Thrombotic and cardiac disease in the antiphospholipid syndrome

The antiphospholipid syndrome (APS) is a highly heterogeneous disease that presents with obstetric complications and/or thromboembolic events that can hit any side of the vascular tree in an unpredictable way. The common trait among all patients affected by the syndrome is the persistent presence of the antiphospholipid antibodies (aPL) and/or a prolonged coagulation time in vitro, the lupus anticoagulant (LA) test. The pathogenesis of APS has not yet been clearly defined. Many molecules are involved in the maintenance of the equilibrium called hemostasis, interacting and cross-reacting in an incredibly perfect orchestrated balance that somehow, in APS, is broken. The aim of this thesis has been to try to shed some light on the complex mechanisms behind APS, by focusing on some of the many pieces of the puzzle that characterize the disease. The complement, coagulation and fibrinolytic systems have been the subjects of this fascinating journey, and two proteins in particular have been on focus: C4b-binding protein (C4BP) and Thrombin activatable fibrinolysis inhibitor (TAFI). These are both regulators of complement activation that at the same time play a role in coagulation. Moreover, the link between myocardial infarction (MI) and aPL/LA has been explored. Paper I: TAFI and its activated form, TAFIa, were studied in patients affected by mainly primary APS (i.e. without other autoimmune diseases) and compared with a healthy control group. Moreover, C5a, a marker of complement activation, and markers of fibrinolysis were investigated and correlated with TAFI and TAFIa. Both TAFI and TAFIa are significantly higher in APS compared to controls. TAFIa is increased in APS patients affected by arterial thrombosis compared to other clinical manifestations, independently of traditional cardiovascular risk factors. TAFI is positively correlated with C5a, confirming its increase upon inflammation. TAFIa positively correlates with thrombomodulin, marker of endothelial damage/activation. The values of the clot lysis time (CLT) and of the permeability coefficient confirm impaired fibrinolysis in APS, with clots more resistant to lysis. Paper II: we investigated the prevalence of aPL in a large and well-characterized cohort of patients after 6-10 weeks from a first MI, and compared it with age, gender and region matched controls. We demonstrated ten times higher prevalence of aPL of the IgG isotype in patients versus controls, independently of traditional cardiovascular risk factors, suggesting that IgG aPL positivity may be considered a potential risk factor for MI in the general population. No significant differences were observed for IgM and IgA isotypes. Paper III: C4BP was investigated in a large cohort of patients affected by systemic lupus erythematosus (SLE), in primary APS and in controls. C4BP is lower in patients persistently positive for aPL and in patients treated with warfarin. C4BP correlates with markers of complement activation. Both persistent aPL positivity and warfarin are associated with C4BP reduction, and by means of a mediation analysis we were able to assess the relative contribution of these two variables: aPL have a direct reducing effect on C4BP of 11%, while warfarin contributes to 9% of the observed reduction. Paper IV: After the results of paper III, we decided to study the effect of warfarin on complement and C4BP in the general population, comparing it with the direct oral anticoagulants (DOACs), during and after treatment discontinuation. Warfarin, as opposed to DOACs, is associated with increased markers of complement activation, which persist for at least three weeks after withdrawal. Higher C4BP levels characterize the patients after warfarin discontinuation, as a rebound effect. DOACs have no effect on complement, but, in contrast, we demonstrate that warfarin is associated with complement activation, partly but probably not only through inhibition of C4BP. This study is of relevance in the context of APS, since different anticoagulant mechanisms have been subjects of debate in recent years. In conclusion, as also Ames stated regarding paper I , this thesis has tried to insert other linking pieces in the puzzle of APS. We confirm the presence of impaired fibrinolysis and complement activation in APS, and we have opened the path for a new era of research in the syndrome, where also the treatment with anticoagulants has to be considered for its potential impact on complement activation. Moreover, although causality could not be proven, we demonstrate that the prevalence of aPL after myocardial infarction in the general population is considerable and higher than generally anticipated

Arterial hypertension and dyslipidemia in a HIV-positive patient treated with antiretroviral therapy

The introduction of antiretroviral therapy (ART) has substantially modified the clinical history and epidemiology of HIV infection with an important decline in infective causes of death and an increase in non-infective comorbidities particularly in cardiovascular complications. HIV infection has been related to an increased cardiovascular risk due to the presence of three factors: classic cardiovascular risk factors (shared with the general population), HIV infection itself (indirectly due to the inflammation and directly due to viral molecule) and ART-related chronic metabolic alterations. We describe a peculiar case of metabolic alteration in an HIV infected patient on ART with particular attention to the diagnosis and therapeutic aspects. Giving the higher cardiovascular risk of this specific population it is advisable that the clinician performs a frequent re-assessment of risk factors and cardiovascular organ damage. An early detection of metabolic alteration must lead to an aggressive specific therapy; this must be done by taking care of the HIV-infected subject fragility and the interactions with ART

First and Second Level Haemoglobinopathies Diagnosis: Best Practices of the Italian Society of Thalassemia and Haemoglobinopathies (SITE)

The purpose of this best practice paper is to review the current recommendations for the identification and prenatal diagnosis of hemoglobinopathies. Methods: The management committee of SITE selected and gathered a multidisciplinary team in order to formulate recommendations based on the available scientific evidence integrated with the opinions of experts, with the purpose of supporting clinicians. Results: We provide recommendations for first level tests (complete blood count, hemoglobin separation and iron balance), second level tests (molecular diagnosis) and prenatal diagnosis. Five Italian experts in hemoglobinopathies were consulted regarding the orientation of prenatal diagnosis, and for each indication, the degree of agreement among the experts has been specified. Conclusions: Best practice recommendations are the final outcome of this translational research and allow transfer to daily clinical practice

A new case of 13q12.2q13.1 microdeletion syndrome contributes to phenotype delineation.

A recently described genetic disorder has been associated with 13q12.3 microdeletion spanning three genes, namely, KATNAL1, LINC00426, and HMGB1. Here, we report a new case with similar clinical features that we have followed from birth to 5 years old. The child carried a complex rearrangement with a double translocation: 46,XX,t(7;13)(p15;q14),t(11;15)(q23;q22). Array-CGH identified a de novo microdeletion at 13q12.2q13.1 spanning 3–3.4 Mb and overlapping 13q12.3 critical region. Clinical features resembling those reported in the literature confirm the existence of a distinct 13q12.3 microdeletion syndrome and provide further evidence that is useful to characterize its phenotypic expression during the 5 years of development

Large cryptic genomic rearrangements with apparently normal karyotypes detected by array-CGH.

Background: Conventional karyotyping (550 bands resolution) is able to identify chromosomal aberrations >5-10 Mb, which represent a known cause of intellectual disability/developmental delay (ID/DD) and/or multiple congenital anomalies (MCA). Array-Comparative Genomic Hybridization (array-CGH) has increased the diagnostic yield of 15-20%. Results: In a cohort of 700 ID/DD cases with or without MCA, including 15 prenatal diagnoses, we identified a subgroup of seven patients with a normal karyotype and a large complex rearrangement detected by array-CGH (at least 6, and up to 18 Mb). FISH analysis could be performed on six cases and showed that rearrangements were translocation derivatives, indistinguishable from a normal karyotype as they involved a similar band pattern and size. Five were inherited from a parent with a balanced translocation, whereas two were apparently de novo. Genes spanning the rearrangements could be associated with some phenotypic features in three cases (case 3: DOCK8; case 4: GATA3, AKR1C4; case 6: AS/PWS deletion, CHRNA7), and in two, likely disease genes were present (case 5: NR2F2, TP63, IGF1R; case 7: CDON). Three of our cases were prenatal diagnoses with an apparently normal karyotype. Conclusions: Large complex rearrangements of up to 18 Mb, involving chromosomal regions with similar size and band appearance may be overlooked by conventional karyotyping. Array-CGH allows a precise chromosomal diagnosis and recurrence risk definition, further confirming this analysis as a first tier approach to clarify molecular bases of ID/DD and/or MCA. In prenatal tests, array-CGH is confirmed as an important tool to avoid false negative results due to karyotype intrinsic limit of detection

A New Case of 13q12.2q13.1 Microdeletion Syndrome Contributes to Phenotype Delineation

A recently described genetic disorder has been associated with 13q12.3 microdeletion spanning three genes, namely, KATNAL1, LINC00426, and HMGB1. Here, we report a new case with similar clinical features that we have followed from birth to 5 years old. The child carried a complex rearrangement with a double translocation: 46,XX,t(7;13)(p15;q14),t(11;15)(q23;q22). Array-CGH identified a de novo microdeletion at 13q12.2q13.1 spanning 3–3.4 Mb and overlapping 13q12.3 critical region. Clinical features resembling those reported in the literature confirm the existence of a distinct 13q12.3 microdeletion syndrome and provide further evidence that is useful to characterize its phenotypic expression during the 5 years of development

Array-Comparative Genomic Hybridization Analysis in Fetuses with Major Congenital Malformations Reveals that 24% of Cases Have Pathogenic Deletions/Duplications

Karyotyping and aCGH are routinely used to identify genetic determinants of major congenital malformations (MCMs) in fetal deaths or terminations of pregnancy after prenatal diagnosis. Pathogenic rearrangements are found with a variable rate of 9-39% for aCGH. We collected 33 fetuses, 9 with a single MCM and 24 with MCMs involving 2-4 organ systems. aCGH revealed copy number variants in 14 out of 33 cases (42%). Eight were classified as pathogenic which account for a detection rate of 24% (8/33) considering fetuses with 1 or more MCMs and 33% (8/24) taking into account fetuses with multiple malformations only. Three of the pathogenic variants were known microdeletion syndromes (22q11.21 deletion, central chromosome 22q11.21 deletion, and TAR syndrome) and 5 were large rearrangements, adding up to >11 Mb per subject and comprising strong phenotype-related genes. One of those was a de novo complex rearrangement, and the remaining 4 duplications and 2 deletions were 130-900 kb in size, containing 1-7 genes, and were classified as variants of unknown clinical significance. Our study confirms aCGH as a powerful technique to ascertain the genetic etiology of fetal major congenital malformations

Genomic Studies in a Large Cohort of Hearing Impaired Italian Patients Revealed Several New Alleles, a Rare Case of Uniparental Disomy (UPD) and the Importance to Search for Copy Number Variations

Hereditary hearing loss (HHL) is a common disorder characterized by a huge genetic heterogeneity. The definition of a correct molecular diagnosis is essential for proper genetic counseling, recurrence risk estimation, and therapeutic options. From 20 to 40% of patients carry mutations in GJB2 gene, thus, in more than half of cases it is necessary to look for causative variants in the other genes so far identified (~100). In this light, the use of next-generation sequencing technologies has proved to be the best solution for mutational screening, even though it is not always conclusive. Here we describe a combined approach, based on targeted re-sequencing (TRS) of 96 HHL genes followed by high-density SNP arrays, aimed at the identification of the molecular causes of non-syndromic HHL (NSHL). This strategy has been applied to study 103 Italian unrelated cases, negative for mutations in GJB2, and led to the characterization of 31% of them (i.e., 37% of familial and 26.3% of sporadic cases). In particular, TRS revealed TECTA and ACTG1 genes as major players in the Italian population. Furthermore, two de novo missense variants in ACTG1 have been identified and investigated through protein modeling and molecular dynamics simulations, confirming their likely pathogenic effect. Among the selected patients analyzed by SNP arrays (negative to TRS, or with a single variant in a recessive gene) a molecular diagnosis was reached in ~36% of cases, highlighting the importance to look for large insertions/deletions. Moreover, copy number variants analysis led to the identification of the first case of uniparental disomy involving LOXHD1 gene. Overall, taking into account the contribution of GJB2, plus the results from TRS and SNP arrays, it was possible to reach a molecular diagnosis in ~51% of NSHL cases. These data proved the usefulness of a combined approach for the analysis of NSHL and for the definition of the epidemiological picture of HHL in the Italian population

Impaired activation of plasmacytoid dendritic cells via toll-like receptor 7/9 and STING is mediated by melanoma-derived immunosuppressive cytokines and metabolic drift

IntroductionPlasmacytoid dendritic cells (pDCs) infiltrate a large set of human cancers. Interferon alpha (IFN-α) produced by pDCs induces growth arrest and apoptosis in tumor cells and modulates innate and adaptive immune cells involved in anti-cancer immunity. Moreover, effector molecules exert tumor cell killing. However, the activation state and clinical relevance of pDCs infiltration in cancer is still largely controversial. In Primary Cutaneous Melanoma (PCM), pDCs density decreases over disease progression and collapses in metastatic melanoma (MM). Moreover, the residual circulating pDC compartment is defective in IFN-α production.MethodsThe activation of tumor-associated pDCs was evaluated by in silico and microscopic analysis. The expression of human myxovirus resistant protein 1 (MxA), as surrogate of IFN-α production, and proximity ligation assay (PLA) to test dsDNA-cGAS activation were performed on human melanoma biopsies. Moreover, IFN-α and CXCL10 production by in vitro stimulated (i.e. with R848, CpG-A, ADU-S100) pDCs exposed to melanoma cell lines supernatants (SN-mel) was tested by intracellular flow cytometry and ELISA. We also performed a bulk RNA-sequencing on SN-mel-exposed pDCs, resting or stimulated with R848. Glycolytic rate assay was performed on SN-mel-exposed pDCs using the Seahorse XFe24 Extracellular Flux Analyzer.ResultsBased on a set of microscopic, functional and in silico analyses, we demonstrated that the melanoma milieu directly impairs IFN-α and CXCL10 production by pDCs via TLR-7/9 and cGAS-STING signaling pathways. Melanoma-derived immunosuppressive cytokines and a metabolic drift represent relevant mechanisms enforcing pDC-mediated melanoma escape.DiscussionThese findings propose a new window of intervention for novel immunotherapy approaches to amplify the antitumor innate immune response in cutaneous melanoma (CM)