Complement factor H deficiency combined with smoking promotes retinal degeneration in a novel mouse model.

Age-related macular degeneration is the leading cause of blindness in the elderly. The Y402H polymorphism in complement factor H promotes disease-like pathogenesis, and a Cfh+/- murine model can replicate this phenotype, but only after two years. We reasoned that by combining CFH deficiency with cigarette smoke exposure, we might be able to accelerate disease progression to facilitate preclinical research in this disease. Wild-type and Cfh+/- mice were exposed to nose-only cigarette smoke for three months. Retinal tissue morphology and visual function were evaluated by optical coherence tomography, fundus photography and autofluorescence, and electroretinogram. Retinal pigment epithelial cell phenotype and ultrastructure were evaluated by immunofluorescence staining and transmission electron microscopy. Cfh+/- smoking mice showed a dome-like protruding lesion at the ellipsoid zone (drusen-like deposition), many retinal hyper-autofluorescence spots, and a marked decrease in A- and B-wave amplitudes. Compared with non-smoking mice, wild-type and Cfh+/- smoking mice showed sub-retinal pigment epithelium complement protein 3 deposition, activation of microglia, metabolic waste accumulation, and impairment of tight junctions. Microglia cells migrated into the photoreceptor outer segment layer in Cfh+/- smoking mice showed increased activation. Our results suggest that exposing Cfh+/- mice to smoking leads to earlier onset of age-related macular degeneration than in other animal models, which may facilitate preclinical research into the pathophysiology and treatment of this disease.

Disseminated gonococcal infection in a Japanese man with complement 7 deficiency with compound heterozygous variants: A case report.

RATIONALE: Complement deficiency are known to be predisposed to disseminated gonococcal infection (DGI). We herein present a case of DGI involving a Japanese man who latently had a complement 7 deficiency with compound heterozygous variants. PATIENT CONCERNS: A previously healthy 51-year-old Japanese man complained of sudden-onset high fever. Physical examination revealed various skin lesions including red papules on his trunk and extremities, an impetigo-like pustule on left forearm, and tendinitis of his right forefinger. DIAGNOSIS: Blood culture testing detected gram-negative cocci, which was confirmed to be Neisseria gonorrhoeae based on mass spectrometry and a pathogen-specific PCR test. INTERVENTIONS: Screening tests for underlying immunocompromised factors uncovered that complement activities (CH50) was undetectable. With a suspicion of a congenital complement deficiency, genetic analysis revealed rare single nucleotide variants in complement 7 (C7), including c.281-1G>T and a novel variant c.1454C>T (p.A485V). CH50 was normally recovered by adding purified human C7 to the patient's serum, supporting that the patient has C7 deficiency with compound heterozygous variants. OUTCOMES: Under a diagnosis of DGI, the patient underwent an antibiotic treatment with cefotaxime for a week and was discharged without any sequela. LESSONS: DGI is a rare sexually-transmitted infection that potentially induces systemic complications. Complement immunity usually defeats N. gonorrhoeae and prevents the organism from causing DGI. This case highlighted the importance of suspecting a complement deficiency when a person develops DGI.

Complement C6 deficiency exacerbates pathophysiology after spinal cord injury.

Historically, the membrane attack complex, composed of complement components C5b-9, has been connected to lytic cell death and implicated in secondary injury after a CNS insult. However, studies to date have utilized either non-littermate control rat models, or mouse models that lack significant C5b-9 activity. To investigate what role C5b-9 plays in spinal cord injury and recovery, we generated littermate PVG C6 wildtype and deficient rats and tested functional and histological recovery after moderate contusion injury using the Infinite Horizon Impactor. We compare the effect of C6 deficiency on recovery of locomotor function and histological injury parameters in PVG rats under two conditions: (1) animals maintained as separate C6 WT and C6-D homozygous colonies; and (2) establishment of a heterozygous colony to generate C6 WT and C6-D littermate controls. The results suggest that maintenance of separate homozygous colonies is inadequate for testing the effect of C6 deficiency on locomotor and histological recovery after SCI, and highlight the importance of using littermate controls in studies involving genetic manipulation of the complement cascade.

Complement factor H-deficient mice develop spontaneous hepatic tumors.

Hepatocellular carcinoma (HCC) is difficult to detect, carries a poor prognosis, and is one of few cancers with an increasing yearly incidence. Molecular defects in complement factor H (CFH), a critical regulatory protein of the complement alternative pathway (AP), are typically associated with inflammatory diseases of the eye and kidney. Little is known regarding the role of CFH in controlling complement activation within the liver. While studying aging CFH-deficient (fH-/-) mice, we observed spontaneous hepatic tumor formation in more than 50% of aged fH-/- males. Examination of fH-/- livers (3-24 months) for evidence of complement-mediated inflammation revealed widespread deposition of complement-activation fragments throughout the sinusoids, elevated transaminase levels, increased hepatic CD8+ and F4/80+ cells, overexpression of hepatic mRNA associated with inflammatory signaling pathways, steatosis, and increased collagen deposition. Immunostaining of human HCC biopsies revealed extensive deposition of complement fragments within the tumors. Investigating the Cancer Genome Atlas also revealed that increased CFH mRNA expression is associated with improved survival in patients with HCC, whereas mutations are associated with worse survival. These results indicate that CFH is critical for controlling complement activation in the liver, and in its absence, AP activation leads to chronic inflammation and promotes hepatic carcinogenesis.

Complement Deficiencies Result in Surrogate Pathways of Complement Activation in Novel Polygenic Lupus-like Models of Kidney Injury.

Lupus nephritis (LN) is a major contributor to morbidity and mortality in lupus patients, but the mechanisms of kidney damage remain unclear. In this study, we introduce, to our knowledge, novel models of LN designed to resemble the polygenic nature of human lupus by embodying three key genetic alterations: the Sle1 interval leading to anti-chromatin autoantibodies; Mfge8-/- , leading to defective clearance of apoptotic cells; and either C1q-/- or C3-/- , leading to low complement levels. We report that proliferative glomerulonephritis arose only in the presence of all three abnormalities (i.e., in Sle1.Mfge8 -/- C1q -/- and Sle1.Mfge8 -/- C3 -/- triple-mutant [TM] strains [C1q -/-TM and C3-/- TM, respectively]), with structural kidney changes resembling those in LN patients. Unexpectedly, both TM strains had significant increases in autoantibody titers, Ag spread, and IgG deposition in the kidneys. Despite the early complement component deficiencies, we observed assembly of the pathogenic terminal complement membrane attack complex in both TM strains. In C1q-/- TM mice, colocalization of MASP-2 and C3 in both the glomeruli and tubules indicated that the lectin pathway likely contributed to complement activation and tissue injury in this strain. Interestingly, enhanced thrombin activation in C3-/- TM mice and reduction of kidney injury following attenuation of thrombin generation by argatroban in a serum-transfer nephrotoxic model identified thrombin as a surrogate pathway for complement activation in C3-deficient mice. These novel mouse models of human lupus inform the requirements for nephritis and provide targets for intervention.

Clinical and Genetic Spectrum of a Large Cohort With Total and Sub-total Complement Deficiencies.

The complement system is crucial for defense against pathogens and the removal of dying cells or immune complexes. Thus, clinical indications for possible complete complement deficiencies include, among others, recurrent mild or serious bacterial infections as well as autoimmune diseases (AID). The diagnostic approach includes functional activity measurements of the classical (CH50) and alternative pathway (AP50) and the determination of the C3 and C4 levels, followed by the quantitative analysis of individual components or regulators. When biochemical analysis reveals the causal abnormality of the complement deficiency (CD), molecular mechanisms remains frequently undetermined. Here, using direct sequencing analysis of the coding region we report the pathogenic variants spectrum that underlie the total or subtotal complement deficiency in 212 patients. We identified 107 different hemizygous, homozygous, or compound heterozygous pathogenic variants in 14 complement genes [C1Qß (n = 1), C1r (n = 3), C1s (n = 2), C2 (n = 12), C3 (n = 5), C5 (n = 12), C6 (n = 9), C7 (n = 17), C8 ß (n = 7), C9 (n = 3), CFH (n = 7), CFI (n = 18), CFP (n = 10), CFD (n = 2)]. Molecular analysis identified 17 recurrent pathogenic variants in 6 genes (C2, CFH, C5, C6, C7, and C8). More than half of the pathogenic variants identified in unrelated patients were also found in healthy controls from the same geographic area. Our study confirms the strong association of meningococcal infections with terminal pathway deficiency and highlights the risk of pneumococcal and auto-immune diseases in the classical and alternative pathways. Results from this large genetic investigation provide evidence of a restricted number of molecular mechanisms leading to complement deficiency and describe the clinical potential adverse events of anti-complement therapy.

Classical and Non-classical Presentations of Complement Factor I Deficiency: Two Contrasting Cases Diagnosed via Genetic and Genomic Methods.

Deficiency of complement factor I is a rare immunodeficiency that typically presents with increased susceptibility to encapsulated bacterial infections. However, non-infectious presentations including rheumatological, dermatological and neurological disease are increasingly recognized and require a high-index of suspicion to reach a timely diagnosis. Herein, we present two contrasting cases of complement factor I deficiency: one presenting in childhood with invasive pneumococcal disease, diagnosed using conventional immunoassays and genetics and the second presenting in adolescence with recurrent sterile neuroinflammation, diagnosed via a genomic approach. Our report and review of the literature highlight the wide spectrum of clinical presentations associated with CFI deficiency and the power of genomic medicine to inform rare disease diagnoses.

Impaired insulin signaling in the B10.D2-Hc0 H2d H2-T18c/oSnJ mouse model of complement factor 5 deficiency.

Given the chemoattractant potential of complement factor 5 (C5) and its increased expression in adipose tissue (AT) of obese mice, we determined whether this protein of the innate immune system impacts insulin action. C5 control (C5cont) and spontaneously C5-deficient (C5def, B10.D2-Hc0 H2d H2-T18c/oSnJ) mice were placed on low- and high-fat diets to investigate their inflammatory and metabolic phenotypes. Adenoviral delivery was used to evaluate the effects of exogenous C5 on systemic metabolism. C5def mice gained less weight than controls while fed a high-fat diet, accompanied by reduced AT inflammation, liver mass, and liver triglyceride content. Despite these beneficial metabolic effects, C5def mice demonstrated severe glucose intolerance and systemic insulin resistance, as well as impaired insulin signaling in liver and AT. C5def mice also exhibited decreased expression of insulin receptor (INSR) gene and protein, as well as improper processing of pro-INSR. These changes were not due to the C5 deficiency alone as other C5-deficient models did not recapitulate the INSR processing defect; rather, in addition to the mutation in the C5 gene, whole genome sequencing revealed an intronic 31-bp deletion in the Insr gene in the B10.D2-Hc0 H2d H2-T18c/oSnJ model. Irrespective of the genetic defect, adenoviral delivery of C5 improved insulin sensitivity in both C5cont and C5def mice, indicating an insulin-sensitizing function of C5.

Caracterización fenotípica del Síndrome Aarskog / Phenotypical characterization of the Aarskog's Syndrome

Introducción: el síndrome Aarskog es una enfermedad genética con expresividad variable y está caracterizada por retardo del crecimiento, rasgos faciales típicos, manos y pies cortos, discapacidad intelectual y anomalías en genitales. Se describió un patrón de herencia recesiva ligada al cromosoma X, con expresión parcial en mujeres. Se han reportado casos con transmisión autosómica dominante. Objetivos: identificar las características fenotípicas de diez pacientes afectados con diagnóstico del síndrome Aarskog, encontrado tanto hembras como varones. Materiales y métodos: se realizó un estudio descriptivo, donde la muestra estuvo formada por diez enfermos del municipio Urbano Noris, provincia de Holguín, durante enero a diciembre de 2015. Resultados: la característica facial más frecuente fue el puente nasal ancho (90 %), narinas antevertidas (40 %), el filtrum largo (90 %), con labios gruesos (60 %) y la fisuras palpebrales hacia abajo (90 %); seguido por el hipertelorismo y las cejas gruesas en un 70 %; la braquidactílea fue la alteración en los miembros más común (70 %) y la sindactílea membranosa en 80 %, que se acompañó de discapacidad intelectual leve en el 80 %. Conclusiones: existió variabilidad de expresión clínica entre los enfermos, estando tanto en hembras como en varones, existiendo diferencias fenotípicas que se pudieran explicarse a través de la heterogeneidad genética del síndrome. Aún no se cuenta en el país con estudios moleculares que permitan caracterizar genotípicamente a estos afectados (AU).

Introduction: Aarskog's syndrome is a genetic disease with variable manifestation, characterized by growth retardation, typical facial features, short hand and feet, intellectual disability and genital anomalies. It was described a pattern of recessive inheritance linked to X chromosome, with partial expression in women. Cases with dominanta autosomal transmission have been reported. Objective: describing the phenotypical characteristics of ten patients with Aarskog's syndrome diagnosis, found as much in female as in male patients. Materials and methods: we carried out a descriptive, retrospective study, from January to December 2015, with a sample formed by ten patients from Urbano Noris Municipality, province of Holguin. Results: the most frequent facial characteristics were wide nasal bridge (90 %), anteverted nares (40 %), long philtrum (90 %), with thick lips (60 %) and palpebral fissures down (90 %), followed by hypertelorism and thick eyebrows in a 70 %; brachydactyly was the most common alteration of the limbs (70 %) and membranous syndactyly (80 %), accompanied by mild intellectual disability in 80 %. Conclusions: the patients showed variability of the clinical expression, found as much in female as in male ones; the phenotypical differences may be explained by the syndrome´s genetic heterogeneity. There are not still in the country molecular researches allowing the genotypic characterization of these patients (AU).

Caracterización fenotípica del Síndrome Aarskog / Phenotypical characterization of the Aarskog's Syndrome

Introducción: el síndrome Aarskog es una enfermedad genética con expresividad variable y está caracterizada por retardo del crecimiento, rasgos faciales típicos, manos y pies cortos, discapacidad intelectual y anomalías en genitales. Se describió un patrón de herencia recesiva ligada al cromosoma X, con expresión parcial en mujeres. Se han reportado casos con transmisión autosómica dominante. Objetivos: identificar las características fenotípicas de diez pacientes afectados con diagnóstico del síndrome Aarskog, encontrado tanto hembras como varones. Materiales y métodos: se realizó un estudio descriptivo, donde la muestra estuvo formada por diez enfermos del municipio Urbano Noris, provincia de Holguín, durante enero a diciembre de 2015. Resultados: la característica facial más frecuente fue el puente nasal ancho (90 %), narinas antevertidas (40 %), el filtrum largo (90 %), con labios gruesos (60 %) y la fisuras palpebrales hacia abajo (90 %); seguido por el hipertelorismo y las cejas gruesas en un 70 %; la braquidactílea fue la alteración en los miembros más común (70 %) y la sindactílea membranosa en 80 %, que se acompañó de discapacidad intelectual leve en el 80 %. Conclusiones: existió variabilidad de expresión clínica entre los enfermos, estando tanto en hembras como en varones, existiendo diferencias fenotípicas que se pudieran explicarse a través de la heterogeneidad genética del síndrome. Aún no se cuenta en el país con estudios moleculares que permitan caracterizar genotípicamente a estos afectados (AU).

Introduction: Aarskog's syndrome is a genetic disease with variable manifestation, characterized by growth retardation, typical facial features, short hand and feet, intellectual disability and genital anomalies. It was described a pattern of recessive inheritance linked to X chromosome, with partial expression in women. Cases with dominanta autosomal transmission have been reported. Objective: describing the phenotypical characteristics of ten patients with Aarskog's syndrome diagnosis, found as much in female as in male patients. Materials and methods: we carried out a descriptive, retrospective study, from January to December 2015, with a sample formed by ten patients from Urbano Noris Municipality, province of Holguin. Results: the most frequent facial characteristics were wide nasal bridge (90 %), anteverted nares (40 %), long philtrum (90 %), with thick lips (60 %) and palpebral fissures down (90 %), followed by hypertelorism and thick eyebrows in a 70 %; brachydactyly was the most common alteration of the limbs (70 %) and membranous syndactyly (80 %), accompanied by mild intellectual disability in 80 %. Conclusions: the patients showed variability of the clinical expression, found as much in female as in male ones; the phenotypical differences may be explained by the syndrome´s genetic heterogeneity. There are not still in the country molecular researches allowing the genotypic characterization of these patients (AU).