1 5506 112 RHEUMATOID ARTHRITIS AND PRIMARY BILIARY CIRRHOSIS: CAUSE, CONSEQUENCE, OR COINCIDENCE? PRIMARY BILIARY CIRRHOSIS (PBC) IS A PROGRESSIVE CHOLESTATIC LIVER DISEASE CHARACTERIZED SEROLOGICALLY BY CHOLESTASIS AND THE PRESENCE OF HIGH-TITRE ANTIMITOCHONDRIAL ANTIBODIES AND HISTOLOGICALLY BY CHRONIC NONSUPPURATIVE CHOLANGITIS AND GRANULOMATA. PBC PATIENTS OFTEN HAVE CONCOMITANT AUTOIMMUNE DISEASES, INCLUDING ARTHROPATHIES. THIS RAISES THE QUESTION AS TO WHETHER THERE ARE SHARED FEATURES IN THE PATHOGENESIS OF THOSE DISEASES WITH THE PATHOGENESIS OF PBC. EPIDEMIOLOGICAL AND LARGE CASE STUDIES HAVE INDICATED THAT ALTHOUGH THE INCIDENCE OF RHEUMATOID ARTHRITIS (RA) IS NOT SIGNIFICANTLY RAISED IN PBC PATIENTS, THERE APPEARS TO BE A HIGHER RATE OF RA IN PBC PATIENTS AND THEIR RELATIVES. GENETIC STUDIES HAVE DEMONSTRATED THAT SEVERAL GENES IMPLICATED IN PBC HAVE ALSO BEEN IMPLICATED IN RA. EPIGENETIC STUDIES PROVIDED A WEALTH OF DATA REGARDING RA, BUT THE FINDINGS ON EPIGENETIC CHANGES IN PBC ARE VERY LIMITED. AS WELL, CERTAIN INFECTIOUS AGENTS IDENTIFIED IN THE PATHOGENESIS OF PBC MAY ALSO PLAY A ROLE IN THE PATHOGENESIS OF RA. THESE DATA SUGGEST THAT ALTHOUGH RA IS NOT SIGNIFICANTLY PRESENT IN PBC, SOME INDIVIDUALS WITH CERTAIN GENETIC TRAITS AND ENVIRONMENTAL EXPOSURES MAY DEVELOP BOTH CONDITIONS. THIS CONCEPT MAY ALSO APPLY TO OTHER CONCOMITANT DISEASES FOUND IN PBC PATIENTS. 2012 2 3012 45 GENETICS AND EPIGENETICS IN THE PATHOGENESIS OF PRIMARY BILIARY CHOLANGITIS. PRIMARY BILIARY CHOLANGITIS (PBC) IS A CHRONIC, SLOWLY PROGRESSIVE CHOLESTATIC AUTOIMMUNE LIVER DISEASE PREDOMINANTLY AFFLICTING WOMEN. PBC IS CHARACTERIZED BY THE PRESENCE OF DISEASE-SPECIFIC ANTIMITOCHONDRIAL ANTIBODIES AND THE HISTOLOGICAL DESTRUCTION OF INTRAHEPATIC BILE DUCTS, WHICH EVENTUALLY LEAD TO CIRRHOSIS AND HEPATIC FAILURE. FORTUNATELY, URSODEOXYCHOLIC ACID THERAPY HAS IMPROVED THE OUTCOME OF THE VAST MAJORITY OF PBC CASES. ALTHOUGH THE ETIOLOGY OF PBC HAS NOT YET BEEN ELUCIDATED, HUMAN LEUKOCYTE ANTIGEN (HLA) CLASS II ALLELES HAVE BEEN CONSISTENTLY ASSOCIATED WITH DISEASE ONSET FOR DECADES. PBC PATIENTS MAY ALSO HAVE GENETICALLY DETERMINED RISK FACTORS IN NON-HLA REGIONS. MEANWHILE, EXPOSURE TO ENVIRONMENTAL FACTORS, SUCH AS INFECTIOUS DISEASES AND HARMFUL CHEMICALS, CAN PRODUCE EPIGENETIC ALTERATIONS IN SOME INDIVIDUALS AND SUBSEQUENT PBC ONSET. IN THIS REVIEW, WE DESCRIBE THE INFLUENCE OF HLA ALLELES AND OTHER GENE POLYMORPHISMS ON PBC ALONG WITH THE RESULTS OF GENOME-WIDE ASSOCIATION STUDIES ON THIS DISEASE AND ITS FUTURE PROSPECTS IN TERMS OF EPIGENETICS. 2018 3 5220 33 PRIMARY BILIARY CHOLANGITIS: A TALE OF EPIGENETICALLY-INDUCED SECRETORY FAILURE? PRIMARY BILIARY CHOLANGITIS (PBC) IS A CHRONIC CHOLESTATIC LIVER DISEASE ASSOCIATED WITH AUTOIMMUNE-RELATED DESTRUCTION OF SMALL TO MEDIUM SIZE INTRAHEPATIC BILE DUCTS. THE AETIOLOGY OF PBC IS UNKNOWN AND ITS PATHOGENESIS REMAINS OBSCURE. BOTH GENETIC VARIANTS AND ENVIRONMENTAL FACTORS HAVE BEEN LINKED TO INCREASED PBC SUSCEPTIBILITY, WITH OTHER ALTERATIONS KNOWN TO COOPERATE IN DISEASE PATHOBIOLOGY. INCREASING EVIDENCE INDICATES THE PRESENCE OF EPIGENETIC ABNORMALITIES IN PBC, PARTICULARLY ALTERATIONS OF CHOLANGIOCELLULAR MICRORNAS (MIRNAS OR MIRS). THIS REVIEW HIGHLIGHTS AND DISCUSSES THE MOST RELEVANT EPIGENETIC ALTERATIONS FOUND IN PATIENTS WITH PBC, FOCUSING ON THE ROLE OF MIR-506 IN THE PROMOTION OF CHOLESTASIS AND IMMUNE ACTIVATION. 2018 4 5146 55 POTENTIAL ROLES FOR INFECTIOUS AGENTS IN THE PATHOPHYSIOLOGY OF PRIMARY BILIARY CIRRHOSIS: WHAT'S NEW? PRIMARY BILIARY CIRRHOSIS (PBC) IS A PROGRESSIVE CHOLESTATIC LIVER DISEASE SEROLOGICALLY CHARACTERIZED BY THE PRESENCE OF HIGH-TITER ANTIMITOCHONDRIAL ANTIBODIES AND, HISTOLOGICALLY BY CHRONIC NONSUPPURATIVE CHOLANGITIS AND GRANULOMATA. THE AETIOLOGY OF THE DISEASE REMAINS ELUSIVE, ALTHOUGH GENETIC, EPIGENETIC, ENVIRONMENTAL, AND INFECTIOUS FACTORS HAVE BEEN CONSIDERED IMPORTANT FOR THE INDUCTION OF THE DISEASE IN GENETICALLY PRONE INDIVIDUALS. THE DISEASE SHOWS A STRIKING FEMALE PREDOMINANCE AND BECOMES CLINICALLY OVERT AT THE FOURTH TO SIXTH DECADE. THESE CHARACTERISTICS HAVE PROMPTED INVESTIGATORS TO CONSIDER INFECTIONS THAT PREDOMINATE IN WOMEN AT THESE AGES AS THE LIKELY CANDIDATES FOR TRIGGERING THE DISEASE. RECURRENT URINARY TRACT INFECTIONS DUE TO ESCHERICHIA COLI WERE THE FIRST INFECTIONS TO BE CONSIDERED PATHOGENETICALLY RELEVANT. OVER THE YEARS, SEVERAL OTHER MICROORGANISMS HAVE BEEN LINKED TO THE PATHOGENESIS OF PBC OWING TO EPIDEMIOLOGICAL, IMMUNOLOGICAL, MICROBIOLOGICAL, OR EXPERIMENTAL FINDINGS IN ANIMAL MODELS. RECENT STUDIES HAVE PROVIDED DATA SUPPORTING THE PATHOGENIC ROLE OF NOVOSPHINGOBIUM AROMATICIVORANS AND BETARETROVIRUSES. SEVERAL REPORTS HAVE LINKED OTHER ORGANISMS TO THE INDUCTION OF THE DISEASE AND/OR THE MAINTENANCE OF THE AUTO-AGGRESSIVE RESPONSES THAT ARE PERPETUATED OVER THE COURSE OF THE DISEASE. THIS REVIEW HIGHLIGHTS THE FINDINGS OF THE MOST RECENT STUDIES INVESTIGATING THE LINK BETWEEN INFECTIONS AND PBC. WE ALSO DISCUSS THE CLOSE INTERPLAY OF THE INFECTIOUS AGENTS WITH OTHER ENVIRONMENTAL AND GENETIC FACTORS, WHICH MAY EXPLAIN THE MULTIFACETED NATURE OF THIS PUZZLING DISEASE. 2013 5 2588 35 EPIGENETICS OF PRIMARY BILIARY CHOLANGITIS. PRIMARY BILIARY CHOLANGITIS (PBC) IS A CHRONIC CHOLESTATIC LIVER DISEASE WITH NON-SUPPURATIVE DESTRUCTION OF THE INTRAHEPATIC BILE DUCTS. THE INTERPLAY OF GENETICS AND ENVIRONMENTAL TRIGGERS CONTRIBUTES TO THE ONSET OF THE DISEASE AND SUBSEQUENTLY RESULTS IN CHOLESTASIS AND PROGRESSIVE FIBROSIS. RECENTLY, GENOME-WIDE ASSOCIATION STUDIES (GWAS) HAVE IDENTIFIED MULTIPLE GENES INFLUENCING THE SUSCEPTIBILITY TO PBC IN HLA AND NON-HLA LOCI. HOWEVER, IT IS ESTIMATED THAT THE KNOWN RISK VARIANTS MERELY ACCOUNT FOR NO MORE THAN 20% OF THE HERITABILITY OF PBC AND CAUSES OF THE REMAINING HERITABILITY REMAIN UNCERTAIN. INCREASING EVIDENCE SUGGESTS THAT THE PRESENCE OF EPIGENETIC ABNORMALITIES MAY EXPLAIN THE "MISSING HERITABILITY" THAT CANNOT BE CAPTURED BY GWAS. AMONG THESE EPIGENETIC MECHANISMS, DNA METHYLATION, HISTONE MODIFICATION, AND NONCODING RNAS (I.E. MIRNA AND LNCRNA) ARE INVOLVED IN THE PATHOGENESIS OF PBC. ADDITIONALLY, TELOMERE DYSREGULATION IN BILIARY EPITHELIAL CELLS (BECS) MAY PLAY A ROLE IN DISEASE ONSET, WHEREAS A DEFICIENCY IN SEX CHROMOSOME AND SKEWED GENE EXPRESSION IN THE X CHROMOSOME MAY TO SOME EXTENT EXPLAIN THE FEMALE DOMINANCE IN PBC. 2020 6 2512 44 EPIGENETICS AND PRIMARY BILIARY CIRRHOSIS: A COMPREHENSIVE REVIEW AND IMPLICATIONS FOR AUTOIMMUNITY. PRIMARY BILIARY CIRRHOSIS (PBC) IS A CHRONIC INFLAMMATORY AUTOIMMUNE DISEASE THAT DEVELOPS BASED UPON THE INTERACTION OF GENETIC AND ENVIRONMENTAL FACTORS. RECENT GENOME-WIDE ASSOCIATION STUDIES (GWAS) HAVE IDENTIFIED DOZENS OF PREDISPOSING VARIANTS INCLUDING HLA, IL12A, AND CTLA4 BUT HAVE BEEN DISAPPOINTED IN IDENTIFYING A "SMOKING GUN." THESE DISCOVERIES HIGHLIGHT THE IMPORTANCE OF THE GENETIC BACKGROUND INVOLVED IN IMMUNOLOGICAL DYSREGULATION. ALTHOUGH CONCORDANCE RATE OF PBC IN MONOZYGOTIC (MZ) TWINS IS AMONG THE HIGHEST REPORTED IN AUTOIMMUNE DISORDERS, INCOMPLETE DISEASE CONCORDANCE IN TWINS ASSOCIATED WITH DIFFERENTIALLY EXPRESSED GENES HAS BEEN DEMONSTRATED. HOWEVER, LITTLE IS UNDERSTOOD ABOUT HOW ENVIRONMENTAL ASPECTS CONTRIBUTE TO THE DISEASE AND WHY MIDDLE-AGED WOMEN ARE MORE SUSCEPTIBLE. AS A RESULT, EPIGENETIC FACTORS, WHICH CONVERT SIGNALS INDICATING ENVIRONMENTAL CHANGES INTO DYNAMIC AND HERITABLE ALTERATIONS OF TRANSCRIPTIONAL POTENTIAL, ARE GETTING INCREASED ATTENTION BY RESEARCHERS IN BOTH BASIC AND CLINICAL STUDIES. AMONG EPIGENETIC MECHANISMS, THE INSTABILITY AND SKEWED GENE EXPRESSION IN THE X CHROMOSOME MAY ACCOUNT FOR THE FEMALE PREPONDERANCE IN PBC. IN ADDITION, TRANSCRIPTIONAL REGULATION OF HISTONE MODIFICATION AND DNA METHYLATION UNDERSCORES POTENTIAL INVOLVEMENT IN DISEASE PATHOGENESIS. HIGH-THROUGHPUT TECHNIQUES ARE BEING USED TO IDENTIFY EPIGENETIC REGULATORS. IN THIS REVIEW, WE ATTEMPT TO OUTLINE RECENT PROGRESS REGARDING EPIGENETICS IN PBC AND OTHER AUTOIMMUNE DISEASES. 2016 7 3112 42 GEOEPIDEMIOLOGY AND (EPI-)GENETICS IN PRIMARY BILIARY CHOLANGITIS. PRIMARY BILIARY CHOLANGITIS (PBC) IS A RARE FEMALE PREPONDERANT CHRONIC AUTOIMMUNE CHOLESTATIC LIVER DISEASE, CHARACTERIZED BY INTRAHEPATIC DUCTOPENIA AND PROGRESSIVE FIBROSIS. DURING LAST DECADES INCIDENCE AND PREVALENCE SHOWED AN INCREASING RATE WHICH VARY WIDELY WORLDWIDE DEMONSTRATING AN IMPORTANT INTERACTION BETWEEN ENVIRONMENTAL AND GENETIC FACTORS. HERITABILITY SUGGESTED BY FAMILIAL OCCURRENCE AND MONOZYGOTIC TWINS CONCORDANCE HAVE BEEN CONFIRMED IN MORE STUDIES. EPIGENETICS MECHANISMS SUCH AS HISTONE MODIFICATION AND DNA METHYLATION CAN PARTIALLY EXPLAIN PREDISPOSITION AND INHERITANCE OF THIS DISEASE. NEVERTHELESS, AN ASSOCIATION WITH SPECIFIC CLASS II HUMAN LEUKOCYTE ANTIGEN (HLA) VARIANTS HAVE BEEN REPORTED, SHOWING AN INCREASE RISK IN SUSCEPTIBILITY. MORE RECENTLY, DATA REGARDING A STRONG PROTECTIVE ASSOCIATION BETWEEN PBC AND HLA ALLELES CONFIRMED THIS ASSOCIATION. AFTER RECENT GENOME-WIDE ASSOCIATION STUDIES (GWAS), A MORE INTRICATE INTERACTION BETWEEN PBC AND THE HLA REGION HAS BEEN SHOWN. FURTHERMORE, GWAS ALSO IDENTIFIED SEVERAL IMMUNE-RELATED-GENES IMPLICATED. MORE GENOME-WIDE ASSOCIATION STUDIES ON THIS DISEASE ARE NEEDED TO REACH A COMPLETE AND SYSTEMATIC KNOWLEDGE OF THIS DISEASE. IN THIS REVIEW WE DISCUSS MORE RECENT ISSUED DATA ON GEOEPIDEMIOLOGY OF PBC AND THE ROLE OF (EPI-)GENETIC MECHANISMS IN ITS PATHOGENESIS. 2018 8 5222 34 PRIMARY BILIARY CIRRHOSIS: FAMILY STORIES. PRIMARY BILIARY CIRRHOSIS (PBC) IS A CHRONIC IMMUNE-MEDIATED CHOLESTATIC LIVER DISEASE OF UNKNOWN AETIOLOGY WHICH AFFECTS MOSTLY WOMEN IN MIDDLE AGE. FAMILIAL PBC IS WHEN PBC AFFECTS MORE THAN ONE MEMBER OF THE SAME FAMILY, AND DATA SUGGEST THAT FIRST-DEGREE RELATIVES OF PBC PATIENTS HAVE AN INCREASED RISK OF DEVELOPING THE DISEASE. MOST OFTEN, THESE FAMILIAL CLUSTERS INVOLVE MOTHER-DAUGHTER PAIRS, WHICH IS CONSISTENT WITH THE FEMALE PREPONDERANCE OF THE DISEASE. THESE CLUSTERS PROVIDE EVIDENCE TOWARDS A GENETIC BASIS UNDERLYING PBC. HOWEVER, CLUSTERS OF NONRELATED INDIVIDUALS HAVE ALSO BEEN REPORTED, GIVING STRENGTH TO AN ENVIRONMENTAL COMPONENT. TWIN STUDIES HAVE DEMONSTRATED A HIGH CONCORDANCE FOR PBC IN MONOZYGOTIC TWINS AND A LOW CONCORDANCE AMONG DIZYGOTIC TWINS. IN CONCLUSION, STUDIES OF PBC IN FAMILIES CLEARLY DEMONSTRATE THAT GENETIC, EPIGENETIC, AND ENVIRONMENTAL FACTORS PLAY A ROLE IN THE DEVELOPMENT OF THE DISEASE. 2011 9 3031 38 GENETICS OF RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS AN INFLAMMATORY AUTOIMMUNE DISEASE INVOLVING SYMMETRIC JOINTS AND IS GENERALLY CHARACTERIZED BY PERSISTENT PAIN, TENDERNESS, AND DESTRUCTION OF JOINTS. THE VAST MAJORITY OF RA PATIENTS PRODUCE AUTOANTIBODIES, AND IMMUNE CELL INVOLVEMENT IN DISEASE DEVELOPMENT IS WELL RECOGNIZED, AS IS THE CONTRIBUTION OF OTHER TYPES OF CELLS IN SYNOVIAL TISSUE, LIKE FIBROBLASTS. IT IS KNOWN THAT THERE ARE MAJOR GENETIC ASSOCIATIONS WITH THE HLA LOCUS, WHILE MULTIPLE NON-HLA GENETIC VARIANTS DISPLAY RELATIVELY LOW RISK OF RA. BOTH HLA AND NON-HLA ASSOCIATIONS SUGGEST THAT THE PROFILES OF GENETIC ASSOCIATIONS FOR AUTOANTIBODY-POSITIVE VS. AUTOANTIBODY-NEGATIVE RA ARE DIFFERENT. SEVERAL ALLELES OF HLA-DRB1 ARE ASSOCIATED WITH HIGH RISK FOR AUTOANTIBODY-POSITIVE RA, WITH THE STRONGEST RISK CHARACTERIZED BY VALINE AT POSITION 11 OF THE PROTEIN SEQUENCE (HLA-DRB1*04 AND *10 ALLELES). THERE IS A STRONG PROTECTIVE EFFECT FOR THE RISK OF AUTOANTIBODY-POSITIVE RA ASSOCIATED WITH HLA-DRB1*13 ALLELES. ALTHOUGH MAJOR GENETIC ASSOCIATIONS HAVE BEEN KNOWN FOR SEVERAL YEARS, UNDERSTANDING OF THE SPECIFIC MECHANISMS IN THE DEVELOPMENT OF INCREASED RISK OF RA FOR THESE VARIATIONS IS WORK IN PROGRESS. CURRENT STUDIES FOCUS ON THE BINDING OF IMMUNE RECEPTORS INVOLVED IN RECOGNITION OF PUTATIVE PEPTIDES IN ACTIVATION OF T CELLS, AS WELL AS INVESTIGATION OF CELL SIGNALING MECHANISMS. AT LEAST A PART OF RA RISK COULD BE EXPLAINED BY GENE-GENE AND GENE-ENVIRONMENT INTERACTIONS. THERE ARE CURRENTLY MORE THAN 150 CANDIDATE LOCI WITH POLYMORPHISMS THAT ASSOCIATE WITH RA, MAINLY RELATED TO SEROPOSITIVE DISEASE, AND NEW DISCOVERIES ARE ANTICIPATED IN THE FUTURE FROM INVESTIGATION OF DIVERSE HUMAN POPULATIONS. THIS NEW RESEARCH WILL HELP CREATE A STRONG FOUNDATION FOR THE CONTINUING PROCESS OF INTEGRATING GENETIC, EPIGENETIC, TRANSCRIPTOMIC, AND PROTEOMIC DATA IN STUDIES OF RA. 2022 10 2294 44 EPIGENETIC REGULATION IN THE PATHOGENESIS OF SJOGREN SYNDROME AND RHEUMATOID ARTHRITIS. AUTOIMMUNE RHEUMATIC DISEASES, SUCH AS SJOGREN SYNDROME (SS) AND RHEUMATOID ARTHRITIS (RA), ARE CHARACTERIZED BY CHRONIC INFLAMMATION AND AUTOIMMUNITY, WHICH CAUSE JOINT TISSUE DAMAGE AND DESTRUCTION BY TRIGGERING REDUCED MOBILITY AND DEBILITATION IN PATIENTS WITH THESE DISEASES. INITIATION AND MAINTENANCE OF CHRONIC INFLAMMATORY STAGES ACCOUNT FOR SEVERAL MECHANISMS THAT INVOLVE IMMUNE CELLS AS KEY PLAYERS AND THE INTERACTION OF THE IMMUNE CELLS WITH OTHER TISSUES. INDEED, THE OVERLAPPING OF CERTAIN CLINICAL AND SEROLOGIC MANIFESTATIONS BETWEEN SS AND RA MAY INDICATE THAT NUMEROUS IMMUNOLOGIC-RELATED MECHANISMS ARE INVOLVED IN THE PHYSIOPATHOLOGY OF BOTH THESE DISEASES. IT IS WIDELY ACCEPTED THAT EPIGENETIC PATHWAYS PLAY AN ESSENTIAL ROLE IN THE DEVELOPMENT AND FUNCTION OF THE IMMUNE SYSTEM. ALTHOUGH MANY PUBLISHED STUDIES HAVE ATTEMPTED TO ELUCIDATE THE RELATION BETWEEN EPIGENETIC MODIFICATIONS (E.G. DNA METHYLATION, HISTONE POST-TRANSLATIONAL MODIFICATIONS, MIRNAS) AND AUTOIMMUNE DISORDERS, THE CONTRIBUTION OF EPIGENETIC REGULATION TO THE PATHOGENESIS OF SS AND RA IS AT PRESENT POORLY UNDERSTOOD. THIS REVIEW ATTEMPTS TO SHED LIGHT FROM A CRITICAL POINT OF VIEW ON THE IDENTIFICATION OF THE MOST RELEVANT EPIGENETIC MECHANISMS RELATED TO RA AND SS BY EXPLAINING INTRICATE REGULATORY PROCESSES AND PHENOTYPIC FEATURES OF BOTH AUTOIMMUNE DISEASES. MOREOVER, WE POINT OUT SOME EPIGENETIC MARKERS WHICH CAN BE USED TO MONITOR THE INFLAMMATION STATUS AND THE DYSREGULATED IMMUNITY IN SS AND RA. FINALLY, WE DISCUSS THE INCONVENIENCE OF USING EPIGENETIC DATA OBTAINED FROM BULK IMMUNE CELL POPULATIONS INSTEAD SPECIFIC IMMUNE CELL SUBPOPULATIONS. 2019 11 5739 34 SMOKING AND RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY DISEASE CAUSED BY BOTH GENETIC AND ENVIRONMENTAL FACTORS. SMOKING HAS BEEN IMPLICATED AS ONE OF THE MOST IMPORTANT EXTRINSIC RISK FACTORS FOR ITS DEVELOPMENT AND SEVERITY. RECENT DEVELOPMENTS HAVE SHED LIGHT ON THE PATHOPHYSIOLOGY OF RA IN SMOKERS, INCLUDING OXIDATIVE STRESS, INFLAMMATION, AUTOANTIBODY FORMATION AND EPIGENETIC CHANGES. THE ASSOCIATION OF SMOKING AND THE DEVELOPMENT OF RA HAVE BEEN DEMONSTRATED THROUGH EPIDEMIOLOGIC STUDIES, AS WELL AS THROUGH IN VIVO AND ANIMAL MODELS OF RA. WITH INCREASED USE OF BIOLOGICAL AGENTS IN ADDITION TO STANDARD DISEASE-MODIFYING ANTIRHEUMATIC DRUGS (DMARDS), THERE HAS BEEN INTEREST IN HOW SMOKING AFFECTS DRUG RESPONSE IN RA TREATMENT. RECENT EVIDENCE SUGGESTS THE RESPONSE AND DRUG SURVIVAL IN PEOPLE TREATED WITH ANTI-TUMOUR NECROSIS FACTOR (ANTI-TNF) THERAPY IS POORER IN HEAVY SMOKERS, AND POSSIBLE IMMUNOLOGICAL MECHANISMS FOR THIS EFFECT ARE PRESENTED IN THE CURRENT PAPER. 2014 12 6791 34 [DOES THE NUMBER OF PATIENTS WITH AUTOIMMUNE DISORDERS AND THE FREQUENCY OF AUTOIMMUNE DISEASES INCREASE?]. AUTOIMMUNE DISEASES GENERALLY BELONG TO THE RARE DISEASES, HOWEVER, SOME OF THEM ARE FREQUENT IN THE POPULATION. IN THE PRESENT WORK THE AUTHORS ANALYSE WHETHER CAN ANY INCREASE BE OBSERVED IN THE NUMBER OF PATIENTS SUFFERING FROM AUTOIMMUNE DISEASES AND WHETHER DO THE FREQUENCY OF CERTAIN AUTOIMMUNE DISORDERS INCREASE. DUE MAINLY TO EPIGENETIC FACTORS THE INCIDENCE OF AUTOIMMUNE DISEASES ARE INCREASING, THEREFORE THERE ARE MORE PATIENTS RECOGNISED WITH PARTICULAR DISORDERS. ON THE OTHER HAND THE INCIDENCE IS INCREASED BY IMPROVING DIAGNOSTIC POSSIBILITIES, BY THE USE OF MORE SPECIFIC AND SENSITIVE CLASSIFICATION CRITERIA AND MORE SOPHISTICATED LABORATORY TESTS, RESULTED IN THE RECOGNITION OF MILDER AND ATYPICAL DISEASE VARIANTS AS WELL. THE PREVALENCE IS ALSO INCREASING IN CONSEQUENCE OF NOVEL IMMUNE SUPPRESSIVE THERAPEUTIC POSSIBILITIES AND THE CONSEQUENT IMPROVEMENT OF SURVIVAL IN THE MOST OF THESE DISEASES. BESIDES, MORE AND MORE DISEASES HAVE BEEN REVEALED TO HAVE AUTOIMMUNE BACKGROUND, AND LOT OF NEW AUTOIMMUNE SYNDROMES, DISEASES HAVE BEEN CHARACTERISED RECENTLY. THIS INCREASES THE NUMBER OF THE KNOWN AUTOIMMUNE RHEUMATIC DISORDERS WITH A CONSEQUENT INCREASE IN THE NUMBER OF AUTOIMMUNE PATIENTS. ASSIGNED TO THE INCREASING NUMBER OF VARIABLE CHRONIC AUTOIMMUNE DISORDERS, AND THE INCREASING NUMBER OF DISABLED PATIENTS WITH SUCH DISEASES INCREASING MEDICAL AND SOCIAL ATTENTION HAS TO BE FOCUSED ON. 2007 13 6178 31 THE HISTONE MODIFICATION CODE IN THE PATHOGENESIS OF AUTOIMMUNE DISEASES. AUTOIMMUNE DISEASES ARE CHRONIC INFLAMMATORY DISORDERS CAUSED BY A LOSS OF SELF-TOLERANCE, WHICH IS CHARACTERIZED BY THE APPEARANCE OF AUTOANTIBODIES AND/OR AUTOREACTIVE LYMPHOCYTES AND THE IMPAIRED SUPPRESSIVE FUNCTION OF REGULATORY T CELLS. THE PATHOGENESIS OF AUTOIMMUNE DISEASES IS EXTREMELY COMPLEX AND REMAINS LARGELY UNKNOWN. RECENT ADVANCES INDICATE THAT ENVIRONMENTAL FACTORS TRIGGER AUTOIMMUNE DISEASES IN GENETICALLY PREDISPOSED INDIVIDUALS. IN ADDITION, ACCUMULATING RESULTS HAVE INDICATED A POTENTIAL ROLE OF EPIGENETIC MECHANISMS, SUCH AS HISTONE MODIFICATIONS, IN THE DEVELOPMENT OF AUTOIMMUNE DISEASES. HISTONE MODIFICATIONS REGULATE THE CHROMATIN STATES AND GENE TRANSCRIPTION WITHOUT ANY CHANGE IN THE DNA SEQUENCE, POSSIBLY RESULTING IN PHENOTYPE ALTERATION IN SEVERAL DIFFERENT CELL TYPES. IN THIS PAPER, WE DISCUSS THE SIGNIFICANT ROLES OF HISTONE MODIFICATIONS INVOLVED IN THE PATHOGENESIS OF AUTOIMMUNE DISEASES, INCLUDING RHEUMATOID ARTHRITIS, SYSTEMIC LUPUS ERYTHEMATOSUS, SYSTEMIC SCLEROSIS, PRIMARY BILIARY CIRRHOSIS, AND TYPE 1 DIABETES. 2017 14 5643 34 SEX AND AUTOIMMUNITY: PROPOSED MECHANISMS OF DISEASE ONSET AND SEVERITY. CHRONIC AUTOIMMUNE DISEASES AFFECT 5-10% OF THE POPULATION WORLDWIDE AND ARE LARGELY PREDOMINANT IN WOMEN. SEX HORMONE CHANGES HAVE BEEN WIDELY INVESTIGATED BASED ON CHANGES IN THE CLINICAL PHENOTYPES OBSERVED DURING PREGNANCY AND MENOPAUSE. IT IS KNOWN THAT FEMALES WITH AUTOIMMUNE DISEASES MANIFEST A HIGHER RATE OF CIRCULATING LEUKOCYTES WITH A SINGLE X CHROMOSOME, AND THERE HAVE BEEN SEVERAL REPORTS ON THE ROLE OF X CHROMOSOME GENE DOSAGE THROUGH INACTIVATION OR DUPLICATION IN AUTOIMMUNITY. HOWEVER, IT IS ALSO IMPORTANT NOT TO OVERLOOK MEN WITH AUTOIMMUNE DISEASES, WHO MIGHT MANIFEST A MORE FREQUENT LOSS OF THE Y CHROMOSOME IN CIRCULATING LEUKOCYTES. AREAS COVERED: IN THE PRESENT REVIEW, WE WILL DISCUSS THE CURRENT EVIDENCE SUPPORTING THE MECHANISMS OF FEMALE PREDOMINANCE IN RHEUMATIC DISEASES, BY DISCUSSING THE ROLE OF REPRODUCTIVE HISTORY, SEX HORMONES AND ABNORMALITIES RELATED TO THEM, CLINICAL DIFFERENCES BETWEEN MALE AND FEMALE PATIENTS, AND EPIGENETIC CHANGES THAT HAVE BEEN EVALUATED THROUGH TWIN STUDIES ON GENETIC AND ENVIRONMENTAL CHANGES IN RHEUMATIC PATIENTS. EXPERT OPINION: THE INFLUENCE OF SEX HORMONES AND CHROMOSOMES ON THE FUNCTION OF THE INNATE AND ADAPTIVE IMMUNE SYSTEMS NEEDS TO BE CLARIFIED, TO BETTER UNDERSTAND THE RISK OF AUTOIMMUNE DISEASES, EARLY DIAGNOSTIC TOOLS, AND THERAPEUTIC RESPONSE. 2019 15 2945 25 GENETIC AND EPIGENETIC BASIS OF PSORIASIS PATHOGENESIS. PSORIASIS IS A CHRONIC INFLAMMATORY SKIN DISEASE WHOSE PREVALENCE VARIES AMONG DIFFERENT POPULATIONS WORLDWIDE. IT IS A COMPLEX MULTI-FACTORIAL DISEASE AND THE EXACT ETIOLOGY IS LARGELY UNKNOWN. FAMILY BASED STUDIES HAVE INDICATED A GENETIC PREDISPOSITION; HOWEVER THEY CANNOT FULLY EXPLAIN THE DISEASE PATHOGENESIS. IN ADDITION TO GENETIC SUSCEPTIBILITY, ENVIRONMENTAL AS WELL AS GENDER AND AGE RELATED FACTORS WERE ALSO BEEN FOUND TO BE ASSOCIATED. RECENTLY, IMBALANCES IN EPIGENETIC NETWORKS ARE INDICATED TO BE CAUSATIVE ELEMENTS IN PSORIASIS. THE PRESENT KNOWLEDGE OF EPIGENETIC INVOLVEMENT, MAINLY THE DNA METHYLATION, CHROMATIN MODIFICATIONS AND MIRNA DEREGULATION IS SURVEYED HERE. AN INTEGRATED APPROACH CONSIDERING GENETIC AND EPIGENETIC ANOMALIES IN THE LIGHT OF IMMUNOLOGICAL NETWORK MAY EXPLORE THE PATHOGENESIS OF PSORIASIS. 2015 16 6262 36 THE MULTIFACETED FUNCTIONAL ROLE OF DNA METHYLATION IN IMMUNE-MEDIATED RHEUMATIC DISEASES. GENOMIC PREDISPOSITION CANNOT EXPLAIN THE ONSET OF COMPLEX DISEASES, AS WELL ILLUSTRATED BY THE LARGELY INCOMPLETE CONCORDANCE AMONG MONOZYGOTIC TWINS. EPIGENETIC MECHANISMS, INCLUDING DNA METHYLATION, CHROMATIN REMODELLING AND NON-CODING RNA, ARE CONSIDERED TO BE THE LINK BETWEEN ENVIRONMENTAL STIMULI AND DISEASE ONSET ON A PERMISSIVE GENETIC BACKGROUND IN AUTOIMMUNE AND CHRONIC INFLAMMATORY DISEASES. THE PARADIGMATIC CASES OF RHEUMATOID ARTHRITIS (RA), SYSTEMIC LUPUS ERYTHEMATOSUS (SLE), SYSTEMIC SCLEROSIS (SSC), SJOGREN'S SYNDROME (SJS) AND TYPE-1 DIABETES (T1D) SHARE THE LOSS OF IMMUNOLOGICAL TOLERANCE TO SELF-ANTIGEN INFLUENCED BY SEVERAL FACTORS, WITH A LARGELY INCOMPLETE ROLE OF INDIVIDUAL GENOMIC SUSCEPTIBILITY. THE MOST WIDELY INVESTIGATED EPIGENETIC MECHANISM IS DNA METHYLATION WHICH IS ASSOCIATED WITH GENE SILENCING AND IS DUE TO THE BINDING OF METHYL-CPG BINDING DOMAIN (MBD)-CONTAINING PROTEINS, SUCH AS MECP2, TO 5-METHYLCYTOSINE (5MC). INDEED, A CAUSAL RELATIONSHIP OCCURS BETWEEN DNA METHYLATION AND TRANSCRIPTION FACTORS OCCUPANCY AND RECRUITMENT AT SPECIFIC GENOMIC LOCUS. IN MOST CASES, THE RESULTS OBTAINED IN DIFFERENT STUDIES ARE CONTROVERSIAL IN TERMS OF DNA METHYLATION COMPARISON WHILE FASCINATING EVIDENCE COMES FROM THE COMPARISON OF THE EPIGENOME IN CLINICALLY DISCORDANT MONOZYGOTIC TWINS. IN THIS MANUSCRIPT, WE WILL REVIEW THE MECHANISMS OF EPIGENETICS AND DNA METHYLATION CHANGES IN SPECIFIC IMMUNE-MEDIATED RHEUMATIC DISEASES TO HIGHLIGHT REMAINING UNMET NEEDS AND TO IDENTIFY POSSIBLE SHARED MECHANISMS BEYOND DIFFERENT TISSUE INVOLVEMENTS WITH COMMON THERAPEUTIC OPPORTUNITIES. KEY POINTS * DNA METHYLATION HAS A CRUCIAL ROLE IN REGULATING AND TUNING THE IMMUNE SYSTEM. * EVIDENCES SUGGEST THAT DYSREGULATION OF DNA METHYLATION IS PIVOTAL IN THE CONTEXT OF IMMUNE-MEDIATED RHEUMATIC DISEASES. * DNA METHYLATION DYSREGULATION IN FOXP3 AND INTERFERONS-RELATED GENES IS SHARED WITHIN SEVERAL AUTOIMMUNE DISEASES. * DNA METHYLATION IS AN ATTRACTIVE MARKER FOR DIAGNOSIS AND THERAPY. 2021 17 3564 38 IMPACT OF GENETIC AND ENVIRONMENTAL FACTORS ON AUTOIMMUNE HEPATITIS. AUTOIMMUNE HEPATITIS (AIH) IS A CHRONIC NON-RESOLVING LIVER DISEASE CHARACTERIZED BY DIFFUSE HYPERGAMMAGLOBULINEMIA, THE PRESENCE OF AUTOANTIBODIES AND CHARACTERISTIC HISTOLOGICAL FINDINGS. THE DISEASE CAN HAVE CATASTROPHIC OUTCOME WITH THE DEVELOPMENT OF END-STAGE LIVER DISEASE IF MISDIAGNOSED/UNDIAGNOSED AND LEFT UNTREATED. AIH PATHOGENESIS REMAINS OBSCURE AND THE MAIN HYPOTHESIS SUPPORTS ITS DEVELOPMENT IN GENETICALLY PREDISPOSED INDIVIDUALS AFTER BEING EXPOSED TO CERTAIN ENVIRONMENTAL TRIGGERS. GENETIC PREDISPOSITION IS LINKED TO THE PRESENCE OF CERTAIN HLA ALLELES, MAINLY HLA-DR3 AND HLA-DR4. HOWEVER, A WIDE NUMBER OF NON-HLA EPITOPES HAVE ALSO BEEN ASSOCIATED WITH THE DISEASE ALTHOUGH DATA VARY SIGNIFICANTLY AMONG DIFFERENT ETHNIC GROUPS. THEREFORE, IT IS LIKELY THAT EPIGENETIC ALTERATIONS MAY ALSO PLAY A CRUCIAL ROLE IN DISEASE'S PATHOGENESIS, ALTHOUGH NOT YET EXTENSIVELY STUDIED. THE AIM OF THIS REVIEW WAS TO SUMMARIZE THE GENETIC AND ENVIRONMENTAL FACTORS THAT HAVE BEEN ASSOCIATED WITH AIH, BUT ALSO TO OPEN NEW INSIGHTS TOWARDS THE ROLE OF EPIGENETIC MODIFICATIONS IN THE ETIOLOGY OF THE DISEASE. 2021 18 2017 37 EPIGENETIC BIOMARKERS IN RHEUMATOLOGY - THE FUTURE? EPIGENETIC CHANGES ARE STABLE MODIFICATIONS OF DNA OR HISTONES THAT PROFOUNDLY ALTER GENE EXPRESSION. THEY CAN BE CHANGED BY ENVIRONMENTAL INFLUENCES AND CAN THEN BE PASSED ON TO DAUGHTER CELLS OR VIA THE GERM LINE TO OFFSPRING. A VARIETY OF CHANGES IN EPIGENETIC MARKS AND IN THE EXPRESSION OF NONCODING RNA HAS BEEN FOUND IN CANCER AS WELL AS IN CHRONIC INFLAMMATORY DISEASES. INTERESTINGLY, IN BOTH DISEASES SIMILAR MECHANISMS AND PATHWAYS ARE AFFECTED ALBEIT OFTEN TO A DIFFERENT EXTENT. DNA METHYLATION IS OFTEN LOST IN REPETITIVE SEQUENCES, WHILE IN PROMOTER REGIONS HYPO- AS WELL AS HYPERMETHYLATION IS FOUND. CHANGES IN MICRORNA LEVELS TYPICALLY AFFECT MICRORNAS THAT ARE CHANGED BY AN INFLAMMATORY ENVIRONMENT, BUT DISEASE SPECIFIC CHANGES HAVE ALSO BEEN FOUND IN THE BLOOD AND VARIOUS CELL TYPES OF PATIENTS WITH RHEUMATOID ARTHRITIS, SYSTEMIC LUPUS ERYTHEMATOSUS AND OTHER RHEUMATIC DISEASES. THEREFORE, CHANGES IN THE EXPRESSION OF MICRORNA IN PARTICULAR, BUT ALSO DEMETHYLATED GENE LOCI, HAVE BEEN PROPOSED AS POTENTIAL BIOMARKERS IN CHRONIC INFLAMMATORY DISEASES AND IN CANCER. POTENTIALLY, THESE CHANGES COULD BE USED FOR EARLY DIAGNOSIS AND ALSO TO PREDICT TREATMENT RESPONSE. UNFORTUNATELY MOST STUDIES IN RHEUMATOLOGY UP TO NOW WERE NOT DESIGNED TO VALIDATE THESE EPIGENETIC CHANGES AS BIOMARKERS. SINCE THE CANCER FIELD IS MUCH MORE ADVANCED IN THE USAGE OF BIOMARKERS FOR DISEASE SUBCLASSIFICATIONS AND SUBSEQUENT THERAPEUTIC DECISIONS, IT IS WORTHWHILE TO TAKE A CLOSER LOOK AT THE BIOMARKERS, METHODS AND PROCEDURES USED IN ONCOLOGY AND TO SEE WHICH OF THESE COULD ALSO BE APPLIED TO PREDICTING DISEASE SEVERITY AND THERAPEUTIC RESPONSE IN RHEUMATIC DISEASES. THIS ARTICLE WILL HIGHLIGHT COMMON EPIGENETIC PATHWAYS ACTIVATED IN CANCER AND VARIOUS RHEUMATIC DISEASES AND SUMMARISE EPIGENETIC CHANGES THAT HAVE THE POTENTIAL TO BECOME BIOMARKERS IN RHEUMATIC DISEASES. 2016 19 4472 41 MOLECULAR PATHOGENESIS OF CHOLANGIOCARCINOMA. BACKGROUND: CHOLANGIOCARCINOMAS ARE A HETEROGENEOUS GROUP OF MALIGNANCIES ARISING FROM A NUMBER OF CELLS OF ORIGIN ALONG THE BILIARY TREE. ALTHOUGH MOST CASES IN WESTERN COUNTRIES ARE SPORADIC, LARGE POPULATION-BASED STUDIES HAVE IDENTIFIED A NUMBER OF RISK FACTORS. THIS REVIEW SUMMARISES THE EVIDENCE BEHIND REPORTED RISK FACTORS AND CURRENT UNDERSTANDING OF THE MOLECULAR PATHOGENESIS OF CHOLANGIOCARCINOMA, WITH A FOCUS ON INFLAMMATION AND CHOLESTASIS AS THE DRIVING FORCES IN CHOLANGIOCARCINOMA DEVELOPMENT. RISK FACTORS FOR CHOLANGIOCARCINOGENESIS: CHOLESTATIC LIVER DISEASES (E.G. PRIMARY SCLEROSING CHOLANGITIS AND FIBROPOLYCYSTIC LIVER DISEASES), LIVER CIRRHOSIS, AND BILIARY STONE DISEASE ALL INCREASE THE RISK OF CHOLANGIOCARCINOMA. CERTAIN BACTERIAL, VIRAL OR PARASITIC INFECTIONS SUCH AS HEPATITIS B AND C AND LIVER FLUKES ALSO INCREASE CHOLANGIOCARCINOMA RISK. OTHER RISK FACTORS INCLUDE INFLAMMATORY DISORDERS (SUCH AS INFLAMMATORY BOWEL DISEASE AND CHRONIC PANCREATITIS), TOXINS (E.G. ALCOHOL AND TOBACCO), METABOLIC CONDITIONS (DIABETES, OBESITY AND NON-ALCOHOLIC FATTY LIVER DISEASE) AND A NUMBER OF GENETIC DISORDERS. MOLECULAR PATHOGENESIS OF CHOLANGIOCARCINOMA: REGARDLESS OF AETIOLOGY, MOST RISK FACTORS CAUSE CHRONIC INFLAMMATION OR CHOLESTASIS. CHRONIC INFLAMMATION LEADS TO INCREASED EXPOSURE OF CHOLANGIOCYTES TO THE INFLAMMATORY MEDIATORS INTERLEUKIN-6, TUMOUR NECROSIS FACTOR-A, CYCLO-OXYGENASE-2 AND WNT, RESULTING IN PROGRESSIVE MUTATIONS IN TUMOUR SUPPRESSOR GENES, PROTO-ONCOGENES AND DNA MISMATCH-REPAIR GENES. ACCUMULATING BILE ACIDS FROM CHOLESTASIS LEAD TO REDUCED PH, INCREASED APOPTOSIS AND ACTIVATION OF ERK1/2, AKT AND NF-KAPPAB PATHWAYS THAT ENCOURAGE CELL PROLIFERATION, MIGRATION AND SURVIVAL. OTHER MEDIATORS UPREGULATED IN CHOLANGIOCARCINOMA INCLUDE TRANSFORMING GROWTH FACTOR-BETA, VASCULAR ENDOTHELIAL GROWTH FACTOR, HEPATOCYTE GROWTH FACTOR AND SEVERAL MICRORNAS. INCREASED EXPRESSION OF THE CELL SURFACE RECEPTOR C-MET, THE GLUCOSE TRANSPORTER GLUT-1 AND THE SODIUM IODIDE SYMPORTER LEAD TO TUMOUR GROWTH, ANGIOGENESIS AND CELL MIGRATION. STROMAL CHANGES ARE ALSO OBSERVED, RESULTING IN ALTERATIONS TO THE EXTRACELLULAR MATRIX COMPOSITION AND RECRUITMENT OF FIBROBLASTS AND MACROPHAGES THAT CREATE A MICROENVIRONMENT PROMOTING CELL SURVIVAL, INVASION AND METASTASIS. CONCLUSION: REGARDLESS OF AETIOLOGY, MOST RISK FACTORS FOR CHOLANGIOCARCINOMA CAUSE CHRONIC INFLAMMATION AND/OR CHOLESTASIS, LEADING TO THE ACTIVATION OF COMMON INTRACELLULAR PATHWAYS THAT RESULT IN REACTIVE CELL PROLIFERATION, GENETIC/EPIGENETIC MUTATIONS AND CHOLANGIOCARCINOGENESIS. AN UNDERSTANDING OF THE MOLECULAR PATHOGENESIS OF CHOLANGIOCARCINOMA IS VITAL WHEN DEVELOPING NEW DIAGNOSTIC BIOMARKERS AND TARGETED THERAPIES FOR THIS DISEASE. 2019 20 2516 40 EPIGENETICS AND SYSTEMIC LUPUS ERYTHEMATOSUS: UNMET NEEDS. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS A CHRONIC RELAPSING-REMITTING AUTOIMMUNE DISEASE AFFECTING SEVERAL ORGANS. ALTHOUGH THE MANAGEMENT OF LUPUS PATIENTS HAS IMPROVED IN THE LAST YEARS, SEVERAL ASPECTS STILL REMAIN CHALLENGING. MORE SENSITIVE AND SPECIFIC BIOMARKERS FOR AN EARLY DIAGNOSIS AS WELL AS FOR MONITORING DISEASE ACTIVITY AND TISSUE DAMAGE ARE NEEDED. GENOME-WIDE ASSOCIATION AND GENE MAPPING STUDIES HAVE SUPPORTED THE GENETIC BACKGROUND FOR SLE SUSCEPTIBILITY. HOWEVER, THE RELATIVELY MODEST RISK ASSOCIATION AND THE STUDIES IN TWINS HAVE SUGGESTED A ROLE FOR ENVIRONMENTAL AND EPIGENETIC FACTORS, AS WELL AS GENETIC-EPIGENETIC INTERACTION. ACCORDINGLY, THERE IS EVIDENCE THAT DIFFERENCES IN DNA METHYLATION, HISTONE MODIFICATIONS, AND MIRNA PROFILING CAN BE FOUND IN LUPUS PATIENTS VERSUS NORMAL SUBJECTS. MOREOVER, IMPAIRED DNA METHYLATION ON THE INACTIVE X-CHROMOSOME WAS SUGGESTED TO EXPLAIN, AT LEAST IN PART, THE FEMALE PREVALENCE OF THE DISEASE. EPIGENETIC MARKERS MAY BE HELP IN FULFILLING THE UNMET NEEDS FOR SLE BY OFFERING NEW DIAGNOSTIC TOOLS, NEW BIOMARKERS FOR MONITORING DISEASE ACTIVITY, OR TO BETTER CHARACTERIZE PATIENTS WITH A SILENT CLINICAL DISEASE BUT WITH AN ACTIVE SEROLOGY. ANTI-DNA, ANTI-PHOSPHOLIPID, AND ANTI-RO/SSA AUTOANTIBODIES ARE THOUGHT TO BE PATHOGENIC FOR GLOMERULONEPHRITIS, RECURRENT THROMBOSIS AND MISCARRIAGES, AND NEONATAL LUPUS, RESPECTIVELY. HOWEVER, TISSUE DAMAGE OCCURS OCCASIONALLY OR, IN SOME PATIENTS, ONLY IN SPITE OF THE PERSISTENT PRESENCE OF THE ANTIBODIES. PRELIMINARY STUDIES SUGGEST THAT EPIGENETIC MECHANISMS MAY EXPLAIN WHY THE DAMAGE TAKES PLACE IN SOME PATIENTS ONLY OR AT A GIVEN TIME. 2016