HLA-B27 and bacteria

Ocular complications of cat scratch disease

Cat scratch disease (CSD) in humans is caused by infection with Bartonella henselae or other Bartonella spp. The name of the disease reflects the fact that patients frequently have a history of contact (often involving bites or scratches) with infected cats. Patients with CSD typically develop lesions at the site where the skin is broken together with regional lymphadenopathy but may go on to exhibit systemic symptoms and with deep-seated infections at a range of sites including the eye. Patients with CSD may present with a range of inflammatory eye conditions, including Parinaud's oculoglandular syndrome, neuroretinitis, multifocal retinitis, uveitis and retinal artery occlusion. Bartonella spp. are fastidious bacteria that are difficult to culture from clinical specimens so microbiological diagnosis is frequently made on the basis of positive serology for anti-Bartonella antibodies or detection of bacterial DNA by PCR. Due to the lack of clinical trials, the evidence base for optimal management of patients with CSD-associated eye infections (including the role of antibiotics) is weak, being derived from single reports or small, uncontrolled case series.

Prevalence and levels of serum antibodies to gram negative microorganisms in Turkish patients with HLA-B27 positive acute anterior uveitis and controls

PURPOSE

Acute anterior uveitis (AAU), seronegative spondyloarthropathies such as ankylosing spondylitis and reactive arthritis form the group of "HLA-B27-associated diseases." The aim of this study was to analyze the prevalence and levels of serum antibodies against gram negative bacteria in Turkish patients with AAU.

METHODS

Twenty-five patients each with previously diagnosed HLA-B27 positive and negative AAU and 25 age-and sex-matched healthy control subjects were included in the study. Serum IgM, IgG and IgA antibodies to Yersiniae enterocolitica, Campylobacter jejuni and Chlamydia trachomatis were measured using enzyme linked immunosorbent assay (ELISA). Categorical data were analyzed by chi-square test. Serum levels were analyzed using the Kruskal-Wallis test.

RESULTS

The prevalence of serum IgM, IgG and IgA antibodies did not differ significantly between the HLA-B27 positive AAU, HLA-B27 negative AAU and control groups with the exception of serum IgA antibodies against Yersiniae enterocolitica. IgA antibody against Yersiniae enterocolitica was found to be more frequently positive in the control group. Comparison of serum IgM, IgG and IgA antibody levels did not significantly differ between three groups.

CONCLUSIONS

Serum antibody positivity against Yersiniae enterocolitica, Campylobacter jejuni and Chlamydia trachomatis is not frequent in the HLA-B27 positive and negative AAU patients. Serum levels of IgM, IgG, and IgA antibodies also did not show significant difference between three groups. No association between these microorganisms and the etiology of AAU was evident.

Identical T-cell expansions in the colon mucosa and the synovium of a patient with enterogenic spondyloarthropathy

Intestinal T lymphocytes activated by antigen are suspected to play a key role in enterogenic spondyloarthropathies (SpA). Therefore, we aimed to identify and functionally characterize T-cell clones that are coexpanded in the intestinal mucosa and the synovium. Colon, peripheral blood, and synovium of a patient with enterogenic SpA were screened for clonal T-cell expansions by TCRB-CDR3 length analysis and sequencing. T-cell clones expanded in vivo were isolated from archived synovial cells by targeted T-cell cloning and characterized for phenotype, cytokine production, and antigen specificity. The synovial TCRBV18(+) T-cell repertoire of the patient was dominated by 2 CD8(+) T-cell clones using related CDR3. Both clones were expanded throughout the colon and were present in the peripheral blood. Upon in vitro stimulation with PDB/ionomycin, they showed predominantly interferon gamma and interleukin (IL)-4 but also tumor necrosis factor alpha and IL-10 production and did not specifically lyse autologous T-cell blasts, B-cell lines, or other autologous or allogeneic target or CD1d-transfected cells. These findings strongly suggest that T lymphocytes activated by antigen in the intestinal mucosa contribute to joint inflammation in enterogenic SpA by recognition of antigens specific for the inflamed synovium.

Bartonella henselae associated uveitis and HLA-B27

AIM

To investigate the frequency of HLA-B27 in patients with presumed Bartonella henselae associated uveitis and to describe the clinical characteristics of HLA-B27 positive patients with uveitis and presumed ocular bartonellosis (POB).

METHODS

The diagnosis of POB was considered in 19 patients with unexplained uveitis (except for the HLA-B27 association) and high positive IgG (titre >/=1:900) and/or IgM (titre >/=1:250) antibodies against B henselae. In addition to B henselae serology and HLA-B27 typing, all patients underwent an extensive standard diagnostic screening procedure for uveitis and in all cases the results were within the normal limits. The control group consisted of 25 consecutive patients with panuveitis and negative B henselae serology.

RESULTS

HLA-B27 was positive in six of the 19 patients (32%) with POB in contrast to the 4% frequency of HLA-B27 in the control group (p=0.03) and 8% prevalence of HLA-B27 in the Dutch population (p=0.003). At the time of positive Bartonella serological testing five of six HLA-B27 positive patients with POB had severe posterior segment involvement with papillitis, macular oedema, and vitreitis. The duration of intraocular inflammatory activity was more than 6 months in five HLA-B27 positive patients. Although four of the six HLA-B27 positive patients had previous recurrent attacks of acute anterior uveitis, the clinical presentation at the time of positive Bartonella serology differed, as illustrated by the involvement of the posterior segment and chronic course of the ocular disease.

CONCLUSIONS

The frequency of HLA-B27 in patients with uveitis and serological characteristics of acute infection with B henselae is higher than in the general Dutch population. The findings of this study also suggest a relation between infection with Bartonella species and HLA-B27.

HLA-B27 transgenic mice are susceptible to collagen-induced arthritis: type II collagen as a potential target in human disease

HLA-B27 is highly linked with a group of human diseases called spondyloarthropathies (SpA). Many of these disorders begin after an infection with an enterobacteria. The symptoms seen in patients with spondyloarthropathies are inflammatory pain in the spine and asymmetrical arthritis of lower limbs. Additional symptoms related to SpA include inflammation in the eyes, bowel, and skin. The autoantigen(s) in SpA are not known. Proteins such as collagen and proteoglycans have been thought to be potent autoantigens in arthritidis including B27-associated human diseases. Type II collagen is a common denominator among eyes and joints, affected tissues in B27-linked diseases. Moreover, a few reports indicated CII specific T cells and antibodies in patients with spondyloarthropathies. We and others have previously described development of spontaneous arthritis and nail disease in HLA-B27 transgenic animals. To determine whether CII may be a target antigen in the B27-linked diseases, B27 + m beta 2 m% (HLA-B27) transgenic mice lacking mouse beta 2m with and without human beta 2m) mice were immunized with type II collagen inside the barrier facility. Male HLA-B27 transgenic mice developed collagen-induced arthritis compared to transgene negative littermates or female counterparts. There was no difference in the incidence of arthritis in HLA-B27 transgenic mice with and without human beta 2m. Our data suggest that beta 2m free heavy chain of HLA-B27 may present soluble antigens such as type II collagen to trigger specific T cells contributing in the development of arthritis. Our data also suggest that CII may be a potential target antigen in the cartilage during the disease process.

Presentation of HLA class I-derived peptides: potential involvement in allorecognition and HLA-B27-associated arthritis

Some 25 years ago, when purified HLA class I allotypes were first being analyzed, of major concern was that the papain used for solubilization might produce a mess of proteolytic fragments that would prove impossible to separate and sequence. Those fears proved unfounded (Parham et al. 1975), and the homogeneity of the preparations was sufficient to allow crystallization and determination of the three-dimensional structure (Bjorkman et al. 1987). Ironically the least ordered region of the electron density map provoked the most interest because it gave a first view of the diverse peptides bound by an MHC molecule. With this image a second chapter of HLA class I biochemistry began, its charge to determine the structures of bound peptides and their influence on the immune system. The extraordinary polymorphism of HLA class I heavy chains now seems quite manageable compared to the vast complexity of the peptides, and our present ignorance as to which ones are important for health and disease. The comparative weakness of most HLA class I associations with disease has made HLA-B27 an especially favored target for investigation, and more is known of the structure and peptide-presenting function of HLA-B27 than for any other HLA-B allotype (López de Castro 1994). Much of this information relates to the native HLA-B27 molecule and has been collected in the belief that disease is a direct consequence of its antigen-presenting function. If one subscribes to the relevance of the transgenic rodent models, this position has almost become untenable. For rats and mice 'non-functional' forms of HLA-B27 are the agents of disease, raising the possibility that B27-associated arthritis is induced by HLA class II presentation of a B27-derived peptide, a variant of the mechanism advanced for the classical HLA class II-associated diseases: type 1 diabetes, multiple sclerosis and rheumatoid arthritis (Gregersen et al. 1987, Roudier et al. 1989, Cucca & Todd 1996, Hall & Bowness 1996). Such speculation invites the obvious question as to whether other diseases associated with HLA class I and chronic inflammation, HLA-C and psoriasis for example (Tiilikainen et al. 1980, Yanagisawa et al. 1995), result from class II presentation of class I peptides.