[Pathogenesis of ankylosing spondylitis-mechanisms of disease manifestation and chronicity]

Despite intensive research during the last three decades, it is still not clear which precise mechanisms determine the interactions between host factors (HLA-B27 and other genes, cytokines, T lymphocytes) and microbial factors leading to the manifestation and chronicity of ankylosing spondylitis (AS). Rheumatologists and histopathologists have focused their interest on decoding the immune-mediated inflammatory processes and on studying new bone formation and ankylosis. Concerning the genetic basis of AS, there is considerable effort in large genome-wide and candidate gene analyses to discover new genes that are associated with AS. Moreover, such genetic studies could identify genomic regions that determine clinical manifestations and the course of disease.

HLA-B27-restricted T cells from patients with ankylosing spondylitis recognize peptides from B*2705 that are similar to bacteria-derived peptides

Ankylosing spondylitis (AS) is an inflammatory systemic disease affecting the spine, sacroiliacal and peripheral joints. Although the aetiology of AS remains unknown, the strong association with the HLA-B27 allele might reflect directly a detrimental effect of the HLA-B27 molecule itself, resulting from its potential capability to present 'arthritogenic' peptides to CD8+ T cells. Because some forms of SpA are triggered by enterobacterial infection, such arthritogenic peptides might originate from autologous and/or bacterial proteins triggering cross-reactive CD8+ T cell clones. Intriguingly, two peptides from the second extracellular domain of HLA-B*2705 share sequence homologies with several enterobacterial antigens, exhibit the HLA-B27-binding-motif, and are presented by HLA-B*2705 itself. The objective of this study was to examine the clonal T cell reactivity against these peptides in patients with AS. To this end, we screened peripheral blood lymphocytes (PBL) of 26 patients with AS and 24 healthy donors for TNF-alpha-producing cells using ELISPOT assays. PBL and synovial fluid-derived lymphocytes (SFL) of peptide-responsive patients were then stimulated and cultured with the relevant peptide and control peptides in vitro. Antigen-specific T cell lines (TCL) were identified by standard chromium release assays. Clonal analysis was performed subsequently applying TCRB-CDR3 spectratyping. Among eight peptides tested, only the HLA-B27 168-176 peptide LRRYLENGK was recognized by PBL from B27+ AS patients but not from B27+ healthy controls (P=0.001). LRRYLENGK-specific T cell clones used preferentially the TCRBV5S1 and the BV14 segment. These results suggest that an HLA-B27-derived peptide with homology to bacterial peptides may play a role in AS.

Conserved TCR beta chain usage in reactive arthritis; evidence for selection by a putative HLA-B27-associated autoantigen

Previous work suggested that expanded CD8+ T-cell clones in the synovial fluid (SF) of HLA-B27+ patients with reactive arthritis (ReA) preferentially use the T-cell receptor variable region (TCRBV) 1, similar CDR3 sequences, and joining region (BJ) 2S3. To determine the range of conservation and disease-specificity of CDR3-sequences, we analyzed the TCRBV1-J2S3 repertoire from 33 healthy HLA-B27+ individuals, patients with various types of spondyloarthropathies (SpA), and with rheumatoid arthritis (RA) by CDR3-spectratyping. After collection and database submission of all available TCRB-CDR3 from HLA-B27-restricted or SpA-derived T cells, we systematically screened the entire human sequence database for sequences similar to the B27/SpA-related CDR3. Spectratyping revealed expanded T cell clones using conserved TCRBV1J2S3 in the SF from 5/6 of the patients with acute ReA but not among the controls. In database searches, 50 HLA-B27 or SpA-related CDR3-sequences generated similar clusters of matched sequences, and matched reciprocally. Identical or closely related sequences were identified in 15 different individuals and a canonical ReA-associated TCRB was defined [BV1-CASSVG(V/I/L)(Y/F)STDTQYF-J2S3]. All but one patient-derived conserved sequences originated from acute stage ReA-patients, and were not present among approximately 3800 other human TCRB sequences in the database. Five of the conserved sequences originated from T cell clones that recognized uninfected cells in an HLA-B27-restricted fashion, implying a role of HLA-B27-restricted CD8+ T cells specific for a ubiquitous self- or cross-reactive microbial determinant in the early phase of ReA. Related sequences were independently identified in four different laboratories. The consensus TCRB motif could be a helpful diagnostic marker in HLA-B27-associated 'undifferentiated arthritis'.

Influence of the estrous cycle on the presence and distribution of immune cells in the rat reproductive tract

PROBLEM

Previous studies have shown that the uterus and vagina contain cells that can present antigen to ovalbumin-specific T-cells. The objective of the present study was to systematically characterize the immune cells [major histocompatibility complex (MHC) class-II+, macrophages, granulocytes, dendritic cells, and CD8+ cells] present in the uterus and vagina of the rat and to examine their distribution at various stages of the estrous cycle.

METHOD OF STUDY

Uterine and vaginal tissues from female rats were selected at various stages of the estrous cycle and were examined by immunohistochemical analysis. MHC class-II (Ia)-positive cells were detected using the OX-6 monoclonal antibody; macrophages, granulocytes, and dendritic cells were detected by OX-41 monoclonal antibody and CD8-positive T-cells were identified by OX-8 monoclonal antibody.

RESULTS

Immunohistochemical analysis showed cycle-dependent changes in the immune cell populations in the uterus and vagina. Ia+ cells, macrophages, granulocytes, and dendritic cells were present in large numbers in the stroma of the endometrium and around the glandular epithelium in the uterus at estrus, the stage of the reproductive cycle when estradiol levels are known to be high, relative to those seen at diestrus, when estrogen levels are low and progesterone is the predominant hormone. CD8+ cells were observed in the uterus interspersed between glandular epithelial cells at estrus. Immune cells were more numerous in the vagina, relative to the uterus. OX-6 and OX-41-positive cells were present in greater numbers in the subepithelial layers of the vagina at diestrus, in contrast to estrus.

CONCLUSION

This study demonstrates that a variety of immune cells are present in the reproductive tract and that their number and distribution vary in a tissue-specific manner with the stage of the estrous cycle.

Polymeric immunoglobulin A receptor in the rodent female reproductive tract: influence of estradiol in the vagina and differential expression of messenger ribonucleic acid during estrous cycle

Previously we have shown that estradiol and progesterone regulate the levels of secretory component, the external domain of polymeric immunoglobin A (IgA) receptor responsible for transporting IgA from tissues into secretions, at both the mRNA and protein levels in the rodent uterus. In the present study, experiments were designed to determine whether polymeric immunoglobulin receptor (pIgR) is synthesized locally in the vagina and whether it is under the control of estradiol and progesterone. Polymeric IgR message corresponding in size to that previously reported in the liver and uterus was detected by Northern blot analysis of total RNA from the vagina. Levels of pIgR mRNA and pIgR in the vagina were found to vary with the stage of the cycle. Polymeric IgR mRNA levels were elevated at diestrus, reduced at estrus, and undetectable at proestrus. Immunohistochemical analysis of pIgR in the vagina indicated that the expression of protein correlated with the mRNA levels. When ovariectomized rats were treated with estradiol, progesterone, or a combination of the two for 3 days, pIgR mRNA levels were significantly reduced in estradiol-treated animals relative to saline-treated controls. No significant changes were observed in the pIgR mRNA levels of animals treated with progesterone alone or with a combination of estradiol and progesterone. Polymeric IgR expression analyzed by immunohistochemical staining correlated well with variations in mRNA levels seen following hormone treatment. In situ hybridization localized pIgR in uterine and vaginal epithelial cells. In the uterus, pIgR message was abundant in luminal and glandular epithelial cells at estrus and low at diestrus. In contrast, expression of pIgR mRNA was pronounced in vaginal epithelial cells at diestrus, while very little message could be localized in the epithelium at estrus. These findings demonstrate that pIgR is synthesized locally in the uterus and vagina and is under tissue-specific hormone regulation.

[The lactate-pyruvate quotient in the framework of modern thyroid diagnosis]

In literature a big number of central and peripheral parameters for the diagnosis and control of therapeutical measures in diseases of human thyroid gland is described. That means, that none of the methods used has a sufficient weight. The enzymatic estimation of pyruvate and lactate reflect the peripheral effect of the hormones of thyroid gland. The pyruvate and lactate levels differ in the several groups of patients with euthyreosis, hypothyreosis, hyperthyreosis and euthyreotic goitre. Between these all groups the lactate/pyruvate ratio showed highly significant differences. The comparison of the lactate/pyruvate ratio and the T3-values showed highly significant correlation between both parameters. This good conformity is underlined by the behaviour of the parameters in courses of therapy, with additional support by farther functional tests--ETR-, T3- and T4-test. Our results confirmed the suggestion, also in agreement with literature, that the lactate/pyruvate ratio represent a possible enrichment in the laboratory programme for diagnosis and control of therapy in patients with thyroid diseases.