The viral-autoimmunity relationship

Human immunodeficiency virus and multiple sclerosis: a review of the literature

Multiple sclerosis (MS) and human immunodeficiency virus (HIV) infection are frequent and well-studied nosological entities. Yet, comorbidity of MS and HIV has only been rarely reported in the medical literature. We conducted a literature search using the databases PubMed, Ovid and Google Scholar, with the aim of identifying published studies and reports concerning HIV and MS. Recent epidemiological studies indicated a negative association between MS and HIV in terms of a reduced risk of developing MS in HIV positive patients. Accumulating clinical evidence additionally suggests a possibly reduced relapse rate of MS in HIV patients. Nevertheless, it remains currently unclear whether this observed inverse correlation could be due to the HIV infection itself, HIV treatment or the combination of both. Among the limited cases of MS in HIV infected patients, MS occurrence was mainly reported during acute HIV infection or during HIV seroconversion. This finding is in line with reports of HIV-related autoimmune disorders, which also occur in early phases of HIV disease. Beneficial effects of antiretroviral therapy on MS activity were reported in few clinical cases. Yet, the single phase II clinical trial (INSPIRE), which investigated the effects of antiretroviral medication (using the integrase inhibitor raltegravir) in patients with relapsing-remitting MS, failed to corroborate any beneficial effects at group level. Nevertheless, recently published experimental evidence suggests that HIV treatments may hold therapeutic potential for MS treatment. Thus, further studies are warranted to firstly, delineate the immunological mechanisms underlying possible efficacy of HIV treatments in MS, and to secondly, assess whether repurposing of HIV drugs for MS could be a worthwhile future research objective.

Autoimmune diseases and HIV infection: A cross-sectional study

To describe the clinical manifestations, treatments, prognosis, and prevalence of autoimmune diseases (ADs) in human immunodeficiency virus (HIV)-infected patients.All HIV-infected patients managed in the Infectious Diseases Department of the Lyon University Hospitals, France, between January 2003 and December 2013 and presenting an AD were retrospectively included.Thirty-six ADs were found among 5186 HIV-infected patients which represents a prevalence of 0.69% including immune thrombocytopenic purpura (n = 15), inflammatory myositis (IM) (n = 4), sarcoidosis (n = 4), Guillain-Barré syndrome (GBS) (n = 4), myasthenia gravis (n = 2), Graves' disease (n = 2), and 1 case of each following conditions: systemic lupus erythematosus, rheumatoid arthritis, autoimmune hepatitis, Hashimoto thyroiditis and autoimmune hemolytic anemia. One patient presented 2 ADs. Thirty patients were known to be HIV-infected when they developed an AD. The AD preceded HIV infection in 2 patients. GBS and HIV infection were diagnosed simultaneously in 3 cases. At AD diagnosis, CD4 T lymphocytes count were higher than 350/mm in 63% of patients, between 200 and 350/mm in 19% and less than 200/mm in 19%. Twenty patients benefited from immunosuppressant treatments, with a good tolerance.ADs during HIV infection are uncommon in this large French cohort. Immune thrombocytopenic purpura, sarcoidosis, IM, and GBS appear to be more frequent than in the general population. Immunosuppressant treatments seem to be effective and well tolerated.

Acquired hemophilia A in the HIV-infected patient: a case report and literature review

Acquired hemophilia A is a rare bleeding disorder caused by autoantibodies against factor VIII (FVIII). Spontaneous bleeding in the various sites and severity is the most common clinical presentation. Here, we report a 74-year-old Thai woman with HIV infection who presented with spontaneous ecchymoses. The laboratory revealed isolated activated partial thromboplastin time prolongation with low FVIII activity and a presence of FVIII inhibitor. She was diagnosed with acquired hemophilia A. Corticosteroid monotherapy was the treatment regimen for inhibitor eradication. We demonstrate the clinical course of the rare condition and review the relevant literature.

Association between antiretrovirals and thyroid diseases: a cross-sectional study

OBJECTIVE

This study aims to estimate the prevalence of thyroid diseases and anti-TPO status. We searched for an association among presence of immune reconstitution and use of stavudine, didanosine and protease inhibitors with thyroid diseases.

MATERIALS AND METHODS

A cross-sectional study was performed to analyze the records of 117 HIV-infected patients who had their CD4+ cell count, viral load, anti-TPO, TSH and free T4 levels collected on the same day. Immune reconstitution was considered in those whose T CD4+ count was below 200 cells/mm3, but these values increased above 200 cells/mm3 after the use of antiretrovirals. The odds ratio obtained by a 2x2 contingency table and a chi-square test were used to measure the association between categorical variables.

RESULTS

The prevalence of thyroid disease was 34.18%; of these, 4.34% were positive for anti-TPO. There was an association of risk between stavudine use and subclinical hypothyroidism (OR = 4.19, 95% CI: 1.29 to 13.59, X2 = 6.37, p = 0.01). Immune reconstitution achieved protection associated with thyroid disease that was near statistical significance OR = 0.45, 95% CI: 0.19 to 1.04, X2 = 3.55, p = 0.059.

CONCLUSION

The prevalence of thyroid disease in the sample studied was higher than what had been found in the literature, with a low positive anti-TPO frequency. The historical use of stavudine has an association of risk for the presence of subclinical hypothyroidism, and immune reconstitution has trends towards protection for the presence of thyroid diseases.

Destructive arthritis in a patient with chikungunya virus infection with persistent specific IgM antibodies

Background

Chikungunya fever is an emerging arboviral disease characterized by an algo-eruptive syndrome, inflammatory polyarthralgias, or tenosynovitis that can last for months to years. Up to now, the pathophysiology of the chronic stage is poorly understood.

Case presentation

We report the first case of CHIKV infection with chronic associated rheumatism in a patient who developed progressive erosive arthritis with expression of inflammatory mediators and persistence of specific IgM antibodies over 24 months following infection.

Conclusions

Understanding the specific features of chikungunya virus as well as how the virus interacts with its host are essential for the prevention, treatment or cure of chikungunya disease.

Fine specificity of autoantibodies induced by mouse hepatitis virus A59

We have shown that mice infected with mouse hepatitis virus A59 (MHV-A59) develop autoantibodies (autoAb) to liver and kidney fumarylacetoacetate hydrolase (FAH). The autoAb recognized conformational as well as linear antigenic determinants in the enzyme, and the autoimmune response was not entirely restricted to molecular mimicry and/or epitope spreading. Since the N- and C-terminal portions of the enzyme were the most reactive with autoAb, the fine specificity of these Ab was investigated. Immobilized 15-mer linear peptides (overlapping by 14 amino acids) spanning the N-terminal FAH sequence 1-49 were recognized by Ab from MHV-infected mice. The pattern of reactivity indicated the existence of two major epitope cores (i.e., sequences 9-23 and 30-44), and sequence comparison permitted the identification of two minimal epitopes, DSDFPIQ (amino acids 9-15) and IGDQILD (amino acids 36-42). Mutational analysis of sequences 9-23 and 30-44 indicated that residues 9-12 (DSDF) from the first major N-terminal epitope, and residue 36 (I) from the second, were the key amino acids energetically important for Ab contact. Interestingly, those residues were inside the two minimal epitopes previously predicted. The C-terminal portion of the enzyme (sequence 390-419) presented only one major epitope, located between residues 390 and 409. In this case, the minimal epitope had nine amino acids, CQGDGYRVG, corresponding to the FAH sequence 396-404 that outlines a loop specific for the enzyme. Data indicated that neither the FAH minimal epitopes nor the key residues important for binding to Ab from MHV-infected mice have their counterparts in the viral proteins. However, location of the energetically important residues in the tertiary structure of the enzyme originates a virtual conformational epitope. Such hypothetical B-cell epitopes could be present in any viral protein, originating a cross-reaction leading to the autoimmune response induced by MHV.

The autoimmune response induced by mouse hepatitis virus A59 is expanded by a hepatotoxic agent

Mouse hepatitis virus strain A59 (MHV-A59) triggers various pathologies in several mouse strains, including hypergammaglobulinaemia, hepatitis and thymus involution. We reported previously the presence of autoantibodies (autoAb) to liver and kidney fumarylacetoacetate hydrolase (FAH) in sera from mice infected with MHV-A59.

Long-term MHV-infected mice represented a good model of non-pathogenic autoimmune response since the animals were apparently healthy in spite of the presence of autoAb. The aim of this work was to see whether a severe liver injury, which releases endogenous adjuvants, i.e. danger signals, could elicit a broader spectrum of autoAb and perhaps signs of autoimmune hepatitis. Carbon tetrachloride (CCl₄) was injected into mice 30 days after MHV infection, and serum was assayed for autoAb and total IgG 20 days later. The association of MHV infection with the toxic effects of CCl₄ resulted in hypergammaglobulinaemia and the production of autoAb to various liver and kidney proteins. Histological examination of liver samples showed tissue damages but without significant differences between the animals submitted to MHV + CCl₄ and controls, which were either infected by MHV without CCl₄, or poisoned by CCl₄ in the absence of MHV infection. Those results show that liver injury after viral infection may lead to the spreading of the immune response and to an increase of serum IgG, suggesting that the procedure used herein could simulate the onset of autoimmune hepatitis.

The peptide specificities of the autoantibodies elicited by mouse hepatitis virus A59

Synthetic decapeptides (N = 206) covering the entire sequence of mouse liver fumarylacetoacetate hydrolase (FAH) were used to analyze the specificities of the autoantibodies (autoAb) elicited towards this enzyme in mice infected with mouse hepatitis virus (MHV). These autoAb bound mainly to N- and C-terminal FAH peptides, the most reactive sequences being 1–50 and 390–420, respectively. Surprisingly, although FAH sequence 1–50 shares a high degree of homology with various MHV proteins, the C-terminal portion does not. Moreover, whereas the autoAb reacted with homologous peptides surrounding residues 70, 160 and 360, non-similar sequences around residues 130, 210, 240, 250, and 300 were also recognized, indicating that autoAb were not restricted to epitopes with sequence homologies. There was also a lack of correlation between the amount of anti-MHV or anti-FAH antibodies produced and the reactivity towards the peptides. Moreover, the spectrum of peptides recognized by the autoAb of a given mouse did not change significantly with time, which suggests that the MHV-elicited autoimmune response does not induce an epitope recognition spreading. Finally, anti-FAH Ab produced after immunization with rat liver FAH recognized essentially the same mouse FAH regions than autoAb from MHV-infected mice. Results indicated that the induction of the autoAb is not only related to molecular or structural mimicry, but rather supports the Danger model, in which any aggression, in this case the MHV infection, is susceptible to trigger the production of autoAb.

Prediction and prevention of autoimmune diseases: additional aspects of the mosaic of autoimmunity

Autoimmune connective tissue diseases are chronic, potentially life threatening complex multisystem disorders. Their etiology is unknown but genetic, hormonal and environmental factors are important. The clinical disease is preceded by a long period of time (sometimes many years) when the patients can be identified by characteristic antibodies in their serum. When such a patient is identified he is usually followed and treated if clinical disease manifests itself. However, other factors besides the existence of autoantibodies have a predictive value for those disorders; some of them hereditary or genetic, and can be used only to predict likelihood of future disease, and others, connected to lifestyle and environment, could be modified in order to try and prevent it. Several non-randomized small scale studies have suggested that autoimmune disease could be prevented if treated aggressively prior to manifestations of symptoms. However, if such is the case, criteria would have to be formalized for selection of patients for this preventive treatment. Only patients whose probability to develop clinical disease is higher then a certain threshold should be treated while asymptomatic. The aim of this article is to review the major risk factors for autoimmune disease, both hereditary and environmental, and so to help define those future criteria. Individuals who are at risk to develop an autoimmune disease should be advised to refrain from activities and lifestyle which endangers their health and quality of life.

Sequence similarity and structural homologies are involved in the autoimmune response elicited by mouse hepatitis virus A59

The features of autoantibodies (autoAb) to liver fumarylacetoacetate hydrolase (FAH) elicited in mice infected with mouse hepatitis virus (MHV) were studied by ELISA and western-blot competition assays. All sera tested contained Ab to cryptic FAH epitopes according with results from western-blot tests, whereas ELISA data indicated that some of these same sera did recognize native epitopes of the autoantigen (autoAg). Such differences were detected in individual sera from various mouse strains, and were ascribed to the fact that proteins insolubilized on solid supports expose a variety of conformational and cryptic antigenic determinants.

On the other hand, whereas results from both experimental protocols showed that anti-MHV Ab did not cross-react with the soluble autoAg, the opposite situation did not show analogous results. Thus, binding of autoAb to insolubilized FAH could be inhibited by MHV depending on the mouse serum or the experimental protocol used.

Additionally, a set of synthetic homologous peptides from mouse FAH and various viral proteins was employed to analyze the Ab repertoire of MHV-infected mice. Results indicated that two homologous peptides were recognized by most Ab: the N-terminal sequences (1–10) from FAH and the nucleocapside, both sharing 50% of identity, and sequence 2317–2326 of the RNA polymerase, a peptide showing 30% of identity with FAH 11–20.

Results indicated that MHV-infection triggers at least three distinct Ab populations: anti-MHV, anti-FAH and cross-reacting Ab. This cross-reaction implies either sequential or conformational epitopes from both the viral proteins and the autoAg and may differ between individuals.

Helicobacter pylori infection and gastric autoimmune diseases: is there a link?

BACKGROUND

Helicobacter pylori is thought to be involved in atrophic body gastritis. We explored the prevalence of H. pylori infection in asymptomatic subjects with gastric parietal cell antibodies, as well as in patients with pernicious anemia, to evaluate a possible role of H. pylori gastric infection in gastric autoimmunity.

PATIENTS AND METHODS

We studied 79 consecutive asymptomatic subjects with parietal cell antibodies, 24 patients with pernicious anemia, and 66 parietal cell antibody-negative controls. All patients underwent gastric biopsies for histology and detection of H. pylori. Red blood cell count and volume, serum levels of gastrin, pepsinogen I, iron, folic acid, vitamin B12, and circulating antibodies to H. pylori and to intrinsic factor were also determined.

RESULTS

We found an atrophic body gastritis in 14 of the 79 asymptomatic subjects with parietal cell antibodies (18%) and in 2 of the 66 controls (3%) (p =.01). Mean levels of gastrin were increased (p <.0001), while those of pepsinogen were reduced (p <.001) compared with controls. H. pylori was identified at the gastric level and/or circulating anti-H. pylori antibodies were detected in 46 parietal cell antibody-positive subjects (58%) compared with 26 controls (39%) (p =.03). In patients with pernicious anemia we found an atrophic body gastritis in 18 of 24 cases (75%) (p <.001 vs. controls). Mean levels of gastrin were markedly increased (p <.0001) and those of pepsinogen I decreased (p <.0001) relative to controls. Only five of these patients (21%) had evidence of H. pylori infection compared with 46 of the parietal cell antibody-positive subjects (58%) (p =.003) and 26 of the controls (39%). Considering all patients with gastric autoimmunity (i.e. with parietal cell antibodies and/or with pernicious anemia), H. pylori was found in 44 of 72 of those without atrophy (61%) but in 6 of 31 with gastric body atrophy (19%) (p <.001), indicating that H. pylori infection is greatly reduced when gastric acid secretion decreases.

CONCLUSIONS

The frequent detection of H. pylori infection in subjects with early gastric autoimmunity, indicated by the presence of parietal cell antibodies, suggests that H. pylori could have a crucial role in the induction and/or the maintenance of autoimmunity at the gastric level.

Effects of various adjuvants and a viral infection on the antibody specificity toward native or cryptic epitopes of a protein antigen

An immunization protocol that induces antibodies (Abs) directed to cryptic epitopes of a protein antigen (Ag) reduces the efficacy of vaccines that ideally should induce Abs against native epitopes. We have shown earlier that viral infections concomitant with immunization against a protein tend to shift the Ab specificity toward cryptic epitopes and tend to induce the production of autoantibodies (autoAbs). Here, we show the effects of three adjuvants on the Ab specificity in the absence or presence of a viral infection (lactate dehydrogenase-elevating virus or LDV), with human growth hormone (hGH) being, as before, the protein Ag. Pathogen-free CBA/Ht and BALB/c mice were immunized with hGH in the presence of complete Freund's adjuvant (CFA), monophosphoryl lipid A (MPL) or alum, with the animals being either infected with LDV or not infected with LDV. Conventional and competition enzyme-linked immunosorbent assays (ELISAs) indicated that in noninfected mice, CFA induced higher titres of anti-hGH Ab than did MPL or alum, with the Ab being almost totally directed to cryptic hGH epitopes. Strikingly, CFA plus LDV infection in CBA/Ht mice shifted the specificity of the anti-hGH Ab toward native epitopes, whereas the virus decreased the Ab titre when MPL or alum was used. Our Western blot results showed that 70% of mice immunized with hGH in the presence of any adjuvant produced autoAbs against a variety of tissue Ags. The amount of autoAb and the concentration of Ab to hGH cryptic epitopes did correlate, suggesting a relationship between both kinds of Ab. Significant differences were observed in the various effects of adjuvants and the viral infection between the two mouse strains used in this work.

HIV and autoimmunity

The association of immune dysfunction in patients with human immunodeficiency virus (HIV) infection and AIDS and the development of autoimmune diseases is intriguing. Yet, the spectrum of reported autoimmune phenomena in these patients is increasing. An infectious trigger for immune activation is one of the postulated mechanisms and derives from molecular mimicry. During frank loss of immunocompetence, autoimmune diseases that are predominantly T cell subtype CD8 driven predominate. There is evidence for B cell stimulation and many autoantibodies are reported in HIV patients. We propose a staging of autoimmune manifestations related to HIV/AIDS manifestations and the total CD4 count and viral load that may be beneficial in identifying the type of autoimmune disease and establishing the proper therapy. In stage I there is the acute HIV infection, and the immune system is intact. In this stage, autoimmune diseases may develop. Stage II describes the quiescent period without overt manifestations of AIDS. However, there is a declining CD4 count indicative of some immunosuppression. Autoimmune diseases are not found. During stage III there is immunosuppression with a low CD4 count and the development of AIDS. CD8 T cells predominant and diseases such as psoriasis and diffuse immune lymphocytic syndrome (similar to Sjogren's syndrome) may present or even be the initial manifestation of AIDS. Also during this stage no autoimmune diseases are found. In stage IV there is restoration of immune competence following highly active anti-retroviral therapy (HAART). In this setting, there is a resurgence of autoimmune diseases. The frequency of reported rheumatological syndromes in HIV-infected patients ranges from 1 to 60%. The list of reported autoimmune diseases in HIV/AIDS include systemic lupus erythematosus, anti-phospholipid syndrome, vasculitis, primary biliary cirrhosis, polymyosits, Graves' disease, and idiopathic thrombocytopenic purpura. Also, there is an array of autoantibodies reported in HIV/AIDS patients which include anti-cardiolipin, anti-beta2 GPI, anti-DNA, anti-small nuclear ribonucleoproteins (snRNP), anti-thyroglobulin, anti-thyroid peroxidase, anti-myosin, and anti-erythropoietin antibodies. The association of autoantibodies in HIV-infected patients to clinical autoimmune disease is yet to be established. With the upsurge of HAART, the incidence of autoimmune diseases in HIV-infected patients is increasing. In this review, we describe the various autoimmune diseases that develop in HIV/AIDS patients through possible mechanisms related to immune activation.

Identification of two liver proteins recognized by autoantibodies elicited in mice infected with mouse hepatitis virus A59

Western blot experiments showed that sera from mice infected with the mouse hepatitis virus strain A59 (MHV-A59) contained autoantibodies (autoAb) that bound to a 40-kDa protein present in liver and kidney extracts. No reaction was observed with extracts of the heart, muscles, spleen, brain and lung. The Ab cross-reacted with a 40-kDa protein from human, rat and sheep liver, but not with liver extracts from the silver side fish (Odontesthes bonariensis). No correlation was found between the development of the hypergammaglobulinemia that followed the viral infection and the occurrence of the autoAb. Reactive immunoglobulins pertained to the IgG1, IgG2a and IgG2b subclasses, recognized cryptic epitopes and were detected from 10 days up to 8 weeks after MHV-infection. The 40-kDa protein was purified from mouse liver extracts by ion-exchange chromatography, gel filtration and SDS-PAGE. Because the N-terminal was blocked, we digested the protein in-gel with trypsin and sequenced various peptides. Results indicated a 100% homology of sequence between the protein recognized by the autoAb and liver fumarylacetoacetate hydrolase (FAH), the enzyme that mediates the last step of tyrosine catabolism. Additionally, a second protein recognized by the autoAb was detected during FAH purification steps and was identified as liver alcohol dehydrogenase.

Evidence for antigenic cross-reactivity between herpesvirus and the acetylcholine receptor

Herpes simplex virus (HSV) is neurotropic and can pass from neuron to neuron at nerve terminals. During the long evolutionary relationship between HSV and vertebrates, this virus may have evolved surface ligands that mimic nerve cell receptors. The present study was undertaken to determine if herpes simplex virus type 1 (HSV-1) has an antigenic relationship with the acetylcholine receptor (AChR). Mice immunized with HSV-1 antigens or an AChR-expressing cell line were tested for antibodies directed against the AChR. By flow cytometry and ELISA, mouse anti-HSV-1 sera were found to contain antibodies that would bind to an epitope on the plasma membrane of AChR-expressing cells. Mice immunized with the AChR-expressing cells were tested for their resistance to HSV-1 infection. Statistically significantly more of the animals immunized with AChR-expressing cells resisted infection and fatal encephalitis, compared to control animals immunized with a cell line not expressing the AChR. Sera from AChR-immunized mice were tested for anti-HSV antibody by ELISA and were found to contain antibodies cross-reactive with HSV-1 antigens. These sera also neutralized virus in a plaque inhibition assay. The results indicate that there are one or more antigenic epitopes shared by herpesvirus and the AChR. Studies are in progress to define the pathogenetic significance of this molecular mimicry.

Adenovirus-Mediated Human Immunodeficiency Virus-1 Nef Expression in Human Monocytes/Macrophages and Effect of Nef on Downmodulation of Fcγ Receptors and Expression of Monokines

To characterize the effect of human immunodeficiency virus-1 (HIV-1)nef expression in human monocytes/macrophage (HMØ) and U937 on the levels of FcγRs, HLA antigens, and monokines, elutriated HMØs and U937 cells were transfected with an adenovirus-mediated Nef expression system. Nef-expressing cells downmodulated FcγRI, FcγRII, and upregulated HLA class I molecules. Nef-expressing HMØs, treated with lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate (PMA), overexpressed tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-10. However, IL-6 was induced by LPS and inhibited by PMA. Additionally, a subpopulation of Nef-expressing HMØs underwent apoptosis. Our data suggest that HIV-1 nefdownmodulated FcγRs in myeloid cells in a manner similar to that previously reported for its effect on CD4+ in T cells.

Adenovirus-Mediated Human Immunodeficiency Virus-1 Nef Expression in Human Monocytes/Macrophages and Effect of Nef on Downmodulation of Fcγ Receptors and Expression of Monokines

To characterize the effect of human immunodeficiency virus-1 (HIV-1)nef expression in human monocytes/macrophage (HMØ) and U937 on the levels of FcγRs, HLA antigens, and monokines, elutriated HMØs and U937 cells were transfected with an adenovirus-mediated Nef expression system. Nef-expressing cells downmodulated FcγRI, FcγRII, and upregulated HLA class I molecules. Nef-expressing HMØs, treated with lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate (PMA), overexpressed tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-10. However, IL-6 was induced by LPS and inhibited by PMA. Additionally, a subpopulation of Nef-expressing HMØs underwent apoptosis. Our data suggest that HIV-1 nefdownmodulated FcγRs in myeloid cells in a manner similar to that previously reported for its effect on CD4+ in T cells.

[Autoimmunity: a concept to be revisited?]

Autoimmunity is thought to be a defect in immunologic tolerance, resulting in the activation and expansion of self antigen-specific T and B lymphocyte clones and the production of circulating antibodies, and a myriad of cytokines and other inflammatory mediators. This hypothesis, which speculates on an aberrant response of the immune system to normal self antigens has exerced a powerful influence on clinical investigations and therapeutic researches. Although much information has accumulated, the mechanism of autoimmune disease remains poorly understood and little attention has been paid to the hypothesis that autoimmune diseases might be caused by a conventional immunological response against self antigens for which tolerance has never been established. Clinical practice would undoubtedly get a lot out of it, as well as new therapeutic measures.