In clinical rheumatology, the diagnosis of Chlamydia reactive arthritis is difficult because an incomplete form of the disease can closely resemble an undifferentiated seronegative mono/oligoarthritis. We investigated whether measuring specific isotypes of anti-Chlamydia antibodies in serum can improve the diagnosis, by comparing such antibody concentrations in the serum of patients with well-defined disease, i.e. Chlamydia trachomatis sexually acquired reactive arthritis (CT-SARA), with other arthritides. Antibody levels were determined by enzyme-linked immunosorbent assay (ELISA). When considering two different isotypes and their combination, the best sensitivity (63%) was obtained for IgM and/or IgA results with a specificity of 81%. The patients with CT-SARA and SARA had the highest levels of antibodies of all isotypes tested. It is concluded that, in our experimental conditions, only very high values of specific isotypes could indicate a diagnosis of Chlamydia reactive arthritis.

SUMMARYSince the presence of Chlamydia has been shown in synovial fluid (SF) from some patients with Chlamydia reactive arthritis, we investigated whether anti-Chlamydia antibodies present in the joint are derived from the circulation or are locally produced. We compared titres of IgG, IgM and IgA antibodies against Chlamydia, and against a control antigen (tetanus toxoid), by an enzyme-linked immunosorbent assay (ELISA), in paired samples of serum and SF from Chlamydia trachomatis sexually acquired reactive arthritis (CT-SARA) patients and from patients with other forms of arthritis. The ratio of serum/SF IgA anU-Chlamydia antibodies was significantly decreased in CT-SARA patients. It is concluded that, in our experimental conditions, we found evidence for intra-articular production of IgA anti-Chlamydia antibodies.

mice to evaluate the host immune responses towards the fusion protein.Results: A functionally active HA1 fusion protein consisting of the HA1 and AcmA protein, linked together by a scFv linker was successfully expressed and purified. The fusion protein has a molecular mass of approximately 50 kDa. Examination of the conditions for binding of the fusion protein to L. lactis showed that a mixture of 20 g of fusion protein with 10 8 -10 9 L. lactis cells, GM17 as buffer for binding and a binding incubation period of 2 hours are most suitable.Conclusion: L. lactis surface displaying HA1 fusion protein could potentially develop as an alternative oral vaccine for preventing influenza virus infection in humans.

An idiopathic, asymmetrical oligoarthritis affecting young adults is prevalent in the tropical regions of Africa, Asia and Melanesia. A serological study was undertaken in 23 consecutive patients with polyarthritis. Each patient was assigned two paired control subjects. A standardized history, physical examination and investigations were performed. Acute and convalescent sera were examined for evidence of recent infection. The presence of HLA‐B27 was determined. Twelve (52%) of the 23 patients had more than one of the clinical features of a reactive arthritis. No serological evidence was found of acute infection with viruses (arboviruses, enteroviruses, mumps, rubella, adenoviruses, Epstein–Barr virus and hepatitis B), Chlamydia, Mycoplasma, Yersinia or syphilis. HLA‐B27 was found in 14 (61%) of the 23 patients in contrast with in seven (17%) of the 41 control subjects (p <0.001). In two patients with HLA‐B27, diagnostic titres of antibodies to Campylobacter jejuni–Campylobacter coli indicated recent infection. The presence of HLA‐B27 antigen was significantly (p < 0.05) asssociated with the presence of the clinical features of reactive arthritis. This study suggests that ‘tropical arthritis’ commonly is a reactive arthritis that is associated with the presence of HLA‐B27.

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