Safety and efficacy of tixagevimab/cilgavimab for pre-exposure prophylaxis in kidney transplant recipients: a multicenter retrospective cohort study.

BACKGROUND: Immunocompromised patients show an impaired vaccine response and remain at high risk of severe COVID-19, despite vaccination. Neutralizing monoclonal antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed for prophylaxis and treatment. The combination tixagevimab/cilgavimab (AZD7442) has been authorized for emergency use as pre-exposure prophylaxis for COVID-19, but data on safety and efficacy in kidney transplant recipients during the Omicron period are limited. METHODS: We conducted a multicenter retrospective cohort study including 253 kidney transplant recipients, of whom 98 were treated with tixagevimab/cilgavimab 150 mg/150 mg and 155 who received only four doses of the BNT162b2 mRNA vaccine. RESULTS: Only 13.3% of patients developed SARS-CoV-2 infection after the administration of tixagevimab/cilgavimab; in comparison, 34.2% of patients had been infected after the fourth dose of vaccine (p = 0.00013). Most infected patients in the AZD7442 group remained asymptomatic (92.3% vs 54.7%), 7.7% had mild symptoms and none had severe disease, need for hospitalization or died, while in the control group, 9.4% of patients had moderate or severe disease (p = 0.04). Using Kaplan-Meier curves we demonstrated that the controls presented early infection compared to the AZD7442 group (p = 0.000014). No changes in eGFR or proteinuria, assessed before and after the administration, were observed. CONCLUSIONS: In conclusion, our study showed that tixagevimab/cilgavimab 150/150 mg is effective and safe in preventing infection and severe disease when administered to patients with weak or no response to COVID-19 vaccine.

Can Galectin-3 be a reliable predictive biomarker for post-COVID syndrome development?

BACKGROUND AND OBJECTIVES: Reliable biomarkers able to predict post-COVID syndrome development are still lacking. The aim of the study was to evaluate the relationship between Galectin-3 blood concentrations and the development of post-COVID syndrome. METHODS: We performed a single-center, prospective, observational study, enrolling 437 consecutive patients attending our outpatient clinic for the post-COVID assessment. For each patient, we recorded the main clinical, functional and radiological findings. We also dosed several blood biomarkers which have been related to COVID-19 disease, including Galectin-3. We performed Receiver Operating Characteristic (ROC) and multivariate regression analysis to evaluate the predictive performance of Galectin-3 for post-COVID syndrome development. RESULTS: Among the blood biomarkers tested, Galectin-3 resulted the only one correlated with the outcome, although the insufficient performance of the Cox regression model from a statistical standpoint. Correlation coefficients and ROC curves analysis revealed the close relationship between Galectin-3 levels and the time passed from the acute phase of COVID-19 disease, suggesting a possible predictive role for this biomarker when dosed from 60 to 120 days after the infection. CONCLUSIONS: Galectin-3 could play an important role as predictive biomarker for COVID-19 sequelae, but its evaluation must be carefully planned along the follow up to avoid misinterpretations.

Beneficial effects of recombinant CER-001 high-density lipoprotein infusion in sepsis: results from a bench to bedside translational research project.

BACKGROUND: Sepsis is characterized by a dysregulated immune response and metabolic alterations, including decreased high-density lipoprotein cholesterol (HDL-C) levels. HDL exhibits beneficial properties, such as lipopolysaccharides (LPS) scavenging, exerting anti-inflammatory effects and providing endothelial protection. We investigated the effects of CER-001, an engineered HDL-mimetic, in a swine model of LPS-induced acute kidney injury (AKI) and a Phase 2a clinical trial, aiming to better understand its molecular basis in systemic inflammation and renal function. METHODS: We carried out a translational approach to study the effects of HDL administration on sepsis. Sterile systemic inflammation was induced in pigs by LPS infusion. Animals were randomized into LPS (n = 6), CER20 (single dose of CER-001 20 mg/kg; n = 6), and CER20 × 2 (two doses of CER-001 20 mg/kg; n = 6) groups. Survival rate, endothelial dysfunction biomarkers, pro-inflammatory mediators, LPS, and apolipoprotein A-I (ApoA-I) levels were assessed. Renal and liver histology and biochemistry were analyzed. Subsequently, we performed an open-label, randomized, dose-ranging (Phase 2a) study included 20 patients with sepsis due to intra-abdominal infection or urosepsis, randomized into Group A (conventional treatment, n = 5), Group B (CER-001 5 mg/kg BID, n = 5), Group C (CER-001 10 mg/kg BID, n = 5), and Group D (CER-001 20 mg/kg BID, n = 5). Primary outcomes were safety and efficacy in preventing AKI onset and severity; secondary outcomes include changes in inflammatory and endothelial dysfunction markers. RESULTS: CER-001 increased median survival, reduced inflammatory mediators, complement activation, and endothelial dysfunction in endotoxemic pigs. It enhanced LPS elimination through the bile and preserved liver and renal parenchyma. In the clinical study, CER-001 was well-tolerated with no serious adverse events related to study treatment. Rapid ApoA-I normalization was associated with enhanced LPS removal and immunomodulation with improvement of clinical outcomes, independently of the type and gravity of the sepsis. CER-001-treated patients had reduced risk for the onset and progression to severe AKI (stage 2 or 3) and, in a subset of critically ill patients, a reduced need for organ support and shorter ICU length of stay. CONCLUSIONS: CER-001 shows promise as a therapeutic strategy for sepsis management, improving outcomes and mitigating inflammation and organ damage. TRIAL REGISTRATION: The study was approved by the Agenzia Italiana del Farmaco (AIFA) and by the Local Ethic Committee (N° EUDRACT 2020-004202-60, Protocol CER-001- SEP_AKI_01) and was added to the EU Clinical Trials Register on January 13, 2021.

Kinetics of humoral immune response and severity of infection after three doses of SARS-CoV-2 mRNA vaccine in a large cohort of kidney transplant recipients.

BACKGROUND: COVID-19 in kidney transplant recipients is associated with high morbidity and mortality. In this study we aimed to evaluate: (i) the seroconversion rate after BNT162b2 (Pfizer-BioNTech) SARS-CoV-2 vaccine, (ii) factors associated with humoral response, (iii) clinical outcome of COVID-19 in kidney transplanted patients. METHODS: We enrolled a cohort of 743 kidney transplant recipients followed up from March 2020 until April 2022. A subset of 336 patients, who received three-doses of SARS-CoV-2 vaccine, was analyzed in terms of kinetics of humoral immune response and compared to a control group of 94 healthcare workers. Antibody response was tested before vaccination (T0), 15 and 90 days after the second dose (T1 and T2), on the day of the third dose (T3) and one month after the third dose (T4). RESULTS: We observed that 66 out of 743 subjects had COVID-19 infection pre-vaccination: 65.2% had severe symptoms, 27.3% were hospitalized (9 deaths), none were asymptomatic. After three doses, 51 patients had COVID-19 infection, 60.8% were asymptomatic, 27.5% reported mild symptoms, 3.9% showed severe symptoms, 7.8% were hospitalized (2 deaths). In the subset of 336 vaccinated patients, an antibody level > 0.8 U/ml was detected at T1, that increased at T2 and T3, peaking at T4. Independent factors associated with a negative antibody titer at T4 were decreasing estimated glomerular filtration rate, time from transplantation, and antimetabolites (all p < 0.001) and age (p = 0.007). CONCLUSIONS: The kinetics of humoral response after three doses of vaccine in kidney transplant patients is characterized by a late but effective immune response against SARS-CoV-2, reducing morbidity and mortality.

Analysis of Quality Indicators of the Pre-Analytical Phase on Blood Gas Analyzers, Point-Of-Care Analyzer in the Period of the COVID-19 Pandemic.

AIM OF THE STUDY: We evaluated and compared blood gas analysis (EGA) non-conformities (NC) considered operator-dependent performed in Point-Of-Care (POC) analyzer as quality indicators (IQ) of the pre-analytical phase. To this end, four different NC registered in the resuscitation departments of the Hospital Polyclinic Bari from the beginning of the pandemic (March 2020) until February 2022 were evaluated. The results obtained were compared with those recorded in the pre-COVID period (March 2018-February 2020) to check if there were differences in number and type. MATERIAL AND METHODS: GEM 4000 series blood gas analyzers (Instrumentation Laboratory, Bedford, MA, United States) are installed with integrated Intelligent Quality Management (iQM®), which automatically identify and log pre-analytical errors. All blood gas analyzers are connected to the company intranet and interfaced with the GEM Web Plus (Werfen Instrumentation Laboratory, Bedford, MA, United States) data management information system, which allows the core laboratory to remotely supervise all decentralized POC stations. The operator-dependent process NC were expressed in terms of absolute and relative proportions (percentiles and percentage changes). For performance evaluation, the Mann-Whitney U test, Chi-squared test and Six-Sigma Metric calculation for performance classification were performed. RESULTS: In the COVID period, 31,364 blood gas tests were performed vs. 16,632 tests in the pre-COVID period. The NC related to the suitability of the EGA sample and manageable by the operators were totals of 652 (3.9%) and 749 (2.4%), respectively, in the pre-COVID and COVID periods. The pre-analytical phase IQs used did not show statistically significant differences in the two periods evaluated. The Sigma evaluation did not show an increase in error rates. CONCLUSIONS: Considering the increase in the number of EGAs performed in the two periods, the training procedures performed by the core laboratory staff were effective; the clinical users of the POC complied with the indications and procedures shared with the core laboratory without increasing the operator-dependent NCs. Furthermore, the core laboratory developed monitoring activities capable of guaranteeing the maintenance of the pre-analytical quality.

MUC1 Expression Affects the Immunoflogosis in Renal Cell Carcinoma Microenvironment through Complement System Activation and Immune Infiltrate Modulation.

Mucin1 (MUC1), a glycoprotein associated with an aggressive cancer phenotype and chemoresistance, is aberrantly overexpressed in a subset of clear cell renal cell carcinoma (ccRCC). Recent studies suggest that MUC1 plays a role in modulating cancer cell metabolism, but its role in regulating immunoflogosis in the tumor microenvironment remains poorly understood. In a previous study, we showed that pentraxin-3 (PTX3) can affect the immunoflogosis in the ccRCC microenvironment by activating the classical pathway of the complement system (C1q) and releasing proangiogenic factors (C3a, C5a). In this scenario, we evaluated the PTX3 expression and analyzed the potential role of complement system activation on tumor site and immune microenvironment modulation, stratifying samples in tumors with high (MUC1H) versus tumors with low MUC1 expression (MUC1L). We found that PTX3 tissue expression was significantly higher in MUC1H ccRCC. In addition, C1q deposition and the expressions of CD59, C3aR, and C5aR were extensively present in MUC1H ccRCC tissue samples and colocalized with PTX3. Finally, MUC1 expression was associated with an increased number of infiltrating mast cells, M2-macrophage, and IDO1+ cells, and a reduced number of CD8+ T cells. Taken together, our results suggest that expression of MUC1 can modulate the immunoflogosis in the ccRCC microenvironment by activating the classical pathway of the complement system and regulating the immune infiltrate, promoting an immune-silent microenvironment.

Correlation between In Vitro Neutralization Assay and Serological Tests for Protective Antibodies Detection.

Serological assays are useful in investigating the development of humoral immunity against SARS-CoV-2 in the context of epidemiological studies focusing on the spread of protective immunity. The plaque reduction neutralization test (PRNT) is the gold standard method to assess the titer of protective antibodies in serum samples. However, to provide a result, the PRNT requires several days, skilled operators, and biosafety level 3 laboratories. Therefore, alternative methods are being assessed to establish a relationship between their outcomes and PRNT results. In this work, four different immunoassays (Roche Elecsys® Anti SARS-CoV-2 S, Snibe MAGLUMI® SARS-CoV-2 S-RBD IgG, Snibe MAGLUMI® 2019-nCoV IgG, and EUROIMMUN® SARS-CoV-2 NeutraLISA assays, respectively) have been performed on individuals healed after SARS-CoV-2 infection. The correlation between each assay and the reference method has been explored through linear regression modeling, as well as through the calculation of Pearson's and Spearman's coefficients. Furthermore, the ability of serological tests to discriminate samples with high titers of neutralizing antibodies (>160) has been assessed by ROC curve analyses, Cohen's Kappa coefficient, and positive predictive agreement. The EUROIMMUN® NeutraLISA assay displayed the best correlation with PRNT results (Pearson and Spearman coefficients equal to 0.660 and 0.784, respectively), as well as the ROC curve with the highest accuracy, sensitivity, and specificity (0.857, 0.889, and 0.829, respectively).

New Analytical Approach for the Alignment of Different HE4 Automated Immunometric Systems: An Italian Multicentric Study.

Human epididymal secretory protein 4 (HE4) elevation has been studied as a crucial biomarker for malignant gynecological cancer, such us ovarian cancer (OC). However, there are conflicting reports regarding the optimal HE4 cut-off. Thus, the goal of this study was to develop an analytical approach to harmonize HE4 values obtained with different laboratory resources. To this regard, six highly qualified Italian laboratories, using different analytical platforms (Abbott Alinity I, Fujirebio Lumipulse G1200 and G600, Roche Cobas 601 and Abbott Architett), have joined this project. In the first step of our study, a common reference calibration curve (designed through progressive HE4 dilutions) was tested by all members attending the workshop. This first evaluation underlined the presence of analytical bias in different devices. Next, following bias correction, we started to analyze biomarkers values collected in a common database (1509 patients). A two-sided p-value < 0.05 was considered statistically significant. In post-menopausal women stratified between those with malignant gynecological diseases vs. non-malignant gynecological diseases and healthy women, dichotomous HE4 showed a significantly better accuracy than dichotomous Ca125 (AUC 0.81 vs. 0.74, p = 0.001 for age ≤ 60; AUC 0.78 vs. 0.72, p = 0.024 for age > 60). Still, in post-menopausal status, similar results were confirmed in patients with malignant gynecological diseases vs. patients with benign gynecological diseases, both under and over 60 years (AUC 0.79 vs. 0.73, p = 0.006; AUC 0.76 vs. 0.71, p = 0.036, respectively). Interestingly, in pre-menopausal status women over 40 years, HE4 showed a higher accuracy than Ca125 (AUC 0.73 vs. 0.66, p = 0.027), thus opening new perspective for the clinical management of fertile patients with malignant neoplasms, such as ovarian cancer. In summary, this model hinted at a new approach for identifying the optimal cut-off to align data detected with different HE4 diagnostic tools.

Predictive Machine Learning Models and Survival Analysis for COVID-19 Prognosis Based on Hematochemical Parameters.

The coronavirus disease 2019 (COVID-19) pandemic has affected hundreds of millions of individuals and caused millions of deaths worldwide. Predicting the clinical course of the disease is of pivotal importance to manage patients. Several studies have found hematochemical alterations in COVID-19 patients, such as inflammatory markers. We retrospectively analyzed the anamnestic data and laboratory parameters of 303 patients diagnosed with COVID-19 who were admitted to the Polyclinic Hospital of Bari during the first phase of the COVID-19 global pandemic. After the pre-processing phase, we performed a survival analysis with Kaplan-Meier curves and Cox Regression, with the aim to discover the most unfavorable predictors. The target outcomes were mortality or admission to the intensive care unit (ICU). Different machine learning models were also compared to realize a robust classifier relying on a low number of strongly significant factors to estimate the risk of death or admission to ICU. From the survival analysis, it emerged that the most significant laboratory parameters for both outcomes was C-reactive protein min; HR=17.963 (95% CI 6.548-49.277, p < 0.001) for death, HR=1.789 (95% CI 1.000-3.200, p = 0.050) for admission to ICU. The second most important parameter was Erythrocytes max; HR=1.765 (95% CI 1.141-2.729, p < 0.05) for death, HR=1.481 (95% CI 0.895-2.452, p = 0.127) for admission to ICU. The best model for predicting the risk of death was the decision tree, which resulted in ROC-AUC of 89.66%, whereas the best model for predicting the admission to ICU was support vector machine, which had ROC-AUC of 95.07%. The hematochemical predictors identified in this study can be utilized as a strong prognostic signature to characterize the severity of the disease in COVID-19 patients.

Determination of the Upper Reference Limit of Human Epididymis Secretory Protein 4 (HE4) in Healthy Male Individuals and Correlation with Renal and Fertility Markers.

BACKGROUND: Elevated human epididymis secretory protein 4 (HE4) serum levels have been widely investigated in patients with ovarian cancer. However, high levels of HE4 can be also found in other tumors and in renal fibrosis. To date, the HE4 assay manufacturer features the reference value only for the female pre- and post-menopausal population. The aim of this study was to determine the upper reference limit (URL) of HE4 in a well-defined and large cohort of healthy male individuals and investigate potential factors influencing HE4 levels in healthy subjects. METHODS: The study included 307 Italian healthy male individuals. HE4 was measured using a chemiluminescent assay (Abbott Laboratories, Wiesbaden, Germany). The URL was calculated using the non-parametric percentile method. Differences in HE4 concentrations according to age, estimated glomerular filtration rate (eGFR), free and bioavailable testosterone were also evaluated. RESULTS: The 97.5th percentile URL of serum HE4 in our study population was 57 pmol/L (90% CI). After stratifying subjects according to age, we found that the URL of HE4 was higher in older (> 50 years) than in younger subjects (18-30 years old), and overlapping with the URL in males from 31 to 50 years old (P=4.769e-16, r=0.44). A strong negative correlation between HE4 and eGFR was observed (P=8.412e-12, r=-0.38). Moreover, a statistically significant negative correlation was also found between HE4 and free and bioavailable testosterone. CONCLUSION: This study determined the URL of HE4 in a large cohort of healthy male subjects. Our findings indicate that the HE4 age-dependent differences in males need to be taken into account. The definition of the HE4 URL in males and the correlation observed with eGFR and testosterone should foster the clinical use of HE4 beyond gynecologic cancer.

New Insights in Laboratory Testing for COVID-19 Patients: Looking for the Role and Predictive Value of Human epididymis secretory protein 4 (HE4) and the Innate Immunity of the Oral Cavity and Respiratory Tract.

COVID-19 is a viral pandemic caused by the new coronavirus SARS-CoV-2, an enveloped positive stranded RNA virus. The mechanisms of innate immunity, considered as the first line of antiviral defense, is essential towards viruses. A significant role in host defense of the lung, nasal and oral cavities is played by Human epididymis secretory protein 4 (HE4) HE4 has been demonstrated to be serum inflammatory biomarker and to show a role in natural immunity at the level of oral cavity, nasopharynx and respiratory tract with both antimicrobial/antiviral and anti-inflammatory activity. Several biomarkers like IL-6, presepsin (PSP), procalcitonin (PCT), CRP, D-Dimer have showed a good function as predictor factors for the clinical evolution of COVID-19 patients (mild, severe and critical). The aim of this study was to correlate the blood levels of CRP, IL-6, PSP, PCT, D-Dimer with He4, to identify the predictive values of these biomarkers for the evolution of the disease and to evaluate the possible role of HE4 in the defense mechanisms of innate immunity at the level of oral cavity, nasopharynx and respiratory tract. Of 134 patients admitted at COVID hospital of Policlinico-University of Bari, 86 (58 men age 67.6 ± 12.4 and 28 women age 65.7 ± 15.4) fulfilled the inclusion criteria: in particular, 80 patients (93%) showed prodromal symptoms (smell and/or taste dysfunctions) and other typical clinical manifestations and 19 died (13 men age 73.4 ± 7.7 and 6 women age 74.8 ± 6.7). 48 patients were excluded because 13 finished chemotherapy and 6 radiotherapy recently, 5 presented suspected breast carcinoma, 5 suspected lung carcinoma, 6 suspected ovarian carcinoma or ovary cyst, 1 cystic fibrosis, 3 renal fibrosis and 9 were affected by autoimmune diseases in treatment with monoclonal antibodies. The venous sample was taken for each patient on the admission and during the hospital stay. For each patient, six measurements relating to considered parameters were performed. Significant correlations between He4 and IL-6 levels (r = 0.797), between He4 and PSP (r = 0.621), between He4 and PCT (r = 0.447), between He4 and D-Dimer (r = 0.367), between He4 and RCP (r = 0.327) have been found. ROC curves analysis showed an excellent accuracy for He4 (AUC = 0.92) and IL-6 (AUC = 0.91), a very good accuracy for PSP (AUC = 0.81), a good accuracy for PCT (AUC = 0.701) and D-Dimer (AUC = 0.721) and sufficient accuracy for RCP (AUC = 0.616). These results demonstrated the important correlation between He4, IL6 and PSP, an excellent accuracy of He4 and IL6 and showed a probable role of He4 in the innate immunity in particularly at the level of oral cavity, nasopharynx and respiratory tract. Besides He4 together with IL6 might be involved in the onset of smell and/or taste disorders and it might be used as innovative biomarker to monitor clinical evolution of COVID-19 because He4 could indicate a multi-organ involvement.

Taste and Smell Disorders in COVID-19 Patients: Role of Interleukin-6.

The rapid recovery of smell and taste functions in COVID-19 patients could be attributed to a decrease in interleukin-6 levels rather than central nervous system ischemic injury or viral damage to neuronal cells. To correlate interleukin-6 levels in COVID-19 patients with olfactory or gustatory dysfunctions and to investigate the role of IL-6 in the onset of these disorders, this observational study investigated 67 COVID-19 patients with taste or smell disorders or both, who did not require intensive care admission, admitted at COVID Hospital of Policlinico of Bari from March to May 2020. Interleukin-6 was assayed in COVID-19 patients with taste or smell disturbances at the time of admission and at the time of swab negativization. At the same time, patients have been given a specific survey to evaluate the severity of taste and smell disturbances. Of 125 patients with smell or taste dysfunctions at onset of disease, 67 fulfilled the inclusion criteria, while 58 were excluded because 35 of them required intensive care admission, 5 were unable to answer, 5 died, 7 had finished chemotherapy recently, and 5 refused to participate. The evaluation of taste and smell disorders was carried out using a survey performed at the time of admission and at the time of swab negativization. Sinonasal outcome test 22 (SNOT-22) was used as a reference for olfactory function assessment, and Taste and Smell Questionnaire Section of the US NHANES 2011-2014 protocol (CDC 2013b) was used as reference for gustatory function assessment. A venous blood sample was taken for each patient to measure IL-6 levels upon entry and at swab negativization. Interleukin-6 levels in COVID-19 patients in relation to olfactory or gustatory disorders were correlated from the time of their admission to the time of swab negativization. Statistically significant correlations were obtained between the decrease of interleukin-6 levels and the improvement of smell (p value < 0.05) and taste (p = 0.047) functions at swab negativization. The acquired results demonstrate the key role of interleukin-6 in the pathogenesis of chemosensitive disorders in COVID-19 patients.

Rapamycin for treatment of type I autosomal dominant polycystic kidney disease (RAPYD-study): a randomized, controlled study.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the most common form of cystic kidney disease. An inappropriate stimulation of mammalian target of rapamycin may represent the converging point in the molecular pathways leading to renal cyst growth. METHODS: The primary objectives of this prospective, open-label, randomized clinical trial were to assess whether rapamycin may reduce the progressive increase in single cyst and total kidney volume in type I ADPKD and the decline in renal function and to identify the optimal rapamycin dose. Fifty-five patients with type I ADPKD were enrolled and randomized to receive ramipril (Group A), ramipril + high-dose rapamycin (Group B, trough level 6-8 ng/mL) and ramipril + low-dose rapamycin (Group C, trough levels 2-4 ng/mL). Rapamycin efficacy was monitored measuring p70 phosphorylation in peripheral blood mononuclear cells. RESULTS: Both rapamycin doses significantly reduced p70 phosphorylation. Nevertheless, total kidney volume increased in all groups after 24 months, although only in Groups A and B, was the final volume significantly higher compared with the baseline. Single cyst final volume was not significantly different in the three groups, although it was increased in Group A compared with the baseline, whereas in Groups B and C, it was significantly reduced. We did not observe any difference in renal function at 24 months among the three study groups. Group A presented a significant worsening of renal function that remained stable in both Groups B and C. CONCLUSIONS: Our study would suggest that rapamycin does not influence the progression of type I ADPKD, although the higher drug dose tested prevented both the increase in kidney volume and the worsening of renal function (RAPYD-study, EUDRACT No. 2007-006557-25).

TRPC6 mutations in children with steroid-resistant nephrotic syndrome and atypical phenotype.

BACKGROUND AND OBJECTIVES: Mutations in the TRPC6 gene have been recently identified as the cause of late-onset autosomal-dominant focal segmental glomerulosclerosis (FSGS). To extend the screening, we analyzed TRPC6 in 33 Italian children with sporadic early-onset SRNS and three Italian families with adult-onset FSGS. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: TRPC6 mutation analysis was performed through PCR and sequencing. The effects of the detected amino acid substitutions were analyzed by bioinformatics tools and functional in vitro studies. The expression levels of TRPC6 and nephrin proteins were evaluated by confocal microscopy. RESULTS: Three heterozygous missense mutations (c.374A>G_p.N125S, c.653A>T_p.H218L, c.2684G>T_p.R895L) were identified. The first new mutation, p.H218L, was found in a 18-year-old boy who presented a severe form of FSGS at the age of 8 years. The second, p.R895L, a new de novo mutation, was identified in a girl with collapsing glomerulosclerosis at the age of 2 years. The former mutation, p.N125S, was found in two siblings with early-onset steroid-resistant nephrotic syndrome (SRNS) at the ages of 4 and 14 years. Renal immunofluorescence revealed upregulated expression of TRPC6 and loss of nephrin in glomeruli. The intracellular calcium concentrations were significantly higher in the cells expressing all mutant TRPC6 channels compared with cells expressing wild-type TRPC6. CONCLUSIONS: Our findings suggest that TRPC6 variants can also be detected in children with early-onset and sporadic SRNS (4 of 33 patients). Moreover, in one patient a new de novo TRPC6 mutation was associated with a rare severe form of childhood collapsing glomerulosclerosis with rapid progression to uremia.

Identification of GLA gene deletions in Fabry patients by Multiplex Ligation-dependent Probe Amplification (MLPA).

Fabry disease is an under-recognized X-linked lysosomal disorder, due to alpha-galactosidase A deficiency. Most of the mutations in the GLA gene are detectable using genomic sequencing analysis. However, deletions of one or more exons or deletion encompassing the entire gene are undetectable, especially in heterozygous females. The Multiplex Ligation-dependent Probe Amplification (MLPA) is an efficient tool for discovering these rearrangements. In this study two novel different deletions were detected using MLPA assay on two Fabry patients, both resulted mutation negative by sequencing analysis. These data suggest that this screening should be systematically included in genetic testing surveys of patients with Fabry disease.

Functional analysis of splicing mutations in exon 7 of NF1 gene.

BACKGROUND: Neurofibromatosis type 1 is one of the most common autosomal dominant disorders, affecting about 1:3,500 individuals. NF1 exon 7 displays weakly defined exon-intron boundaries, and is particularly prone to missplicing. METHODS: In this study we investigated the expression of exon 7 transcripts using bioinformatic identification of splicing regulatory sequences, and functional minigene analysis of four sequence changes [c.910C>T (R304X), c.945G>A/c.946C>A (Q315Q/L316M), c.1005T>C (N335N)] identified in exon 7 of three different NF1 patients. RESULTS: Our results detected the presence of three exonic splicing enhancers (ESEs) and one putative exonic splicing silencer (ESS) element. The wild type minigene assay resulted in three alternative isoforms, including a transcript lacking NF1 exon 7 (NF1DeltaE7). Both the wild type and the mutated constructs shared NF1DeltaE7 in addition to the complete messenger, but displayed a different ratio between the two transcripts. In the presence of R304X and Q315Q/L316M mutations, the relative proportion between the different isoforms is shifted toward the expression of NF1DeltaE7, while in the presence of N335N variant, the NF1DeltaE7 expression is abolished. CONCLUSION: In conclusion, it appears mandatory to investigate the role of each nucleotide change within the NF1 coding sequence, since a significant proportion of NF1 exon 7 mutations affects pre-mRNA splicing, by disrupting exonic splicing motifs and modifying the delicate balance between aberrantly and correctly spliced transcripts.