Background Kidney transplant recipients and patients receiving hemodialysis are immunocompromised populations that are prioritized for COVID-19 vaccination but were excluded from clinical trials of SARS-CoV-2 mRNA vaccines. Antibody titers and rates of seroconversion following vaccination are lower among patients with chronic kidney disease and those taking immunosuppressants compared with controls. Data are lacking regarding their humoral response to vaccination to prevent COVID-19. Methods This investigation of early serological response after COVID-19 vaccination with the Pfizer/BioNTech (BNT162b2) mRNA vaccine included 78 patients undergoing hemodialysis, 74 kidney transplant recipients, and 7 healthy controls. We recorded data from the medical file for various clinical parameters, including response to hepatitis B vaccination, and measured antibody titers against SARS-CoV-2 at 0, 14, 28, 36 and 58 days after the first injection. Results In controls, we detected antibodies at a positive level (>13 arbitrary units per milliliter [AU/ml]) at day 14 postinjection, which increased progressively to peak at day 36 (1082 AU/ml; interquartile range [IQR], 735.0-1662.0]). Patients undergoing hemodialysis had lower titers that peaked at day 58 (276 AU/ml [IQR, 83.4-526.0]. We detected a positive antibody level in only three transplant recipients at day 36. In hemodialysis patients, those younger than 75 years had a higher antibody response versus those older than 75 years and serum albumin and Kt/V were positively correlated with serological response (P< 0.043 and P<0.019, respectively); nonresponders to HBV vaccine had the lowest anti-SARS-CoV-2 antibody titers. Conclusions Our results suggest that the postvaccination humoral response is strongly inhibited by immunosuppressant therapy in kidney transplant recipients and is reduced by the uremic condition in patients undergoing hemodialysis.

Kidney transplant recipients (KTRs) tend to develop infections with characteristic epidemiology, presentation, and outcome. While infective endocarditis (IE) is among such complications in KTRs, the literature is scarce. We describe the presentation, epidemiology, and factors associated with IE in KTRs. We performed a retrospective case/control study which included patients from two centers. First episodes of definite or possible IE (Duke criteria) in adult KTRs from January 2010 to December 2018 were included, as well as two controls per case, and followed until 31 December 2019. Clinical, biological, and microbiological data and the outcome were collected. Survival was studied using the Kaplan–Meier method. Finally, we searched for factors associated with the onset of IE in KTRs by the comparison of cases and controls. Seventeen cases and 34 controls were included. IE was diagnosed after a mean delay of 78 months after KT, mostly on native valves of the left heart only. Pathogens of digestive origin were most frequently involved (six Enterococcus spp, three Streptococcus gallolyticus, and one Escherichia coli), followed by Staphylococci (three cases of S. aureus and S. epidermidis each). Among the risk factors evaluated, age, vascular nephropathy, and elevated calcineurin inhibitor through levels were significantly associated with the occurrence of IE in our study. Patient and death-censored graft survival were greatly diminished five years after IE, compared to controls being 50.3% vs. 80.6% (p < 0.003) and 29.7% vs. 87.5% (p < 0.002), respectively. IE in KTRs is a disease that carries significant risks both for the survival of the patient and the transplant.

Purpose: Kidney Transplant Recipients (KTRs) tend to develop infections with characteristic epidemiology, presentation and outcome. While infective endocarditis (IE) is among such complications in KTRs, literature is scarce. We describe the presentation, epidemiology, and factors associated with IE in KTRs. Methods: We performed a retrospective case/control study which included patients from two centers. First episodes of definite or possible IE (Duke criteria), in adult KTRs from January 2007 to December 2018 were included, as well as two controls per case, and followed until December 31 2019. Clinical, biological, and microbiological data and the outcome were collected. Survival was studied using the Kaplan-Meier method. Finally, we searched for factors associated with the onset of IE in KTRs by the comparison of cases and controls. Results: Seventeen cases and 34 controls were included. IE was diagnosed after a mean delay of 78 months after KT, mostly on native valves of the left heart only. Pathogens of digestive origin were most frequently involved (six Enterococcus spp, three Streptococcus gallolyticus and one Escherichia coli), followed by Staphylococci (three cases of S. aureus and S. epidermidis each). Among the risk factors evaluated only age was significantly associated with the occurrence of IE in our study (63.8 years for cases vs. 55.6 years for controls, P=0.03) Patient and death-censored graft survival were greatly diminished five years after IE compared to controls being 50.3% vs. 80.6% (p&lt;0.003) and 29.7% vs. 87.5% (p&lt;0.002), respectively. Conclusion: IE in KTRs is a disease that carries significant risks both for the survival of the patient and the transplant.

Background Thymomas have been associated with a broad spectrum of autoimmune diseases. Minimal change disease (MCD) is the most frequent pathological lesion reported. Pathophysiological mechanisms involved in secondary MCD, and linking MCD to thymoma are not yet fully explained, although the hypothesis of T cell dysfunction has been suggested. The fundamental therapeutic principles are steroids and surgical treatment of thymoma, but failures and relapses often require immunosuppressant combinations. Case presentation A 62-year-old female was admitted in our unit for a nephrotic syndrome associated with a thymoma. The diagnosis of thymoma associated MCD was confirmed by kidney biopsy. After surgical resection of the thymoma and steroid therapy, no remission was observed. Immunosuppressive therapy was then intensified with introduction of rituximab. Here, we report a steroid-resistant nephrotic syndrome secondary to MCD associated thymoma, which achieved complete remission after rituximab therapy. To the best of our knowledge, this is the first report of the use and efficacy of rituximab therapy in this pathology. Conclusions Our case report suggests that primary and secondary MCD may share similar pathophysiological mechanisms. It does not allow us to draw any conclusions about the mechanism of action of rituximab, but we believe this report argues for the safety and efficacy of rituximab use in thymoma-associated MCD, and therefore constitutes a rationale for future studies.

Introduction Kidney transplant recipients and patients on hemodialysis are immunocompromised populations, prioritized for COVID 19 vaccination, but excluded from vaccine trials. Data are lacking regarding humoral response to COVID vaccination in immunocompromised patients. Description We investigated early serological response after COVID 19 vaccination with Pfizer/BioNTech (BNT162b2) mRNA vaccine in groups of patients undergoing hemodialysis ( n = 78), kidney transplant recipients ( n = 74), and in healthy controls. Antibody titers against SARS-CoV-2 at days 0, 14, 28, 36 and 58 after the first injection were measured. Methods Antibody titers against SARS-CoV-2 at days 0, 14, 28, 36 and 58 after the first injection were measured. Results A total of 74 transplant recipients (mean age 64.8 ± 11.5 years, 38.9% women), 78 hemodialysis patients (mean age 73.5 ± 12.8 years, 40.2% women) and 7 healthy controls (mean age 51.6 ± 6.8, 42% women) were included. In controls, antibodies were detected at a significant level (> 13 AU/ml) at day 14 post-injection, and increased progressively, to peak at day 36 (median 1372 AU/mL [IQR 490.2-4540.5]). Patients undergoing hemodialysis had lower titers that peaked at day 58 (median 4.0 AU/mL [IQR: 1.85-12.2] at day 14; 6.6 AU/mL [IQR 2.1-19.0] at day 36; 276 AU/mL [IQR 83.4-526.0] at day 58). A significant antibody level was detected in only 3 kidney transplant recipients at day 36. In hemodialysis patients, age, serum albumin and Kt/V were positively correlated with serological response ( P < 0.043 and P < 0.019 respectively); non responders to HBV vaccine had the lowest titers of anti-SARS-CovV-2 antibodies ( Fig. 1 ). Conclusion Our results suggest that the post-vaccine humoral response is strongly inhibited by immunosuppressant therapy in kidney transplant recipients, while it is lowered by the uremic condition in patients undergoing hemodialysis.

Background and Aims Primary IgA nephropathy (IgAN) and IgA vasculitis nephritis (IgAVN) share common features e.g. clinical, histological, pathophysiological. Their prognosis assessment is usually considered to be dependent on histological findings which are therefore useful to establish therapeutic intervention. The validated MEST-C classification is widely used for IgAN. Regarding IgAVN, various classifications are used in clinical practice. However, there is no consensus regarding their feasibility, correlations with renal outcome and their usefulness regarding therapeutic decisions. The aim of this study was to compare the Pillebout and Nochy French classification (PNC), created as a specific IgAVN prognosis scoring system MEST-C classification. Method Renal biopsies (RB) of patients with IgAVN were selected from two previous national IGAV cohorts and then reclassified according to the MEST-C and PNC classifications. For both classifications, the primary endpoint was the renal remission defined as a final glomerular filtration rate (GFR) greater than 60 ml / min. We also analyse: a) the renal survival defined as the absence of dialysis or transplantation; b) clinical-pathological correlation between the 2 classifications and c) the interobserver reproducibility. Results 372 RB from 316 patients were analysed, with 240 patients followed for at least 1 year. The median age was 48 yrs (14 to 86), with a sex ratio of 1.76 for men and a median follow-up of 4.3 years (range 1 to 22.7). Renal impairment was more severe over the age of 60 yrs. The presence of general signs, the initial GFR, and hypertension were significantly associated with renal survival. Proteinuria and albuminemia were associated with proliferative lesions (MEST-C score: E, C). The fibrous lesions (MEST-C: T and PNC stage V) were associated with GFR at the end of the follow-up. No significant association was found between the PNC stage and renal survival. Univariate analyses showed significant association with the primary outcome for the MEST-C T variable (p=0.02). However, by multivariate analysis, this association did not persist. The correlation between the observers was better for MEST-C compared with PNC (0.87 vs. 0.75). Conclusion Our results suggest that MEST-C classification has a good clinical and pathological correlation, a good reproducibility, and is interesting to evaluate the long-term renal outcome of patients with IgAVN. However, the correlation is still not perfect. Indeed, fibrosis was the only pathological feature independently associated with renal endpoints. We suggest that MEST-C is a scoring system which is not fully adapted due to the predominant inflammatory mechanism in IgAVN unlike IgAN. PNC should not be used because of the poor interobserver correlation. It is important to identify new specific IgAVN histological markers, taking into account the inflammatory mechanism, to ensure a more accurate prognostic classification, useful to guide therapeutic strategy.