Beyond the First Year: Epidemiology and Management of Late-Onset Opportunistic Infections After Kidney Transplantation

Late opportunistic infections (OI) occurring beyond the first year after kidney transplantation (KT) are poorly described and not targeted by prophylactic strategies. We performed a ten-year retrospective monocentric cohort study describing epidemiology, risk factors and impact of late OI occurring 1 year after KT. We included clinically symptomatic OI requiring treatment besides BK virus nephropathy. Control groups included early OI occurring in the first year after KT, and KT recipients without OI since KT and alive with a functional allograft at 1 year. Among 1066 KT recipients, 185 (19.4%) presented a first episode of OI 21.0 (8.0-45.0) months after KT: 120 late OI (64.9%) and 65 early OI (35.1%). Late OI were mainly viral (N = 83, 69.2%), mostly herpes zoster (HZ) (N = 36, 43.4%). Pneumocystis represented most late fungal infections (N = 12/25, 48%). Compared to early OI, we reported more pneumocystis (p = 0.002) and less invasive aspergillosis (p = 0.01) among late OI. Patients with late OI were significatively younger at KT (54.0 ± 13.3 vs. 60.2 ± 14.3 years, p = 0.05). Patient and allograft survival rates between late OI and control groups were similar. Only age was independently associated with mortality. While late OI were not associated with higher mortality or graft loss, implementing prophylactic strategies might prevent such infections.

Specificities of Meningitis and Meningo-Encephalitis After Kidney Transplantation: A French Retrospective Cohort Study

Kidney transplant recipients develop atypical infections in their epidemiology, presentation and outcome. Among these, meningitis and meningoencephalitis require urgent and adapted anti-infectious therapy, but published data is scarce in KTRs. The aim of this study was to describe their epidemiology, presentation and outcome, in order to improve their diagnostic and management. We performed a retrospective, multicentric cohort study in 15 French hospitals that included all 199 cases of M/ME in KTRs between 2007 and 2018 (0.9 case per 1,000 KTRs annually). Epidemiology was different from that in the general population: 20% were due to Cryptococcus neoformans, 13.5% to varicella-zoster virus, 5.5% to Mycobacterium tuberculosis, and 4.5% to Enterobacteria (half of which produced extended spectrum beta-lactamases), and 5% were Post Transplant Lymphoproliferative Disorders. Microorganisms causing M/ME in the general population were infrequent (2%, for Streptococcus pneumoniae) or absent (Neisseria meningitidis). M/ME caused by Enterobacteria, Staphylococci or filamentous fungi were associated with high and early mortality (50%-70% at 1 year). Graft survival was not associated with the etiology of M/ME, nor was impacted by immunosuppression reduction. Based on these results, we suggest international studies to adapt guidelines in order to improve the diagnosis and the probabilistic treatment of M/ME in SOTRs.

Sévérité de l’infection COVID-19 chez les patients transplantés rénaux d’un centre francilien

Introduction

Le phénotype du COVID-19 est très variable. Identifier et caractériser les populations à risque d’évolution défavorable est cruciale. L’objectif de cette étude est de décrire l’infection COVID-19 dans une population de transplantés rénaux (TR).

Matériels et méthodes

Il s’agit d’une étude rétrospective monocentrique des TR atteints de COVID-19 de février à mai 2020. Les cas confirmés par PCR et les cas possibles (clinique et lésions pulmonaires scanographiques compatibles) ont été inclus. La mortalité a été comparée avec celle de la population générale non transplantée dans le même centre.

Résultats

Parmi 1004 TR, 34 dont 26 hommes ont été atteints de COVID-19, avec un délai médian de 6 ans [2,2–10,3] après la transplantation. Deux patients avaient été transplantés dans les 6 mois précédents. L’âge moyen était de 61 ans [23–81]. Les principales comorbidités étaient une hypertension artérielle (31 cas, 94 %), une cardiopathie (16 cas, 47 %) et un diabète (14 cas, 41 %). Le traitement de maintenance associait les inhibiteurs de la calcineurine, les anti-métabolites et les corticoïdes chez 22 patients (65 %). Le débit de filtration glomérulaire estimé était de 40 mL/min/1,73 m² [32–52]. Neuf patients (26,5 %) avaient déjà présenté des complications infectieuses pulmonaires après la greffe. Trente patients (88 %) ont été hospitalisés avec un délai médian de 7,7 jours [3–9,5] après le début des symptômes.

Les signes cliniques initiaux principaux étaient une fièvre (n = 28,82 %), une toux (n = 23, 68 %), une dyspnée (n = 16, 47 %) et une diarrhée (n = 12, 35 %). À l’admission on observait une lymphopénie chez 18 patients (53 %), une CRP médiane à 84 mg/L [31,2–99,8] et une PCT médiane à 0,25 μg/L [0,19–0,4]. Sept patients sur 18 (39 %) présentaient une atteinte parenchymateuse pulmonaire sévère (plus de 50 %) au scanner. Les traitements spécifiques comprenaient l’hydroxychloroquine (n = 6, 18 %), l’association lopinavir/ritonavir (n = 1, 3 %), les anti-IL6 (n = 2, 6 %). L’arrêt d’un des immunosuppresseurs a été effectué chez 20 patients.

Une forme clinique sévère (admission en réanimation ou oxygénothérapie ≥ 9 L/min) est survenue chez 20 patients (61 %). Le délai d’admission en réanimation était de 2,5 jours [0–6,5] depuis l’hospitalisation. Vingt patients (61 %) ont présenté une insuffisance rénale aiguë dont 6 nécessitant de l’hémodialyse.

Quinze patients (44 %) sont décédés dans un délai de 11 jours [7–16] après l’hospitalisation. Le taux de décès chez les patients hospitalisés pour COVID-19 non TR était de 15,4 %.

Conclusion

Les patients transplantés rénaux sont une population à haut risque de forme sévère de COVID-19 avec un taux de mortalité approchant 50 % dans cette étude. Le renforcement des stratégies préventives et de dépistage semble primordial chez ces patients immunodéprimés et à fort risque cardiovasculaire.

[Evaluation of single kidney graft outcome in patients initially programmed for a dual kidney graft transplantation]

INTRODUCTION

Kidney transplantation is championed as the gold standard treatment for patients with end-stage kidney disease. According to the biomedical agency, there is an increasing number of patients waiting for kidney transplantation. Faced with organ shortage, the use of marginal grafts may well increase the number of available kidney grafts. Occasionally, during dual kidney graft transplantation, the poor quality of one of the two grafts, or other specific circumstances, may lead to transplantation of only one of the two grafts. We have compared patient outcome concerning single kidney transplantation from an initial dual kidney graft with respect to dual kidney graft transplantation.

MATERIAL

Among 67 patients enrolled for a dual kidney graft, 39 dual kidney grafts (group 1) were compared with 12 grafts performed with only one of the two kidneys of a dual kidney graft (group 2) as well as 15 grafts performed following a classic kidney graft protocol (group 3).

RESULTS

The survival of grafts was respectively for groups 1, 2 and 3 of 100%, 72,5% and 75,4% (P=0.17). The survival of patients was respectively for groups 1, 2 and 3 of 78.3%, 89.9% and 87.8% (P=0.47).

CONCLUSION

Our study suggests that transplantation of a single kidney, initially proposed as dual kidney graft candidate, has satisfying results in terms of graft survival and patient mortality at the expense of poorer renal function in comparison to dual kidney graft. Indeed, there was no significant difference in the survival of patients and grafts. This seems promising taking into consideration that the aim of transplantation in elderly recipients is primarily to avoid dialysis, rather than having optimal post-transplantation kidney function.

LEVEL OF EVIDENCE

4.

Low incidence of acute rejection within 6 months of kidney transplantation in HIV-infected recipients treated with raltegravir: the Agence Nationale de Recherche sur le Sida et les Hépatites Virales (ANRS) 153 TREVE trial

OBJECTIVES

High rates of clinical acute rejection after kidney transplantation have been reported in people living with HIV (PLHIV), probably as a consequence of drug interactions. We therefore investigated the incidence of acute rejection within 6 months of transplantation in HIV-infected recipients treated with a protease-inhibitor-free raltegravir-based regimen.

METHODS

The Agence Nationale de Recherche sur le Sida et les Hépatites Virales (ANRS) 153 TREVE (NCT01453192) study was a prospective multicentre single-arm trial in adult PLHIV awaiting kidney transplantation, with viral load < 50 HIV-1 RNA copies/mL, CD4 T-cell count > 200 cells/μL, and HIV-1 strains sensitive to raltegravir, aiming to demonstrate 6-month clinical acute rejection rates < 30%. Time to transplantation was compared with that for uninfected subjects matched for age, sex and registration date.

RESULTS

In total, 61 participants were enrolled in the study, and 26 underwent kidney transplantation. Two participants experienced clinical acute rejection, corresponding to an estimated clinical acute rejection rate of 8% [95% confidence interval (CI) 2-24%] at 6 and 12 months post-transplantation. HIV infection remained under control in all but one participant, who temporarily stopped antiretroviral treatment. Median time to transplantation was longer in PLHIV than in controls (4.3 versus 2.8 years, respectively; P = 0.002) and was not influenced by blood group.

CONCLUSIONS

Acute rejection rates were low after kidney transplantation in PLHIV treated with a raltegravir-based regimen. However, PLHIV have poorer access to transplantation than HIV-uninfected individuals after registration on the waiting list.

Transcriptomic Signature of the CD24hi CD38hi Transitional B Cells Associated With an Immunoregulatory Phenotype in Renal Transplant Recipients

The role of B cells after transplant regarding allograft rejection or tolerance has become a topic of major interest. Recently, in renal transplant recipients, a B cell signature characterized by the overexpression of CD19⁺ CD38^hi CD24^hi transitional B cells has been observed in operationally tolerant patients and in belatacept-treated patients with significantly lower incidence of donor-specific antibodies. The phenotypic and functional characterization of these transitional B cells is far from exhaustive. We present the first transcriptomic and phenotypic analysis associated with this cell phenotype. Three populations were studied and compared: (i) transitional CD24^hi CD38^hi , (ii) CD24⁺ CD38^- , and (iii) CD24^int CD38^int B cells. Transcriptome bioinformatic analysis revealed a particular signature for the CD24^hi CD38^hi population. Phenotypic analysis showed that CD24^hi CD38^hi transitional B cells also expressed CD9, CD10, CD1b and inducible T cell costimulator ligand (ICOS-L) markers. In addition, we found enrichment of IL-10⁺ cells among CD24^hi CD38^hi cells expressing ICOS-L and CD1b, the latter showing regulatory properties. Renal transplant recipients treated with belatacept exhibited significant expression of CD1b. Our results show that transitional CD24^hi CD38^hi B cells exhibit a distinct and specific profile, and this could be helpful for understanding of immune-regulatory mechanisms and immune monitoring in the field of organ transplant and autoimmune disease.

Th-17 Alloimmune Responses in Renal Allograft Biopsies From Recipients of Kidney Transplants Using Extended Criteria Donors During Acute T Cell-Mediated Rejection

Although renal transplantation using expanded criteria donors has become a common practice, immune responses related to immunosenescence in those kidney allografts have not been studied yet in humans. We performed a retrospective molecular analysis of the T cell immune response in 43 kidney biopsies from patients with acute T cell-mediated rejection including 25 from recipients engrafted with a kidney from expanded criteria donor and 18 from recipients grafted with optimal kidney allograft. The clinical, transplant and acute T cell-mediated rejection characteristics of both groups were similar at baseline. The expression of RORγt, Il-17 and T-bet mRNA was significantly higher in the elderly than in the optimal group (p = 0.02, p = 0.036, and p = 0.01, respectively). Foxp3 mRNA levels were significantly higher in elderly patients experiencing successful acute T cell-mediated rejection reversal (p = 0.03). The presence of IL-17 mRNA was strongly associated with nonsuccessful reversal in elderly patients (p = 0.008). Patients with mRNA IL17 expression detection and low mRNA Foxp3 expression experienced significantly more treatment failure (87.5%) than patients with no mRNA IL17 expression and/or high mRNA Foxp3 expression (26.7%; p = 0.017). Our study suggests that the Th17 pathway is involved in pathogenesis and prognosis of acute T cell-mediated rejection in recipients of expanded criteria allograft.

Kidney transplant recipients treated with belatacept exhibit increased naïve and transitional B cells

Phase III clinical studies have shown that kidney transplant (KT) recipients treated with the costimulation blocker belatacept exhibited a better renal allograft function and lower donor-specific anti-HLA immunization when compared to recipients treated with calcineurin inhibitors (CNI). We analyzed B cell phenotype in KT recipients treated with belatacept and stable renal function (N = 13). Results were compared to those observed in stable patients treated with CNI (N = 12), or with chronic antibody-mediated rejection (N = 5). Both transcriptional profile and phenotypic characterization of peripheral B cells were performed by real-time polymerase chain reaction and flow cytometry, respectively. In belatacept group, the frequency and absolute number of transitional B cells as defined by both phenotypes: CD19(+) CD24(hi) CD38(hi) and CD19(+) IgD(hi) CD38(hi) CD27(-) , as well as naïve B cells were significantly higher compared with CNI group. B cell activating factor (BAFF) and BAFF receptor mRNA levels were significantly lower in belatacept group than in CNI group. These results show for the first time that belatacept influences B cell compartment by favoring the occurrence of transitional B cells with potential regulatory properties, as described in operational tolerant patients. This role may explain the lower alloimmunization rate observed in belatacept-treated patients.

Renal transplantation in HIV-infected patients: the Paris experience

Kidney transplantation is now considered as a reasonable option for HIV-infected patients with end-stage renal disease. We describe here a retrospective study conducted in five transplantation centers in Paris. Twenty-seven patients were included. Immunosuppressive protocol associated an induction therapy and a long-term treatment combining mycophenolate mofetil, steroids and either tacrolimus or cyclosporine. All the patients had protocol biopsies at 3 months and 1 year. Patient's survival was 100% at 1 year and 98% at 2 years. Graft survival at 1 and 2 years is 98% and 96% at 1 and 2 years, respectively. The mean glomerular filteration rate values at 12 and 24 months were 60.6 mL/min/1.73 m² (range 23-98) and 65.4 mL/min/1.73 m² (range 24-110), respectively. Acute cellular rejection was diagnosed in four cases (15%). Because of high trough levels of calcineurin inhibitor, protease-inhibitor therapies were withdrawn in 11 cases. HIV disease progression was not observed. One patient developed B-cell lymphoma. In conclusion, our study confirms the safety of renal transplantation in HIV-infected patients with few adverse events and a low incidence of acute rejection.

Predominant Th1 and cytotoxic phenotype in biopsies from renal transplant recipients with transplant glomerulopathy

Transplant glomerulopathy (TGP) appears to be a pathogenic feature of chronic antibody-mediated rejection, but the pathogenesis of this histologic entity is still poorly understood. Previous studies suggest the involvement of lymphocytes but the phenotypes of these cells have never been analyzed. Here, we report the first study of mRNAs for specific markers of CD4+ T cells including Th1 (T-bet and INFgamma), Th2 (IL4 and GATA3), Treg (Foxp3) and Th17 (IL-17 and RORgammat) subsets, cytotoxic CD8 T cells (Granzyme B) and B-cell markers (CD20) in renal biopsies from renal transplant recipients suffering interstitial fibrosis and tubular atrophy (IF/TA) with or without TGP but with a similar inflammatory score and controls including transplant recipients with normal renal function. Only INFgamma, T-bet (both functionally defined markers of Th1 CD4 T cells) and granzyme B (a CD8 cytotoxic marker) were significantly more strongly expressed in patients with TGP than in patients without TGP and normal controls. These results indicate a role of an active T-mediated inflammatory and cytotoxic process in the pathogenesis of TGP.

Outcome of renal transplantation in eight patients with Candida sp. contamination of preservation fluid

The complications of kidney graft preservation fluid infected by Candida sp. may range in severity from trivial infections to life-threatening complications, including graft arteritis and anastomotic rupture. Mandatory nephrectomy has recently been proposed as a means of preventing arterial wall rupture in such cases. We describe the clinical features and outcome of renal transplantation from a cadaveric donor in eight recipients with preservation fluid testing positive for Candida sp. Six patients were treated with antifungal drugs. After 1-2 years of follow-up, including regular imaging, none of the patients had developed arterial aneurysm, and all had a functional allograft and were alive. The contamination of renal graft preservation fluid with Candida sp. may be uneventful and should not systematically lead to removal of the graft. Until other risk factors for vascular complications have been determined, early antifungal treatment and repeated radiological monitoring are advisable for the prevention and/or early detection of such complications.

Risk factors and long-term outcome of transplant renal artery stenosis in adult recipients after treatment by percutaneous transluminal angioplasty

Transplant renal artery stenosis (TRAS) is a common complication of kidney transplantation but attempts to identify predisposing risk factors for TRAS have yielded conflicting results. In order to determine the predisposing factors for transplant (TRAS), we retrospectively reviewed the records of 29 renal allograft recipients with TRAS treated with percutaneous transluminal angioplasty (PTA). The TRAS group was compared with a case-control group of 58 patients. Predisposing factors for TRAS included CMV infection (41.4% vs. 12.1% p = 0.0018) and initial delayed graft function (DGF) (48.3% vs. 15.5% p = 0.0018), respectively in the TRAS and the control group. Acute rejection occurred more frequently in patients from the TRAS group (48.3%) compared with the control group (27.6%), although the difference was not significant (p = 0.06). In a multivariate analysis, only CMV infection (p = 0.005) and DGF (p = 0.009) appear to be significantly and independently associated with TRAS. The long-term graft survival was significantly higher in the control group, compared with the TRAS group (p = 0.03). Our study suggests that CMV infection and DGF are two reliable risk factors for TRAS. Despite treatment by PTA with primary successful results, TRAS significantly affects long-term graft outcome.