT induction between 1998 and 2021, across 6 facilities included in the Michinoku Renal Transplant Network (MRTN). VGCV dosage varied from 450 mg/day (twice weekly) to 900 mg/day (daily), with treatment durations of 3-12 months. The primary and secondary endpoints were the incidence of CMV disease and infection, respectively.

RESULTS

The incidence of CMV disease was significantly higher in the VGCV group (23.5%; 16 patients) than in the non-VGCV group (5.5%; 8 patients) (p < 0.01). The incidence of CMV infection was 54.5% (79 patients) in the non-VGCV group and 48.5% (33 patients) in the VGCV group, with no significant difference (p = 0.42). In the subgroup of CMV-seronegative KTRs receiving allografts from CMV-seropositive donors (CMV IgG (D + /R-)), 18 out of 24 KTRs received VGCV prophylaxis, of whom 10 (55.6%) developed CMV disease. Within this subgroup, only 4 KTRs received VGCV with the standard protocol (900 mg daily for 6 months), and none developed CMV disease.

CONCLUSION

Insufficient VGCV prophylaxis does not reduce the incidence of CMV disease in KTRs following low-dose RIT induction. Despite concerns about leukopenia due to RIT and VGCV, in KTRs with CMV IgG (D + /R-) serostatus, VGCV prophylaxis with a standard protocol may be advisable.

Management of cytomegalovirus in adult solid organ transplant patients: GESITRA-IC-SEIMC, CIBERINFEC, and SET recommendations update

Cytomegalovirus (CMV) infection remains a significant challenge in solid organ transplantation (SOT). The last international consensus guidelines on the management of CMV in SOT were published in 2018, highlighting the need for revision to incorporate recent advances, notably in cell-mediated immunity monitoring, which could alter the current standard of care. A working group including members from the Group for the Study of Infection in Transplantation and the Immunocompromised Host (GESITRA-IC) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) and the Spanish Society of Transplantation (SET), developed consensus-based recommendations for managing CMV infection in SOT recipients. Recommendations were classified based on evidence strength and quality using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. The final recommendations were endorsed through a consensus meeting and approved by the expert panel.

Clinical characteristics and outcomes of kidney transplantation in autosomal dominant polycystic kidney disease patients

BACKGROUND

Kidney transplantation (KT) is the best kidney replacement treatment for autosomal dominant polycystic kidney disease (ADPKD). We aimed to investigate the clinical characteristics and outcomes of KT in ADPKD patients compared to those in non-ADPKD patients.

METHODS

We retrospectively analyzed KT recipients in two Korean transplantation centers from 2005 to 2020. Propensity score-matching and Cox regression analysis were used to assess the clinical outcomes of ADPKD compared to non-ADPKD and identify prognostic factors influencing outcomes in ADPKD.

RESULTS

Among a total of 4452 KT patients, 189 (4.2%) were ADPKD patients. Median age at transplantation was 53.0 and 47.0 in ADPKD and non-ADPKD patients, respectively. In both groups, living-donor KT was more common than deceased-donor KT. The ADPKD group had a 4.09-fold higher risk of post-transplant diabetes mellitus and a 1.65-fold higher risk of post-transplant infection compared to the non-ADPKD group; however, subjects with ADPKD had similar risk of rejection, graft failure, and mortality. In the ADPKD group, kidney volume decreased after KT, irrespective of kidney volume status (Mayo classification), while the size of hepatic cysts increased. Neither kidney volume nor nephrectomy of native kidneys were associated with risk of infection, graft failure, or mortality in the ADPKD group.

CONCLUSIONS

ADPKD patients have a higher risk of post-transplant diabetes mellitus and infection than non-ADPKD patients, with no significant impact of kidney volume or nephrectomy on post-transplant outcomes.

Polyomavirus Nephropathy in ABO Blood Group-Incompatible Kidney Transplantation: Torque Teno Virus and Immunosuppressive Burden as an Approximation to the Problem

Introduction

Earlier reports suggest that patients after ABO-incompatible kidney transplantation (ABOi) are at enhanced risk of developing BK-virus (BKV, also known as BK polyomavirus [BKPyV]) nephropathy (BKPyVAN). It remains elusive whether this is a result of more intense immunosuppression or an ABOi-associated "intrinsic attribute." To address this question, we measured Torque Teno virus (TTV) loads as a quantitative proxy for immunosuppressive depth in ABOi recipients and compared them to human leukocyte antigen-incompatible (HLAi, i.e. pretransplant donor-specific antibody-positive) and standard-risk transplant recipients.

Methods

Our retrospective study screened 2256 consecutive kidney transplantations performed between 2007 and 2020 at the Medical University of Vienna. Out of 629 in-principle eligible transplantations, we were able to include 465 patients: 42 ABOi, 106 HLAi, and 317 control recipients. Longitudinal TTV- polymerase chain reaction (PCR) and BKV-PCR was carried out at predefined timepoints and ranged from pretransplant until month 24 posttransplantation. TTV loads and immunosuppression were evaluated in the context of BKV-associated complications.

Results

ABOi recipients had a higher TTV load compared to HLAi and controls both at month 3 (median 1.5 × 109 vs. 2.4 × 108 vs. 9.1 × 107; P = 0.010) and at month 6 (3.1 × 109 vs. 1.4 × 107 vs. 6.4 × 107; P = 0.014) posttransplantation. Tacrolimus exposure was significantly higher in ABOi patients compared to HLAi and control patients (ABOi vs. HLAi: P = 0.007; ABOi vs. controls: P < 0.0001). Biopsy-proven BKPyVAN was more frequent in ABOi recipients when compared to HLAi and control recipients (11.9% vs. 2.8% vs. 4.1%; P = 0.046).

Conclusion

Our data support the assumption that ABOi patients are indeed at higher risk to develop BKPyVAN. A higher TTV load and immunosuppressive burden suggest that intense immunosuppression, rather than an "intrinsic attribute" conferred by ABOi, may contribute to this finding.

Anti-Donor T-Cell Responses Are Not Necessarily Attenuated During Cytomegalovirus Infection in Kidney Transplant Recipients

BACKGROUND

Cytomegalovirus (CMV), the most common opportunistic infection of kidney transplantation (KT), is preventable by prophylactic and preemptive antiviral drugs in CMV-immunoglobulin (Ig)G-positive donors. Our preemptive therapy optimized immunosuppressive doses based on mixed lymphocyte response (MLR) results, regardless of preoperative CMV-IgG serostatus pairing. This study used the MLR to compare the anti-donor T-cell responses between CMV antigenemia-positive and -negative cases.

METHODS

One hundred patients underwent KT using a cyclosporine (CsA)-based immunosuppressive regimen at Hiroshima University Hospital. CMV antigenemia-positive cells were defined as 4/50,000 CMVpp65-positive cells. T-cell responses to allo-antigens were measured using MLR assays to evaluate patients' anti-donor immune reactivity. After analyzing the proliferation of CD4+ and CD8+ T-cell subsets, the stimulation indices of CD4+ or CD8+ T cells were quantified. The study used no prisoners, and the participants were neither coerced nor paid. The manuscript was created in compliance with the Helsinki Congress and the Declaration of Istanbul.

RESULTS

Forty-three patients tested positive for CMV antigenemia within 3 months after KT. No significant differences were found between the CMV antigenemia-positive and -negative groups in the stimulation indices for CD4+ and CD8+ T-cell responses to anti-donor stimulation. However, T-cell responses to third-party stimuli during the postoperative month 1 were significantly less in the CMV antigenemia-positive than -negative group.

CONCLUSION

Anti-donor T-cell responses are not necessarily attenuated during CMV infection in KT recipients. In CMV-infected KT recipients, caution should be exercised against inadvertent dose reduction of immunosuppressants.

Non-antigen-specific Immunoadsorption Is a Risk Factor for Severe Postoperative Infections in ABO-Incompatible Kidney Transplant Recipients

ABO-incompatible (ABOi) living kidney transplantation (KTx) is an established procedure to address the demand for kidney transplants with outcomes comparable to ABO-compatible KTx. Desensitization involves the use of immunoadsorption (IA) to eliminate preformed antibodies against the allograft. This monocentric retrospective study compares single-use antigen-selective Glycosorb® ABO columns to reusable non-antigen-specific Immunosorba® immunoglobulin adsorption columns regarding postoperative infectious complications and outcome. It includes all 138 ABOi KTx performed at Freiburg Transplant Center from 2004-2020. We compare 81 patients desensitized using antigen-specific columns (sIA) to 57 patients who received IA using non-antigen-specific columns (nsIA). We describe distribution of infections, mortality and allograft survival in both groups and use Cox proportional hazards regression to test for the association of IA type with severe infections. Desensitization with nsIA tripled the risk of severe postoperative infections (adjusted HR 3.08, 95% CI: 1.3-8.1) compared to sIA. nsIA was associated with significantly more recurring (21.4% vs. 6.2%) and severe infections (28.6% vs. 8.6%), mostly in the form of urosepsis. A significantly higher proportion of patients with sIA suffered from allograft rejection (29.6% vs. 14.0%). However, allograft survival was comparable. nsIA is associated with a two-fold risk of developing a severe postoperative infection after ABOi KTx.

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.

ABO Incompatible Kidney Transplantation Without B-cell Depletion is Associated With Increased Early Acute Rejection: A Single-Center Australian Experience

We performed a single-center retrospective cohort study of 66 consecutive ABO incompatible kidney transplants (ABOiKT) performed without B-cell depleting therapy. Outcomes were compared to an earlier era performed with rituximab (n = 18) and a contemporaneous cohort of ABO compatible live donor transplants (ABOcKT). Acute rejection within 3 months of transplant was significantly more common after rituximab-free ABOiKT compared to ABOiKT with rituximab (OR 8.8, p = 0.04) and ABOcKT (OR 2.9, p = 0.005) in adjusted analyses. Six recipients of rituximab-free ABOiKT experienced refractory antibody mediated rejection requiring splenectomy, and a further two incurred early graft loss with no such episodes amongst ABOiKT with rituximab or ABOcKT cohorts. Patient and graft survival were similar between groups over a median follow-up of 3.1 years. This observational evidence lends strong support to the continued inclusion of rituximab in desensitization protocols for ABOiKT.

Conversion to mTOR-Inhibitors Plus IV Immunoglobulins in Kidney-Transplant Recipients with BKV Infection: A Retrospective Comparative Study

BK virus-associated nephropathy (PvAN) increases the risk of graft failure justifying treatment. Conversion to mammalian target of rapamycin inhibitors (mTORi) and Human polyclonal immunoglobulins (IVIg) could prevent the risk of PvAN. Our retrospective study assessed the efficacy of mTORi associated with IVIg therapy (mTORi±IVIg group) versus standard immunosuppression reduction to clear BKV DNAemia. Among forty-three kidney-transplanted patients with positive BKV DNAemia, we included twenty-six patients in the mTORi±IVIg group and reduced immunosuppression therapy for seventeen patients. We focused on BKV DNAemia clearance on the first-year. Renal function, rejection rate, evolution to PvAN, and complications of immunosuppression were assessed. BKV DNAemia decreased faster and significantly in the control group as compared to the mTORi±IVIg group (p < 0.001). Viral clearance was significantly higher in the control group compared to the mTORi±IVIg group (88% vs. 58%; p = 0.033). Death-censored graft loss, rejection rates and kidney-graft function at 12 months did not significantly differ. Multivariate analyses significantly associated BKV DNAemia clearance with reducing immunosuppression (OR = 0.11 (0.06−0.9), p = 0.045), female kidney donor (OR = 0.10 (0.01−0.59/)], p = 0.018) and time to first DNAemia, (OR = 0.88 (0.76−0.96), p = 0.019). In our study, the standard treatment for BKV DNAemia had better outcomes than an mTORi±IVIg conversion.

Long-Term Outcome of ABO-Incompatible Kidney Transplantation in Patients Treated With Low-Dose Rituximab Regimen

BACKGROUND

Introduction of rituximab in the desensitization protocols for ABO-incompatible (ABOI) kidney transplantation (KTX) has afforded excellent results. However, the acceptability of minimal dosage of rituximab in these protocols remains to be defined.

METHODS

Sixty-three patients who underwent ABOI KTX were included in this study. The desensitization protocol consisted of plasmapheresis, tacrolimus, mycophenolate mofetil, methylprednisolone, intravenous immunoglobulin, basiliximab, and low-dose rituximab (100 mg/body). We evaluated the efficacy, safety, and long-term outcome of this protocol (group R, n = 39) and compared them with those of patients who underwent splenectomy (group S, n = 24).

RESULTS

Graft and patient survival at 10 years after KTX were comparable between the groups (94.4% [group R] vs 95.4% [group S] and 94.6% [group R] vs 95.8% [group S], respectively). The incidence of acute antibody-mediated rejection (AAMR) was similar in the 2 groups (10.2% vs 12.5%). There were no significant differences in the incidence of chronic active antibody-mediated rejection. Of the patients, 7 developed AAMR and 3 of these patients (1 in group R and 2 in group S) lost their grafts. There were no significant differences in the incidence of chronic active antibody-mediated rejection. The incidence of postoperative cytomegalovirus infection in group R was significantly lower than that in group S. Furthermore, the incidence of postoperative late-onset neutropenia was low in group R.

CONCLUSIONS

A low-dose rituximab regimen for ABOI KTX is acceptable for preventing AAMR with a low incidence of delayed adverse events.

Temporary Cessation of Immunosuppression for Infection May Contribute to the Development of Graft-vs-Host Disease After ABO-Incompatible Living Donor Liver Transplantation: A Case Report

Graft-vs-host disease (GVHD) after liver transplantation is a rare complication with a high mortality rate. A complex interplay between donor and recipient immunity plays a role in the development of GVHD. Infection following liver transplantation is one of the most common complications in a recipient of an organ transplant who is immunosuppressed. On clinical signs of infection, the immune reaction of the recipient can be reconstituted by withdrawal of immunosuppression in order to help combat infection. However, the discontinuation of immunosuppression could restore the donor's immune activity rather than that of the recipient. There is little information available as to whether the discontinuation of immunosuppression for severe infection could contribute to the development of GVHD in a patient who underwent ABO-incompatible (ABO-I) living donor liver transplantation (LDLT). Herein, we present a unique case of GVHD following ABO-I LDLT, for which the cessation of immunosuppression could be responsible.

Transplantectomy is associated with presensitization with donor-reactive T cells and graft failure after kidney retransplantation: a cohort study

Background

The number of kidney transplant recipients (KTRs) being waitlisted for a subsequent transplantation has disproportionately increased to almost 25%. Evidence for the optimal management of the failed allograft, however, remains inconsistent.

Methods

We studied 111 KTRs who underwent their second kidney transplantation from 1998 to 2015. In 51/111 KTRs (46%) the failed allograft was removed and in 60/111 (54%) the failed allograft was retained. KTRs with primary non-function and allograft loss <12  months of the first failed allograft were excluded from analysis. Samples were collected before transplantation and at  1  month posttransplantation and donor-reactive T cells were measured using an interferon-γ enzyme-linked immunosorbent spot assay.

Results

KTRs with the previous allograft removed showed significantly higher rates of acute cellular rejection compared with KTRs with the previous allograft retained [27/51 KTRs (53%) versus 18/60 KTRs (30%); P = 0.019]. KTRs with the previous allograft removed showed significantly inferior death-censored allograft survival compared with KTRs with the previous allograft retained (P = 0.022). Here, KTRs with the previous allograft removed showed significantly higher donor-reactive T cells pretransplantation compared with KTRs with the previous allograft retained (P = 0.012). Interestingly, no differences were observed for the presence of panel reactive antibodies and for the development of de novo donor-specific antibodies.

Conclusions

Our data suggest higher cellular presensitization among KTRs with the previous allograft removed, which is associated with higher rates of acute cellular rejection and inferior allograft survival. Immunological mechanisms that may account for these differences may include prolonged maintenance immunosuppression to save urine output in KTRs with the first kidney allograft retained and cellular presensitization after withdrawal of maintenance immunosuppression, which lead to allograft rejection and ultimately to allograft nephrectomy.

ABO-Incompatible Kidney Transplant Outcomes: A Meta-Analysis

BACKGROUND AND OBJECTIVES

ABO blood group-incompatible kidney transplantation is considered a safe procedure, with noninferior outcomes in large cohort studies. Its contribution to living kidney transplantation programs is substantial and growing. Outcomes compared with center-matched ABO blood group-compatible control patients have not been ascertained.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Comprehensive searches were conducted in Embase, Medline, Cochrane, Web-of-Science, and Google Scholar. Meta-analyses Of Observational Studies in Epidemiology study guidelines for observational studies and Newcastle Ottawa bias scale were implemented to assess studies. Meta-analysis was performed using Review Manager 5.3. A subgroup analysis on antibody removal technique was performed.

RESULTS

After identifying 2728 studies addressing ABO-incompatible kidney transplantation, 26 studies were included, describing 1346 unique patients who were ABO-incompatible and 4943 ABO-compatible controls. Risk of bias was low (all studies ≥7 of 9 stars). Baseline patient characteristics revealed no significant differences in immunologic risk parameters. Statistical heterogeneity of studies was low (I2 0% for graft and patient survival). One-year uncensored graft survival of patients who were ABO-incompatible was 96% versus 98% in ABO-compatible controls (relative risk, 0.97; 95% confidence interval, 0.96 to 0.98; P<0.001). Forty-nine percent of reported causes of death in patients who were ABO-incompatible were of infectious origin, versus only 13% in patients who were ABO-compatible (P=0.02). Antibody-mediated rejection (3.86; 95% confidence interval, 2.05 to 7.29; P<0.001), severe nonviral infection (1.44; 95% confidence interval, 1.13 to 1.82; P=0.003), and bleeding (1.92; 95% confidence interval, 1.36 to 2.72; P<0.001) were also more common after ABO-incompatible transplantation.

CONCLUSIONS

ABO-incompatible kidney transplant recipients have good outcomes, albeit inferior to center-matched ABO-compatible control patients.

Impact of donor BK polyomavirus replication on recipient infections in living donor transplantation

BACKGROUND

Multiple risk factors for BK polyomavirus (BKPyV) replication after kidney transplantation have been described. Here, we investigated the impact of living donors' urinary BKPyV shedding and recipients' BKPyV antibody status pre-transplant on BKPyV replication during the first year post-transplantation.

METHODS

We assessed a cohort of living kidney donors and their paired recipients (n = 121). All donors were tested before transplantation, and recipients were tested before and after transplantation for BKPyV viruria and viremia. BKPyV-specific serology was assessed in all recipients at transplantation.

RESULTS

Ten of 121 donors (8.3%) had urinary BKPyV shedding pre-transplant, none had viremia. Overall, 33 (27.3%) recipients developed viruria after transplantation: 7 had received a kidney from a donor with BK viruria (7/10 positive donors) and 26 had received a kidney from a donor without BK viruria (26/111 negative donors; P = .0015). Fifteen (12.4%) recipients developed BK viremia after transplantation: 3 received a kidney from a donor with viruria (3/10 positive donors, 30%) and 12 received a kidney from a donor without viruria (12/111 negative donors, 11%; P = .08). One patient developed proven nephropathy. Ninety-one percent of recipients were seropositive for BKPyV. No relationship between recipients' sero-reactivity at transplantation and post-transplant BKPyV replication was observed. Pre-transplant donor urinary shedding was an independent risk factor for post-transplant BKPyV replication.

CONCLUSION

Screening living kidney donors for BKPyV can identify recipients at higher risk for BKPyV replication after transplantation who may benefit from intensified post-transplant screening and treatment strategies.

Simultaneous pancreas/kidney transplant recipients are predisposed to tissue-invasive cytomegalovirus disease and concomitant infectious complications

BACKGROUND

Infections have increased in simultaneous pancreas/kidney transplant recipients (SPKTRs) with cytomegalovirus (CMV) infection being the most important viral infection with adverse impact on patient and allograft outcomes.

METHODS

We studied all primary SPKTRs and deceased-donor kidney transplant recipients (KTRs) between 2008 and 2015 for the development of CMV infection. A total of 21/62 SPKTRs (33.9%) and 90/335 KTRs (26.9%) were diagnosed with CMV infection. A control group of 41 SPKTRs without CMV infection was used for comparison.

RESULTS

SPKTRs showed an increased incidence of CMV infection compared with KTRs. SPKTRs were more likely to develop CMV disease, CMV pneumonia, recurrent CMV infection, higher initial and peak CMV loads, and more need for intravenous antiviral therapy compared with KTRs (P<.05). High-risk CMV serostatus (D+R-) and 2 HLA-B/-DR mismatches increased the risk of CMV infection in SPKTRs (P<.05). No differences were observed for patient and allograft outcomes (P>.05). SPKTRs with CMV infection were more likely to show concomitant Epstein-Barr virus (EBV) viremia compared with SPKTRs without CMV infection (P<.05). SPKTRs with CMV infection showed higher incidences of concomitant BK polyomavirus-associated nephropathy, EBV viremia, and sepsis compared with KTRs with CMV infection (P<.05).

CONCLUSION

Our results suggest a higher incidence and more severe course of CMV infection in SPKTRs compared with KTRs. The increased incidence of concomitant infectious complications among SPKTRs with CMV infection suggests an overall impaired immunity, and calls for more intense screening.

Infectious complications of rituximab therapy in renal disease

Rituximab, an anti-CD20 monoclonal antibody, was originally used to treat B-cell malignancies. Its use has significantly increased in recent years, as it is now also used to treat a variety of autoimmune diseases including rheumatoid arthritis and ANCA-associated vasculitis (AAV). Initial studies suggested that the adverse effects of rituximab were minimal. Though the risk of malignancy with rituximab-based immunosuppressive regimens appears similar to that of the general population, there are now concerns regarding the risk of infectious complications. Rituximab has been associated with serious infections, including Pneumocystis jiroveci pneumonia (PJP) and the reactivation of hepatitis B virus (HBV) and tuberculosis (TB). The risk of infection appears to be the result of a variety of mechanisms, including prolonged B-cell depletion, B-cell–T-cell crosstalk, panhypogammaglobulinaemia, late-onset neutropenia and blunting of the immune response after vaccination. Importantly, the risk of infectious complications is also related to individual patient characteristics and the indication for rituximab. Individualization of treatment is, therefore, crucial. Particular attention should be given to strategies to minimize the risk of infectious complications, including vaccinating against bacterial and viral pathogens, monitoring white cell count and immunoglobulin levels, prophylaxis against PJP and screening for HBV and TB.

Sepsis after renal transplantation: Clinical, immunological, and microbiological risk factors

BACKGROUND

As immunosuppressive therapy and allograft survival have improved, the increased incidence of sepsis has become a major hurdle of disease-free survival after renal transplantation.

METHODS

We identified 112 of 957 kidney transplant recipients (KTRs) with sepsis. In all, 31 KTRs developed severe sepsis or septic shock, and 30 KTRs died from sepsis. KTRs without sepsis were used for comparison. CMV-specific and alloreactive T cells were measured using an interferon-γ Elispot assay. The extent of immunosuppression was quantified by lymphocyte subpopulations.

RESULTS

Five-year patient survival was 70.3% with sepsis compared to 88.2% without (P<.001). Five-year estimated glomerular filtration rate was lower in KTRs developing sepsis (P<.001). Upon multivariate analysis, diabetes, lymphocyte-depleting induction, donor age, CMV replication, and acute rejection increased the risk of sepsis (P<.05). Age, diabetes, underweight/obesity, and pneumonia as site of infection were predictive factors of mortality (P<.05). Early-onset sepsis was associated with decreased CD3+ and CD4+ T cells pre-transplantation (P<.05). Impaired CMV-specific cellular immunity pre-transplantation was associated with CMV replication and early-onset sepsis (P<.05). High frequencies of alloreactive T cells were associated with acute rejection, lymphocyte-depleting rejection treatment, and early-onset sepsis (P<.05).

CONCLUSION

KTRs developing sepsis show inferior patient survival and allograft function. Identified risk factors and differences in lymphocyte counts, CMV-specific immunity, and alloreactivity may prove useful to identify KTRs at increased risk.

Increased alloreactivity and adverse outcomes in obese kidney transplant recipients are limited to those with diabetes mellitus

Previous studies on patient and allograft outcomes of obese kidney transplant recipients (KTRs) remain controversial. To what extent obesity-related comorbidities contribute to adverse outcomes, however, hasn't been addressed. We studied all KTRs from 2005 to 2012. 29 (4%), 317 (48%), 217 (33%), 76 (12%), and 21 KTRs (4%) were identified as underweight, normal-weight, overweight, obese, and morbid obese, respectively. 33 of 97 obese KTRs (34%) had pre-existent diabetes. Samples were collected before transplantation and at +1, +2, +3months posttransplantation. Donor-reactive T-cells were measured using an interferon-γ Elispot assay. Obese KTRs showed an increased incidence pre-existent diabetes (p<0.001), but no differences for hypertension and coronary artery disease (p>0.05). Among obese KTRs, those with pre-existent diabetes showed inferior patient and allograft survival, worse allograft function, delayed graft function, and prolonged hospitalization (p<0.05). Interestingly, no differences were observed between obese non-diabetic, normal-weight diabetic, and normal-weight non-diabetic KTRs (p>0.05). Obese diabetic KTRs showed higher frequencies of donor-reactive T-cells pretransplantation (p<0.05). Our results suggest that the increased risk of mortality, allograft loss, delayed graft function, and prolonged hospitalization in obese KTRs is limited to those with diabetes. A state of obesity-related inflammation plus hyperglycemia may trigger increased alloreactivity and should call for adequate immunosuppression.

Kidney transplant recipients after nonrenal solid organ transplantation show low alloreactivity but an increased risk of infection

The number of kidney transplant recipients (KTRs) after nonrenal solid organ transplantation (SOT) has increased to almost 5%. Knowledge on patient and allograft outcomes, infections, and alloreactivity, however, remains scarce. We studied 40 KTRs after nonrenal SOT. Seven hundred and twenty primary KTRs and 119 repeat KTRs were used for comparison. Samples were collected pretransplantation, at +1, +2, and +3 months post-transplantation. Alloreactive and CMV-specific T cells were measured by interferon-γ ELISPOT assay. Patient survival in KTRs after SOT, primary and repeat KTRs was comparable. While death-censored allograft survival was comparable between KTRs after SOT and primary KTRs, KTRs after SOT showed superior 5-year death-censored allograft survival of 92.5% compared to 81.2% in repeat KTRs. Interestingly, KTRs after SOT show less preformed panel-reactive antibodies, frequencies of alloreactive T cells, and acute rejections compared to repeat KTRs. KTRs after SOT, however, show higher incidences of EBV viremia and PTLD, sepsis, and death from sepsis. Impaired CMV-specific cellular immunity was associated with more CMV replication compared to repeat KTRs. Our results suggest comparable patient and allograft outcomes in KTRs after SOT and primary KTRs. The observed low alloreactivity may contribute to excellent allograft outcomes. Caution should be taken in KTRs after SOT regarding infectious complications due to overimmunosuppression.

Simultaneous pancreas/kidney transplant recipients present with late-onset BK polyomavirus-associated nephropathy

BACKGROUND

Infections have increased in simultaneous pancreas/kidney transplant recipients (SPKTRs) with BK polyomavirus (BKV)-associated nephropathy (BKVN) being the most important infectious cause of allograft loss. Comparisons of BKVN with kidney transplant recipients (KTRs), however, are lacking.

METHODS

We studied all SPKTRs and KTRs at our transplant centre between 2003 and 2012. Eleven of 106 SPKTs (10.4%) and 21 of 1062 KTRs (2.0%) were diagnosed with BKVN with allograft loss in 1 SPKTR (9.1%) and 2 KTRs (9.5%). A control of 95 SPKTRs without BKVN was used for comparison.

RESULTS

SPKTRs showed an increased incidence of BKVN compared with KTRs (P < 0.001). Onset of BKVN in SPKTRs was significantly later compared with KTRs (P = 0.033). While 67% of KTRs showed early-onset BKVN, 64% of SPKTRs developed late-onset BKVN. Older recipient age and male gender increased the risk of BKVN in SPKTRs (P < 0.05). No differences were observed for patient and allograft survival (P > 0.05). However, SPKTRs with BKVN showed inferior estimated glomerular filtration rate and a higher incidence of de novo donor-specific antibodies compared with SPKTRs without BKVN in long-term follow-up (P < 0.05). SPKTRs showed higher peak BKV loads, a need for more intense therapeutic intervention and were more likely not to recover to baseline creatinine after BKVN (P < 0.05).

CONCLUSIONS

Our results suggest a higher incidence, more severe course and inferior outcome of BKVN in SPKTRs. An increased vulnerability of the allograft kidney due to inferior organ quality may predispose KTRs to early-onset BKVN. In contrast, SPKTRs present with late-onset BKVN in the presence of high-dose immunosuppression.

Early post-transplant complications following ABO-incompatible kidney transplantation

Background: Living-kidney transplantation is increasing because of the scarcity of kidneys from deceased donors and the increasing numbers of patients on waiting lists for a kidney transplant. Living-kidney transplantation is now associated with increased long-term patient- and allograft-survival rates.

Objectives: The purpose of this retrospective study was to identify, in a cohort of 44 ABO-incompatible (ABOi) live-kidney transplant patients, the main complications that occurred within 6 months post-transplantation, and to compare these findings with those from 44 matched ABO-compatible (ABOc) live-kidney transplant patients who were also from our center.

Patients and Methods: This single-center retrospective study assessed post-transplantation complications in 44 ABO-i versus 44 matched ABO-c patients. All patients were comparable at baseline except that ABO-i patients had greater immunological risks.

Results: During the 6-month post-transplant period, more ABO-i patients presented with postoperative bleeds, thus requiring significantly more blood transfusions. Bleeds were associated with significantly lower values of fibrinogen, platelets, prothrombin time, and hemoglobin levels. Surgical complications, patient- and graft-survival rates, and kidney-function statuses were similar between both groups at 6 months post-transplantation.

Conclusions: We conclude that impairment of hemostatic factors at pre-transplant explained the increased risk of a post-transplant bleed in ABO-i patients.