Early-onset pulmonary and cutaneous vasculitis driven by constitutively active SRC-family kinase HCK.

BACKGROUND: Inborn errors of immunity are genetic disorders characterized by various degrees of immune dysregulation that can manifest as immune deficiency, autoimmunity, or autoinflammation. The routine use of next-generation sequencing in the clinic has facilitated the identification of an ever-increasing number of inborn errors of immunity, revealing the roles of immunologically important genes in human pathologies. However, despite this progress, treatment is still extremely challenging. OBJECTIVE: We sought to report a new monogenic autoinflammatory disorder caused by a de novo activating mutation, p.Tyr515∗, in hematopoietic cell kinase (HCK). The disease is characterized by cutaneous vasculitis and chronic pulmonary inflammation that progresses to fibrosis. METHODS: Whole-exome sequencing, Sanger sequencing, mass spectrometry, and western blotting were performed to identify and characterize the pathogenic HCK mutation. Dysregulation of mutant HCK was confirmed ex vivo in primary cells and in vitro in transduced cell lines. RESULTS: Mutant HCK lacking the C-terminal inhibitory tyrosine Tyr522 exhibited increased kinase activity and enhanced myeloid cell priming, migration and effector functions, such as production of the inflammatory cytokines IL-1ß, IL-6, IL-8, and TNF-α, and production of reactive oxygen species. These aberrant functions were reflected by inflammatory leukocyte infiltration of the lungs and skin. Moreover, an overview of the clinical course of the disease, including therapies, provides evidence for the therapeutic efficacy of the Janus kinase 1/2 inhibitor ruxolitinib in inflammatory lung disease. CONCLUSIONS: We propose HCK-driven pulmonary and cutaneous vasculitis as a novel autoinflammatory disorder of inborn errors of immunity.

Proven Invasive Pulmonary Aspergillosis in Stem Cell Transplant Recipient Due to Aspergillus sublatus, a Cryptic Species of A. nidulans.

Invasive fungal disease represents one of the severe complications in haematopoietic stem cell transplant recipients. We describe a case of a patient treated for relapse of chronic lymphoblastic leukaemia 6 years after HSCT. The patient was treated for invasive pulmonary aspergillosis but died 3 months later from multiple organ failures consisting of haemorrhagic necrotizing fungal pneumonia, refractory chronic hepatic graft versus host disease and cytomegalovirus hepatitis. Autopsy samples revealed histopathological evidence of fungal hyphae and an unusual Aspergillus nidulans-like species was isolated in pure culture. More precise identification was achieved by using scanning electron microscopy of ascospores and sequencing of calmodulin gene, and the isolate was subsequently re-identified as A. sublatus (section Nidulantes) and showed good in vitro susceptibility against all classes of antifungals. Commonly used ITS rDNA region and ß-tubulin gene fail to discriminate A. sublatus from related pathogenic species, especially A. quadrilineatus and A. nidulans. Although this is the first case of proven IPA attributed to A. sublatus, we demonstrated that at least some previously reported infections due to A. quadrilineatus were probably caused by this cryptic species.

Diffuse parenchymal lung disease as first clinical manifestation of GATA-2 deficiency in childhood.

BACKGROUND: GATA-2 transcription factor deficiency has recently been described in patients with a propensity towards myeloid malignancy associated with other highly variable phenotypic features: chronic leukocytopenias (dendritic cell-, monocyto-, granulocyto-, lymphocytopenia), increased susceptibility to infections, lymphatic vasculature abnormalities, and sensorineural deafness. Patients often suffer from opportunistic respiratory infections; chronic pulmonary changes have been found in advanced disease. CASE PRESENTATION: We present a case of a 17-year-old previously healthy Caucasian male who was admitted to the hospital with fever, malaise, headache, cough and dyspnea. A chest X-ray revealed bilateral interstitial infiltrates and pneumonia was diagnosed. Despite prompt clinical improvement under antibiotic therapy, interstitial changes remained stable. A high resolution computer tomography showed severe diffuse parenchymal lung disease, while the patient's pulmonary function tests were normal and he was asymptomatic. Lung tissue biopsy revealed chronic reparative and resorptive reaction with organizing vasculitis. At the time of the initial presentation to the hospital, serological signs of acute infection with Epstein-Barr virus (EBV) were present; EBV viremia with atypical serological response persisted during two-year follow up. No other infectious agents were found. Marked monocytopenia combined with B-cell lymphopenia led to a suspicion of GATA-2 deficiency. Diagnosis was confirmed by detection of the previously published heterozygous mutation in GATA2 (c.1081 C > T, p.R361C). The patient's brother and father were both carriers of the same genetic defect. The brother had no clinically relevant ailments despite leukocyte changes similar to the index patient. The father suffered from spondylarthritis, and apart from B-cell lymphopenia, no other changes within the leukocyte pool were seen. CONCLUSION: We conclude that a diagnosis of GATA-2 deficiency should be considered in all patients with diffuse parenchymal lung disease presenting together with leukocytopenia, namely monocyto-, dendritic cell- and B-lymphopenia, irrespective of severity of the clinical phenotype. Genetic counseling and screening for GATA2 mutations within the patient's family should be provided as the phenotype is highly variable and carriers without apparent immunodeficiency are still in danger of developing myeloid malignancy. A prompt recognition of this rare condition helps to direct clinical treatment strategies and follow-up procedures.

[Soft tissue tumors - the view of the molecular biologist]. / Nádory mekkých tkání ocima molekulárního patologa.

Soft tissue tumors (SSTs) constitute a broad spectrum of neoplasms with diverse biological properties. Rare or unusual types are often difficult to classify. Recent studies show, that a significant subset of SSTs including many types of sarcomas are associated with specific genetic changes such as chromosomal translocations producing chimeric genes, which play a role in the pathogenesis of SSTs. Because SSTs represent a diagnostically challenging group of tumors, molecular-genetic techniques (FISH or PCR) are useful as supplementary and/or confirmatory diagnostic tools. In the present paper we demonstrate the usefulness of a combined diagnostic approach using the tools of classical histopathology and immunohistochemistry together with the molecular diagnostic approach in selected nosologic entites.

Homozygous EXOSC3 mutation c.92G→C, p.G31A is a founder mutation causing severe pontocerebellar hypoplasia type 1 among the Czech Roma.

Pontocerebellar hypoplasia type 1 (PCH1) is characterized by cerebellar and anterior horn motor neuron degeneration and loss, signs of spinal muscular atrophy plus. Patients manifest severe perinatal weakness, hypotonia, and respiratory insufficiency, causing death frequently before the age of 1 year. Recently, causative mutations in EXOSC3 were reported in a majority of PCH1 patients, but the detailed clinical phenotype caused by EXOSC3 mutations, genotype-phenotype correlations, and prevalent mutations in specific ethnic groups is not yet known. Three unrelated Czech Roma patients with PCH1 were investigated clinically, electrophysiologically, neuroradiologically, and neuropathologically (patients 1 and 2). The entire coding region of the EXOSC3 gene, including the adjacent intron sequences, was sequenced in all three patients. The same mutation c.92G→C, p.G31A in EXOSC3 was found in all three affected patients in homozygous state and in heterozygous state in the parents from two of the families. Haplotype analysis with four flanking microsatellite markers showed identical haplotype in 9 out of 11 haplotypes carrying the c.92G→C, p.G31A mutation. Furthermore, four heterozygotes for this mutation were found in anonymous DNA samples from 90 unrelated Roma individuals. All four of these samples shared the same haplotype. No heterozygous sample was found among 120 anonymous DNA samples from Czech non-Roma individuals with no familial relation. It may therefore be concluded that EXOSC3 c.92G→C, p.G31A mutation is a founder mutation with high prevalence among the Czech Roma causing a similar and particularly severe phenotype of PCH1. These observations from the Czech Roma may have consequences also for other Roma from other countries. PCH1 caused by EXOSC3 founder mutation c.92G→C, p.G31A extends the list of autosomal recessive disorders rare among the general population but more frequent among Roma at least in the Czech Republic.

Spectrum of postmortem autopsy findings in native and surgically corrected hearts with congenital malformations: a 10-year single-center experience.

OBJECTIVES: We reviewed a spectrum of congenital heart defects assessed in our center between 1/2010 and 4/2020, evaluated their gross anatomy, assessed the age distribution, evaluated performed surgical procedures, and correlated gross and ultrasound findings. METHODS: All necroptic cases and explanted hearts that underwent specialized cardiac autopsy were included in this study. Autopsy findings including gross description of congenital heart defects together with echocardiographic findings were retrospectively assessed. In surgically corrected hearts, the operation records were included as well. All congenital heart defects and surgical procedures were subclassified into main and additional category. RESULTS: The study included 92 necroptic cases of live-born children, 7 stillbirths, 2 cases of young adults, 50 induced abortions, and 5 explanted hearts, with median age 36 weeks. The most frequently encountered leading congenital heart defects were hypoplastic left heart syndrome, aortic stenosis, septal defects, or persistent arterial trunk. Fifty-one patients underwent surgical repair represented mainly by valvuloplasties, aortoplasty, and procedures leading to univentricular circulation. In the native hearts, 4 postnatal and 16 abortion/stillbirth cases showed discordance between gross and sonographic findings, mainly attributed to missed ventricular septal defect. Gestational age of the discordant group was significantly lower compared to the concordant group (P= .007). CONCLUSIONS: Autopsy continues to provide essential information about the morphology of congenital heart defects. However, the encountered congenital heart defects were usually complex, often surgically corrected or evaluated as a result of induced abortion or still birth. Cardiac autopsy therefore places high demands on pathologists with regards to proper gross heart assessment. It is also an invaluable part of quality control in prenatal cardiology.

Histopathological evidence of aortopathy in newborns and infants with Tetralogy of Fallot at the time of the surgical repair.

OBJECTIVES: The purpose of this study was to evaluate the microscopic structural abnormalities of the ascending aorta in infants with Tetralogy of Fallot (ToF) and compare them with aortic samples from control group of small children that died of other diseases. We aimed at identification of the specific histopathological changes associated with ToF and correlation of the severity of these changes with time to surgery and mean levels of saturation in the ToF group, and age at death in control group. METHODS: The full-thickness ascending aortic wall sample was taken from 23 children with ToF at the time of surgical reconstruction (age spread 2 to 19 months) and evaluated by light microscopy. Corresponding samples were taken from 16 cadaverous cases of children with other diseases (0-76 months). The assessed morphological variables included elastic fiber fragmentation/loss, thinning and disorganisation, presence of laminar medial necrosis, intralamellar and translamellar mucoid extracellular matrix accumulations, smooth muscle cell disorganisation, presence of fibrosis, calcifications and neovascularisation and finally grade of overall medial degeneration. RESULTS: No difference was found between the two groups in the individual morphological variables. However, there was a difference in the distribution of the grades of the overall medial degeneration (P = .016). ToF group showed uniform mild degenerative changes, whereas control group harboured spectrum of changes ranging from normal to moderate. The presence of the given histopathological changes and their severity were associated neither with age at surgery or mean levels of saturation in ToF group, nor with the age at death in the control group. CONCLUSIONS: This study emphasizes the histopathological assessment of the bioptic samples of the ascending aorta during the surgical repair of ToF, since the patients demonstrating moderate or severe degenerative changes already in the early childhood may be in increased risk of the subsequent late complications.

Low predictive value of histopathological scoring system for complications development in children with Crohn's disease.

OBJECTIVES: In pediatric Crohn's disease (PCD), the benefit of microscopy in disease activity assessment and prediction of clinical outcome is, due to the focality and transmurality of the inflammation, disputable. We investigated whether histopathological scoring system predicts complications in pediatric CD and correlates with endoscopical and clinical scores. METHODS: We performed a retrospective study on 63 patients. Endoscopy in the time of diagnosis was evaluated using the Simple Endoscopic Score (SES) and histopathology with the Global Histology Activity Score, both in its original version (GHAS) and its modification (modGHAS). Pediatric Crohn's Disease Activity Index (PCDAI) was also calculated. The patients were grouped according to the presence or absence of defined complications (intraabdominal abscess or fistula, perianal fistulating disease or stricture impenetrable for endoscope or with prestenotic dilatation) during one year of follow-up, or the necessity to initiate anti-TNF treatment for persisting or relapsing active disease in the same time period. Associations were tested with Cox regression analysis. RESULTS: SES was higher in patients with complications. However, in case of GHAS, modGHAS and PCDAI we did not find any significant association with complicated course of disease. SES above 16 points was revealed as an independent risk factor for complications development in PCD, in contrary to GHAS, modGHAS and PCDAI. We demonstrated only a weak correlation between GHAS, modGHAS and SES and no correlation between the histopathological scoring systems and PCDAI. CONCLUSIONS: In conclusion, the histopathological scoring system cannot be recommended as a reliable predictor of development of complications in children with CD.

Congenital bronchopulmonary malformation: CT histopathological correlation.

BACKGROUND: This study evaluated the accuracy of postnatal computed tomography (CT) imaging in the identification of congenital bronchopulmonary malformation (BPM) in comparison with histopathological analysis. METHODS: CT scans of prenatally diagnosed BPMs from 24 patients with available histology were analysed retrospectively. The CT images were reviewed blinded to histological findings by two radiologists. Specific diagnosis was assigned based on predetermined criteria. The accuracy of CT was evaluated. RESULTS: The agreement rate in CT diagnosis between two radiologists was 100%. In 75% the lesions were located in the lower lobes. An overlap of 71% in CT and histopathological diagnoses was reached. The least matching diagnosis was type 2 CPAM. CONCLUSION: Contrast enhanced chest CT is very accurate in characterizing the BPM spectrum and provides important information on lesion type and structure.