Significance of immunoglobulin A titres in the diagnosis of urogenital chlamydial infections

Enzyme immunoassay with enhanced specificity for detection of antibodies to Chlamydia trachomatis

Two different methods for preventing the binding of cross-reacting antibodies to the genus-reactive chlamydial lipopolysaccharide (LPS) were used to improve the specificity of an enzyme immunoassay for the determination of antibodies to Chlamydia trachomatis. Coated elementary bodies were treated with either sodium periodate, to oxidize the antigenic sites of the LPS, or Triton X-100, to extract the LPS. By using these new enzyme immunoassays, the standard enzyme immunoassay, and the whole inclusion fluorescence (WIF) assay, antibodies to C. trachomatis were determined in sera from different groups of patients and controls. Paired serum samples from patients with culture-proven urogenital C. trachomatis infections showed similar responses in all three assays. Paired serum samples from patients with Chlamydia psittaci infections showed similar responses in the WIF assay and the standard enzyme immunoassay, whereas significantly reduced titers were obtained in the enzyme immunoassays with treated antigen, especially in the convalescent-phase serum samples. Serum samples from patients with symptoms suggestive of infection with C. trachomatis, pregnant women, and blood donors were evaluated by all three types of assays. Eighty percent of the significant reductions in immunoglobulin G (IgG), IgA, and IgM titers were observed in sera with WIF assay titers in the lower classes (IgG, 1: < or = 256; IgA, 1: < or = 32; IgM, 1: < or = 16). From these results we conclude that oxidation of the antigen by sodium periodate is a simple and effective method of producing an enzyme immunoassay with enhanced specificity that could be useful for diagnostic purposes and seroepidemiological studies.

Male infertility: current concepts

The purpose of the article is to review the current concepts regarding the etiology and treatment of male-factor infertility. The following general conclusions can be drawn: (a) conventional parameters for sperm quality and male fertility are inadequate and any assessment should involve several different tests of sperm cell function to increase the fertility prognosis; (b) the causes of disturbed sperm quality are still poorly understood; (c) the role of the varicocele is still controversial but some of the discrepancies reported in the literature may be explained by the negative influence of other factors such as smoking, epididymal pathology or glandular infections operating either in conjunction or independent of the varicocele; (d) the role of chronic inflammatory processes in the reproductive organs, in particular the involvement of chronic chlamydial infections, has been underestimated, largely because it is often asymptomatic and difficult to demonstrate objectively; (e) partial androgen insensitivity may account for a significant number of cases of severe oligozoospermia; (f) no major advances have been made in the medical treatment of poor sperm quality; (g) assisted fertilization techniques such as IVF and GIFT offer encouraging possibilities for the treatment of male-factor infertility; and (h) recent advances in microsurgical techniques are increasing the treatment possibilities for certain forms of obstructive azoospermia and severe oligozoospermia.

Spread of subclinical Chlamydia pneumoniae infection in a closed community

Chlamydia pneumoniae infections may spread subclinically. The present investigation took place in a military setting. Sera drawn when the conscripts had entered their military service 2 months previously had been kept frozen and were available. In a camp with 500 people, 35 (7%) developed clinical symptoms of pneumonia. The infection was serologically verified with C. pneumoniae-specific micro-immunofluorescence technique. Of 40 healthy controls, 21 turned out to fulfil the serological criteria of infection, thus, representing subclinical cases. These 21 cases, when extrapolated to the whole camp, equalled a rate of 49% which, added to the 7% of pneumonic cases, gave a total infection rate of 56%. Pre-existing IgG antibodies were demonstrated in 10% of the pneumonic cases, 48% of the subclinical cases, and 89% of the non-infected, healthy controls. Without the access to pre-epidemic sera permitting us to establish 4-fold titre rises, the spread of subclinical C. pneumoniae infection would have been noted at 5%, and not 49% as here demonstrated.