Slow bacterial infections or autoimmunity?

Sarcoidosis, Mycobacterium paratuberculosis and Noncaseating Granulomas: Who Moved My Cheese

Clinical and histological similarities between sarcoidosis and tuberculosis have driven repeated investigations looking for a mycobacterial cause of sarcoidosis. Over 50 years ago, "anonymous mycobacteria" were suggested to have a role in the etiology of sarcoidosis. Both tuberculosis and sarcoidosis have a predilection for lung involvement, though each can be found in any area of the body. A key histopathologic feature of both sarcoidosis and tuberculosis is the granuloma-while the tuberculous caseating granuloma has an area of caseous necrosis with a cheesy consistency; the non-caseating granuloma of sarcoidosis does not have this feature. This article reviews and reiterates the complicity of the infectious agent, Mycobacterium avium subsp. paratuberculosis (MAP) as a cause of sarcoidosis. MAP is involved in a parallel story as the putative cause of Crohn's disease, another disease featuring noncaseating granulomas. MAP is a zoonotic agent infecting ruminant animals and is found in dairy products and in environmental contamination of water and air. Despite increasing evidence tying MAP to several human diseases, there is a continued resistance to embracing its pleiotropic roles. "Who Moved My Cheese" is a simple yet powerful book that explores the ways in which individuals react to change. Extending the metaphor, the "non-cheesy" granuloma of sarcoidosis actually contains the difficult-to-detect "cheese", MAP; MAP did not move, it was there all along.

Takayasu's Arteritis and Its Association With Mycobacterium Tuberculosis: A Systematic Review

Takayasu's arteritis (TAK) is a rare large vessel vasculitis of unknown etiology that chiefly targets the aorta and its branches. It predominantly affects females under 50 years of age. A relationship between TAK and Mycobacterium tuberculosis (TB) has been suggested for a long time, but only a few systematic studies have been done centering on this association. The present systematic review aimed to analyze the possible association between TAK and TB based on the studies conducted previously. A detailed search was conducted until April 2021 using three databases: PubMed, Cochrane Library, and MedlinePlus. PubMed search on the related topic identified 1053 articles, four on Cochrane Library, and three on MedlinePlus. Finally, 13 papers were pertinent for our review. The appropriate data was extracted from these articles, and the risk of bias assessment was done. The systematic review of these finalized articles found that the majority of the current studies supported the presence of TB in patients with TAK. Out of 13 final observational studies, only one study failed to detect a link between TAK and TB. However, data are still lacking that show a direct link between them. Future large-scale studies are needed to probe the exact role of Mycobacterium tuberculosis infection in the etiopathogenesis of TAK.

Age-associated B Cells Appear in Patients with Granulomatous Lung Diseases

Rationale: A subpopulation of B cells (age-associated B cells [ABCs]) is increased in mice and humans with infections or autoimmune diseases. Because depletion of these cells might be valuable in patients with certain lung diseases, the goal was to find out if ABC-like cells were at elevated levels in such patients.Objectives: To measure ABC-like cell percentages in patients with lung granulomatous diseases.Methods: Peripheral blood and BAL cells from patients with sarcoidosis, beryllium sensitivity, or hypersensitivity pneumonitis and healthy subjects were analyzed for the percentage of B cells that were ABC-like, defined by expression of CD11c, low levels of CD21, FcRL 1-5 (Fc receptor-like protein 1-5) expression, and, in some cases, T-bet.Measurements and Main Results: ABC-like cells in blood were at low percentages in healthy subjects and higher percentages in patients with sarcoidosis as well as at high percentages among BAL cells of patients with sarcoidosis, beryllium disease, and hypersensitivity pneumonitis. Treatment of patients with sarcoidosis led to reduced percentages of ABC-like cells in blood.Conclusions: Increased levels of ABC-like cells in patients with sarcoidosis may be useful in diagnosis. The increase in percentage of ABC-like cells in patients with lung granulomatous diseases and decrease in treated patients suggests that depletion of these cells may be valuable.

Case Study: Cardiac sarcoidosis resolved with Mycobacterium avium paratuberculosis antibiotics (MAP)

Background: The author presents a clinical history and personal case study following his diagnosis of inactive sarcoidosis in 2004, followed by an acute episode of cardiac sarcoidosis (CS) in 2012 which resulted in complete heart block, cardiac myopathy, heart failure and insertion of an implantable cardioverter defibrillator (ICD) pacemaker. Methods: Following a detailed review of the clinical and scientific literature he concluded that sarcoidosis may be a mycobacterial infection and could be treated with anti-MAP antibiotic regime (1) developed to treat Crohn's disease. Findings: After successful culture and identification of viable MAP in his blood, treatment with the MAP antibiotic regime for one year led to complete metabolic resolution of the previously avid cardiac sarcoidosis and no PET evidence of any metabolically active sarcoidosis anywhere. Such reversal of cardiac sarcoidosis has never previously been reported. (Sarcoidosis Vasc Diffuse Lung Dis 2018; 35: 171-177).

Unique macrophages different from M1/M2 macrophages inhibit T cell mitogenesis while upregulating Th17 polarization

Mycobacterial infection induces suppressor macrophages (MΦs), causing disease exacerbation. There are two major MΦ subsets (M1 and M2 MΦs) that are phenotypically and functionally different. Here, we examined which of the MΦ subsets the mycobacterial infection-induced suppressor MΦs (MIS-MΦs) belong to. MIS-MΦs down-regulated T cell production of Th1 and Th2 cytokines but markedly increased production of interleukin (IL)-17A and IL-22 through up-regulation of Th17 cell expansion. In this phenomenon, a novel MΦ population, which is functionally distinguishable from M1 and M2 MΦ subsets and possesses unique phenotypes (IL-12(+), IL-1β(high), IL-6(+), tumor necrosis factor (TNF)-α(+), nitric oxide synthase (NOS) 2(+), CCR7(high), IL-10(high), arginase (Arg)-1(-), mannose receptor (MR)(low), Ym1(high), Fizz(low), and CD163(high)), played central roles through the action of IL-6 and transforming growth factor (TGF)-β but not IL-21 and IL-23. This new type of MΦ population was induced in infected mice and actively supported the in vivo expansion of Th17 cells.

Non-infectious granulomatous diseases of the skin and their associated systemic diseases: an evidence-based update to important clinical questions

Non-infectious granulomatous diseases of the skin are a broad group of distinct reactive inflammatory conditions that share important similarities. As a group, they are relatively difficult to diagnose and distinguish both clinically as well as histologically. Many of these disorders have significant associations with systemic diseases that impact the patient's overall prognosis. In this update, we offer a discussion of emerging concepts and controversies in this field, as presented through evidence-based answers to seven important clinical questions regarding palisading and epithelioid granulomata. These questions offer an opportunity to review ten non-infectious granulomatous conditions that have implications for systemic disease: granuloma annulare, annular elastolytic giant cell granuloma, necrobiosis lipoidica, methotrexate-induced accelerated rheumatoid nodulosis, necrobiotic xanthogranuloma, interstitial granulomatous dermatitis, interstitial granulomatous drug reaction, palisaded neutrophilic granulomatous dermatitis, sarcoidosis, and metastatic Crohn disease. Recent clinical, epidemiologic, and laboratory studies have shed some light on these diseases, the association of these conditions with systemic disorders, and their overall prognoses.

Autoantibodies in patients treated for active pulmonary tuberculosis

The genesis of auto-immune antibodies directed against the own tissue antigens of a host may be due to the host's immune response to mycobacteria. The prospective study included 110 patients treated for active pulmonary tuberculosis and the control group of 60 healthy subjects, volontary blood donors. Applying the method of indirect immnunofluorescence and cryostat sections of rat organs and human larynx cancer epithelial cell line (HEp-2 cells), the prescence of the following autoantibodies in the serum of the examined patients was examined: anti,nclear (ANA), anticardiac (ACA), antimitochondrial (AMA), antiparietal (APA), anti smooth muscular (ASMA), antithyroidal (ATA), rheumnatoid factor (RF). These autoantibodies were determined in the course oftreatment and five years later. Low levels of some examined autoantibodies were detected in the serum of a number of the examined patients. No significant difference in the presence of the analysed antibodies was registered between the sexes. In the course of the treatment a reversible hyper-gammaglobulinemia developed, which was at least partially due to the presence of autoantibodies in the patients blood serum. Besides possibly involved mechanisms of molecular mimicry and polyclonal lymphocyte activation, the presence of antinuclear antibodies in the patient's serum is at least partially due to isoniazide treatment. The finding of other autoantibodies is nonspecific and not related to the mycobacterial infection or antituberculosis drug administration.

A molecular analysis of prokaryotic and viral DNA sequences in prostate tissue from patients with prostate cancer indicates the presence of multiple and diverse microorganisms

BACKGROUND

Inflammation, both acute and chronic, is a common feature of prostate histology. While inflammation has been proposed to play an important role in both benign and malignant growth of the prostate, the stimuli for this inflammation remain poorly characterized. Infectious pathogens are potential stimuli for prostatic inflammation.

METHODS

Universal eubacterial PCR was used to test 170 prostate tissue core samples from 30 cancer patients for 16S rDNA gene sequences. Positive PCR products (n=64, 37%) were cloned and sequenced. For comparison, tissue samples from 30 patients were cultured using standard clinical microbiological techniques. DNA samples from 200 additional patients were tested by organism-specific PCR for the presence of Chlamydia trachomatis, Propionibacterium acnes, Trichomonas vaginalis, BK virus, Epstein-Barr virus, human cytomegalovirus, human papillomavirus, and xenotropic murine leukemia-related virus.

RESULTS

16S sequencing results indicated the presence of 83 distinct microorganisms. Microbiological culture isolated markedly fewer species. In general, organism-specific PCR failed to detect multiple organisms previously reported as common in the prostate. There was no significant association between the presence of particular species of bacteria and histologic evidence of acute or chronic inflammation.

CONCLUSIONS

Most prostates from men undergoing prostatectomy (87%) contain bacterial DNA from one or more species. However, the majority of individual tissue core samples were negative, suggesting regional heterogeneity in the presence of bacteria and a lack of a generalized or ubiquitous prostatic flora. Culture results suggest either the "unculturable" nature of species present in the prostate or that 16S rDNA sequences were derived from non-viable bacteria.

Cytokine Single Nucleotide Polymorphisms in Iran

Overall expression and secretion of cytokines are dependent on genetic nucleotide variations within or adjacent to regulatory regions of cytokine genes. This study allows the comparison of the prevalence of particular genetic markers. In 40 Iranian healthy subjects, cytokine single nucleotide polymorphisms (SNPs) were used to determine allelic and genotypic frequencies for the following cytokine genes: interleukin-1alpha (IL-1alpha) (T/C -889), IL-1beta (C/T -511, T/C +3962), IL-12 ( C/A-1188), interferon-gamma (IFN-gamma) (A/T UTR 5644), transforming growth factor-beta (TGF-beta) (C/T codon 10, G/C codon 25), tumor necrosis factor alpha (TNF-alpha) (G/A -308, G/A -238), IL-2 (T/G -330, G/T +166), IL-4 (T/G -1089, T/C -590, T/C -33), IL-6 (G/C -174, G/A nt565), IL-10 (G/A -1082, C/T -819, C/A -592), IL-1R (C/T pst11970), IL-1RA (T/C mspa 111100), IL-4RA (G/A +1902). All typing was performed using the PCR-SSP assay. Iranian and Italian, English, German, and Greek populations had similar cytokine profiles, but in some cases, the Iranian allele and genotype frequencies were significantly different from those of other Asian and African American populations for the majority of polymorphisms.

Heterogeneity of cytokine single-nucleotide polymorphisms among the Iranian and in the other East-South Asian populations

Cytokine gene polymorphisms may affect their transcription, influence their level of production and may be implicated in inducing susceptibility or resistance to diseases. In 40 Iranian healthy subjects, cytokine single-nucleotide polymorphisms (SNPs) were used to determine allelic and genotypic frequencies for the following cytokine genes: IL-1a (T/C -889), IL-1beta (C/T -511, T/C 3962), IL-12 (C/A -1188), IFN-gamma (A/T UTR 5644), TGF-beta (C/T codon 10, G/C codon 25), TNF-a (G/A -308, G/A -238), IL-2 (T/G -330, G/T 166), IL-4 (T/G -1089, T/C -590, T/C -33), IL-6 (G/C -174, G/A nt565), IL-10 (G/A -1082, C/T -819, C/A -592), IL-1R (C/T pst11970), IL-1RA (T/C mspa111100) and IL-4RA (G/A 1902). All typing were performed with polymerase chain reaction with sequence specific primers assay. Significant heterogeneity of cytokine SNPs among the Iranian and the other East-South Asian populations was observed. Heterogeneity of cytokine SNPs may explain the role of natural selection in susceptibilities of populations to different disorders.

Systemic autoimmune disease induced by dendritic cells that have captured necrotic but not apoptotic cells in susceptible mouse strains

Systemic lupus erythematosus (SLE) is an autoimmune disorder of a largely unknown etiology. Anti-double-stranded (ds) DNA antibodies are a classic hallmark of the disease, although the mechanism underlying their induction remains unclear. We demonstrate here that, in both lupus-prone and normal mouse strains, strong anti-dsDNA antibody responses can be induced by dendritic cells (DC) that have ingested syngeneic necrotic (DC/nec), but not apoptotic (DC/apo), cells. Clinical manifestations of lupus were evident, however, only in susceptible mouse strains, which correlate with the ability of DC/nec to release IFN-gamma and to induce the pathogenic IgG2a anti-dsDNA antibodies. Injection of DC/nec not only accelerated disease progression in the MRL/MpJ-lpr/lpr lupus-prone mice but also induced a lupus-like disease in the MRL/MpJ-+/+ wild-type control strain. Immune complex deposition was readily detectable in the kidneys, and the mice developed proteinuria. Strikingly, female MRL/MpJ-+/+ mice that had received DC/nec, but not DC/apo, developed a 'butterfly' facial lesion resembling a cardinal feature of human SLE. Our study therefore demonstrates that DC/nec inducing a Th1 type of responses, which are otherwise tightly regulated in a normal immune system, may play a pivotal role in SLE pathogenesis.

Cytokine gene polymorphisms in Taiwan

Cytokine gene polymorphisms may affect their transcription, influence their level of production, and may be implicated in inducing susceptibility or resistance to diseases. Cytokine single-nucleotide polymorphisms (SNPs) were used to determine allelic and genotypic frequencies in the Minnan, the Hakka, and in four indigenous tribes: the Ami, the Tsou, the Atayal, and the Tao (or Yami). The following cytokine gene polymorphisms were analyzed: interleukin-1alpha (IL-1alpha) (T/C -889), IL-1beta (C/T -511, T/C +3962), IL-1R (C/T Pst-I 1970), IL-1Ralpha (T/C Mspa1-I 1100), IL-2 (T/G -330, G/T +166), IL-4 (T/G -1098, T/C -590, T/C -33), IL-4Ralpha (G/A +1902), IL-6 (G/C -174, G/A nt565), IL-10 (G/A -1082, C/T -819, C/A -592), IL-12 (C/A -1188), interferon-gamma (A/T UTR 5644), transforming growth factor-beta (C/T codon 10, G/C codon 25), and TNF-alpha (G/A -308, G/A -238). Little differences were observed between the Minnan and the Hakka. On the other hand, the Minnan and Hakka showed significant differences with the indigenous people.

Direct Toll-like receptor 2 mediated co-stimulation of T cells in the mouse system as a basis for chronic inflammatory joint disease

The pathogenesis of chronic inflammatory joint diseases such as adult and juvenile rheumatoid arthritis and Lyme arthritis is still poorly understood. Central to the various hypotheses in this respect is the notable involvement of T and B cells. Here we develop the premise that the nominal antigen-independent, polyclonal activation of preactivated T cells via Toll-like receptor (TLR)-2 has a pivotal role in the initiation and perpetuation of pathogen-induced chronic inflammatory joint disease. We support this with the following evidence. Both naive and effector T cells express TLR-2. A prototypic lipoprotein, Lip-OspA, from the etiological agent of Lyme disease, namely Borrelia burgdorferi, but not its delipidated form or lipopolysaccharide, was able to provide direct antigen-nonspecific co-stimulatory signals to both antigen-sensitized naive T cells and cytotoxic T lymphocyte (CTL) lines via TLR-2. Lip-OspA induced the proliferation and interferon (IFN)-γ secretion of purified, anti-CD3-sensitized, naive T cells from C57BL/6 mice but not from TLR-2-deficient mice. Induction of proliferation and IFN-γ secretion of CTL lines by Lip-OspA was independent of T cell receptor (TCR) engagement but was considerably enhanced after suboptimal TCR activation and was inhibitable by monoclonal antibodies against TLR-2.

Molecular analysis of sarcoidosis tissues for mycobacterium species DNA

We performed polymerase chain reaction analysis, for Mycobacterium species 16S rRNA, rpoB, and IS6110 sequences, on 25 tissue specimens from patients with sarcoidosis and on 25 control tissue specimens consisting of mediastinal or cervical lymph nodes and lung biopsies. Mycobacterium species 16S rRNA sequences were amplified from 12 (48%) rpoB sequences and from 6 (24%) of the sarcoidosis specimens. In total, 16S rRNA or rpoB sequences were amplified from 15 sarcoidosis specimens (60%) but were not detected in any of the control tissues (p=0.00002, chi square). In three specimens, the sequences resembled Mycobacterium species other than M. tuberculosis. All specimens with sequences consistent with M. tuberculosis were negative for IS6110. We provide evidence that one of a variety of Mycobacterium species, especially organisms resembling M. tuberculosis, is found in most patients with sarcoidosis.

What causes sarcoidosis?

Limited but encouraging progress has been made over the last several years in our understanding of the etiology of sarcoidosis as a result of recent investments in epidemiologic, immunologic, and molecular biologic studies. A recent US multicenter study of sarcoidosis found few environmental or occupational exposures associated with a two-fold or higher risk of development of sarcoidosis, suggesting noninfectious exposures play a small, if any, role in causing systemic sarcoidosis. In contrast, recent studies have linked infectious agents including mycobacterial and propionibacterial organisms with sarcoidosis. The association of sarcoidosis with the use of Th1-promoting biologic response modifiers is consistent with a central role for enhanced Th1 immune responses in the pathogenesis of sarcoidosis. Given evidence for a genetic predisposition to sarcoidosis, these findings suggest that the etiology of systemic sarcoidosis is linked to genetically determined enhanced Th1 immune responses to a limited number of microbial pathogens.

IL-6 in autoimmune disease and chronic inflammatory proliferative disease

Interleukin 6 (IL-6), which was originally identified as a B-cell differentiation factor, is now known to be a multifunctional cytokine that regulates the immune response, hematopoiesis, the acute phase response, and inflammation. Deregulation of IL-6 production is implicated in the pathology of several disease processes. The expression of constitutively high levels of IL-6 in transgenic mice results in fatal plasmacytosis, which has been implicated in human multiple myeloma. Increased IL-6 levels are also observed in several diseases, including rheumatoid arthritis (RA), systemic-onset juvenile chronic arthritis (JCA), osteoporosis, and psoriasis. IL-6 is critically involved in experimentally induced autoimmune disease, such as antigen-induced arthritis (AIA), and experimental allergic encephalomyelitis. All these clinical data and animal models suggest that IL-6 plays critical roles in the pathogenesis of autoimmune diseases. Here we review the evidence for the involvement of IL-6 in the pathophysiology of autoimmune diseases and chronic inflammatory proliferative diseases (CIPD) and discuss the possible molecular mechanisms of its involvement.

Reactive arthritis or chronic infectious arthritis?

Microbes reach the synovial cavity either directly during bacteraemia or by transport within lymphoid cells or monocytes. This may stimulate the immune system excessively, triggering arthritis. Some forms of ReA correspond to slow infectious arthritis due to the persistence of microbes and some to an infection triggered arthritis linked to an extra-articular site of infection.

HspX is present within Mycobacterium paratuberculosis-infected macrophages and is recognized by sera from some infected cattle

A portion of the gene encoding HspX has been previously identified as a sequence specific to Mycobacterium avium subspecies paratuberculosis (hereafter referred to as M. paratuberculosis) based on DNA hybridization experiments. In this study, rabbit antisera were raised against a recombinant protein of HspX fused to the Escherichia coli maltose binding protein (MBP/HspX). Immunoblots of lysates of M. paratuberculosis-infected macrophages probed with the rabbit antisera showed that HspX was present within infected macrophages of bovine and murine origin. This observation was confirmed by immunofluorescence microscopy of infected macrophages. Lysates of E. coli expressing HspX without the MBP fusion partner were loaded onto preparative SDS-PAGE gels and used to determine whether infected cattle generated a humoral immune response to the antigen. Sera from four of 24 paratuberculous cows (17%) detected HspX. No reactivity was present in sera from control cows. While HspX may be immunogenic during infection in some cows, the protein is not secreted and it does not stimulate cell-mediated immunity. Collectively, these data give a preliminary characterization of the first described M. paratuberculosis protein identified within infected macrophages.

IL-12, Independently of IFN-γ, Plays a Crucial Role in the Pathogenesis of a Murine Psoriasis-Like Skin Disorder

The onset of acute psoriasis and the exacerbation of chronic psoriasis are often associated with a history of bacterial infection. We demonstrate that while only few scid/scid mice develop disease when CD4+CD45Rbhigh T cells are transferred alone, coadministration of LPS plus IL-12 or staphylococcal enterotoxin B into scid/scid mice 1 day after CD4+CD45Rbhigh T cell transfer greatly enhances disease penetrance and severity. Most importantly, the skin lesions induced by this method exhibit many of the histologic hallmarks observed in human psoriasis. Skin infiltrating CD4+ T cells were predominantly memory/effector cells (CD45Rblow) and exhibited a highly polarized Th1 phenotype. To test whether the development of pathogenic T cells was dependent on their production of IFN-γ, we transferred IFN-γ−/− CD4+CD45Rbhigh T cells into scid/scid or into T, B and NK cell-deficient scid/beige mice. Surprisingly, the incidence of psoriasis was similar to scid/scid animals that received IFN-γ+/+ T cells, although acanthosis of the skin was attenuated. In contrast, the development of psoriasis was abolished if anti-IL-12 mAb was administered on day 7 and 35 after T cell transfer. Skin-derived IFN-γ−/− inflammatory cells, but not cells from anti-IL-12-treated animals, secreted substantial amounts of TNF-α, suggesting that the inflammatory effect of IFN-γ−/− T cells may be partly exerted by TNF-α and that the therapeutic effect of anti-IL-12 may depend on its ability to down-regulate both TNF-α and IFN-γ. Overall, these results suggest that IL-12, independently of IFN-γ, is able to induce pathogenic, inflammatory T cells that are able to induce psoriasiform lesions in mice.

Analysis of the Kveim-Siltzbach test reagent for bacterial DNA

The sarcoid spleen-derived reagent for the Kveim-Siltzbach test (KST) elicits a sarcoid-specific, granulomatous, cutaneous response used to establish the diagnosis of sarcoidosis. In the context of the ongoing discussion of a bacterial cause of sarcoidosis we asked the question whether bacterial DNA could be found in the KST reagent. For this purpose two different KST reagents, an identical preparation from a normal spleen, and a native sarcoid spleen were analyzed by polymerase chain reaction (PCR) employing universal primers detecting conserved DNA sequences coding for bacterial ribosomal 16S RNA. Neither KST reagents, the control preparation, nor the spleen yielded a positive signal, indicating that the preparations are free of bacterial contamination. Because the KST reagent elicits granuloma, these results do not support the hypothesis of a bacterial cause of sarcoid granuloma.

Inflammatory arthritic process, iridocyclitis and immune response to articular and ocular antigens in Wistar rats injected with T. gondii trophozoites

The present study deals with the potential role of T. gondii in inducing an arthritic inflammatory process. Wistar rats were injected subcutaneously (sc) into the right footpad with viable T. gondii trophozoites emulsified in incomplete Freund's adjuvant (IFA). The control group was injected with IFA. All parasite-injected animals developed a local inflammatory process characterized by hind limb swelling and marked restriction of ankle motility approximately 25 days after injection. Histopathogical studies of the joints, carried out 90 days after injection, revealed intense mononuclear infiltration, proliferation of granulation tissue, giant cells and necrosis in the synovia of 90% of T. gondii-injected rats. Strikingly, 40% (4/10) of the parasite-injected animals developed iridocyclitis, which was characterized by intense mononuclear infiltration around the iris-ciliary microvasculature in two animals and a slightly pronounced infiltrate of polymorphonuclear and mononuclear cells in two other animals. Antibodies to soluble T. gondii antigens (STAg) were detected in all parasite-injected rats. Antibodies against articular and ocular antigens such as proteoglycans, type II collagen, retinal S antigen and iris antigens were detected by ELISA in 40, 80, 70 and 70% of T. gondii -injected animals, respectively. Control animals injected with IFA failed to develop any articular or ocular process or humoral immune response. The present study demonstrated that footpad sc injection of Wistar rats with viable T. gondii trophozoites was able to induce a localized inflammatory arthritic process which, in some of the animals, was accompanied by iridocyclitis and immune response against articular and ocular components.

Heat shock proteins and experimental autoimmune encephalomyelitis. II: environmental infection and extra-neuraxial inflammation alter the course of chronic relapsing encephalomyelitis

We wished to study how infections might trigger relapses of autoimmune diseases such as multiple sclerosis (MS) and encephalomyelitis (EAE). We hypothesized that immune responses to heat shock proteins (hsp) induced by an infection could modulate responses to autoantigens. We induced extra-neuraxial inflammation in SJL mice housed either in specific-pathogen free (SPF) or conventional facilities. Mice in conventional housing are continuously exposed to large numbers of infectious agents. Spleen cell proliferative responses to human HSP60 and bacterial HSP65 were measured as were numbers of cells secreting IFN-gamma or IL-5. Proliferative responses to HSP60 were increased in conventionally housed mice compared to SPF mice and this was associated with skewing of secreted cytokines toward a Th2 pattern. Skewing toward a Th1 pattern was noted in SPF mice. Acute and relapsing EAE was induced in both groups of mice. Acute EAE was, in general, equivalent in all groups. However, SPF mice had more severe relapses than did conventionally housed animals and these differences were amplified by extra-neuraxial inflammation. Immunocytochemical analyses of brains from mice with relapsing EAE showed that increased numbers of brain gamma/delta cells were associated with disease remission. Our data suggest that frequent exposure to infectious agents leads to a relative Th2 skewing of immune responses to hsp and that this is associated with milder, less frequent relapses of EAE. They also support the concept that immune responses to hsp are of potential importance in exacerbating and perpetuating organ-restricted autoimmune diseases.

Interleukin 6 and its receptor: ten years later

Ten years have passed since the molecular cloning of interleukin 6 (IL-6) in 1986. IL-6 is a typical cytokine, exhibiting functional pleiotropy and redundancy. IL-6 is involved in the immune response, inflammation, and hematopoiesis. The IL-6 receptor consists of an IL-6 binding alpha chain and a signal transducer, gp130, which is shared among the receptors for the IL-6 related cytokine subfamily. The sharing of a receptor subunit is a general feature of cytokine receptors and provides the molecular basis for the functional redundancy of cytokines. JAK tyrosine kinase is a key molecule that can initiate multiple signal-transduction pathways by inducing the tyrosine-phosphorylation of the cytokine receptor, gp130 in the case of IL-6, on which several signaling molecules are recruited, including STAT, a signal transducer and activator of transcription, and SHP-2, which links to the Ras-MAP kinase pathway. JAK can also directly activate signaling molecules such as STAT and Tec. These multiple signal-transduction pathways intimately regulate the expression of several genes including c-myc, c-myb, junB, IRF1, egr-1, and bcl-2, leading to the induction of cell growth, differentiation, and survival. The deregulated expression of IL-6 and its receptor is involved in a variety of diseases.

Etiology of sarcoidosis

Since sarcoidosis was first recognized as a distinct clinical entity, investigators have speculated that a transmissible agent may cause sarcoidosis. Recent attempts at directly isolating infectious organisms or indirectly detecting microbial DNA or RNA from sarcoid tissue have led to inconclusive results. Studies on the immunopathogenic origins of sarcoidosis have provided evidence of persistent antigenic stimulation at sites of inflammation that are associated with dysregulated cytokine production. To date, however, the challenge of defining the cause of sarcoidosis remains unmet.

Peritoneal cellular immunity and endometriosis

PROBLEM

An immunologic basis has long been considered to be very important in the pathogenesis of endometriosis. Interactions of the peritoneal cells, which comprise macrophages, B cells, T cells, natural killer (NK) cells, and retrograde endometrial cells, are critical, but remain controversial, for exploring the pathogenesis of endometriosis.

METHOD OF STUDY

Accumulated data from the literature were reviewed, and our data were analyzed.

RESULTS

The data show that peritoneal macrophages are activated by the recurrent reflux of menstrual shedding. Humoral and local endometrial autoantibodies are detected in patients with endometriosis, but B cells are not quantitatively increased. There is decreased NK cell activity in the peritoneal cavity and peripheral blood, and this decreased activity may be related to the failure to clear out the ectopic endometrial tissue. Peritoneal T cells are predominant by Th1 inflammatory cells, and these cells are impaired because of a decrease in activation (especially HLA-DR+CD4+CD3+ population) and in the production of interleukin-2. Inflammatory cytokines such as interleukin-1, interleukin-6, and tumor necrosis factor-alpha are elevated in the peritoneal fluid of women with endometriosis.

CONCLUSIONS

The peritoneal NK and T lymphocytes are suppressed in women with endometriosis, but whether these immunologic deviations are the cause or the result of endometriosis is still unclear. Further studies are required to determine what role immunologic factors play in the pathophysiology of endometriosis.

Inflammatory bowel disease: an immunity-mediated condition triggered by bacterial infection with Helicobacter hepaticus

Inflammatory bowel disease (IBD) is thought to result from either an abnormal immunological response to enteric flora or a normal immunological response to a specific pathogen. No study to date has combined both factors. The present studies were carried out with an immunologically manipulated mouse model of IBD. Mice homozygous for the severe combined immunodeficiency (scid) mutation develop IBD with adoptive transfer of CD4+ T cells expressing high levels of CD45RB (CD45RB(high) CD4+ T cells). These mice do not develop IBD in germfree conditions, implicating undefined intestinal flora in the pathogenesis of lesions. In controlled duplicate studies, the influence of a single murine pathogen, Helicobacter hepaticus, in combination with the abnormal immunological response on the development of IBD was assessed. The combination of H. hepaticus infection and CD45RB(high) CD4+ T-cell reconstitution resulted in severe disease expression similar to that observed in human IBD. This study demonstrates that IBD develops in mice as a consequence of an abnormal immune response in the presence of a single murine pathogen, H. hepaticus. The interaction of host immunity and a single pathogen in this murine system provides a novel model of human IBD, an immunity-mediated condition triggered by bacterial infection.

Whipple disease. Clinical review of 52 cases. The SNFMI Research Group on Whipple Disease. Société Nationale Française de Médecine Interne

Whipple disease is a rare, multiorgan disease with prominent intestinal manifestations. We report a retrospective clinical study of 52 patients recruited in various parts of France from 1967 to 1994. Seventy-three percent of the patients were male. Clinical manifestations preceding the diagnosis were articular for 35 patients (67%), digestive for 8 patients (15%), general for 7 patients (14%), and neurologic for 2 patients (4%). At a later stage of the disease, 44 patients (85%) presented diarrhea, weight loss, and malabsorption, while 8 patients (15%) did not show any gastrointestinal symptom throughout the development of the disease. Forty-three patients (83%) presented arthralgia or arthritis, and 11 (21%) had prominent neurologic symptoms. In addition, cardiovascular symptoms were present in 9 patients (17%); mucocutaneous symptoms, in 9 patients (17%); pleuropulmonary symptoms, in 7 patients (13%); and ophthalmologic symptoms, in 5 patients (10%). All patients but 1 were given a positive diagnosis on histopathologic criteria: jejunal biopsy for 46 patients (90%), lymph node biopsy for 3 patients (6%), brain biopsy for 1 patient (2%), postmortem jejunal and cerebral biopsy for 1 patient (2%). With treatment, the disease evolved favorably in 47 patients (90%), while 5 patients (10%) had unfavorable outcomes (2 deaths from neurologic involvement, 1 patient with chronic dementia, and 2 patients with digestive symptoms insensitive to antimicrobial therapy). Of the 41 patients initially treated successfully and whose treatment has been completed, clinical evolution after discontinuation of treatment was favorable in 34 cases (83%). Clinical relapses occurred in 7 patients. No relapse was observed after treatment by trimethoprim-sulfamethoxazole, alone or following a combination of penicillin and streptomycin, or after the combination of penicillin and streptomycin, whatever the oral follow-up treatment prescribed. The evolution of patients showing a relapse was favorable in all cases after reintroduction of antibiotic therapy. These results are discussed in the light of previously published series and case reports of Whipple disease. The diagnosis of the disease remains difficult at an early phase or when digestive symptoms are absent. It is noteworthy that proximal enteroscopy is sometimes misleading, considered normal on macroscopic examination and nonspecific on pathologic grounds. A normal erythrocyte sedimentation rate represents another pitfall. Histopathology is the key for positive and differential diagnosis, and may require multiple and repeated biopsies. Findings from molecular biology confirm the central role of an uncultured Gram-positive bacillus which was named in 1992 Tropheryma whippelii. A recent report suggests that polymerase chain reaction (PCR) analysis of peripheral blood might allow the diagnosis of Whipple disease in some cases. However, immunologic or cellular parameters such as macrophagic function may play an important, although not clearly elucidated, role in the pathogeny of the disease. Trimethoprim-sulfamethoxazole should be considered the antimicrobial agent of choice in the treatment of Whipple disease, minimizing the risk of cerebral involvement and relapses.

Bacterial persistence and expression of disease

A considerable body of experimental and clinical evidence supports the concept that difficult-to-culture and dormant bacteria are involved in latency of infection and that these persistent bacteria may be pathogenic. This review includes details on the diverse forms and functions of individual bacteria and attempts to make this information relevant to the care of patients. A series of experimental studies involving host-bacterium interactions illustrates the probability that most bacteria exposed to a deleterious host environment can assume a form quite different from that of a free-living bacterium. A hypothesis is offered for a kind of reproductive cycle of morphologically aberrant bacteria as a means to relate their diverse tissue forms to each other. Data on the basic biology of persistent bacteria are correlated with expression of disease and particularly the mechanisms of both latency and chronicity that typify certain infections. For example, in certain streptococcal and nocardial infections, it has been clearly established that wall-defective forms can be induced in a suitable host. These organisms can survive and persist in a latent state within the host, and they can cause pathologic responses compatible with disease. A series of cases illustrating idiopathic conditions in which cryptic bacteria have been implicated in the expression of disease is presented. These conditions include nephritis, rheumatic fever, aphthous stomatitis, idiopathic hematuria, Crohn's disease, and mycobacterial infections. By utilizing PCR, previously nonculturable bacilli have been identified in patients with Whipple's disease and bacillary angiomatosis. Koch's postulates may have to be redefined in terms of molecular data when dormant and nonculturable bacteria are implicated as causative agents of mysterious diseases.

Possible mechanisms of chronic leprosy-related arthritis

Microbial agents induce arthritis through mechanisms such as direct infiltration of tissue and by inducing autoimmune phenomena. The mechanisms involved in this last type of arthritis have been investigated. In experimental models of adjuvant and reactive arthritis, the involvement of T cells in some cases mycobacteria in the development of arthritis have been confirmed. Cross-reactivity between the 65 kD mycobacterial protein and cartilage proteoglycans has been postulated as a possible mechanism. In this study, chronic peripheral arthritis was observed in patients with Hansen's disease, in patients with resolved Hansen's and in those with paucibacillary forms. This arthritis was not related to reactional states (erythema nodosum leprosum and reversal reaction), in contrast to several reports in the literature. The mechanisms by which microbes could induce chronic arthritis are discussed herein.

Analysis of culture filtrate and cell wall-associated antigens of Mycobacterium paratuberculosis with monoclonal antibodies

Proteins secreted by Mycobacterium species have been suggested as major immune targets in the early phase of infection. In this study, we sought to identify specific antigens in culture filtrates and in soluble cell extracts of Mycobacterium paratuberculosis. The release of antigens into the culture medium during growth of the bacilli and the distribution of specific epitopes within the Mycobacterium species were investigated by immunoblot analysis with monoclonal antibodies (MAbs) raised against M. paratuberculosis antigens. MAb B6A interacted with a cellular antigen with an apparent molecular mass of 34.5 kDa in lysates of M. paratuberculosis. MAb B6A did not interact with lysates from any other mycobacterial species, suggesting recognition of an M. paratuberculosis species-specific epitope. MAb FL1-A1 reacted with an antigen of 44.3 kDa in M. paratuberculosis and a 9-kDa antigen in Mycobacterium kansasii. MAb PII-B1 reacted with concanavalin A (ConA)-binding cellular and filtrate molecules of M. paratuberculosis and with lysates of Mycobacterium kansasii and Mycobacterium avium 18. The affinity-purified glycosylated antigens migrated as a diffuse band of between 35 and 45.6 kDa and reacted strongly with ovine and bovine paratuberculosis serum and polyclonal serum against M. tuberculosis lipoarabinomannan antigens. These glycoconjugates were the earliest antigens detected in culture filtrates of M. paratuberculosis. Deglycosylation of the ConA-binding molecules with alpha-mannosidase enzyme abolished the reaction with MAb PII-B1 and with bovine but not ovine paratuberculosis serum, suggesting selective immunogenicity in the different animal species.

Takayasu's arteritis: role of Mycobacterium tuberculosis and its 65 kDa heat shock protein

BACKGROUND

Mycobacterium tuberculosis has been implicated in the pathogenesis of Takayasu's arteritis (TA). Recently, its 65 kDa heat shock protein (HSP) has been implicated in the pathogenesis of other autoimmune diseases. We thus decided to study humoral immune response to Mycobacterium tuberculosis antigens in patients with TA.

AIM

To study humoral immune response to Mycobacterium tuberculosis and its 65 kDa HSP, a putative autoantigen, in patients with TA.

METHODS

Antibodies to sonicated Mycobacterium tuberculosis extract (MBA) and its recombinant 54 kDa protein were measured using ELISA in 36 patients with TA and 35 healthy controls. Levels exceeding mean +2 S.D. of the controls were taken as positive responses.

RESULTS

Abnormally elevated levels of IgG, IgM and IgA antibodies against MBA were present in 6, 20 and 7 patients respectively whereas those against r65 kDa protein were present in 6, 7 and 33 patients, respectively. Though the levels of IgG antibodies were also elevated, those of IgM and IgA antibodies were elevated to a greater extent.

CONCLUSIONS

Patients with TA have heightened immune response to Mycobacterium tuberculosis antigens, in particular to its 65 kDa HSP, suggesting that this organism may have a role in the immunopathogenesis of this disease.

Agalactosyl IgG and materno-fetal transmission of autoimmune neonatal lupus

Neither the incidence nor the severity of neonatal autoimmune disease correlates with maternal or neonatal autoantibody titres. However, there is now evidence that the agalactosyl [Gal(0)] fractions of autoantibodies are the most pathogenic. We found that systemic lupus erythematosus (SLE) mothers whose infants developed congenital heart block (CHB) had higher %Gal(0) at the end of pregnancy than did mothers of unaffected infants (P < 0.05) or control mothers (P < 0.01). Similarly, affected infants had higher %Gal(0) than control infants (P < 0.01). Then we studied the Gal(0) content of the anti-Ro and we found that it was higher in affected neonates than in unaffected neonates (P < 0.05), though there was no difference between the corresponding groups of mothers by this criterion. We propose that agalactosyl IgG may have a regulatory or effector role and that the risk of neonates developing maternal autoantibody-mediated disorders may be related to the quantity of agalacotsyl autoantibody present at birth, rather than to its absolute titre.

Sacroiliitis in sarcoidosis: case reports and review of the literature

We report the occurrence of bilateral sacroiliitis in 2 cases of biopsy-proven sarcoidosis. Tuberculosis was excluded by tuberculin testing and bronchoalveolar lavage in both cases. In the literature, 5 cases of sacroiliitis and sarcoidosis have thus far been described, but in all tuberculosis was not excluded (tuberculin testing was not performed or revealed a positive test result). In 1 of these cases tuberculosis was even simultaneously suspected to be present. In all previous cases, antituberculous or other antimicrobial agents were given. Previously reported cases of sacroiliitis in sarcoidosis are briefly reviewed, and possible relations between seronegative spondylarthropathies, slow bacterial infections, sarcoidosis and other granulomatous diseases are discussed.

Nucleotide sequence analysis and seroreactivities of the 65K heat shock protein from Mycobacterium paratuberculosis

Mycobacterium paratuberculosis is the causative agent of Johne's disease, a chronic enteritis in ruminants. It has also been implicated as a possible cause of Crohn's disease, an inflammatory bowel disease of unknown etiology. The mycobacterial 65K heat shock proteins (hsp-65K) are among the most extensively studied mycobacterial proteins, and their immunogenic characteristics have been suggested to be the basis for autoimmunization in chronic inflammatory diseases. In this context, we isolated and sequenced the hsp-65K-encoding gene from our M. paratuberculosis PTB65K genomic library. A high degree of identity was found between the open reading frame (ORF) of the PTB65K gene and those of Mycobacterium tuberculosis (89.6%), Mycobacterium leprae (86.6%), and Mycobacterium avium 18 (98.8%). The amino acid sequence alignment of the PTB65K protein with the hsp-65K homologs revealed that the M. tuberculosis and M. leprae proteins each differed by 36 amino acid residues and that the M. avium 18 protein differed by 8 residues. We also investigated the humoral immune responses of animals with Johne's disease and patients with Crohn's disease against the recombinant PTB65K antigen. Immunoblot analysis showed that sera from only 3 of 10 clinically ill and 5 of 25 subclinically ill cows reacted with PTB65K. In addition, sera from two of two sheep and one of two goats with clinical symptoms of Johne's disease also reacted with PTB65K; 0 samples from 10 normal cows reacted. In humans, sera from 7 of 13 patients with Crohn's disease, 3 of 4 with tuberculosis, 5 of 6 with leprosy, 5 of 12 with non-inflammatory bowel disease, and 0 of 4 with ulcerative colitis reacted with the recombinant PTB65K antigen. These results indicate that this PTB65K heat shock protein is uninformative when used for serodiagnosis of Johne's disease in animals. However, in humans, the high intensity of antibody reactions of some sera from Crohn's disease patients compared with that from noninflammatory bowel disease patients showed a positive correlation with mycobacterial diseases.

Proinflammatory cytokine production and cartilage damage due to rheumatoid synovial T helper-1 activation is inhibited by interleukin-4

OBJECTIVES

To investigate the role of T helper-1 cell (Th1) activation in the induction of proinflammatory cytokine production and cartilage damage by rheumatoid arthritis (RA) synovial fluid mononuclear cells (SFMNC) and the subsequent possible beneficial role of the T helper-2 cell (Th2) cytokine interleukin-4 (IL-4) in the inhibition of this process.

METHODS

SFMNC were stimulated with bacterial antigen (hsp60) to activate Th1 cells. Th1 and Th2 specific cytokine profiles (interferon gamma (IFN gamma) and IL-4) and proinflammatory cytokines interleukin-1 (IL-1) and tumour necrosis factor alpha (TNF alpha) in the conditioned media were analysed. In addition, the conditioned media were tested for their ability to induce cartilage damage. The same parameters were measured in the presence of IL-4.

RESULTS

Stimulation of SFMNC with bacterial antigen resulted in an increase in IFN gamma, IL-1, and TNF alpha production which was accompanied by the induction of cartilage damage. Th1 activation could be inhibited by IL-4 as shown by a reduction of IFN gamma. This was accompanied by a decrease in IL-1 and TNF alpha production and inhibition of cartilage damage.

CONCLUSIONS

Th1 activation is a possible mechanism by which inflammation in RA joints is enhanced. The Th2 cytokine IL-4 inhibits this Th1 activity and may diminish inflammation and induction of cartilage damage in RA joints.

Glycosylation of IgG during potentially arthritogenic lentiviral infections

Agalactosyl IgG [Gal(0)] was first discovered in patients with rheumatoid arthritis (RA). However, the proportion of this glycoform is also raised in tuberculosis and leprosy. This has helped reinforce the suggestion that RA may be triggered by a mycobacterium-like slow bacterial infection. On the other hand, arthritis can occur in mycobacterial diseases, so raised Gal(0) could be associated with a tendency to arthritis, rather than with a particular type of infection. Therefore, we wished to find out whether the percentage of Gal(0) [%Gal(0)] is increased in sheep and goats following infection with maedi visna virus or caprine arthritis encephalitis virus (CAEV), both of which can lead to inflammatory synovitis. We found that the normal level of Gal(0) in these species is much lower than in humans. Goats infected with CAEV or Mycobacterium paratuberculosis (used as a control mycobacterial infection) had a significant increase in %Gal(0), though it was still below the level seen in normal humans. Studies by Western blot confirmed the presence of terminal N-acetylglucosamine on heavy chains, and percentages of Gal(0) comparable to those seen in human RA could be generated by exposing goat IgG to streptococcal beta-galactosidase. The rise in %Gal(0) was greatest in members of infected herds that were just starting to manifest arthritis, and tended to be lower in those in which severe carpitis had developed at the time of bleeding, implying the possibility that raise %Gal(0) may be an early or predisposing event for the development of arthritis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, endocrines and conserved epitopes; factors to consider when designing "therapeutic vaccines"

Research into immunity to complex intracellular parasites has recently placed emphasis on the identification of peptide sequences recognised by T-cells, often with the dual objectives of finding species-specific protective epitopes, and of understanding selection of Th1 versus Th2 response patterns. In this review it is suggested that although such work is interesting, it will not achieve these objectives, which must, however, be addressed before we can design the new generation of therapeutic vaccines which may eventually replace antimicrobial drugs in the treatment of infection. First, we suggest that the balance of Th1 to Th2 lymphocyte activity is not determined by epitopes, but rather by adjuvant effects of microbial components which we have barely begun to define, and local endocrine effects mediated by conversion of prohormones into active metabolites by enzymes in lymph node macrophages. Cytokines play a role as mediators within these pathways. In chronic disease states there is a tendency for T-cell function to shift towards Th2. We describe immunopathological consequences of this tendency, including a putative role for agalactosyl IgG, and review evidence for involvement of changes in the endocrine system, brought about not only by the cytokine-hypothalamus-pituitary-adrenal axis, but also by direct actions on peripheral endocrine organs of excess levels of cytokines such as TNF alpha, TGF beta and IL-6. We summarise evidence that the epitopes that are targets for protective cell-mediated responses to complex organisms are usually not species specific. In tuberculosis, cellular responses to species-specific components appear to be associated with immunopathology rather than protection. Finally, we discuss how application of these principles has led to remarkable results in the immunotherapy of tuberculosis, including multidrug-resistant disease.

Central tolerance of T cells

The immune system is constructed to tolerate self antigens but give vigorous responses to foreign antigens. How this state of self/nonself discrimination is maintained is controversial. In the case of T cells, many self antigens are transported to the thymus via the bloodstream and induce tolerance (clonal deletion) of self-reactive thymocytes in situ. Although such central tolerance in the thymus is well documented, it is often argued that full induction of tolerance requires peripheral mechanisms such as suppression or induction of anergy. This article proposes that steady-state tolerance of T cells to self components is due solely to central tolerance to circulating self antigens combined with sequestration of tissue-specific antigens. Backup mechanisms for tolerance do exist but such immunoregulation only operates when self tolerance breaks. This scheme allows the immune system to give unrestricted primary responses to foreign antigens.

Differential expression of heat shock protein 70 (HSP70) and heat shock cognate protein 70 (HSC70) in human epidermis

Autoimmunity and microbial agents have been suggested as playing a pathogenetic role in psoriasis. Since immune responses to microbial infections are often directed towards heat shock proteins (HSP), we investigated the expression of three HSP families in normal and inflamed human skin. Specimens from ten patients with psoriasis and three patients with positive patch tests for nickel and from five healthy volunteers were analysed by means of immunohistochemistry. The patterns observed were qualitatively similar in these conditions showing only minor quantitative differences. Psoriatic epidermis exhibited the highest level of expression. HSP27, HSP70 and heat shock cognate protein 70 (HSC70) were readily detectable. HSP27 was homogeneously distributed throughout the epidermis, whereas HSP70 was restricted to the basal layer and HSC70 primarily to the suprabasal layers. Other HSPs were detected to a lesser degree and showed a more irregular pattern. Thus, the qualitative expression pattern of HSPs seems to be constant between different skin conditions, but the expression of constitutive and inducible HSP70 depends on the differentiation state of keratinocytes.