A Heterozygous CFHR3-CFHR1 Gene Deletion in a Pediatric Patient With Transplant-associated Thrombotic Microangiopathy Who was Treated With Eculizumab

Genetic Susceptibility in Endothelial Injury Syndromes after Hematopoietic Cell Transplantation and Other Cellular Therapies: Climbing a Steep Hill

Hematopoietic stem cell transplantation (HSCT) remains a cornerstone in the management of patients with hematological malignancies. Endothelial injury syndromes, such as HSCT-associated thrombotic microangiopathy (HSCT-TMA), veno-occlusive disease/sinusoidal obstruction syndrome (SOS/VOD), and capillary leak syndrome (CLS), constitute complications after HSCT. Moreover, endothelial damage is prevalent after immunotherapy with chimeric antigen receptor-T (CAR-T) and can be manifested with cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS). Our literature review aims to investigate the genetic susceptibility in endothelial injury syndromes after HSCT and CAR-T cell therapy. Variations in complement pathway- and endothelial function-related genes have been associated with the development of HSCT-TMA. In these genes, CFHR5, CFHR1, CFHR3, CFI, ADAMTS13, CFB, C3, C4, C5, and MASP1 are included. Thus, patients with these variations might have a predisposition to complement activation, which is also exaggerated by other factors (such as acute graft-versus-host disease, infections, and calcineurin inhibitors). Few studies have examined the genetic susceptibility to SOS/VOD syndrome, and the implicated genes include CFH, methylenetetrahydrofolate reductase, and heparinase. Finally, specific mutations have been associated with the onset of CRS (PFKFB4, CX3CR1) and ICANS (PPM1D, DNMT3A, TE2, ASXL1). More research is essential in this field to achieve better outcomes for our patients.

CFHR1 involvement in bile duct carcinoma: Insights from a data mining study

The aim of this study is to investigate the role of CFHR1 in bile duct carcinoma (BDC) and its mechanism of action, and we hope that our analysis and research will contribute to a better understanding of cholangiocarcinoma (BDC) disease genesis, progression and the development of new therapeutic strategies. The prognostic receiver operating characteristic curve of CFHR1 was generated using survival ROC. The ROC curve for CFHR1 showed that there is a correlation between CFHR1 expression and clinicopathological parameters and has an impact on poor prognosis. STRING was used to predict the protein-protein interaction network of the identified genes, and the Microenvironment Cell Populations counter algorithm was used to analyze immune cell infiltration within the BDC. The combined analysis showed that CFHR1 was found to be upregulated in BDC tissues, along with a total of 20 related differentially expressed genes (DEGs) (8 downregulated and 12 upregulated genes). Also, the results showed that the expression of CFHR1 is correlated with immune cell infiltration in tumor and immune cell markers in BDC (P < 0.05). In addition, we have verified experimentally the biological function of CFHR1. These findings suggest that CFHR1 may be a prognostic marker and a potential therapeutic target for BDC. Information regarding the detailed roles of CFHR1 in BDC could be valuable for improving the diagnosis and treatment of this rare cancer.

Eculizumab treatment in paediatric patients diagnosed with aHUS after haematopoietic stem cell transplantation: a HSCT-TMA case series from Japanese aHUS post-marketing surveillance

Haematopoietic stem-cell transplantation (HSCT)-associated thrombotic microangiopathy (HSCT-TMA) is a serious complication with high mortality. Accumulating evidence suggests that complement dysregulation is potentially involved in the development of HSCT-TMA. We retrospectively analysed the clinical characteristics and outcomes of thirteen paediatric patients who were diagnosed with atypical haemolytic uremic syndrome and treated with eculizumab to manage HSCT-TMA during post-marketing surveillance in Japan. The median time from HSCT to TMA was 31 days (Interquartile range, IQR;21-58) and the median doses of eculizumab was three (IQR;2-5). Seven patients (54%) were alive at the last follow-up while six died due to complications related to HSCT. Six of seven survivors initiated eculizumab after insufficient response to plasma therapy. Following eculizumab treatment, median platelet counts and LDH levels in all survivors significantly improved and renal function improved in 4/7 patients. All survivors possessed potential risk factors of complement overactivation. During the follow-up period after eculizumab discontinuation (median;111.5 days, IQR;95-555), no TMA recurrence was observed. In this analysis, eculizumab showed benefit in over half of this paediatric patient population. Ongoing clinical studies are expected to optimize the treatment regimen of terminal complement pathway inhibitor, and it may become a therapeutic option for paediatric HSCT-TMA in the future.

A case of non-lupus full-house nephropathy diagnosed by kidney biopsy but observed IgA nephropathy on second biopsy

We describe a case of full-house nephropathy without any underlying disease, including systemic lupus erythematosus. A 40-year-old woman was referred to our hospital with mild proteinuria and microscopic hematuria. The patient was diagnosed with immune complex-mediated glomerulonephritis with a predominant mesangioproliferative pattern based on renal histopathological results using full-house immunofluorescence staining. She showed no clinical criteria for the diagnosis of systemic lupus erythematosus, except for kidney disorders, and tested negative for antinuclear antibodies throughout her clinical course. However, in the second kidney biopsy, no C1q or C4 were detected in the immunofluorescence study, suggesting an immunoglobulin A nephropathy-like pattern. The patient responded favorably to corticosteroid treatment. We found a heterozygous CFHR3-CFHR1 deletion. The association between full-house nephropathy and CFHR3-CFHR1 deletion is unknown, but its influence on the histological pattern in our case is suspected. This indicates the diversity in the pathogenesis of non-lupus full-house nephropathy and warrants further investigation.

Mutations in the alternative complement pathway in multiple myeloma patients with carfilzomib-induced thrombotic microangiopathy

Thrombotic microangiopathy (TMA) has been reported to occur in multiple myeloma (MM) patients in association with treatment with carfilzomib, an irreversible proteasome inhibitor (PI). The hallmark of TMA is vascular endothelial damage leading to microangiopathic hemolytic anemia, platelet consumption, fibrin deposition and small-vessel thrombosis with resultant tissue ischemia. The molecular mechanisms underlying carfilzomib-associated TMA are not known. Germline mutations in the complement alternative pathway have been recently shown to portend increased risk for the development of atypical hemolytic uremic syndrome (aHUS) and TMA in the setting of allogeneic stem cell transplant in pediatric patients. We hypothesized that germline mutations in the complement alternative pathway may similarly predispose MM patients to carfilzomib-associated TMA. We identified 10 MM patients with a clinical diagnosis of TMA in the context of carfilzomib treatment and assessed for the presence of germline mutations in the complement alternative pathway. Ten, matched MM patients exposed to carfilzomib but without clinical TMA were used as negative controls. We identified a frequency of deletions in the complement Factor H genes 3 and 1 (delCFHR3-CFHR1) and genes 1 and 4 (delCFHR1-CFHR4) in MM patients with carfilzomib-associated TMA that was higher as compared to the general population and matched controls. Our data suggest that complement alternative pathway dysregulation may confer susceptibility to vascular endothelial injury in MM patients and predispose to development of carfilzomib-associated TMA. Larger, retrospective studies are needed to evaluate whether screening for complement mutations may be indicated to properly counsel patients about TMA risk with carfilzomib use.

Identification of Altered Primary Immunodeficiency-Associated Genes and Their Implications in Pediatric Cancers

BACKGROUND

Cancer is the leading cause of disease-related mortality in children and malignancies are more frequently observed in individuals with primary immunodeficiencies (PIDs). This study aimed to identify and highlight the molecular mechanisms, such as oncogenesis and immune evasion, by which PID-related genes may lead to the development of pediatric cancers.

METHOD

We implemented a novel bioinformatics framework using patient data from the TARGET database and performed a comparative transcriptome analysis of PID-related genes in pediatric cancers between normal and cancer tissues, gene ontology enrichment, and protein-protein interaction analyses, and determined the prognostic impacts of commonly mutated and differentially expressed PID-related genes.

RESULTS

From the Fulgent Genetics Comprehensive Primary Immunodeficiency panel of 472 PID-related genes, 89 genes were significantly differentially expressed between normal and cancer tissues, and 20 genes were mutated in two or more patients. Enrichment analysis highlighted many immune system processes as well as additional pathways in the mutated PID-related genes related to oncogenesis. Survival outcomes for patients with altered PID-related genes were significantly different for 75 of the 89 DEGs, often resulting in a poorer prognosis.

CONCLUSIONS

Overall, multiple PID-related genes demonstrated the connection between PIDs and cancer development and should be studied further, with hopes of identifying new therapeutic targets.

Copy number variation analysis using next-generation sequencing identifies the CFHR3/CFHR1 deletion in atypical hemolytic uremic syndrome: a case report

OBJECTIVES

Atypical hemolytic uremic syndrome (aHUS) is characterized by a triad of thrombocytopenia, microangiopathic hemolytic anemia, and acute renal failure resulting from platelet thrombi in the microcirculation of the kidney and other organs, in the absence of a preceding diarrheal illness. This report describes a case in which copy number variation (CNV) analysis using next-generation sequencing (NGS) identified the CFHR3/CFHR1 deletion in a patient with aHUS.

METHODS

A 49-year-old Korean female was diagnosed with aHUS based on clinical findings, including schistocytes in peripheral blood and marked thrombocytopenia, suggesting the presence of thrombotic microangiopathy, elevated serum lactate dehydrogenase, and acute kidney injury. Sequence variants and CNV generated from NGS data were estimated to determine if there was a potential genetic cause. Multiplex ligation-dependent probe amplification (MLPA) was conducted to confirm the CFHR3/CFHR1 deletion identified by NGS with CNV analysis.

RESULTS

No known or novel pathogenic single nucleotide variant or small insertion/deletion that would be predicted to have damaging effects that could lead to aHUS were identified. However, CNV analysis of NGS data identified the heterozygous CFHR3/CFHR1 deletion. MLPA confirmed this loss of one copy number between the CFHR3 and the CFHR1 genes on chromosome 1q31.3.

CONCLUSION

We genetically diagnosed a Korean woman harboring a heterozygous CFHR3/CFHR1 deletion of a known causative gene for aHUS. Our report emphasizes the need for CNV analysis of NGS data and gene dosage assays, such as MLPA, to evaluate large-scale deletions or duplications and generate hybrid CFH genes in patients with suspected aHUS.

Clinical features and outcomes of four atypical hemolytic uremic syndrome cases at a single institution in Miyazaki Prefecture from 2015 to 2019

Background

Although atypical hemolytic uremic syndrome (aHUS) is a life-threatening clinical entity that was characterized by thrombotic microangiopathy (TMA) with the activation of the complement system and the efficient treatment of eculizumab, the clinical features of aHUS have been unclear because of the rare incidence.

Case presentation

We retrospectively analyzed 4 aHUS cases at a single institution during 2015–2019. Here, we presented 4 aHUS cases with renal transplantation (one case), influenza/acute interstitial pneumonia/disseminated intravascular coagulation (two cases), and severe fever with thrombocytopenia syndrome (one case), respectively. Initial clinical symptoms were microangiopathic hemolytic anemia (four cases), renal dysfunction (four cases), thrombocytopenia (four cases), and pulmonary hemorrhage (three cases) consisted with TMA features. Subsequent further examinations ruled out thrombotic thrombocytopenic purpura, Shiga toxin-producing E.coli-induced hemolytic uremic syndrome, and secondary TMA. Taken these findings together, we made the clinical diagnosis of aHUS. Furthermore, all cases also presented the high levels of plasma soluble C5b-9 (871.1 ng/ml, 1144.3 ng/ml, 929.2 ng/ml, and 337.5 ng/ml), suggesting persistent activation of complementary system. Regarding the treatment, plasma exchange (PE) (four cases) and eculizumab (two cases) therapy were administered for aHUS cases. Consequently, case 2 and case 4 were still alive with 768 days and 235 days, respectively. The other two cases were dead at 34 days and 13 days, respectively. Finally, although the previous reported genetic pathogenetic mutations were not detected in our cases, multiple genetic variants of complement factors were detected as CFH (H402Y, E936D), and THBD (A473V) in case 1, CFH (V62I, H402Y, V837I) in case 2, and CFH (H402Y, E 936D) and THBD (A473V) in case 3, CFH (V62I, H402Y, E936D) and THBD (473V) in case 4, respectively.

Conclusions

Because of still high mortality in our study, an urgent diagnosis of aHUS and subsequent immediate treatment including PE and eculizumab should be essential in clinical practice. Furthermore, the multiple genetic variants and the triggers may be related to one of the pathogenesis of aHUS. Thus, we assume that such a case-oriented study would be highly useful to the physicians who directly care for aHUS cases in clinical practice.

Hemolytic uremic syndrome and kidney transplantation in uncontrolled donation after circulatory death (DCD): A two-case report

Background: Hemolytic uremic syndrome (HUS) is a rare disease characterized by microangiopathic hemolysis, thrombocytopenia, and renal involvement. Complement-mediated atypical HUS (aHUS) is a result of genetic defects in the alternative complement pathway components or regulators. The introduction of eculizumab has improved renal and overall survival of aHUS patients. Nowadays, given organ shortage, it is necessary to consider kidney transplantation (KT) even in protocols with a high risk of HUS recurrence, such as from donation after circulatory death (DCD) donors. Here, we describe two patients with HUS who underwent a KT from an uncontrolled DCD (uDCD). Case summary: The first patient, affected by aHUS due to a heterozygous deletion in CFHR3-CFHR1 and a novel heterozygous variant in CFHR5 gene, underwent a KT with eculizumab prophylaxis. The patient did not experience a post-transplant aHUS recurrence. The second patient, who experienced an HUS episode characterized by a hypertensive crisis and with no underlying mutations in complement system genes, underwent a KT without eculizumab prophylaxis. At day 5, anti-complement treatment commenced due to hematological signs of thrombotic microangiopathy (TMA). After the introduction of eculizumab, we observed a stabilization of kidney function and hematological remission. Conclusion: We present herein two different patients with HUS who both underwent successful KT from uDCD donation under the umbrella of eculizumab therapy. Taking into account the importance of increasing the number of organs available for transplantation, uDCD could represent an additional resource in this subset of HUS patients.