Plasma cell densities and glomerular filtration rates predict renal allograft outcomes following acute rejection

Biomarkers for Kidney-Transplant Rejection: A Short Review Study

Kidney transplantation is the preferred treatment for end-stage renal failure, but the limited availability of donors and the risk of immune rejection pose significant challenges. Early detection of acute renal rejection is a critical step to increasing the lifespan of the transplanted kidney. Investigating the clinical, genetic, and histopathological markers correlated to acute renal rejection, as well as finding noninvasive markers for early detection, is urgently needed. It is also crucial to identify which markers are associated with different types of acute renal rejection to manage treatment effectively. This short review summarizes recent studies that investigated various markers, including genomics, histopathology, and clinical markers, to differentiate between different types of acute kidney rejection. Our review identifies the markers that can aid in the early detection of acute renal rejection, potentially leading to better treatment and prognosis for renal-transplant patients.

Understanding humoral immunity and multiple sclerosis severity in Black, and Latinx patients

People identified with Black/African American or Hispanic/Latinx ethnicity are more likely to exhibit a more severe multiple sclerosis disease course relative to those who identify as White. While social determinants of health account for some of this discordant severity, investigation into contributing immunobiology remains sparse. The limited immunologic data stands in stark contrast to the volume of clinical studies describing ethnicity-associated discordant presentation, and to advancement made in our understanding of MS immunopathogenesis over the past several decades. In this perspective, we posit that humoral immune responses offer a promising avenue to better understand underpinnings of discordant MS severity among Black/African American, and Hispanic/Latinx-identifying patients.

Endothelial Cell-Derived Interleukin-18 Released During Ischemia Reperfusion Injury Selectively Expands T Peripheral Helper Cells to Promote Alloantibody Production

BACKGROUND

Ischemia reperfusion injury (IRI) predisposes to the formation of donor-specific antibodies, a factor contributing to chronic rejection and late allograft loss.

METHODS

We describe a mechanism underlying the correlative association between IRI and donor-specific antibodies by using humanized models and patient specimens.

RESULTS

IRI induces immunoglobulin M-dependent complement activation on endothelial cells that assembles an NLRP3 (NOD-like receptor pyrin domain-containing protein 3) inflammasome via a Rab5-ZFYVE21-NIK axis and upregulates ICOS-L (inducible costimulator ligand) and PD-L2 (programmed death ligand 2). Endothelial cell-derived interleukin-18 (IL-18) selectively expands a T-cell population (CD4+CD45RO+PD-1^hiICOS+CCR2+CXCR5-) displaying features of recently described T peripheral helper cells. This population highly expressed IL-18R1 and promoted donor-specific antibodies in response to IL-18 in vivo. In patients with delayed graft function, a clinical manifestation of IRI, these cells were Ki-67+IL-18R1+ and could be expanded ex vivo in response to IL-18.

CONCLUSIONS

IRI promotes elaboration of IL-18 from endothelial cells to selectively expand alloreactive IL-18R1+ T peripheral helper cells in allograft tissues to promote donor-specific antibody formation.

Association of medication non-adherence with short-term allograft loss after the treatment of severe acute kidney transplant rejection

Background

Medication non-adherence is a risk factor for acute kidney transplant rejection. The association of non-adherence with short-term allograft loss in patients who develop acute rejection and are subsequently treated with maximal therapy is unknown.

Methods

We conducted a retrospective single center cohort study of adult patients who developed acute rejection from January 2003 to December 2017 and were treated with lymphocyte depletion. Clinicopathologic characteristics including adherence status were collected and descriptive statistics utilized to compare groups. The primary outcome was all-cause graft loss at 6 months after acute rejection treatment. A multivariable logistic regression quantified the association of non-adherence with the outcome.

Results

A total of 182 patients were included in the cohort, of whom 71 (39%) were non-adherent. Compared to adherent patients, non-adherent patients were younger (mean age 37y vs 42y), more likely to be female (51% vs 35%) and developed acute rejection later (median 2.3y vs 0.5y from transplant). There were no differences in estimated glomerular filtration rate or need for dialysis on presentation, Banff grade, or presence of antibody mediated rejection between the 2 groups. Overall, 48 (26%) patients lost their grafts at 6 months after acute rejection treatment. In adjusted analysis, non-adherence was associated with all-cause graft loss at 6 months after acute rejection treatment [OR 2.64 (95% CI 1.23–5.65, p = 0.012].

Conclusions

After adjusting for common confounders, non-adherent patients were at increased risk for short-term allograft loss after a severe acute rejection despite lymphocyte depletion. This finding may aid clinicians in risk stratifying patients for poor short-term outcomes and treatment futility.

Clinical and pathological features of kidney transplant patients with concurrent polyomavirus nephropathy and rejection-associated endarteritis

AIM: To describe the clinicopathologic features of concurrent polyomavirus nephropathy (PVN) and endarteritis due to rejection in renal allografts.

METHODS: We searched our electronic records database for cases with transplant kidney biopsies demonstrating features of both PVN and acute rejection (AR). PVN was defined by the presence of typical viral cytopathic effect on routine sections and positive polyomavirus SV40 large-T antigen immunohistochemistry. AR was identified by endarteritis (v1 by Banff criteria). All cases were subjected to chart review in order to determine clinical presentation, treatment course and outcomes. Outcomes were recorded with a length of follow-up of at least one year or time to nephrectomy.

RESULTS: Of 94 renal allograft recipients who developed PVN over an 11-year period at our institution, we identified 7 (7.4%) with viral cytopathic changes, SV40 large T antigen staining, and endarteritis in the same biopsy specimen, indicative of concurrent PVN and AR. Four arose after reduction of immunosuppression (IS) (for treatment of PVN in 3 and tuberculosis in 1), and 3 patients had no decrease of IS before developing simultaneous concurrent disease. Treatment consisted of reduced oral IS and leflunomide for PVN, and anti-rejection therapy. Three of 4 patients who developed endarteritis in the setting of reduced IS lost their grafts to rejection. All 3 patients with simultaneous PVN and endarteritis cleared viremia and were stable at 1 year of follow up. Patients with endarteritis and PVN arising in a background of reduced IS had more severe rejection and poorer outcome.

CONCLUSION: Concurrent PVN and endarteritis may be more frequent than is currently appreciated and may occur with or without prior reduction of IS.

BK Virus-Associated Nephropathy with Plasma Cell-Rich Infiltrates Treated by Bortezomib-Based Regimen

BK virus infection accompanied with plasma cell-rich infiltrates is a dilemma in renal transplant recipients. One young female patient diagnosed as BK virus-associated nephropathy with plasma cell-rich infiltrates at 16 months after renal transplant was treated with bortezomib and a sequential immuno-suppressive protocol of tacrolimus combined with leflunomide. After a short period of reduction, her serum creatinine increased slowly with stable BK viruria. The patient underwent repeat biopsy. The histologic changes showed a decrease in plasma cells and CD20+ cells in the allograft, but the other mononuclear cells showed no difference from the first biopsy. The immunosuppressive protocol was converted to tacrolimus combined with enteric-coated mycophenolate sodium. Her serum creatinine decreased gradually during 6 months of follow-up. We speculate that bortezomib can be used in BK virus-associated nephropathy accompanied with plasma cell-rich infiltrates, and this effect might be mediated through a decrease of plasma cells and CD20+ cells in the allograft. The dosage and time of therapy need to be explored in the future; additional studies of large samples are needed.

Inflammatory cell burden and phenotype in endomyocardial biopsies with antibody-mediated rejection (AMR): a multicenter pilot study from the AECVP

This multicenter case-controlled pilot study evaluated myocardial inflammatory burden (IB) and phenotype in endomyocardial biopsies (EMBs) with and without pathologic antibody-mediated rejection (pAMR). Sixty-five EMBs from five European heart transplant centers were centrally reviewed as positive (grade 2, n = 28), suspicious (grade 1, n = 7) or negative (n = 30) for pAMR. Absolute counts of total, intravascular (IV) and extravascular (EV) immunophenotyped mononuclear cells were correlated with pAMR grade, capillary C4d deposition, donor specific antibody (DSA) status and acute cellular rejection (ACR). In pAMR+ biopsies, equivalent number of IV CD3+ T lymphocytes (23 ± 4/0.225 mm(2) ) and CD68+ macrophages (21 ± 4/0.225 mm(2) ) were seen. IB and cell phenotype correlated with pAMR grade, C4d positivity and DSA positivity (p < 0.0001). High numbers of IV T lymphocytes were associated with low grade ACR (p = 0.002). In late-occurring AMR EV plasma cells occurring in 34% of pAMR+ EMBs were associated with higher IB. The IB in AMR correlated with pAMR+, C4d positivity and DSA positivity. In pAMR+ equivalent numbers of IV T lymphocytes and macrophages were found. The presence of plasma cells was associated with a higher IB and occurrence of pAMR late after transplantation.

Low-dose RATG with or without basiliximab in renal transplantation: a matched-cohort observational study

BACKGROUND/AIMS

In renal transplantation, peri-operative low-dose rabbit-antithymocyte-globulin (RATG) plus basiliximab induction prevented acute allograft rejection more effectively than post-operative RATG plus basiliximab induction. We investigated the specific antirejection contribution of basiliximab in this context.

METHODS

This single-center, observational, matched-cohort study evaluated allograft rejections (primary outcome), steroid exposure and side effects, GFR (iohexol plasma clearance) and treatment costs in 16 deceased-donor renal transplant recipients induced with RATG (0.5 mg/kg/day) and 32 age-, gender- and treatment-matched reference-patients given RATG plus basiliximab (20 mg on days 0 and 4).

RESULTS

Induction was well tolerated. At 18 months, 8 patients (50%) vs. 3 reference-patients (9.4%) rejected the graft [HR (95% CI): 6.53 (1.73-24.70), p = 0.006]. Difference was significant (p < 0.01) even after adjusting for recipient/donor age and gender, cold ischemia time and HLA mismatches. There were 1 antibody-mediated rejection and 2 moderate cellular rejections in patients vs. none in reference-patients (p = 0.032). The median (interquartile range) prednisone cumulative dose was remarkably higher in patients than reference-patients [4.78 (1.12-6.10) vs. 0.19 (0.18-3.81) grams, p = 0.002]. Three patients vs. 24 reference-patients were off-steroid at study end (p < 0.001). Three patients vs. no reference-patient developed new-onset diabetes (p = 0.003). Both inductions similarly depleted B-cells. Outcomes of AZA- vs. MMF-treated participants were similar. GFR was similar in all groups. Compared to MMF, AZA therapy saved ≈ EUR 2,500/year and by month 14.3 post-transplant compensated basiliximab costs.

CONCLUSION

In renal transplantation, basiliximab plus peri-operative low-dose RATG more efficiently prevented allograft rejection than RATG monotherapy, and minimized steroid exposure and toxicity. AZA- vs MMF-based maintenance immunosuppression largely compensated the extra costs of basiliximab.