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Immunosuppressants used to treat autoimmunity are often not curative and have many side effects. Our purpose was to identify therapeutics for autoimmunity of the skeletal muscle termed idiopathic inflammatory myopathies (myositis). Recent evidence shows that the pro-inflammatory type I interferons (IFN) and a downstream product major histocompatibility complex (MHC) class I are pathogenic in myositis. We conducted quantitative high-throughput screening on >4500 compounds, including all approved drugs, through a series of cell-based assays to identify those that inhibit the type I IFN-MHC class I pathway in muscle precursor cells (myoblasts). The primary screen utilized CRISPR/Cas9 genome-engineered human myoblasts containing a pro-luminescent reporter HiBit fused to the C-terminus of endogenous MHC class I. Active compounds were counter-screened for cytotoxicity and validated by MHC class I immunofluorescence, Western blot, and RT-qPCR. Actives included Janus kinase inhibitors, with the most potent being ruxolitinib, and epigenetic/transcriptional modulators like histone deacetylase inhibitors and the hypoxia-inducible factor 1 inhibitor echinomycin. Testing in animal models and clinical trials is necessary to translate these therapies to myositis patients. These robust assay technologies can be further utilized to interrogate the basic mechanisms of the type I IFN-MHC class I pathway, identify novel molecular probes, and elucidate possible environmental triggers that may lead to myositis.

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Drug-induced liver injury (DILI) to flucloxacillin is rare and is classified as idiosyncratic, as it is dependent on individual susceptibility, unpredictable, and dose-independent. The authors present the case of a 74 - year - old man with a history of monoclonal gammopathy under investigation and alcoholic habits of 24 g/day, with asthenia, anorexia, nausea, abdominal discomfort, and fever with three days of evolution. He was treated with two courses of antibiotic therapy with flucloxacillin to erysipelas previously (3 months and 2 weeks before admission). Lab tests showed serum AST levels of 349 U/L, ALT 646 U/L, alkaline phosphatase 302 U/L, GGT 652 U/L, total bilirubin 3.3 mg/dL and direct bilirubin 2.72 mg/dL. Infectious, autoimmune, and metabolic causes were ruled out. Magnetic resonance cholangiopancreatography showed normal results. Liver biopsy showed mild multifocal (predominantly microvesicular) steatosis; marked changes in the centrilobular areas (sinusoidal dilatation, marked congestion, hemorrhage, and multifocal hepatocyte collapse); expansion of the portal areas with the formation of bridges; proliferated bile ducts and inflammatory infiltrate of variable density, predominantly mononuclear type. The HLA-B*5701 screening test was positive. Hepatic biochemical tests remain abnormal with a significative increase in total bilirubin, which reached levels of 24.1 mg/dL, with the development of jaundice, pruritus, and choluria. DILI was assumed, and the patient was treated with ursodeoxycholic acid. There was favorable evolution, without evidence of blood coagulation dysfunction or encephalopathy. The analytic normalization was, however, slow, with evolution to chronicity. The authors present this case to remind the possibility of moderate/severe drug-induced liver injury to flucloxacillin, an antibiotic commonly used in clinical practice and association with the HLA-B * 5701 allele reported in the literature.

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SUMMARY Drug-induced liver injury (DILI) to flucloxacillin is rare and is classified as idiosyncratic, as it is dependent on individual susceptibility, unpredictable, and dose-independent. The authors present the case of a 74 - year - old man with a history of monoclonal gammopathy under investigation and alcoholic habits of 24 g/day, with asthenia, anorexia, nausea, abdominal discomfort, and fever with three days of evolution. He was treated with two courses of antibiotic therapy with flucloxacillin to erysipelas previously (3 months and 2 weeks before admission). Lab tests showed serum AST levels of 349 U/L, ALT 646 U/L, alkaline phosphatase 302 U/L, GGT 652 U/L, total bilirubin 3.3 mg/dL and direct bilirubin 2.72 mg/dL. Infectious, autoimmune, and metabolic causes were ruled out. Magnetic resonance cholangiopancreatography showed normal results. Liver biopsy showed mild multifocal (predominantly microvesicular) steatosis; marked changes in the centrilobular areas (sinusoidal dilatation, marked congestion, hemorrhage, and multifocal hepatocyte collapse); expansion of the portal areas with the formation of bridges; proliferated bile ducts and inflammatory infiltrate of variable density, predominantly mononuclear type. The HLA-B*5701 screening test was positive. Hepatic biochemical tests remain abnormal with a significative increase in total bilirubin, which reached levels of 24.1 mg/dL, with the development of jaundice, pruritus, and choluria. DILI was assumed, and the patient was treated with ursodeoxycholic acid. There was favorable evolution, without evidence of blood coagulation dysfunction or encephalopathy. The analytic normalization was, however, slow, with evolution to chronicity. The authors present this case to remind the possibility of moderate/severe drug-induced liver injury to flucloxacillin, an antibiotic commonly used in clinical practice and association with the HLA-B * 5701 allele reported in the literature.

RESUMO A hepatotoxicidade à flucloxacilina é rara e classifica-se como idiossincrática, uma vez que é dependente da suscetibilidade individual, não expectável e independente da dose. Apresentamos o caso de um homem, 74 anos, antecedentes de gamapatia monoclonal e hábitos alcoólicos de 24 g/dia, com quadro de astenia, anorexia, náuseas, desconforto abdominal e febrícula com três dias de evolução. Referência a dois ciclos de antibioterapia com flucloxacilina por erisipela (três meses e duas semanas antes da admissão). Analiticamente com AST 349 U/L, ALT 646 U/L, FA 302 U/L, GGT 652 U/L, bilirrubina total 3,3 mg/dL, bilirrubina direta 2,72 mg/dL. Excluídas etiologias infecciosa, autoimune, metabólica, bem como patologia das vias biliares por colangio-RM. Biópsia hepática mostrou esteatose multifocal ligeira (predominantemente microvesicular); alterações acentuadas nas áreas centrolobulares (dilatação sinusoidal, congestão acentuada, hemorragia e colapso multifocal de hepatócitos); expansão das áreas portais com constituição de pontes; ductos biliares proliferados e infiltrado inflamatório de densidade variável, predominantemente de tipo mononucleado. Tipagem de HLA-B*5701 positiva. Agravamento analítico atingindo bilirrubina total 24,1 mg/dL, com desenvolvimento de icterícia, prurido e colúria. Admitida a hepatotoxicidade, iniciou terapêutica com ácido ursodesoxicólico. Verificou-se evolução favorável, sem evidência de coagulopatia ou encefalopatia. A normalização analítica foi, no entanto, lenta, com evolução para cronicidade. Os autores apresentam este caso para alertar para a possibilidade de hepatotoxicidade moderada a grave à flucloxacilina, antibiótico de uso comum na prática clínica e associação com o alelo HLA-B*5701 relatada na literatura.

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Abacavir is an antiretroviral drug used to reduce human immunodeficiency virus (HIV) replication and decrease the risk of developing acquired immune deficiency syndrome (AIDS). However, its therapeutic value is diminished by the fact that it is associated with drug hypersensitivity reactions in up to 8% of treated patients. This hypersensitivity is strongly associated with patients carrying human leukocyte antigen (HLA)-B*57:01, but not patients carrying closely related alleles. Abacavir's specificity to HLA-B*57:01 is attributed to its binding site within the peptide-binding cleft and subsequent influence of the repertoire of peptides that can bind HLA-B*57:01. To further our understanding of abacavir-induced hypersensitivity we used molecular dynamics (MD) to analyze the dynamics of three different peptides bound to HLA-B*57:01 in the presence and absence of abacavir or abacavir analogues. We found that abacavir and associated peptides bind to HLA-B*57:01 in a highly diverse range of conformations that are not apparent from static crystallographic snapshots, but observed no difference in either the conformations, nor degree of flexibility when compared to abacavir-unbound systems. Our results support hypersensitivity models in which abacavir-binding alters the conformational ensemble of neopeptides, so as to favour exposed peptide surfaces that are no longer recognized as self by circulating CD8+ T cells, and are conducive to TCR binding. Our findings highlight the need to also consider the role of dynamics in understanding drug-induced hypersensitivities at the molecular and mechanistic level. This additional insight can help inform the chemical modification of abacavir to prevent hypersensitivity reactions in HLA-B*57:01+ HIV patients whilst retaining potent antiretroviral activity.

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Positive HLA-B*5701 genotype has recently been identified as the main genetic risk factor for flucloxacillin drug-induced liver injury (DILI). Testing for HLA-B*5701 is routine in many HIV clinics to identify those at risk of hypersensitivity reaction (HSR) to abacavir. Considering the high prevalence of soft-tissue infections in HIV patients, we conducted a retrospective study to investigate whether flucloxacillin use was associated with adverse events in HIV patients known to be HLA-B*5701 positive.

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OBJECTIVE: To review Behçet's disease and to describe its clinical features in the head, neck and upper respiratory tract. METHOD: A literature review was undertaken, following a Medline search of publications over a 30-year period, and utilising the expert knowledge of one of the authors (RJM) with a specialist interest in Behçet's disease. RESULTS: Twenty-seven articles with ENT relevance were obtained. Otorhinolaryngological manifestations included symptoms and signs in the mouth, nose, sinus, larynx and ear. CONCLUSION: Behçet's disease is usually considered to be a condition affecting the oral cavity, eyes and genitals. This article shows that most patients will also exhibit other ENT symptoms, hearing loss in particular. Indeed, Behçet's disease may present with features other than the classic triad of symptoms. Raised awareness of the clinical features within the head and neck region will hopefully enable early diagnosis and treatment of this potentially serious condition.

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OBJECTIVES: This study attempted to determine whether human leukocyte antigen (HLA) type changes would be caused by lithium. METHODS: A total of 15 patients were chosen as subjects (4 males, 11 females) and completed tests in class I. Eight of the 15 patients completed tests in class II. Their mean age was 27 +/- 7 years. For an average of 51 +/- 17 days, lithium, 600-1,200 mg/day (mean daily dose: 920 +/- 211 mg) was administered for the HLA testing and then compared with the HLA type prior to the time the drug was administered. Class I type test was performed according to the Terasaki microcytotoxicity method and class II type by the Erlich polymerase chain reaction method. RESULTS: Of the 15 subjects, 11 had changes in HLA-A, B, C types and two of the eight subjects had changes in HLA DR type. CONCLUSION: Lithium, in the therapeutic dose, is considered to bring about changes in HLA expressions in as short a time period as 2 months.

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Assembly of MHC class I-beta 2 microglobulin (beta 2m) dimers in the endoplasmic reticulum involves two chaperones. Calnexin has previously been shown to interact with free class I heavy chains. Here, we show that the related chaperone, calreticulin, binds human class I-beta 2m dimers prior to peptide loading. Calreticulin remains associated with at least a subset of class I molecules when they, in turn, bind to TAP. Further evidence suggests that the interaction of class I-beta 2m dimers with TAP occurs via a novel uncharacterized 48 kDa glycoprotein, tapasin, which can bind independently to TAP and class I-beta 2m-calreticulin complexes. Tapasin is absent from the mutant cell line .220, in which class I-TAP association and peptide loading is defective.

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Thalidomide dramatically relieves the signs and symptoms of erythema nodosum leprosum (ENL). ENL is an acute inflammatory complication of lepromatous leprosy. The cause(s) of ENL as well as the mechanism of action of thalidomide in arresting ENL are unknowns. It has been suggested that ENL is the consequence of a transient activation of a cell-mediated-immune (CMI) response to Mycobacterium leprae. To initiate a CMI response, an interaction between adhesion and/or signal transducing molecules on T-cells and molecules on antigen presenting cells would occur. An alteration, induced by thalidomide, of one or more of the molecules on T-cells or antigen presenting cells that are essential to maintaining the reactive state of ENL, could explain Thalidomide's ability to attenuate ENL. Thalidomide did not modify: (a) adhesion and/or signal transducing molecules such as CD2, CD4, CD5 and CD8, or (b) molecules that facilitate antigen presentation such as HLA-DR, HLA-A, HLA-B, or HLA-C.

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The author investigated the effect of 20%, 15%, 10%, 5%, 2.5%, 1.25% chloroquine on HLA-A,B antigens on lymphocytes and on the reaction HLA-A,B antigen-antibody. HLA-A,B antigens are not released by chloroquine from the lymphocyte surface and their expressivity does not change, as was revealed by examination of the micro-lymphocytotoxic and absorption test. Higher concentrations of chloroquine cause poly-reactivity of lymphocytes. A 20%, 15% and sometimes also 10% and 5% of chloroquine solution block the reaction HLA-A, B antigen--HLA antibodies. The reason for this is the destructive action of chloroquine on rabbit complement.

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Intercellular adhesion molecule-1 (ICAM-1), HLA-A, B, C and HLA-DR antigen on endothelial cells (EC) play important roles in the development of inflammatory processes in autoimmune disorders. In the present study, we investigated the effect of nicotinamide, an inhibitor of poly(ADP ribose) synthetase, on interferon-gamma (IFN gamma)-induced ICAM-1 and HLA-DR antigen expression on the surface of cultured human umbilical vein endothelial cells, assessed by flow cytometry, and EC proliferation by counting cell numbers and [3H]thymidine incorporation assays. Nicotinamide dose-dependently inhibited the IFN-gamma-induced ICAM-1 and HLA-DR antigen expression, but not HLA-A, B, C antigen expression on cultured EC. Furthermore, nicotinamide significantly inhibited endothelial cell proliferation, as assessed by [3H]thymidine incorporation assay. Our findings suggest that nicotinamide may suppress mononuclear cell infiltration, antigen presentation and angiogenesis in the lesions of autoimmune disorders by reducing both IFN gamma-induced ICAM-1 and HLA-DR antigen expression on EC, and EC proliferation. Therefore, nicotinamide can be used for the treatment and prevention of the development of autoimmune disorders.

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