Simplified serological test for antibodies to Chlamydia trachomatis

Diagnosis of some genital-tract infections: part 1. An historical perspective

Making a prompt and accurate diagnosis of genital tract infections is the key to instituting appropriate treatment and the linchpin of sexually transmitted infection control. We present a brief history, not covering syphilis, of diagnostic events for each of six bacteria and one protozoan from the time of discovery up to the molecular revolution. The latter is touched upon but its impact will form the substance of a further presentation. Here, hindsight is helpful in understanding the way in which progress was made over 135 years, often when microbiology, not even seen as a distinct discipline, had a difficult time in providing what was required in terms of dependable diagnostic techniques. Gram-staining, growth on artificial media, growth in cultured cells, enzyme immunoassays, metabolic and immunofluorescence tests have all had their place and some still do despite the avalanche of the molecular era. Serology to determine the existence of organism-specific antibodies has been important in managing syphilis, but has only sometimes been helpful in supporting a diagnosis for other infections and has rarely been the primary deciding factor.

Urethral inflammation in male chimpanzees caused by ureaplasmas and Chlamydia trachomatis

Specimens from men with acute non-gonococcal urethritis were tested to determine their microbial content and then given intra-urethrally to male chimpanzees. Two animals received ureaplasmas only and one became infected. The second did so when given a different strain. Both developed a polymorphonuclear leukocyte (PMNL) response. Two chimpanzees received a mixture of ureaplasmas and Chlamydia trachomatis and there was a suggestion that the ureaplasmas delayed or suppressed the chlamydial response. The latter, that is urethral infection with a pronounced PMNL response, was most clearly seen in a chimpanzee given C. trachomatis only. No inflammation was detected in two chimpanzees acting as controls. Three of five chimpanzees given ureaplasmas genitally, and one that had them endogenously, had them transiently in the oropharynx about 2 weeks later. The occurrence of ureaplasmas in the conjunctiva of three chimpanzees inoculated at this site was also transient and without inflammation. The possibility that Mycoplasma genitalium might have been in the inocula and caused urethral inflammation was discounted largely because no animal had antibody to this mycoplasma.

Difficulties experienced in defining the microbial cause of pelvic inflammatory disease

Clinical assessment of women with pelvic pain was a poor indicator of disease seen at laparoscopy. Thus, of 109 women, 22 at laparoscopy had salpingitis, 19 had adhesions without salpingitis, 20 had endometriosis or ovarian pathology and 48 no observable abnormality. In all laparoscopic categories, Ureaplasma spp. and Mycoplasma hominis, but not Mycoplasma genitalium, were at least as common in the cervix/vagina as Chlamydia trachomatis and equally frequent in the endometrium. However, C. trachomatis had the greatest propensity for spread to the Fallopian tubes. Thus, of 28 women who had C. trachomatis organisms in the vagina/cervix, 13 had them in a Fallopian tube (ratio 2.2:1); the ratio was 6:1 for Neisseria gonorrhoeae, 8:1 for M. genitalium, 21:1 for M. hominis and 31:1 for Ureaplasma spp. M. hominis organisms in a large number were detected most often in women with salpingitis. The likelihood of spread of Ureaplasma urealyticum and U. parvum from the lower to the upper genital tract was about the same and they were detected only once each in a tube, which was not inflamed in either case. Multiple bacteria were often detected at a single site, making it difficult to establish the exact cause of disease. However N. gonorrhoeae was considered to be the sole cause of salpingitis in one woman and the primary or equal primary contributor in four others; C. trachomatis was involved in at least 11 women, mostly as the sole cause or as the primary contributor; M. genitalium was considered the cause in one woman and had possible involvement in three others; and M. hominis was a questionable sole cause in one woman and the primary or equal primary contributor in three. Serologically, C. trachomatis was related to adhesions, without salpingitis, more often (63%) than any other micro-organism. M. genitalium may have been implicated in one case. Serologically, a previous C. trachomatis infection was indicated in 40% of women without an observable laparoscopic abnormality. C. trachomatis in the endometrium and tubes of women without any laparoscopic abnormality suggests subclinical disease, endometritis or endosalpingitis. There was evidence for a smaller proportion (19%) of women without an abnormality having been infected previously with M. genitalium. To some extent this is consistent with the infrequency of acute M. genitalium infections in this cohort of women.

Further observations, mainly serological, on a cohort of women with or without pelvic inflammatory disease

An analysis was undertaken of data pertaining to over 100 women with lower abdominal pain who were laparoscoped. Prior to laparoscopy, 11 of the women were considered to almost certainly have salpingitis, of whom six (55%) had salpingitis at laparoscopy; 17 to probably have salpingitis, of whom six (35%) did; 28 to possibly have salpingitis, of whom five (18%) did; and 56 to be very unlikely to have salpingitis, of whom five (9%) did. Of the 22 women who had salpingitis at laparoscopy, 14 (64%) had a Chlamydia trachomatis IgG antibody titre of >or=1:128 and might reasonably be regarded as having chlamydial disease on this basis; six without such a titre probably did not have chlamydial disease as C. trachomatis could not be detected at any genital site. At laparoscopy, 18 women had adhesions without obvious tubal inflammation; clinically, 15 of them had been regarded as possibly having salpingitis or unlikely to have it, with 12 having chronic pelvic pain. Twelve (67%) of the 18 women had a chlamydial IgG antibody titre of >or=1:128. IgM antibody was also detected most often in the 'salpingitis' group. Of 49 women without any abnormality detected at laparoscopy, nine (18%) had a high chlamydial IgG antibody titre. Overall, a woman who had a high titre of chlamydial IgG antibody and acute pelvic pain, together with a clinical picture of pelvic inflammation, was more likely to have salpingitis than adhesions alone. Likewise, a woman who had a high titre of chlamydial IgG antibody and chronic pelvic pain, together with a clinical picture suggesting that salpingitis was unlikely, was more likely to have adhesions alone than acute chlamydial salpingitis. However, while antibody measurement and seeking cervical C. trachomatis may help in formulating a diagnosis, there seems no simple way of detecting the small proportion of women who are infected by C. trachomatis in the upper genital tract but whose laparoscopic findings indicate normality. So far as patient care is concerned, the only way of preventing damage to the upper genital tract is to treat early on the basis of suspicion.

Antigen capture ELISA for the heat shock protein (hsp60) of Chlamydia trachomatis

AIMS

To develop an indirect ELISA using the heat shock protein (hsp60) of Chlamydia trachomatis as antigen.

METHODS

The hsp60 gene was amplified by PCR, expressed in the vector pDEV-107 and transformed into Escherichia coli. The recombinant protein, expressed as a beta-galactosidase fusion product, was captured onto a solid phase using a monoclonal antibody directed against beta-galactosidase. Following incubation with goat anti-human antibody conjugated to peroxidase and colour development on addition of peroxidase substrate, antibody recognition of antigen was quantified by optical density at 492 nm.

RESULTS

A sensitive and relatively specific ELISA to detect hsp60 has been produced, which can be exploited to determine the antibody response to C trachomatis hsp60.

CONCLUSIONS

This assay will permit the future investigation of the immunopathogenesis of persistent inflammation following C trachomatis infection.

Mycoplasma genitalium in the joints of two patients with arthritis

Mycoplasma genitalium was sought in synovial fluids from 13 patients, of whom five had Reiter's syndrome, four had rheumatoid arthritis, and one each had systemic lupus erythematosus, psoriatic arthritis, rheumatic fever and undefined arthritis. The mycoplasma was detected by a PCR assay in the knee joint of a 25-year-old man with Reiter's syndrome, from whom urethral ureaplasmas were isolated and whose synovial fluid mononuclear cells responded to ureaplasmal antigens in a proliferation assay. Mycoplasma genitalium was also detected in the knee joint during an exacerbation of arthritis in a 58-year-old man who had had seronegative juvenile polyarthritis that had evolved to seronegative rheumatoid arthritis.

A longitudinal study of pelvic inflammatory disease

OBJECTIVE

To study the microbiology and long term prognosis of pelvic inflammatory disease (PID).

DESIGN

A prospective study of women with laparoscopically confirmed PID.

SETTING

Teaching hospital in central London.

SUBJECTS

23 women with PID.

OUTCOME MEASURES

Microbiological investigations at the time of diagnosis and at follow up; subsequent fertility and the occurrence of pelvic pain.

RESULTS

PID diagnosed by laparoscopy was regarded as moderate to severe in 15 cases. Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma hominis and Ureaplasma urealyticum or a combination of these micro-organisms were detected most frequently in the cervix, less often in the endometrium and least in the tubes, C. trachomatis being the micro-organism found most commonly in the tubes. There was serological evidence of acute chlamydial infection in 13 of 20 cases in which paired sera were available and a serological response to M. hominis in 9 of 12 cases in which it was possible to evaluate the results. On the basis of microbiological and serological results, C. trachomatis appeared to be the most important aetiological agent in 10 cases, N. gonorrhoeae in four cases, M. hominis in three cases and U. urealyticum in none; in five cases, two of these micro-organisms appeared to be of equal importance. After 1 to 3 years, 33% of the women were having difficulty conceiving and 56% continued to complain of pelvic pain.

CONCLUSION

It is difficult to be certain of the infectious cause of PID in any given case. However, the evidence that N. gonorrhoeae and C. trachomatis are pathogens is very strong. M. hominis may be responsible for a few cases on its own or together with other micro-organisms.

Chlamydia trachomatis in the fallopian tubes of women without laparoscopic evidence of salpingitis

23 women with lower abdominal pain and Chlamydia trachomatis in the cervix, urethra, or both sites were studied. Laparoscopy was done with sampling of the endometrium and fallopian tubes for detection of C trachomatis. 11 women had laparoscopic evidence of pelvic inflammatory disease (PID); C trachomatis was detected in the upper genital tract of 8, but not in the upper tract of 5 who had laparoscopy again after treatment. The organism was also found in the upper genital tract of 9 of the 12 women without laparoscopic evidence of PID. Most of the women with abdominal pain or tenderness had tubal or endometrial C trachomatis infection, although only half had laparoscopic evidence of salpingitis. This finding suggests that antibiotic treatment should be given as soon as chlamydial infection is detected in the cervix and that pain does not necessarily point to C trachomatis in the upper genital tract. Laparoscopy may miss important pathogens in the upper genital tract, unless the procedure is complemented with detailed microbiological investigation.

Severity of salpingitis in mice after primary and repeated inoculation with a human strain of Chlamydia trachomatis

Groups of inbred female mice of strains CBA or C3H were infected genitally with a pathogenic human strain of Chlamydia trachomatis (N.I.1, serovar F) known to produce salpingitis and infertility in mice. Mice were inoculated under the ovarian bursa or directly into the uterine cavity with chlamydiae (test groups) or with sucrose-phosphate transport medium (control groups) before being challenged with chlamydiae by the same route 12-17 weeks later. Twenty-five pairs of test and control animals were killed from 7 to 77 days after challenge and oviductal inflammatory changes, recovery of organisms, and antibody responses were compared in the two groups. Salpingitis in the mice infected previously (tests groups) was more severe than in the controls in 56% of comparisons, the same in 24% and less severe in 20%. However, despite the increase in the severity of disease, shedding of C. trachomatis from the lower genital tract was less prolonged after rechallenge or did not occur. Salpingitis occurred in spite of the almost certain presence of pre-existing serum antibody, and accelerated and accentuated antibody response in the rechallenged mice. Furthermore, the continued existence of high titres of antibody was not associated with less severe disease. Thus, the results reveal that previous exposure to chlamydiae does not prevent salpingitis and suggest that its severity is influenced by cell-mediated immune mechanisms.

Prevalence of chlamydial antibody in Malaysians

A single antigen indirect immunofluorescence test was used to screen for chlamydial antibody among Malaysian infants, children, sexually active adults and prostitutes. Of 794 serum samples tested, 361 (45.5%) were positive. Seropositivity increased with age and sexual activity and ranged from 10 to 16% among children under 10 years old to 94.4% among prostitutes. Pregnant women and female adolescents showed a higher antibody prevalence than nonpregnant and older women. Six (13%) infants under 6 months of age were positive for chlamydial IgM.

Is serology of any use when searching for correlations between Chlamydia trachomatis infection and male infertility?

Evidence on Chlamydia trachomatis causing male infertility is conflicting. We therefore collected data on epidemiological and clinical correlates of chlamydial infection and male fertility in 184 males visiting our Fertility Unit. Antibodies against Chlamydia trachomatis in serum and semen were also determined. Significant correlations were demonstrated between current chlamydial urethral infection and semen immunoglobulin (Ig) A, serum IgA and serum IgG. These parameters, however, were neither related to a history of sexually transmitted disease nor to lifetime number of sexual partners. Why, in the male, serology does not correlate with chlamydial infection in a more remote past is explained. Our data support, on epidemiological as well as serological grounds, the conclusion that chlamydial infection probably does not contribute significantly to male infertility.

A search for infectious agents in chronic abacterial prostatitis using ultrasound guided biopsy

A series of 60 patients with a diagnosis of chronic abacterial prostatitis, as defined by the Stamey procedure, was studied by transrectal prostatic ultrasound and subsequent transperineal biopsy of the abnormal areas of the prostate in order to ascertain the role of micro-organisms in this condition. Histological assessment revealed a chronic inflammatory infiltrate, generally of low grade, in 53 patients (88%). Organisms were isolated from the prostatic tissue of only 9 patients (15%) and were considered to be contaminants from the perineal skin, since treatment with an appropriate antimicrobial agent failed to alter symptoms or affect the leucocyte count in the urine or prostatic fluid. Chronic abacterial prostatitis may be a non-organismal inflammatory process.

Comparison of a single-antigen microimmunofluorescence assay and inclusion fluorescent-antibody assay for detecting chlamydial antibodies and correlation of the results with neutralizing ability

An inclusion fluorescent-antibody assay (IFA) with McCoy cells infected with Chlamydia trachomatis serovar L2 was compared with a single-antigen (L2) microimmunofluorescence (MIF) assay for the detection of antichalmydial antibodies. A total of 562 serum specimens were tested by both assays, and sera representing a range of titers were tested for their ability to neutralize the infectivity of C. trachomatis. Overall, there was poor correlation between the two assays (r2 = 0.62). With most sera the inclusion IFA was more sensitive. There was better correlation between IFA titer and ability to neutralize the five serovars tested (L2, L3, C, E, and F) than between the MIF assay and neutralization. In summary, the IFA appeared to be more sensitive than the MIF assay for detecting antibodies to C. trachomatis.

The role of Chlamydia trachomatis in chronic abacterial prostatitis: a study using ultrasound guided biopsy

We studied 50 patients with chronic abacterial prostatitis as defined by the Stamey procedure via transrectal prostatic ultrasound and subsequent transperineal biopsy of the abnormal areas of the prostate to ascertain the role of Chlamydia trachomatis organisms (chlamydiae) in this condition. Chlamydiae were detected by an immunofluorescence technique in the urethra of 1 patient (2 per cent) but they were not recovered in McCoy cell culture from the prostatic tissue of any patient nor were they detected in the tissue by immunofluorescence. In addition, serum antibody to Chlamydia trachomatis was not found even in moderate titer. The approach in this study has overcome the problem of urethral contamination in the assessment of prostatic specimens from patients with chronic abacterial prostatitis. There is no evidence that chlamydiae are directly implicated in the disease, although the possibility of an earlier active role cannot be excluded.

Acute epididymitis: a microbiological and ultrasonographic study

In a prospective study of 24 men (mean age 28.3 years) with acute epididymitis who underwent epididymal aspiration, micro-organisms were detected in 15 (62.5%). Chlamydia trachomatis accounted for 10 (42%) of the cases, being located in both the urethra and epididymis in 5 individuals. Chlamydial serology supported the diagnosis of chlamydial infection, there being a strong correlation between the detection of C. trachomatis and elevated titres of both chlamydial IgG and IgM antibodies. In 4 patients (mean age 55.5 years), Escherichia coli was cultured from both mid-stream urine and epididymal aspirate. Transrectal ultrasound revealed abnormal prostatic scans in 19 patients (79%). These data confirm the aetiological role of C. trachomatis, support the notion that micro-organisms spread intra-canalicularly and suggest that the prostate is also involved in the inflammatory process in acute epididymitis.

Immunoblot analysis of antibody response to Chlamydia trachomatis in patients with reactive arthritis and ankylosing spondylitis

Antibodies to Chlamydia trachomatis were found in 60% of patients with reactive arthritis (ReA) and 33% of patients with ankylosing spondylitis (AS), compared with 19% of healthy blood donors. The IgG, IgA and IgM immune responses in patients with ReA and AS were further analysed by immunoblotting. Most patients had IgG antibodies to a large number of C. trachomatis antigens. IgA (and especially IgM) antibodies were less prevalent. Differences in the antibody response to individual antigens were seen between the two groups of patients, with respect to both IgG and IgA. Especially evident was the high prevalence of IgA antibodies to a 60 kD antigen among patients with ReA (67%) compared with patients with AS (20%).

Infection of the epididymis by Ureaplasma urealyticum

Ureaplasma urealyticum organisms (ureaplasmas) were isolated from the urethra and epididymal aspirate of a man aged 24 who had acute right sided epididymitis. No other microorganisms were detected, and he had no chlamydial antibody response. A fourfold antibody response to the epididymal ureaplasma isolate was detected by two methods, however, and the patient responded clinically to doxycycline, to which the ureaplasmal isolates were susceptible in vitro. These findings suggest that U urealyticum had a causative role.

Absence of infection with human immunodeficiency virus in Peruvian prostitutes

We serologically tested 140 female prostitutes (mean age, 30 years) from the port city of Callao, Peru, for evidence of infection with human immunodeficiency virus (HIV), Chlamydia trachomatis, Treponema pallidum, herpes simplex viruses (HSV) I and II, and hepatitis B virus. The women had worked as prostitutes for an average of 5 years; one-fourth serviced foreign visitors exclusively, mainly sailors. Only 4 women used condoms, and only 1 woman gave a history of parenteral narcotic abuse, although 53% were regularly exposed to unsterile needles outside the medical setting for injections of vitamins, antibiotics, or steroids; another 29% are thought to probably use unsterile needles. None of the 140 prostitutes screened was seropositive for HIV, despite a very high prevalence of antibody to T. pallidum (24%), C. trachomatis (97%), HSV I and II (100%), and hepatitis B (51%); 5% were HbsAg positive. These data indicate that HIV has not yet been introduced into female prostitutes in the Peruvian port city. We believe that widespread use of unsterile needles in developing countries, such as Peru, represents a serious health threat and will amplify the spread of HIV, once introduced.

Chlamydia trachomatis genital infections in Tahiti

The rate of Chlamydia trachomatis infection was determined in three populations in Tahiti by means of a direct immunofluorescence test performed in specimens, tissue culture and detection of chlamydial antibody in serum specimens using a single-serotype indirect immunofluorescence test. Chlamydia trachomatis was recovered in 53% of 53 bar girls, 24% of 75 women attending a public maternity clinic for routine care, and 37% of 71 men attending a sexually transmitted disease clinic with acute or subacute urethritis. The presence of chlamydial antibody in a high proportion of the groups studied confirmed the high frequency of chlamydial infections (62.3%, 66.6% and 83.1% respectively). Neisseria gonorrhoeae infection was often associated with chlamydial infection in both bar girls and men with urethritis (11.4% and 18.3% respectively). With regard to clinical manifestations, 58.3% (7/12) of bar girls and 23.2% (10/43) women at the maternity clinic without clinical complaints were found to be Chlamydia trachomatis-positive. The presence of Chlamydia trachomatis in these asymptomatic persons highlights their important role in spread of this organism in Tahiti. The findings indicate that routine testing for Chlamydia trachomatis is warranted in patients attending the sexually transmitted disease and public maternity clinics in Tahiti.

Inflammatory joint disease and human immunodeficiency virus infection

Nine men positive for antibody to human immunodeficiency virus (HIV) who developed peripheral, non-erosive arthritis were followed up. The clinical features were compatible with reactive arthritis but were atypical in several respects: the joint symptoms were generally severe, persistent, and unresponsive to non-steroidal anti-inflammatory drugs. The onset of arthritis was associated with various infections, none of which are known to be associated with the development of reactive arthritis. HLA typing was performed for three patients, all of whom were positive for HLA-B27. HIV was isolated from the synovial fluid of one patient. No patient had AIDS before developing arthritis, but four progressed to having AIDS after a mean of 7.5 months, and two died. Arthritis resolved in only one patient. The possibility of HIV infection should be considered in all patients with conditions suggesting reactive arthritis. Synovitis in patients with severe immunodeficiency has important pathogenetic implications.

Direct immunofluorescence for Chlamydia trachomatis on urogenital smears for epidemiological purposes

A population of 197 asymptomatic women, attending an out-patient department for birth-control advice, was screened for urogenital infection with Chlamydia trachomatis by direct immunofluorescence on cervical and urethral smears. A blood sample was obtained for chlamydial serology and demographic, behavioural and clinical data were recorded. Eleven (5.5%) women had a chlamydial infection. Chlamydial infection, as diagnosed with direct immunofluorescence, correlated with a history of sexually transmitted disease (p less than 0.01), promiscuity (p less than 0.01), use of oral contraceptives (p less than 0.02) and high chlamydial antibody titres (p less than 0.01). These last also correlated with a history of sexually transmitted disease (p less than 0.02) and promiscuity (p less than 0.02). These results, obtained with direct immunofluorescence, are indistinguishable from those obtained previously with chlamydial culture. Direct immunofluorescence on urogenital smears seems a valuable tool for epidemiological investigation. Our data also support the hypothesis that oral contraceptive use is correlated with chlamydial infection because of increased cervical susceptibility to infection and not because of a sampling bias towards oral contraceptive users.

Chlamydia trachomatis and reactive arthritis: the missing link

Reactive inflammatory arthritis is a common sequel to sexually acquired non-gonococcal genital-tract infection. Approximately 50% of cases are associated with Chlamydia trachomatis infection in the genital tract, although conventional cultures of joint material are sterile. Synovium, synovial-fluid cells, or both, from eight patients with sexually acquired reactive arthritis (SARA) and eight with knee effusions associated with other rheumatic diseases were examined by means of a fluorescein-labelled monoclonal antibody to C trachomatis ('Micro Trak'; Syva). Typical chlamydial elementary bodies were seen in joint material from five patients with SARA but in none of the controls. An inclusion-like cluster of elementary bodies was seen in one synovial biopsy sample. All five patients had high titres of serum chlamydial antibody. It is likely that the synovitis of SARA results directly from the presence of chlamydial elementary bodies in the joint.

Seroepidemiology of Chlamydia trachomatis infection in infertile women in Melbourne

A serological study was undertaken to determine the prevalence of antibody to Chlamydia trachomatis in women and to investigate any possible role of the organism in infertility and pelvic inflammatory disease. Thirty-seven per cent of pregnant women were found to have antibodies to Chl. trachomatis, as were 69% of women with pelvic inflammatory disease. Eighty-five per cent of women who were infertile due to inflammatory tubal damage and 78% who were infertile secondary to ectopic pregnancy had antibody as compared with 56% of women who were infertile for other reasons. Sperm bank donors and children showed low prevalences (16% and 3%, respectively). Exposure to Chl. trachomatis is widespread in sexually active women and appears to have a role in pelvic inflammatory disease and infertility that is due to inflammatory tubal disease.

Salpingitis in mice induced by human strains of Chlamydia trachomatis

Human strains of Chlamydia trachomatis were inoculated unilaterally into the genital tracts of female TO, CBA, CBA/nu and C3H mice via the intrauterine route or under the ovarian bursa. Inflammatory changes were not seen in the oviducts or uterus of mice given two laboratory-adapted LGV serovars (L1 and L2), although chlamydiae were recovered from the lower genital tract. However, salpingitis and endometritis occurred after each of three chlamydial strains (serovars D and E) had been inoculated. Oviduct inflammation was seen for up to 6 weeks after inoculation but reached maximum severity usually after about 2 weeks, the lumen sometimes being occluded by exudate and necrotic debris. Pathological changes were seen often in both oviducts indicating canalicular spread of the organisms through the uterus. Pre-treatment of the mice with progesterone had an enhancing effect in that the lesions developed more rapidly; such treatment, in halting the oestrous cycle, probably made a larger number of target cells available for more efficient infection. Involvement of the oviduct on the uninoculated side occurred more rapidly in T-cell impaired nude mice than in immunologically normal mice, although there was little or no effect on the severity of the oviductal changes. There was evidence that the susceptibility of different strains of mice to chlamydial salpingitis varied. Thus, inflammatory changes in C3H mice were more severe than in TO mice and the changes in C3H and CBA strains were longer lasting than those in TO mice. This suggests that a possible genetic predisposition in the human situation should not be ignored. Finally, one chlamydial strain of low passage produced more severe salpingitis in mice than another strain of similar passage. By analogy different chlamydial strains may not be of equal pathogenicity in the human situation.

Antigenic specificity of serological response in Chlamydia trachomatis urethritis detected by immunoblotting

Sera from 19 patients with Chlamydia trachomatis culture positive non-gonococcal urethritis were studied for the presence of antibodies to chlamydial proteins by immunoblotting. Ten C trachomatis negative patients with non-gonococcal urethritis and 10 healthy controls were also studied. Acute phase sera from C trachomatis positive patients with non-gonococcal urethritis reacted only with the major outer membrane protein whereas all the convalescent phase serum samples reacted with the major outer membrane protein and with a 60,000 and a 62,000 molecular weight protein. Some sera also reacted with a 45,000 molecular weight protein. Five of 10 convalescent phase samples from patients with C trachomatis negative non-gonococcal urethritis showed a reaction pattern comparable with that observed in convalescent sera from C trachomatis from C trachomatis positive patients with non-gonococcal urethritis. Sera from healthy seronegative subjects were negative by blotting.

Recent advances in Chlamydia trachomatis

Chlamydia trachomatis is an obligate intracellular energy parasitic bacterium with a genome of 660 X 10(6) daltons, possessing a plasmid and unique life cycle which includes the differentiation of the infective elementary body to a replicative reticulate body. C. trachomatis is the etiological agent of trachoma, which affects approximately 500 million people in developing countries. Recently it became evident that in industrialised Western nations certain strains of C. trachomatis are the most common cause of sexually transmitted infections such as non-gonococcal urethritis, cervicitis, endometritis, salpingitis and subsequent ectopic pregnancies or infertility, perihepatitis, neonatal conjunctivitis and pneumonia, adult conjunctivitis and epididymitis. Since C. trachomatis infections are often asymptomatic, widespread screening of sexually active young people is needed in order to initiate early antibiotic treatment which may prevent serious complications such as ectopic pregnancies and infertility. Development of sensitive and simple techniques for mass screening for detection of Chlamydia in excretions as well as techniques for detection of specific markers of chronic internal infections (such as Chlamydia specific IgA antibodies) is of great importance.

Enzyme-linked immunosorbent assay using three different antigen preparations for detection of antibodies to Chlamydia trachomatis

The ability of an enzyme-linked immunosorbent assay (ELISA) to detect antibodies to Chlamydia trachomatis was evaluated in 100 sera using three different antigen preparations as substrates (sonicated organisms, Triton X solubilized antigen and SDS solubilized antigen). The results were compared to those obtained by a standard microimmunofluorescence assay. The results obtained by the three ELISA techniques and the microimmunofluorescence method were in relatively good agreement (76%); some discrepant results were observed in sera with a low antibody titer. There was good agreement of results obtained by the three ELISA techniques (84%). The microimmunofluorescence method showed the greatest sensitivity. Assuming the microimmunofluorescence method accurately demonstrates antibodies, the ELISA using Triton X solubilized antigen showed the highest degree of specificity (97%), and the ELISA with sonicated organisms the greatest sensitivity (82%) and accuracy (86%).

Microbiological and serological study of non-gonococcal urethritis with special reference to Mycoplasma genitalium

Twenty-two men with non-gonococcal urethritis (NGU), 19 with gonorrhoea, and 22 without urethritis were examined for various micro-organisms. Chlamydia trachomatis was isolated from the urethra of 45% of men with NGU, 21% of those with gonorrhoea, but from none without urethritis. Ureaplasma urealyticum but not Mycoplasma hominis was recovered from a larger proportion of men with NGU than from those in the other groups. M genitalium was isolated presumptively from 32% of men with NGU, 12% of those with gonorrhoea, from 10% of men without urethritis, and from 42% of the men with NGU from whom chlamydiae were not isolated. U urealyticum, M hominis, and M genitalium were sought also in the rectum of men in the three groups. The first two micro-organisms were confined almost exclusively to homosexual men, whereas M genitalium was apparently not restricted in this way and was found particularly in this site in men with NGU. The latter mycoplasma may be a resident primarily of the intestinal tract. A fourfold or greater rise in the titre of antibody to C trachomatis was detected in about 20% of the patients with NGU, but not in other men. A similar rise in the titre of antibody to M genitalium was seen in 29% of the patients with NGU and in 12% of those without urethritis. A concomitant antibody response to M pneumoniae, which is antigenically related to M genitalium, was seen in one patient only. The responses to M genitalium suggest infection by this mycoplasma and indicate the need for further serological studies.

Susceptibility of different serovars of Chlamydia trachomatis to inactivation by normal human serum

The ability of a panel of normal human serum samples to inactivate 12 strains of Chlamydia trachomatis, each of a different serovar, was investigated. A wide range of antichlamydial activity was observed, with survival rates of C trachomatis varying from less than 1% in some experiments to 100% in others. The strain specificity of the anti-chlamydial activity exhibited by individual serum samples was not, however, related to the antigenic cross reactivity between serovars demonstrable by microimmunofluorescence testing, which suggested that type specific antigens were not predominantly involved in the inactivation process.

Pelvic inflammatory disease in patients infected with Chlamydia trachomatis: in vitro cell mediated immune response to chlamydial antigens

Blood samples were obtained from 11 women with laparoscopically confirmed acute salpingitis who yielded positive cultures of Chlamydia trachomatis from the cervix. Four patients also had perihepatitis. Lymphocyte transformation assays, using C trachomatis serovars I and L2 as antigens, showed that the patients' lymphocytes responded to antigenic stimulation more strongly than the lymphocytes of age matched controls. Responses to the I and L2 antigens correlated strongly, but greater responses were obtained to the L2 antigen. No correlation was found between the response in the lymphocyte transformation assay and the degree of the inflammatory changes of the fallopian tubes, the presence of perihepatitis, or the titres of humoral antibodies to C trachomatis as measured by microimmunofluorescence. Sequential transformation assays, however, showed that patients with perihepatitis tended to have a more sustained response.

Detection of IgM antibodies against Chlamydia trachomatis by enzyme linked fluorescence immunoassay

A simple, sensitive enzyme linked fluorescence immunoassay has been developed to detect IgM antibodies against Chlamydia trachomatis. Reticulate bodies and elementary bodies from C trachomatis L2/434 Bu strain were isolated and used as antigens in the assay. Of 113 serum samples obtained from infants with pneumonia, 27 (23.9%) had IgM antibodies to C trachomatis L2 reticulate bodies and nine (8.0%) had IgM antibodies to C trachomatis L2 elementary bodies (titre greater than or equal to 1/500). Specific IgM antibodies were not detected in 20 control serum samples obtained from healthy adults and children. The possible use of enzyme linked fluorescence assay to determine IgM antibodies in the serodiagnosis of C trachomatis infection is discussed.

Neonatal mycoplasmaemia: Mycoplasma hominis as a significant cause of disease?

A full-term baby boy had respiratory distress, fever and pneumonia within 20 h of birth. Isolation of Mycoplasma hominis from blood taken after 20 h and 11 days was accompanied by an antibody response. Although chlamydial IgM antibody was detected, chlamydial infection probably did not cause the pneumonia. Penicillin was ineffective but treatment with gentamicin, and particularly tetracycline, was associated with slow improvement. Mycoplasma hominis should be considered as a cause of respiratory disease and fever in neonates.

Serum specific IgA antibody to Chlamydia trachomatis in patients with chlamydial infections detected by ELISA and an immunofluorescence test

Sera obtained from 34 men with Chlamydia trachomatis positive non-gonococcal urethritis, 34 men with C trachomatis negative non-gonococcal urethritis, 42 women with acute salpingitis, 38 healthy women, and 34 healthy men were studied for the presence of specific serum C trachomatis IgA and IgG antibodies. Serological results were correlated with C trachomatis isolation in cell culture. An enzyme linked immunosorbent assay (ELISA) for C trachomatis specific serum IgA was employed using highly purified elementary bodies of C trachomatis serotype L2 grown in LLC-MK2 cells. Results obtained for C trachomatis IgA antibody by the ELISA test were compared with results obtained for the same sera by a single antigen immunofluorescence technique. A good correlation (r = 0.91) was found between two methods. Serum IgG antibody was also determined in the same sera by the immunofluorescence technique. Patients with C trachomatis positive non-gonococcal urethritis had a significantly (p less than 0.0005) higher prevalence (94.1%) of serum IgA antibody by ELISA compared with patients with C trachomatis negative non-gonococcal urethritis (20.5%) or healthy men (5.9%). Similarly, women with acute salpingitis had a significantly (p less than 0.005) higher prevalence of serum IgA antibody (45.2%) compared with healthy controls (5.2%). Comparable results were obtained for C trachomatis serum IgA antibody using the immunofluorescence technique. The prevalence of C trachomatis IgG antibody was significantly higher in patients with C trachomatis positive non-gonococcal urethritis (97.0%) compared with those with C trachomatis negative non-gonococcal urethritis (33.3%) and healthy controls (23.5%). The importance of using specific C trachomatis serum IgA in the identification of chlamydial infection is discussed.

The distribution and effect of Chlamydia trachomatis in CBA mice inoculated genitally, intra-articularly or intravenously

A "fast" egg-killing human strain of Chlamydia trachomatis was inoculated into normal CBA and congenic CBA/nu mice, which have an impairment of T-cell function and do not produce anti-chlamydial antibodies. The mice were inoculated by the intra-uterine, intra-articular, or intravenous routes. Some of the mice were first treated with progesterone, which allows successful chlamydial infection of the mouse genital tract when the organisms are introduced genitally. Mice were sacrificed up to 27 days after inoculation. Homogenates of joints, genital tract, spleen, liver, kidneys, eyes and lungs were prepared and tested for chlamydiae in cycloheximide-treated McCoy cell cultures. Chlamydiae were detected in the genital tracts and spleens, but not in the joints, of mice inoculated via the intra-uterine route. They were found in the joints and spleens of mice inoculated intra-articularly, and were detected also in spleens and, from the 4th to 6th day after inoculation, in joints of mice given the organisms intravenously. These results were obtained irrespective of whether or not the mice had received progesterone. The numbers of chlamydiae in the spleens and joints of the nude mice were larger and they persisted longer than in the corresponding immunocompetent animals, although this was not true for chlamydiae in the genital tract of mice inoculated via the intra-uterine route. Compartmentalisation of chlamydiae was evident although the spleen was infected consistently irrespective of the route of inoculation and, as mentioned, chlamydiae were found transiently in the joints following intravenous inoculation. This suggests that chlamydiae might also enter the human joint.(ABSTRACT TRUNCATED AT 250 WORDS)

A study of inactivation of Chlamydia trachomatis by normal human serum

To assess the effect of human serum on the viability of Chlamydia trachomatis, organisms were mixed with unheated and heat inactivated homologous serum, and the numbers surviving after incubation at 37 degrees C for 1 hour were compared. With a pool of sera obtained from 12 donors, the number of chlamydiae surviving incubation in unheated serum was less than 1% of that surviving incubation in heat inactivated serum. The antichlamydial activity of the unheated pooled serum samples could be noticeably reduced by treatment with Mg-EGTA (ethyleneglycolbis (beta-amino ethyl ether)-N,N'-tetra-acetic acid). This indicated a requirement for calcium ions and showed that the alternative pathway of complement activation played only a minor role, if any, in the inactivation process. When 12 serum samples were tested individually it was found that four inactivated chlamydiae to an extent comparable with that seen with the pooled serum. The other eight samples showed only moderate (or slight) antichlamydial activity, with survival rates in unheated serum of 20-60% (or more than 60%) of those in heat inactivated serum. There was no correlation between the titres of antichlamydial antibodies and antichlamydial activity, all serum samples having undetectable or low concentrations of antibody on measurement by micro-immunofluorescence. The antichlamydial activity destroyed by heating was restored, however, when heat inactivated serum was mixed with an equal volume of an unheated serum that was not inhibitory to chlamydiae. When the latter serum was heated before addition antichlamydial activity was not restored, indicating the requirement of both a heat stable and a heat labile factor. This observation and the need for calcium ions for inactivation of chlamydiae are compatable with killing mediated by antibody and complement. Thus serum samples from individuals with no clinical or serological evidence of infection with chlamydiae vary in their ability to inactivate the organism, some having antichlamydial activity which is possibly mediated by antibody and complement.

Studies of cellular immunity in male homosexuals in London

97 symptom-free homosexuals were studied clinically, serologically, and with in-vivo and in-vitro tests of cellular immune function in the context of the acquired immunodeficiency syndrome (AIDS). A high proportion of these men showed abnormalities: lymphopenia (33%), decreased T-helper/T-suppressor (Th/Ts) cell ratios (43%), both these abnormalities (12%), decreased total T-helper cells (15%), monocyte chemotactic (10%) and phagocytic (27%) defects, anergy to three recall antigens (32%), and anergy to purified protein derivative despite BCG inoculation (55%). The lymphocyte abnormalities and anergy characteristic of AIDS were seen in 5%. No clear clinical or serological associations were seen for the AIDS-like defects. Trends of association were seen between higher lymphocyte counts, lower Th/Ts ratios, more T-suppressor cells and serological evidence of previous virus infection. The combination of lymphocyte abnormalities and anergy observed in these symptom-free homosexuals may represent a latent phase of AIDS.

Pelvic inflammatory disease associated with Chlamydia trachomatis infection after therapeutic abortion. A prospective study

Chlamydia trachomatis was cultured from the cervix of 70 of 557 (12.6%) patients admitted for therapeutic abortion. Postoperatively, 22 (3.9%) developed acute pelvic inflammatory disease (PID); of these women, 14 (63.6%) had harboured C trachomatis in the cervix before the abortion. Thus of 70 patients with chlamydial infection, 14 (20%) developed PID postoperatively. Of the chlamydia-positive patients, six of the 15 (40%) aged less than 20 years and eight of the 53 (15%) patients aged 20-30 years developed PID. Twelve of the 70 women with chlamydial infections showed a significant increase in serum chlamydial IgG antibody titres over a four week period; four of these women developed PID. Neisseria gonorrhoeae was recovered from only four patients, one of whom developed PID after the abortion. Treatment with a single dose of intravenous doxycycline (200 mg) was given before and during surgery to about half of the patients. In our study, this regimen had no protective effect against the development of PID associated with C trachomatis.

A rapid immunoperoxidase assay for the detection of specific IgG antibodies to Chlamydia trachomatis

A technique, using indirect immunoperoxidase antibody (IPA), was developed for the detection of IgG antibody to Chlamydia trachomatis. The IPA technique employs glass slides with air-dried and acetone-fixed C trachomatis infected cells, which can be stored at -70 degrees C and used for several months. Antibody titres detected by IPA were comparable to those detected by the indirect fluorescent antibody technique.

Use of the enzyme-linked immunosorbent assay for detection of antibodies to Chlamydia trachomatis

An enzyme-linked immunosorbent assay (ELISA) using a soluble antigen prepared from the D strain of Chlamydia trachomatis was used for titration of IgG antibodies to Chlamydia trachomatis in 153 sera from 126 patients with non-specific genital infection and from 27 healthy subjects. The results were compared to those obtained with the micro-immunofluorescence method and were in complete agreement in 143 of the 153 sera. The ELISA proved to be reproducible and as sensitive as the micro-immunofluorescence method.

76 patients with ankylosing spondylitis seen after 30 years of disease

Seventy-six patients treated for ankylosing spondylitis at the Rheumatism Foundation Hospital during the 1950s were re-examined. The mean duration of the disease was 30.5 years. The main interest was in the clinical and radiological progression of the disease, functional and working ability and the number of complications and their severity. The results seem to show that the long-term prognosis for AS is good, on average. A detailed description of the results is presented.

Analysis of the human serological response to proteins of Chlamydia trachomatis

Sera from individuals with culture-proven genital infection with Chlamydia trachomatis were analyzed for the presence of antibodies to chlamydial proteins by an immunoelectrophoretic transfer method. Protein antigens from representative strains of the 15 known serotypes were resolved by gel electrophoresis and transferred to a nitrocellulose solid support before being probed with serum. Sera from infected patients reacted with many different proteins. Most of these sera reacted with a 60,000- and a 62,000-molecular-weight protein which were present in each of the C. trachomatis serotypes and clinical isolates analyzed. In contrast, reactions with the major outer membrane protein were frequently observed but were usually weak. Sera from control groups of children, cloistered nuns, and college women, who were presumed not to have had prior chlamydial infections, did not usually have antibodies against the 60,000- or 62,000-molecular-weight protein, but did react with the major outer membrane protein and a 29,000-molecular-weight protein. These observations may have implications for the development of serodiagnostic tests as well as the identification of candidate antigens for vaccine development.