C3 Glomerulopathy With Concurrent Thrombotic Microangiopathy: Clinical and Immunological Features.

RATIONALE & OBJECTIVE: C3 glomerulopathy (C3GN) and atypical hemolytic uremic syndrome (aHUS) are 2 distinct rare kidney diseases caused by dysregulation of the alternative complement pathway. Patients with C3GN and concurrent kidney lesions of thrombotic microangiopathy (TMA) have been rarely reported. We characterized the clinical features and underlying immunological abnormalities in these patients. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: Patients with C3GN and concomitant TMA lesions on biopsy registered from 2009 to 2019 in the French National Registry of C3GN. FINDINGS: Among 278 registered patients with C3GN, 16 (6%) had biopsy-proven glomerular and/or vascular TMA lesions. Their median age at diagnosis was 39 years (range, 7-76), and 59% were female. Fourteen of the 16 patients (88%) had an estimated glomerular filtration rate of<30mL/min/1.73m2 and 3 of 16 (19%) required dialysis. Twelve of the 14 evaluated patients (86%) showed evidence of mechanical hemolysis. Fifty percent of the patients had low C3 levels. Six of the 14 evaluated patients had a rare variant in complement genes, and 4 of the 16 patients (25%) had monoclonal gammopathy. Among the 16 patients, 10 (63%) received eculizumab, 5 (31%) received immunosuppressive therapy, and 4 (25%) received clone-targeted chemotherapy. Median kidney survival was 49 months. LIMITATIONS: Small retrospective case series with a limited number of biopsies including electron microscopy. CONCLUSIONS: Concomitant C3GN and TMA is extremely rare and is associated with poor kidney outcomes. Genetic or acquired abnormalities of the alternative complement pathway are common as is the presence of monoclonal gammopathy, which may inform the selection of treatment approaches.

Eculizumab for treatment of rapidly progressive C3 glomerulopathy.

C3 glomerulopathy (C3G) is a prototypic complement-mediated kidney disease. Rapidly progressive forms of C3G usually respond poorly to conventional treatments. We report on the efficacy of the terminal complement inhibitor eculizumab in 3 adult patients with rapidly progressive C3G. In all 3 patients, serum creatinine levels had increased by >50% in the 2 months preceding initiation of eculizumab treatment despite the use of conventional immunosuppressive drugs and/or plasma exchanges in 2 of these individuals. Of note, 2 patients had long-standing nephrotic syndrome. Kidney biopsy performed prior to eculizumab treatment disclosed marked glomerular inflammatory changes and increased C5b-9 deposition in all patients. Eculizumab use was associated with significant improvement in kidney function, with estimated glomerular filtration rates of patients increasing 22 to 38 mL/min/1.73 m(2). Eculizumab use also was associated with remission of nephrotic syndrome in the 2 affected patients, an effect observed as early as one week after treatment initiation. Repeat kidney biopsy disclosed regression of glomerular inflammatory changes and decreases in glomerular staining for C5b-9 in all patients. These results warrant further assessment of eculizumab for treatment of rapidly progressive forms of C3G with markedly increased glomerular C5b-9 deposits.

N-cadherin serves as diagnostic biomarker in intrahepatic and perihilar cholangiocarcinomas.

As a definite immunoprofile of this tumor is missing, the histopathologic diagnosis of intrahepatic cholangiocarcinoma is difficult. The aim of this study was to explore E- and N-cadherin expressions in intrahepatic bile duct tumors, and to determine their potential interest in differential diagnosis. Normal liver tissue, 5 cirrhosis with ductular reaction, 5 focal nodular hyperplasia, 5 bile duct hamartomas, 5 bile duct adenomas, and 45 intrahepatic cholangiocarcinomas from Caucasian patients were studied. Tissue-microarrays including 20 esophageal, 86 gastric, 8 small bowel, 64 colonic, 18 pancreatic, 6 gallbladder, and 7 extrahepatic biliary tract adenocarcinomas, 22 hepatocellular carcinomas, and normal tissues were constructed. Immunohistochemistry was performed using E-cadherin, N-cadherin, NCAM, Hep Par1, and cytokeratins 7, 19 and 20. Immunoblot analysis of frozen liver tissues was performed to control the specificity of E- and N-cadherin antibodies used. In normal liver, epithelial cells of intrahepatic bile ducts, whatever their caliber, as well as hepatocytes, coexpressed E- and N-cadherins at their plasma membranes. In cirrhosis, ductular reactions completely expressed E- and N-cadherins. All the benign lesions and 30 of the 45 intrahepatic cholangiocarcinomas (23/29 peripheral and 7/16 hilar) also expressed N-cadherin. E-cadherin was detected in all the lesions. The expression of N-cadherin at the plasma membrane of tumor cells was significantly more frequent in peripheral than in hilar intrahepatic cholangiocarcinomas (P=0.003). Among noncholangiocarcinomas, only 1% gastric and 66% gallbladder adenocarcinomas and all the hepatocellular carcinomas expressed N-cadherin at the membrane of tumor cells. Finally, for the diagnosis of intrahepatic cholangiocarcinomas, the specificity value of membranous expression of N-cadherin was 88%, whereas that of the combination cytokeratin 7/membranous N-cadherin was 98%. In the gastrointestinal and liver tract, membranous N-cadherin is restricted to the hepatocytes and intrahepatic biliary cells. In combination with cytokeratin 7 and Hep Par1, N-cadherin is a reliable tool for the histopathological diagnosis of primary hepatic tumors.

Association of HER1 amplification with poor prognosis in well differentiated gastric carcinomas.

AIMS: The pattern of E-cadherin expression and the HER1/HER2 status were studied in European patients with gastric carcinomas in relation with their differentiation and prognosis. METHODS: 82 gastric carcinomas (five papillary, 52 tubular, 19 poorly cohesive and six mixed according to WHO classification) were investigated for E-cadherin distribution (normal: restricted to the membrane; abnormal: absent or cytoplasmic expression), HER1 and HER2 expression using HercepTest and amplification using fluorescent in situ hybridisation. Statistical analysis assessed the association between the markers and their correlation with clinicopathological parameters and follow-up information. RESULTS: Abnormal E-cadherin distribution was found in 34 of the 82 gastric carcinomas (41%) (18/25 poorly cohesive or mixed (72%); 16/57 papillary or tubular type (28%)). HER1 overexpression (3+) and equivocal expression (2+) were found in five carcinomas (6%; four tubular and one poorly cohesive) and eight carcinomas (10%; six tubular and two poorly cohesive), respectively. HER2 overexpression (3+) and equivocal expression (2+) were found in seven carcinomas (8%; five papillary and two tubular) and three carcinomas (4%; three tubular), respectively. Amplification of HER1 or HER2 was detected in 14 gastric carcinomas (five papillary and nine tubular). All of them showed a normal E-cadherin distribution. In the univariate analysis, only HER1 amplification had a prognostic impact, while HER2 amplification and E-cadherin expression/distribution were not per se prognostically relevant. CONCLUSIONS: E-cadherin immunostaining and HER1 in situ hybridisation define a group of well differentiated gastric carcinomas with poor prognosis eligible for an aggressive therapeutic approach.

Differential roles of Hath1, MUC2 and P27Kip1 in relation with gamma-secretase inhibition in human colonic carcinomas: a translational study.

Hath1, a bHLH transcription factor negatively regulated by the γ-secretase-dependent Notch pathway, is required for intestinal secretory cell differentiation. Our aim was fourfold: 1) determine whether Hath1 is able to alter the phenotype of colon cancer cells that are committed to a differentiated phenotype, 2) determine whether the Hath1-dependent alteration of differentiation is coupled to a restriction of anchorage-dependent growth, 3) decipher the respective roles of three putative tumor suppressor genes Hath1, MUC2 and P27kip1 in this coupling and, 4) examine how our findings translate to primary tumors. Human colon carcinoma cell lines that differentiate along a mucin secreting (MUC2/MUC5AC) and/or enterocytic (DPPIV) lineages were maintained on inserts with or without a γ-secretase inhibitor (DBZ). Then the cells were detached and their ability to survive/proliferate in the absence of substratum was assessed. γ-secretase inhibition led to a Hath1-mediated preferential induction of MUC2 over MUC5AC, without DPPIV modification, in association with a decrease in anchorage-independent growth. While P27kip1 silencing relieved the cells from the Hath1-induced decrease of anchorage-independent growth, MUC2 silencing did not modify this parameter. Hath1 ectopic expression in the Hath1 negative enterocytic Caco2 cells led to a decreased anchorage-independent growth in a P27kip1-independent manner. In cultured primary human colon carcinomas, Hath1 was up-regulated in 7 out of 10 tumors upon DBZ treatment. Parallel MUC2 up-regulation occurred in 4 (4/7) and P27kip1 in only 2 (2/7) tumors. Interestingly, the response patterns of primary tumors to DBZ fitted with the hierarchical model of divergent signalling derived from our findings on cell lines.