Invasive bacillary angiomatosis in a kidney transplant recipient: A challenging case on belatacept immunosuppression.

Bacillary angiomatosis is a disseminated vascular proliferative disease caused by aerobic gram-negative bacilli Bartonella henselae or Bartonella quintana. Bacillary angiomatosis is mostly described in immunosuppressed patients with HIV infection and organ transplant recipients. We describe the case of a female aged 75 years who is a kidney transplant recipient who was admitted for a 3-month history of intermittent fever, chills, vomiting, and a 12-kg weight loss. The maintenance immunosuppression was based on prednisone, mycophenolate, and monthly infusions of belatacept. Physical examination was unremarkable. Laboratory investigations revealed elevated blood acute phase proteins but all blood cultures were negative. Serological tests for Bartonella were negative. Thoracoabdominal computed tomography scan and transesophageal echocardiography were normal. A Positron Emission Tomography scan showed a hypermetabolic mass in the duodenopancreatic region, with multiple hepatic and splenic lesions. Histological findings of spleen and pancreatic biopsies were not conclusive. The histopathological examination of a celiac lymph node biopsy finally demonstrated bacillary angiomatosis. The diagnosis of bacillary angiomatosis in immunocompromised patients is most often delayed in the absence of skin involvement. A high index of clinical suspicion is needed when interpreting negative results.

The spectrum of kidney biopsies in hospitalized patients with COVID-19, acute kidney injury, and/or proteinuria.

We report a multicentric retrospective case series of patients with COVID-19 who developed acute kidney injury and/or proteinuria and underwent a kidney biopsy in the Paris and its metropolitan area. Forty-seven patients (80.9% men) with COVID-19 who underwent a kidney biopsy between March 08 and May 19, 2020 were included. Median age was 63 years IQR [52-69]. Comorbidities included hypertension (66.0%), diabetes mellitus (27.7%), obesity (27.7%), history of chronic kidney (25.5%), cardiac (38.6%) and respiratory (27.3%) diseases. Initial symptoms were fever (85.1%), cough (63.8%), shortness of breath (55.3%), and diarrhea (23.4%). Almost all patients developed acute kidney injury (97.9%) and 63.8% required renal replacement therapy. Kidney biopsy showed two main histopathological patterns, including acute tubular injury in 20 (42.6%) patients, and glomerular injury consisting of collapsing glomerulopathy and focal segmental glomerulosclerosis in 17 (36.2%) patients. Two (4.3%) patients had acute vascular nephropathy, while eight (17%) had alternative diagnosis most likely unrelated to COVID-19. Acute tubular injury occurred almost invariably in the setting of severe forms of COVID-19, whereas patients with glomerular injury had various profiles of COVID-19 severity and collapsing glomerulopathy was only observed in patients harboring a combination of APOL1 risk variants. At last follow-up, 16 of the 30 patients who initially required dialysis were still on dialysis, and 9 died. The present study describes the spectrum of kidney lesions in patients with COVID-19. While acute tubular injury is correlated with COVID-19 severity, the pattern of glomerular injury is intimately associated with the expression of APOL1 risk variants.

The measured glomerular filtration rate (mGFR) before and 6 months after bariatric surgery: A pilot study.

INTRODUCTION: Over the last few decades, the prevalence of obesity has increased dramatically. This increase has been mirrored by a rise in the risk of a number of health conditions, including hypertension, diabetes and chronic kidney disease. Although the weight loss following bariatric surgery has been shown to relieve the severity of diabetes and reduce hypertension, the effect on renal function has been less extensively evaluated. OBJECTIVE: The aims of the present study were to: (i) compare the estimated glomerular filtration rate (eGFR, using the MDRD and CKD-EPI equations) and the calculated glomerular filtration rate (using the 24-hour urine volume) with the measured glomerular filtration rate (mGFR) assessed with the plasma iohexol clearance method in severely obese patients, and (ii) evaluate the effect of weight loss on the mGFR 6 months after bariatric surgery. METHODS: Before and six months after bariatric surgery (Roux-en-Y gastric bypass or sleeve gastrectomy), eligible patients for bariatric surgery were admitted as day cases to the nephrology unit, where they underwent a plasma iohexol clearance test. The GFR was also estimated using the MDRD and CKDEPI equations and the 24-hour urine method. Changes in eGFR and mGFR were compared using a Wilcoxon test for paired data. RESULTS: Data from 16 patients with severe obesity (mean ± standard deviation of Body Mass Index [BMI]: 43.9 ± 7.3 kg/m2) were analyzed. At baseline, 12 (75%) presented with hypertension and 10 (63%) presented with diabetes. The median [range] iohexol clearance rate was 109 [57-194] mL/min. The plasma iohexol clearance test evidenced hyperfiltration (mGFR>120 mL/min) in 7 patients. In contrast, the eGFR values generated by the MDRD equation, the CKDEPI equation and the GFR MFR calculated with the 24-hour urine method only identified hyperfiltration in 1, 0 and 5 patients, respectively. Six months after surgery, the mean BMI had fallen significantly (P<0.0012), and the severity of diabetes (according to the HbA1c level) had decreased significantly from 6.6 [6.0-9.8] % to 5.7 [5.2-8.6] % (P=0.025). The iohexol clearance rate increased slightly after bariatric surgery. Changes in BMI after surgery do not seem to be correlated with the changes in iohexol clearance. In patients displaying hyperfiltration at baseline, the mGFR fell significantly (n=7; P=0.01) and returned to near normal values. No significant changes in the eGFR were observed. CONCLUSION: Our results suggest that MDRD and CKD-EPI equations do not provide accurate estimates of the true GFR in severely obese patients (particularly in those with hyperfiltration). Iohexol clearance or other methods for determining mGFR should constitute the gold standard for the accurate evaluation of renal function in this context. Renal function (as evaluated by the mGFR) improved 6 months after bariatric surgery in severely obese individuals particularly in patients displaying hyperfiltration at baseline. However, these observations must be confirmed in a larger study with a longer follow-up period.

Renal safety of high-dose, sucrose-free intravenous immunoglobulin in kidney transplant recipients: an observational study.

High-dose intravenous immunoglobulin (IVIg) is commonly used during kidney transplantation. Its nephrotoxicity has been attributed to sucrose stabilizers. We evaluated the renal safety of newer formulations of sucrose-free IVIg. We retrospectively studied clinical and histological data from 75 kidney recipients receiving high-dose, sucrose-free IVIg courses. This group was compared with 75 matched kidney recipients not treated with IVIg. Sucrose-free IVIg treatment was not associated with any acute kidney injury episode at 3 months, but an increased frequency of tubular macrovacuoles (28% vs. 2.8%, P < 0.001) was observed. Among IVIg-treated patients, the presence of macrovacuoles at 3 months was associated with increased IF/TA scores at 3 months (1.7 ± 1 vs. 1 ± 1, P = 0.005) and was more often observed in kidneys with higher IF/TA scores on day 0 (0.6 ± 0.9 vs. 0.3 ± 0.8, P = 0.03) at 3 months. Finally, patients treated with amino-acid-stabilized formulations developed fewer macrovacuoles at 3 months (12% vs. 60%; P < 0.001) than those treated with carbohydrate-stabilized IVIg. Our study shows that high-dose, sucrose-free IVIg use in early kidney recipients is clinically well tolerated. Among sucrose-free IVIg, amino-acid-stabilized formulations are associated with less tubular toxicity than carbohydrate-stabilized IVIg.

Cysteamine therapy delays the progression of nephropathic cystinosis in late adolescents and adults.

Nephropathic cystinosis is a multisystem autosomal recessive disease caused by cystine accumulation, which is usually treated by oral cysteamine. In order to determine long-term effects of this therapy, we enrolled 86 adult patients (mean age 26.7 years) diagnosed with nephropathic cystinosis, 75 of whom received cysteamine. Therapy was initiated at a mean age of 9.9 years with a mean duration of 17.4 years. By last follow-up, 78 patients had end-stage renal disease (mean age 11.1 years), 62 had hypothyroidism (mean age 13.4), 48 developed diabetes (mean age 17.1 years), and 32 had neuromuscular disorders (mean age 23.3 years). Initiating cysteamine therapy before 5 years of age significantly decreased the incidence and delayed the onset of end-stage renal disease, and significantly delayed the onset of hypothyroidism, diabetes, and neuromuscular disorders. The development of diabetes and hypothyroidism was still significantly delayed, however, in patients in whom therapy was initiated after 5 years of age, compared with untreated patients. The life expectancy was significantly improved in cysteamine-treated versus untreated patients. Thus, cysteamine decreases and delays the onset of complications and improves life expectancy in cystinosis. Hence, cysteamine therapy should be introduced as early as possible during childhood and maintained lifelong.

[Parvovirus B19 infection after kidney transplantation]. / Infection par le Parvovirus B19 après transplantation rénale.

Prevalence for human parvovirus B19 infection is estimated to be between 2% and 30% in renal transplant recipients. In post-transplant settings, parvovirus B19 infection may occur either as a primary infection or a reactivation. Parvovirus transmission most commonly occurs through respiratory tract but may also result from graft or blood packs contamination. Co-infections with HHV-6 and CMV viruses are frequent. The hallmark symptom is anemia, more rarely pancytopenia and hemophagocytic syndrome. In respect to renal involvement, parvovirus B19 infection has been associated with graft dysfunction in 10% of cases. Both thrombotic microangiopathies and collapsing glomerulopathies have been reported concomitantly with parvovirus B19 infection but the causal link remains unclear. Other complications are seldomly reported, including hepatitis, encephalitis, and myocarditis. Diagnosis is based on pre and post-transplant serological status. In addition, the management of parvovirus B19 infection in immunocompromised patients requires quantitative assessment of blood viral load by PCR. The treatment relies primarily on reduction of immunosuppression combined with intravenous immunoglobulin infusions. Relapses occur in 30% of cases.

FOXP3-enriched infiltrates associated with better outcome in renal allografts with inflamed fibrosis.

BACKGROUND: FOXP3-expressing regulatory T cells (Tregs) play a crucial role in maintaining allogeneic transplant tolerance in experimental models. In clinical transplantation, there are few data about their role in chronic inflammation. We hypothesized that Tregs might accumulate within the graft since enrichment of Tregs has been frequently described in chronically inflamed tissues. METHODS: Sixty-seven biopsies, indicated by a rise in creatinine level, were studied. Thirty-four biopsies showing acute T-cell-mediated rejection and 33 displaying inflamed fibrosis were selected. Tregs frequency was calculated for each infiltrate by counting FOXP3+ and CD3+ cells on two contiguous serial sections. RESULTS: A total of 121 infiltrates were scored with a mean of 309 CD3+ cells per infiltrate (range: 50-700). Tregs were enriched within allografts exhibiting inflamed fibrosis versus acute cellular rejection (10.6 +/- 6.8% versus 5.5 +/- 2.6%, respectively, P = 0.005). In those with inflammation within scarred areas, the subset of patients with a low FOXP3/CD3 ratio (below the median value) displayed a lower frequency of B-cell-enriched nodular cell clusters (20% versus 86%, P = 0.001) and had a significantly lower graft survival (log-rank, P = 0.02). In multivariate analysis, the low FOXP3/CD3 ratio remained an independent indicator of outcome (P = 0.03). Consistently, the FOXP3+/IL-17+ cell ratio was higher in nodular than in diffuse infiltrates. CONCLUSIONS: Our results suggest that Tregs may dampen the graft injury in chronic (versus acute) inflammation and stress the importance of devising strategies to enhance Tregs efficiency.

Recurrent idiopathic thrombotic thrombocytopenic purpura: a role for vaccination in disease relapse?

The presence of antibodies against a disintegrin-like metalloproteinase with thrombospondin type 1 motif, isoform 13 (ADAMTS 13 protease) is the main cause (70% to 80%) of idiopathic and recurrent thrombotic thrombocytopenic purpura (TTP). However, etiologic factors that trigger the onset and potential relapses of TTP remain unclear. Immunologic deregulation and infectious agents are suspected. We report the case of a 51-year-old white man presenting with idiopathic TTP caused by autoantibodies against ADAMTS 13 protease. The first acute TTP episode needed long-term plasma exchanges because of early relapses. Consequently, vincristine therapy and splenectomy were performed. Those treatments induced TTP remission for 18 months. Relapses occurred twice between 1 and 3 months after vaccination. However, those relapses were not as severe as the first acute episode and responded to short-course plasma exchanges. ADAMTS 13 antibodies and decreased ADAMTS 13 protease activity were searched for and detected first during the second relapse. This case challenges the role of vaccination as an etiologic factor in the recurrence of idiopathic TTP.