Chlamydial Antibodies Research Articles

Pelvic Inflammatory Disease

Pelvic inflammatory disease (PID) is an inflammatory process elicited by the migration of pathogenic microorganisms from the lower to upper genital tract. Although PID is known to increase the risk of tubal factor infertility, many other aspects of this disease remain less well defined. For example, while PID is often caused by Chlamydia trachomatis or Neisseria gonorrhoeae infection, frequently, neither of these bacterial pathogens is isolated from the upper genital tract of women with PID. This etiologic ambiguity also creates uncertainty regarding the decision to include antibiotics effective against genital mycoplasmas and anaerobic vaginal flora in PID treatment. Moreover, since clinical signs and laboratory measurements do not precisely identify all PID cases, and as the accuracy with which imaging modalities identify upper genital tract inflammation is not firmly established, PID remains a diagnostic challenge. It is clear, however, that better understanding of disease pathogenesis, diagnosis, and treatment is needed to improve the care provided women with PID, and this issue of Infectious Diseases in Obstetrics and Gynecology was constructed to deliver specific focus on these topics. Three papers in this issue examine the role of C. trachomatis in PID pathogenesis. The first examines findings from C. trachomatis infection control programs that have altered our understanding of the host immune response to chlamydial infection, and considers implications of these findings for prophylactic vaccine development. The second paper concisely reviews how non-human primate models of chlamydia infection have improved our understanding of PID pathogenesis, while the third explores a possible association between C. trachomatis-specific humoral immunity and genital tract inflammation. The fourth PID pathogenesis-focused paper is a case report that reminds readers of the link between Actinomyces israelii and this disease among women using intrauterine devices, while the fifth reviews evidence supporting Mycoplasma genitalium as a cause of PID. The five remaining papers in this issue address PID diagnosis and treatment. The first diagnosis-related paper defines a practical approach for the identification of women with PID, while the second tests an algorithm for PID case identification in epidemiological research using administrative diagnostic codes rather than the more unwieldy medical record review. The third describes an investigation among a cohort of women with high prevalence of HIV-1 that found that the conventional markers of histologic endometritis (i.e., neutrophils and plasma cells) are, at least in this population, unreliable surrogate markers for laparoscopically confirmed salpingitis. The fourth paper reviewed existing literature regarding serologic diagnosis of C. trachomatis infection in order to construct an algorithm for chlamydial serologic antibody testing in clinical work-up of the infertile couple. We close this issue with a comprehensive review of the antimicrobial therapies currently available for PID treatment. Thomas L. Cherpes Peter A. Rice Richard L. Sweet

Antichlamydial Antibodies, Human Fertility, and Pregnancy Wastage

Genital infections with Chlamydia trachomatis (C. trachomatis) continue to be a worldwide epidemic. Immune response to chlamydia is important to both clearance of the disease and disease pathogenesis. Interindividual responses and current chlamydial control programs will have enormous effects on this disease and its control strategies. Humoral immune response to C. trachomatis occurs in humans and persistent antibody levels appear to be most directly correlated with more severe and longstanding disease and with reinfection. There is a close correlation between the presence of antichlamydial antibodies in females and tubal factor infertility; the closest associations have been found for antibodies against chlamydial heat shock proteins. The latter antibodies have also been shown to be useful among infertile patients with prior ectopic pregnancy, and their presence has been correlated with poor IVF outcomes, including early pregnancy loss. We review the existing literature on chlamydial antibody testing in infertile patients and present an algorithm for such testing in the infertile couple.

Seroprevalence of Chlamydia trachomatis in Enugu, Nigeria

Chlamydia infections in women cause pelvic inflammatory disease, which often results in devastating consequences of infertility, ectopic pregnancy, or chronic pelvic pain. The infection is largely asymptomatic. To determine the seroprevalence of Chlamydia trachomatis in Enugu, South Eastern Nigeria. A population-based prospective study comprising female residents of Enugu, South Eastern Nigeria. Indirect solid phase enzyme immunoassay of Chlamydia antibodies was done using ImmunoComb C0. Trachomatis IgG Kit (Orgenics). The population comprised 136 female undergraduate students and 150 non-student women. The overall prevalence of C. trachomatis in the population studied was 29.4%. The percentage of subjects who admitted to be having multiple sexual partners was higher among the student population (71.2%) compared to those from the non-student population (28.8%). The highest percentage of seroprevalence was 28 (33.3%) in the age group of 20-24 years for the student population and 18 (21.4%) in the age group of 25-29 years for the non-student population. The highest seroprevalence of C. trachomatis antibodies (69.0%) in both populations was observed in females without any history of infection. Females that had pelvic inflammatory disease, sexually transmitted infection, and secondary infertility assayed for C. trachomatis had seroprevalence levels of 19%, 9.5%, and 2.4%, respectively. There was a positive correlation between positive Chlamydia assay and the type of subject population (student or non-student) with r2 value of 1.55 at P < 0.01. C. trachomatis infection is largely underdiagnosed and remains a silent disease in the apparently healthy population of Enugu, South eastern Nigeria.

Chlamydia antibody testing and diagnosing tubal pathology in subfertile women: an individual patient data meta-analysis

The Chlamydia IgG antibody test (CAT) shows considerable variations in reported estimates of test accuracy, partly because of the use of different assays and cut-off values. The aim of this study was to reassess the accuracy of CAT in diagnosing tubal pathology by individual patient data (IPD) meta-analysis for three different CAT assays. We approached authors of primary studies that used micro-immunofluorescence tests (MIF), immunofluorescence tests (IF) or enzyme-linked immunosorbent assay tests (ELISA). Using the obtained IPD, we performed pooled receiver operator characteristics analysis and logistic regression analysis with a random effects model to compare the three assays. Tubal pathology was defined as either any tubal obstruction or bilateral tubal obstruction. We acquired data of 14 primary studies containing data of 6191 women, of which data of 3453 women were available for analysis. The areas under the curve for ELISA, IF and MIF were 0.64, 0.65 and 0.75, respectively (P-value < 0.001) for any tubal pathology and 0.66, 0.66 and 0.77, respectively (P-value = 0.01) for bilateral tubal pathology. In Chlamydia antibody testing, MIF is superior in the assessment of tubal pathology. In the initial screen for tubal pathology MIF should therefore be the test of first choice.

Sexually transmitted infections among Pakistani pregnant women and their husbands in Norway

AimTo assess frequency and determine the factors associated with Chlamydia trachomatis, herpes simplex virus type 2, and hepatitis B seropositivity among Pakistani pregnant women and their husbands in Norway.MethodsAll together 112 couples of Pakistani origin living in Norway participated in our study. Blood samples were tested for immunoglobulin G (IgG) antibodies against C. trachomatis, herpes simplex virus type 2, and hepatitis B.ResultsPakistani women had significantly lower age, education level, and years of residence in Norway compared to their male partners. Among the men, 12% had positive chlamydial IgG antibodies in contrast to 1% of the women. These couples were discordant, meaning that the 13 wives of positive men were not infected with C. trachomatis, and the husband of one positive woman was not infected either. Four percent of women and 2% of men were positive for herpes simplex type 2. Only one couple was concordantly positive for herpes simplex type 2, the remaining four couples were discordant. Twelve percent of women and 21% of men were, or had been, infected with hepatitis B.ConclusionSexually transmitted infections did not seem to be prevalent in Pakistani immigrant couples in Norway. However, it was striking that most couples were discordant. Pakistani immigrants should be offered hepatitis B vaccine.

Seroprevalence of Antibodies to Chlamydophila psittaci in Zoo Workers in Brazil

To evaluate the prevalence of antibodies to Chlamydophila psittaci 364 serum samples were collected from veterinarians, biologists, animal scientists, veterinary students, animal keepers and others employees in 20 zoos, and from veterinary practitioners in 10 Brazilian states. Subjects ranged from 15 to 64 years of age, with 268 (74%) males and 96 (26%) females. Chlamydial antibodies were determined by the complement fixation test (CFT) and specific anti-C. psittaci IgG antibodies were determined by the microimmunoflurescence (MIF) test. Complement fixation test showed 23.9% (87/364) and MIF test showed 4.7% (17/364) positive serum samples. Titres ranged from 16 to 256 in both assays, demonstrating evidence of recent or current infection. Although chlamydial antibodies were detected in workers of seventeen zoos, MIF test only detected specific C. psittaci antibodies in seven of them. Previous psittacosis infection was suspected in eight workers of two zoos, five of whom reported having pneumonia, while employed at the zoos. However, diagnosis was not established in any of these cases in the past. Results indicated the occurrence of infection and previous contact of Brazilian zoo workers with C. psittaci, as well as the zoonotic potential of psittacosis in this risk population. Other studies are necessary to evaluate the risk factors of infection in this population. This seroepidemiological survey confirmed the need to adopt preventive measures to control avian chlamydiosis and protect the health of zoo workers in the country.

Chlamydial group antigen: its preparation and use in complement fixation test for measuring chlamydial group antibodies in animals.

Zusammenfassung Chlamydien Gruppentantigen: Seine Herstellung und Anwendung in der Komplementbindungsreaktion zur Messung des Antikorpergehalts in Tieren gegen die Chlamydiengruppe Ein hochwirksames, atherextrahiertes Gruppenantigen (Titer 1:256) wurde hergestellt. Benutzt wurde Stamm Bour von Chlamydia Trachomatis. Bei dieser Technik werden nur solche Einrichtungen benotigt, wie sie in jedem Routinelabor zu finden sind. Insgesamt wurden 886 Seren von gesund erscheinenden Rindern, Buffeln, Schafen und Ziegen (etwa 200 Stuck pro Tierart) mit Hilfe der KBR gegen das Chlamydien-Gruppenantigen getestet. Serologisch positiv reagierten 53% der Rinder, 44% der Buffel, 52,9% der Ziegen und 38% der Schafe. Es wurden Titer zwischen 1:4 und 1:64 beobachtet. Die Verbreitung der Gruppen-Antikorper bei diesen Tieren, die keine offensichtliche Erkrankung zeigen, wird diskutiert.

Immunization with the attenuated plasmidless Chlamydia trachomatis L2(25667R) strain provides partial protection in a murine model of female genitourinary tract infection

Here we report on the safety, immunogenicity, and vaccine efficacy of the naturally occurring plasmid-free attenuated Chlamydia trachomatis L2-25667R (L2R) strain in a murine infection model. Intravaginal immunization induced both chlamydial specific serum antibody and systemic CD4+ Th1 biased immune responses but failed to induce local IgA antibodies. Immunization induced no pathological changes in the urogenital tract. Protective immunity was evaluated by vaginal challenge with a natural occurring non-attenuated plasmid positive C. trachomatis urogenital strain (serovar D). Vaccinated mice were not protected from colonization/infection but exhibited a reduction in infectious burden at early time periods (1–2 weeks) post-challenge. Partial protective immunity did not protect against inflammatory disease. Thus, intravaginal vaccination with the live-attenuated L2R stain is safe, induces a systemic antibody and CD4+ Th1 biased immune response, but its protective efficacy is limited to reducing chlamydial burden at early time periods post-infection.

Chlamydia antibodies and self-reported symptoms of oligo-amenorrhea and hirsutism: A new etiologic factor in polycystic ovary syndrome?

To investigate whether the systemic inflammation induced by chlamydial infections might be associated with symptoms of polycystic ovary syndrome (PCOS). Nested case-control study. A questionnaire including questions about hirsutism and oligo-amenorrhea was distributed to a representative sample of women (at age 31) from the general population-based Northern Finland Birth Cohort. Those who reported both symptoms were defined as symptomatic (n=81). A representative sample of women (at age 31) from the general population-based Northern Finland Birth Cohort. None. To test the presence of serum antibodies to Chlamydia pneumoniae (IgG titers ≥32) and Chlamydia trachomatis (IgG titers ≥8) by microimmunofluorescence in symptomatic and control women. Antibodies were investigated in 79 symptomatic and 1427 control women (C. pneumoniae) and in 79 symptomatic and 425 control women (C trachomatis). C. trachomatis antibodies (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.3-4.6) and C. pneumoniae antibodies (OR, 1.5; 95% CI, 1.0-2.4) were more commonly present in symptomatic women, and the simultaneous presence of elevated highly sensitive C-reactive protein levels strengthened this association. Chronic inflammation, which is associated with chlamydial infections, could contribute to the pathogenetic processes that lead to the metabolic and hormonal disorders of PCOS.

Significance of positive Chlamydia serology in women with normal-looking Fallopian tubes

Chlamydia trachomatis poses a potential threat to the fertility of women by causing tubal damage. Many women with serological evidence of past Chlamydia infection have normal tubal appearances on laparoscopic assessment. The aim of this study was to assess if serological evidence of past chlamydial infection affects the likelihood of conception in women with normal tubes. Infertile couples in which the female partner was under the age of 40 years, with normal ovulatory function and a male partner with normal sperm function were studied. All women had normal tubes as assessed by laparoscopy. Serum Chlamydia antibody titres were assayed using the immunofluorescence test. Pregnancy rates were related to grouped Chlamydia antibody titres (<64, 64-256 and > or =512). A total of 174 women were studied. The cumulative pregnancy rates (SE) according to these titres were 45.1% (6.2), 42.6% (9.3), 59.1% (11.8) and the risk ratios (95% confidence interval) were 1, 1.59 (0.82-3.07) and 1.04 (0.52-2.08) respectively. The differences were not statistically significant. Therefore, in women with normal-looking tubes, serological evidence of past chlamydial infection does not appear to have an adverse effect on pregnancy rates. These findings suggest that laparoscopic findings and not Chlamydia serological titres are the key to prognosis.

Epidemiology of Chlamydia trachomatis infection in women and the cost-effectiveness of screening

The majority of Chlamydia trachomatis infections in women are asymptomatic, but may give rise to pelvic inflammatory disease (PID) and tubal infertility. Screening programmes aim at reducing morbidity in individuals by early detection and treatment, and at decreasing the overall prevalence of infection in the population. A number of modelling studies have tried to calculate the threshold prevalence of chlamydia lower genital tract infection above which screening becomes cost-effective. There is considerable debate over the exact complication rates after chlamydia infections, and more precise estimates of PID and tubal infertility are needed, for instance to be inserted in economic models. With reference to key studies and systematic reviews, an overview is provided focusing on the epidemiology of chlamydia infection and the risk-estimates of its late complications. In the literature, the generally assumed risk of developing PID after lower genital tract chlamydia infection varies considerably, and is up to 30%. For developing tubal infertility after PID the risks are 10-20%. This implies that the risk of test-positive women of developing tubal infertility would range between 0.1 and 6%. We included chlamydia IgG antibody testing in a model and estimated a risk of tubal infertility up to 4.6%. The risk of developing late complications after chlamydia lower genital tract infection appears low. High quality RCTs dealing with the transition from cervicitis to infertility are needed to broaden the evidence. In screening programmes, chlamydia antibody testing, as an intermediate marker for potential adverse sequelae, might enable more precise estimates.

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.

O440 The survey of anti Chlamydia antibody in infertile women undergoing diagnostic laparoscopy in Afzalipour medical centre, Kerman – Iran

O440 The survey of anti Chlamydia antibody in infertile women undergoing diagnostic laparoscopy in Afzalipour medical centre, Kerman – Iran

The relationship between serum Chlamydia antibody levels and severity of disease in infertile women with tubal damage

The study explores the relationship between serum Chlamydia antibody titres (CAT) using the whole-cell inclusion immunofluorescence (WIF) test and severity of tubal damage in infertile women undergoing laparoscopy. Comparisons between the extent of specific lesions, including their severity found at laparoscopy, and CAT levels were analysed in 408 infertile women with tubal damage. CAT levels were assayed using the WIF test. There were significant differences in the severity of individual lesions (tubal occlusion, tubal pathology, fimbrial state, extent and type of tubal and ovarian adhesions, type of tubal and ovarian adhesions) for both left and right adnexa in relation to CAT (P < 0.0001). The presence and severity of lesions found in one adnexum significantly correlated with the findings on the contra-lateral side (r > 0.5; P < 0.01). The American Fertility Society grades for tubal occlusion and adhesions in the right adnexum did not correlate with CAT. CAT levels are quantitatively related to the severity of tubal damage in infertile women. Wide variations in the severity of lesions observed in relation to CAT were suggestive of broad individual differences in response to chlamydial infection.

Prediction of pelvic pathology in subfertile women with combined Chlamydia antibody and CA-125 tests

Objectives Chlamydia antibody test (CAT) has been proposed to predict tubal disease. A correlation between CA-125 and the extent of endometriosis has been found by others. In this study we explored whether a combination of the two tests adds to the predictive value of the individual tests for predicting tubal disease or endometriosis. We also used the combination of tests as a new index test to screen for severe pelvic pathology. Study design This retrospective study compares the findings of 240 laparoscopies with the serological test results. Findings were classified according to the existing ASRM scoring systems for adnexal adhesions, distal tubal occlusion and endometriosis. Severe pelvic pathology was defined as the presence of ASRM classes III and IV tubal disease or ASRM classes III and IV endometriosis. The predictive value was calculated for both tests separately and for the combined test. The combined test was positive if at least one test result was abnormal (CAT positive and/or CA-125 ≥35 IU/ml). Results 67/240 women had tubal disease, 81/240 had some degree of endometriosis. The odds ratios (ORs) of the CAT and the combined test to diagnose severe tubal disease were 6.6 (2.6–17.0) and 7.3 (2.9–19.3), respectively. The ORs of the CA-125 and the combined test to diagnose severe endometriosis were 15.6 (6.2–40.2) and 3.0 (1.2–8.0), respectively. Severe pelvic pathology was present in 65/240 women (27%). The ORs for severe pelvic pathology of the CAT, CA-125 and the combined test were 2.5 (1.4–5.3), 4.9 (1.9–9.6) and 6.6 (3.3–13.4), respectively. If the combined test was normal 15 out 131 women (11%) were shown to have severe pelvic pathology. Conclusions The combined test adds hardly anything to the predictive value of CAT alone to diagnose severe tubal disease. The combined test is better than the CAT to predict severe pelvic pathology, but is not significantly better than the CA-125. If both the CAT and CA-125 are normal one could consider not performing a laparoscopy.

The basic fertility work up in who class II anovulatory women; usefull or redundant? A systematic review

OBJECTIVE: The first line treatment in WHO class II anovulatory patients is clomiphene citrate (CC). Once women become ovulatory after previous anovulation, there is a tendency to start a basic fertility work-up. However, one could hypothesize that in the presence of anovulation, which is an explanation per se for infertility, the prevalence of other causes of subfertility, may be decreased in comparison to patients suffering from subfertility for more than a year. DESIGN: We performed a systematic review to summarize the best available evidence regarding the value of a basic fertility work-up in WHO class II women once ovulatory on CC. MATERIALS AND METHODS: A literature search in MEDLINE, Embase and Cochrane library was performed to assess the potential value of basic fertility work up, including a semen-analysis, postcoital test, Chlamydia antibody titre, hysterosalpingography and diagnostic laparoscopy. RESULTS: We could identify only four studies. A prospective cohort study described the Chlamydia antibody titre. The sensitivity of the test to detect bilateral tubal pathology was 9% and the specificity 96%. A second and third study from 1983 and 1984 reported about the semen analysis, post coital test and tubal tests. Only a part of the population of interest was tested, follow up for pregnancy rates were lacking or total performed tests was unknown and the group size was small which made it impossible to draw conclusions. A fourth prospective follow up study was performed to identify parameters which could predict conception, but no significant predictors in the fertility work up were found. CONCLUSIONS: The present review shows there is no evidence to perform a basic fertility work up the women described and does not allow us to give firm recommendations. Routine use of these tests in these women might lead to unnecessary treatment. Effort should be focussed on studies on this subject, in stead of performing non-validated tests on a non-research setting.

Chlamydia trachomatis infections and the risk of ectopic pregnancy in Khon Kaen women

To determine the prevalence of Chlamydia trachomatis infection and to evaluate the relation of previous and persistent chlamydial infection to ectopic pregnancy (EP) among women in Khon Kaen, Thailand. We enrolled 32 EP patients in the case group. Control subjects were 57 women undergoing tubal ligation after normal labor. Serum immunoglobulin (Ig)G and IgA antibodies to C. trachomatis were determined using ELISA. Chlamydial DNA was investigated using polymerase chain reaction. The prevalence of chlamydial DNA in fallopian tube tissue was 34.38% of EP patients whereas none was detected in controls. In cervical cells, however, no significant difference in chlamydial DNA between cases (3.13%) and controls (3.51%) was detected. Serum-specific IgG was found more in the EP group than in the control group (21.88% and 5.26%, respectively; P < 0.05). Serum-specific IgA was detected in 5.26% of the control women but not in the EP group. Analysis by multivariate conditional logistic regression revealed a significant association between EP and the various risk factors. Among these, abortion, previous EP and age at first intercourse <15 years were strong predictors of EP. However, the association between specific IgG and EP became non-significant in this analysis. No strong independent association was shown between chlamydial antibodies and the EP risk in Thai women despite DNA detection in fallopian tube tissue. In contrast, factors including abortion, previous EP, and age at first intercourse <15 years were the significant predictors of EP. Efforts to address these other variables will help more in reducing the EP burden in Thai women compared to eliminating C. trachomatis.

Abstract: P1211 CARDIOVASCULAR DISEASE PARAMETERS IN PERIODONTITIS

The objective of this study was to investigate if patients with severe heart disease (CHD patients) present more signs of dental infections than patients without heart disease (non-CHD patients), if serum inflammatory markers differ between the groups, and if there is a link between these and the oral health parameters.We performed clinical and radiologic dental examinations and collected serum samples of 256 patients with New York Heart Association class II-IV heart disease (CHD patients) and 250 non-CHD controls. Serum samples were analysed using pertinent methods in the clinical laboratory of the hospital, and the differences in serum biomarkers between CHD patients and non-CHD patients were examined using various statistical methods. A modified dental index (MDI) was constructed and used in the analyses.CHD patients were significantly more likely to be edentulous (34.8% vs. 14.8%) and retain less natural teeth than non-CHD patients (8.6 vs. 17) (P < .001). In CHD patients the remaining teeth and supporting tissues were more often diseased. High MDI scores were significantly associated with CHD status (OR 1.31, CI 1.16-1.48), as was gingivitis (OR 3.37, CI 1.66-6.86), while the presence of deep periodontal pockets was not. Serum C-reactive protein and fibrinogen concentrations and blood erythrocyte sedimentation rates were higher in the CHD group. Also, H. pylori and Chlamydia antibodies were significantly higher in the CHD group.CHD patients presented with poorer oral health status than non-CHD patients. Serum inflammatory markers were significantly higher in the CHD patients compared to the non-CHD group. High MDI scores linked with risk of CHD.

Investigations on the detection of Chlamydia trachomatis infections in infertile male outpatients.

The determination of Chlamydia antibodies in serum is unsuitable for diagnosing infertility in men. The determination of secretory IgA in seminal plasma would seem to be of greater relevance. Since antibodies against C. trachomatis and C. pneumoniae can be detected, a species-specific test for the diagnosis of infections of the male genital tract should be used. Only at relatively high titers (> or = 1:400) do genus-specific tests agree with the species-specific micro-immunofluorescence test. Whether such values can be taken as a true indicator of a local, chronic infection remains to be investigated.

Pgp3 Antibody Enzyme-Linked Immunosorbent Assay, a Sensitive and Specific Assay for Seroepidemiological Analysis of Chlamydia trachomatis Infection

Understanding of the burden of Chlamydia trachomatis infection and its clinical sequelae is hampered by the absence of accurate, well-characterized tests using serological methods to determine past exposure to infection. An "in-house" immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) based on the C. trachomatis-specific antigen Pgp3 was produced and evaluated against three commercial ELISAs derived from the major outer membrane protein: the Medac pELISA plus, the Savyon SeroCT-IgG ELISA, and the Ani Labsystems IgG enzyme immunoassay. Sensitivities and specificities were determined using sera from both male and female patients (n = 356) for whom C. trachomatis had been detected in the lower genital tract at least 1 month prior to the testing of the sample and from 722 Chlamydia-negative children aged 2 to 13 years. The Pgp3 ELISA was significantly more sensitive (57.9% [95% confidence interval {95% CI}, 52.7 to 62.9%]) than the Ani Labsystems (49.2% [95% CI, 44.0 to 54.3%]; P = 0.003), SeroCT (47.2% [95% CI, 42.1 to 52.4%]; P < 0.0005), and Medac (44.4% [95% CI, 39.3 to 49.6%]; P < 0.0005) ELISAs. The Pgp3, Ani Labsystems, and SeroCT assays, but not the Medac assay, had significantly higher sensitivity for female specimens than for male specimens (73.8 versus 44.2%, 59.8 versus 40.5%, 55.5 versus 40%, and 45.7 versus 43.7%, respectively). For female patients, the Pgp3 assay was 14.0% (95% CI, 5.5 to 22.5%) more sensitive than the next most sensitive ELISA, the Ani Labsystems assay (P = 0.001). There was no significant difference in specificity between the Pgp3 (97.6% [95% CI, 96.2 to 98.6%]), Ani Labsystems (99% [95% CI, 97.7 to 99.6%]), SeroCT (97.2% [95% CI, 95.7 to 98.2%]), and Medac (96% [95% CI, 94.3 to 97.2%]) ELISAs. None of the ELISAs showed evidence of cross-reactivity with antibodies to Chlamydia pneumoniae.