CFH-CFHR1 hybrid genes in two cases of atypical hemolytic uremic syndrome.

Atypical hemolytic uremic syndrome (aHUS) is a rare complement-mediated disease that manifests as the triad of thrombotic microangiopathy. We identified two aHUS patients with neither anti-complement factor H (CFH) antibodies nor causative variants of seven aHUS-related genes (CFH, CFI, CFB, C3, MCP, THBD, and DGKE); however, their plasma showed increased levels of hemolysis by hemolytic assay, which strongly suggests CFH-related abnormalities. Using a copy number variation (CNV) analysis of the CFH/CFHR gene cluster, we identified CFH-CFHR1 hybrid genes in these patients. We verified the absence of aHUS-related abnormal CNVs of the CFH gene in control genomes of 2036 individuals in the general population, which suggests that pathogenicity is related to these hybrid genes. Our study emphasizes that, for patients suspected of having aHUS, it is important to perform an integrated analysis based on a clinical examination, functional analysis, and detailed genetic investigation.

The role of anti-complement factor H antibodies in the development of atypical haemolytic uremic syndrome: a possible contribution to abnormality of platelet function.

Atypical haemolytic uremic syndrome (aHUS) is associated with complement system abnormality, such as production of complement factor H (CFH) autoantibodies. The growing evidence indicates complement overactivation on platelets is intimately involved in aHUS pathogenesis, besides endothelial injury. We here showed plasma from patients with anti-CFH antibodies induced aggregation of washed platelets, while purified anti-CFH antibodies suppressed aggregation. This suggested anti-CFH antibody itself suppressed thrombosis, while other plasma factor including complement factors could overactivate the platelets, leading to aggregation, which augmented the notion the state of complement activation influenced by anti-CFH antibodies is important in the aggregation of platelets in aHUS.

Profiles of Coagulation and Fibrinolysis Activation-Associated Molecular Markers of Atypical Hemolytic Uremic Syndrome in the Acute Phase.

AIM: Atypical hemolytic uremic syndrome (aHUS), characterized by thrombotic microangiopathy (TMA), is a genetic, life-threatening disease which needs many differential diagnoses. This study aimed to reveal coagulation and fibrinolysis profiles in aHUS and secondary TMA patients. Furthermore, we investigated whether aHUS patients progress to, and meet, disseminated intravascular coagulation (DIC) criteria. METHODS: The acute phase samples were available in 15 aHUS and 20 secondary TMA patients. We measured PT-ratio, activated partial thromboplastin time (APTT), fibrinogen, fibrin degradation product (FDP), fibrin monomer complex (FMC), antithrombin (AT), plasmin-α2 plasmin inhibitor complex (PIC), and von Willebrand factor antigen (VWF:Ag). We examined and compared these tests among aHUS, secondary TMA patients, and healthy volunteer (HV), and evaluated whether patients with aHUS and secondary TMA met DIC criteria. RESULTS: PT-ratio, APTT, FDP, FMC and PIC in patients with aHUS and secondary TMA were higher than those in HV. Fibrinogen and AT showed no significant difference among three groups. VWF:Ag was higher in only aHUS patients. No tests showed significant difference between aHUS and secondary TMA patients. Three aHUS patients out of 15 met DIC criteria. CONCLUSION: We revealed the profiles and distributions of coagulation and fibrinolysis tests of aHUS and secondary TMA patients. All tests were enhanced compared to HV; however, our results showed the no specificities in distinguishing aHUS from secondary TMA patients. We also clarified that some aHUS patients fulfilled DIC diagnostic criteria, indicating that DIC itself cannot be an exclusion criterion of aHUS.

Correction to: Clinical characteristics and genetic backgrounds of Japanese patients with atypical hemolytic uremic syndrome.

The original article can be found online.

Clinical characteristics and genetic backgrounds of Japanese patients with atypical hemolytic uremic syndrome.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is caused by complement overactivation, and its presentation and prognosis differ according to the underlying molecular defects. The aim of this study was to characterize the genetic backgrounds of aHUS patients in Japan and to elucidate the associations between their genetic backgrounds, clinical findings, and outcomes. METHODS: We conducted a nationwide epidemiological survey of clinically diagnosed aHUS patients and examined 118 patients enrolled from 1998 to 2016 in Japan. We screened variants of seven genes related to complement and coagulation, as well as positivity for anti-CFH antibodies, and assessed clinical manifestations, laboratory findings, and clinical course. RESULTS: The most frequent genetic abnormalities were in C3 (31%) and the frequency of CFH variants was relatively low (10%) compared to Western countries. The predominant variant in this cohort was C3 p.I1157T (23%), which was related to favorable outcomes despite frequent relapses. A total of 72% of patients received plasma therapy, while 42% were treated with eculizumab. The prognosis of Japanese aHUS patients was relatively favorable, with a total mortality rate of 5.4% and a renal mortality rate of 15%. CONCLUSIONS: The common occurrence of genotype C3, especially the p.I1157T variant was the characteristic of the genetic backgrounds of Japanese aHUS patients that differed from those of Caucasian patients. In addition, the favorable prognosis of patients with the unique C3 p.I1157T variant indicates that understanding the clinical characteristics of individual gene alterations is important for predicting prognosis and determining therapeutic strategies in aHUS.

Three cases of posterior reversible encephalopathy syndrome with chronic kidney disease triggered by infection.

Posterior reversible encephalopathy syndrome (PRES) is a clinical and radiological condition with diverse neurological manifestations. Many clinical factors are known causes of PRES, but only a few cases of PRES have been reported in patients with chronic kidney disease (CKD) and infectious disease. We describe three cases of PRES in patients with CKD triggered by various infectious diseases. Characteristic hyperintense signals on magnetic resonance imaging (MRI) indicating reversible vasogenic brain oedema in various parts of the brain were observed. To explain the pathophysiology of PRES, the hypertension/hyperperfusion and hypoperfusion/vasoconstriction theories have been proposed. Patients with CKD have many complications including uraemia, hypertension, and immunosuppression. Therefore, physicians should recognize that patients with CKD are at high risk of PRES triggered by infectious diseases and promptly diagnose PRES because immediate treatment of the triggers often leads to complete resolution.

Colonic perforation in a patient with systemic lupus erythematosus accompanied by cytomegalovirus infection: A case report.

INTRODUCTION: Cytomegalovirus (CMV) infection of the gastrointestinal tract is an uncommon illness, but can be observed in immunocompromised patients. Systemic lupus erythematosus (SLE) patients are generally at high risk of CMV infection. Here we report a subacute progressive case of colitis in SLE accompanied by cytomegalovirus infection. PRESENTATION OF CASE: The patient, a 79-year-old woman, was hospitalized complaining of fever, polyarthritis, and skin ulcer that had lasted seven days. She additionally manifested vomiting, high fever, and right abdominal pain within two weeks thereafter, and was diagnosed with perforation of the intestine. Emergency operation was carried out for panperitonitis due to perforation of one of the multiple colon ulcers. Multidisciplinary postoperative treatment could not save her life. Pathological examination suggested that cytomegalovirus infection as well as cholesterin embolization contributed to the rapid progression of colitis. DISCUSSION: There have been only a limited number of case reports of CMV enteritis in SLE. Moreover, only two SLE patients on multiple medications have been reported to experience gastrointestinal perforation. Viral infections, including CMV, can induce clinical manifestations resembling SLE and for this reason we suspect that there are potentially many more patients misdiagnosed and/or unreported. CONCLUSION: Our case underscores the importance of exploring the possibility of CMV infection as a differential diagnosis in SLE patients with obvious gastrointestinal symptoms who were treated by immunosuppressive drugs.