Chlamydia antibody testing in screening for tubal factor subfertility: the significance of IgG antibody decline over time

[Update of Chlamydia trachomatis infection]

Chlamydia trachomatis (CT) is the most common sexually transmitted bacterial infection worldwide. It is asymptomatic in most cases and mainly affects young women, with potential long term sequelae (pelvic inflammatory disease, tubal infertility, obstetric complications). The impact on male fertility is controversial. Screening methods as well as antibiotics use have recently been reassessed due to resistance phenomena and the negative effect on the urogenital microbiota. Positive CT serology may be indicative of tuboperitoneal pathology, which may not be noticed on hysterosalpingography. New research on single-nucleotide polymorphisms (SNPs) aims to establish a patient profile at higher risk of infectious tubal damage due to CT. CT seropositivity is also associated with decreased spontaneous pregnancy rates and is a predictive factor for obstetrical complications.

Evaluation of a PGP3 ELISA for surveillance of the burden of Chlamydia infection in women from Australia and Samoa

Serological assays can be used to investigate the population burden of infection and potentially sequelae from Chlamydia. We investigated the PGP3 ELISA as a sero-epidemiological tool for infection or sub-fertility in Australian and Samoan women. The PGP3 ELISA absorbance levels were compared between groups of women with infertility, fertile, and current chlamydial infections. In the Australian groups, women with chlamydial tubal factor infertility had significantly higher absorbance levels in the PGP3 ELISA compared to fertile women (P < 0.0001), but not when compared to women with current chlamydial infection (P = 0.44). In the Samoan study, where the prevalence of chlamydial infections is much higher there were significant differences in the PGP3 ELISA absorbance levels between chlamydial sub-fertile women and fertile women (P = 0.003). There was no difference between chlamydial sub-fertile women and women with a current infection (P = 0.829). The results support that the PGP3 assay is effective for sero-epidemiological analysis of burden of infection, but not for evaluation of chlamydial pathological sequelae such as infertility.

Combining individual Chlamydia trachomatis IgG antibodies MOMP, TARP, CPAF, OMP2, and HSP60 for tubal factor infertility prediction

PROBLEM

Tubal factor infertility (TFI) is a severe complication of genital Chlamydia trachomatis infections. In fertility workup, chlamydia antibody test (CAT) is used to predict TFI. The predictive value for TFI of most commonly used CAT is moderate.

METHOD OF STUDY

A total of 183 infertile Dutch Caucasian women were included in this study. All underwent tubal patency testing (hysterosalpingography [HSG] or laparoscopy). Cases had TFI, and controls had no TFI (ie normal findings during HSG or laparoscopy). TFI was categorized based on severity (TFI 1-TFI 4). This study investigated the predictive values of major outer membrane protein (MOMP), translocated actin-recruiting phosphoprotein (TARP), chlamydial protease-like activity factor (CPAF), heat shock protein-60 (HSP60) and outer membrane protein 2 (OMP2) for TFI. A predictive algorithm is developed to detect TFI with a high certainty based on combinations of antibody titres. Serum was tested with the Mikrogen recomLine immunoblot and quantified with the recomScan. A greedy algorithm that explores all possible antibody combinations was developed.

RESULTS

Significant differences in the distributions of antigen titres between cases and controls were observed for CPAF (P = 0.0021), HSP60 (P = 0.0061), MOMP (P = 0.0497) and OMP2 (P = 0.0016). Single antibodies could not discriminate between TFI and controls by themselves. The greedy algorithm performs better in specificity, positive predictive value (PPV), accuracy and clinical utility index than the original Mikrogen algorithm. CPAF combined with HSP60 identified 18.2% of TFI cases with 100% certainty. Most of the TFI 4 cases were identified with cut-offs of CPAF > 10.7 or OMP2 > 3.9.

CONCLUSION

This proof-of-principle study shows that combinations of antibodies in serum are predictive for TFI. A commercially available test can be adapted to predict TFI with a 100% specificity.

Chlamydia trachomatis antibody detection in home-collected blood samples for use in epidemiological studies

Capillary blood collected in serum tubes was subjected to centrifugation delay while stored at room temperature. Chlamydia trachomatis (CT) IgG concentrations in aliquoted serum of these blood samples remained stable for seven days after collection. CT IgG concentrations can reliably be measured in mailed blood samples in epidemiological studies.

Serology reflects a decline in the prevalence of trachoma in two regions of The Gambia

Trachoma is caused by Chlamydia trachomatis (Ct). It is targeted for global elimination as a public health problem. In 2014, a population-based cross-sectional study was performed in two previously trachoma-endemic areas of The Gambia. Participants of all ages from Lower River Region (LRR) (N = 1028) and Upper River Region (URR) (N = 840) underwent examination for trachoma and had blood collected for detection of antibodies against the Ct antigen Pgp3, by ELISA. Overall, 30 (1.6%) individuals had active trachoma; the prevalence in children aged 1-9 years was 3.4% (25/742) with no statistically significant difference in prevalence between the regions. There was a significant difference in overall seroprevalence by region: 26.2% in LRR and 17.1% in URR (p < 0.0001). In children 1-9 years old, seroprevalence was 4.4% in LRR and 3.9% in URR. Reversible catalytic models using information on age-specific seroprevalence demonstrated a decrease in the transmission of Ct infection in both regions, possibly reflecting the impact of improved access to water, health and sanitation as well as mass drug administration campaigns. Serological testing for antibodies to Ct antigens is potentially useful for trachoma programmes, but consideration should be given to the co-endemicity of sexually transmitted Ct infections.

Estimating Loss of Brucella Abortus Antibodies from Age-Specific Serological Data In Elk

Serological data are one of the primary sources of information for disease monitoring in wildlife. However, the duration of the seropositive status of exposed individuals is almost always unknown for many free-ranging host species. Directly estimating rates of antibody loss typically requires difficult longitudinal sampling of individuals following seroconversion. Instead, we propose a Bayesian statistical approach linking age and serological data to a mechanistic epidemiological model to infer brucellosis infection, the probability of antibody loss, and recovery rates of elk (Cervus canadensis) in the Greater Yellowstone Ecosystem. We found that seroprevalence declined above the age of ten, with no evidence of disease-induced mortality. The probability of antibody loss was estimated to be 0.70 per year after a five-year period of seropositivity and the basic reproduction number for brucellosis to 2.13. Our results suggest that individuals are unlikely to become re-infected because models with this mechanism were unable to reproduce a significant decline in seroprevalence in older individuals. This study highlights the possible implications of antibody loss, which could bias our estimation of critical epidemiological parameters for wildlife disease management based on serological data.

Validity of self-reported history of Chlamydia trachomatis infection

BACKGROUND

Chlamydia trachomatis infection is common and largely asymptomatic in women. If untreated, it can lead to sequelae such as pelvic inflammatory disease and infertility. It is unknown whether a patient's self-reported history of Chlamydia trachomatis infection is a valid marker of past infection.

OBJECTIVE

Our objective was to evaluate the validity of women's self-reported history of Chlamydia trachomatis infection compared with Chlamydia trachomatis serology, a marker for previous infection.

STUDY DESIGN

We analyzed data from the Fertility After Contraception Termination study. We compared participants' survey responses with the question, "Have you ever been told by a health care provider that you had Chlamydia?" to serological test results indicating the presence or absence of antibodies to Chlamydia trachomatis as assessed by a microimmunofluorescence assay. Prevalence of past infection, sensitivity, specificity, predictive values, and likelihood ratios were calculated. The Cohen's kappa statistic was computed to assess agreement between self-report and serology.

RESULTS

Among 409 participants, 108 (26%) reported having a history of Chlamydia trachomatis infection, whereas 146 (36%) had positive serological test results. Relative to positive microimmunofluorescence assay, the sensitivity and specificity of self-reported history of Chlamydia trachomatis infection were 52.1% (95% confidence interval, 43.6-60.4%) and 87.8% (95% confidence interval, 83.3-91.5%), respectively. The positive predictive value of the self-report was 70.4% (95% confidence interval, 60.8-78.8%), and the negative predictive value was 76.7% (95% confidence interval, 71.6-81.4%). The likelihood ratio was found to be 4.28. Agreement between self-report and serology was found to be moderate (kappa = 0.42, P < .001).

CONCLUSION

Self-reported history of Chlamydia trachomatis infection commonly yields false-negative and false-positive results. When definitive status of past Chlamydia trachomatis infection is needed, serology should be obtained.

Background review for the '2015 European guideline on the management of Chlamydia trachomatis infections'

SummaryChlamydia trachomatis infections are major public health concerns globally. Of particular grave concern is that the majority of persons with anogenital Chlamydia trachomatis infections are asymptomatic and accordingly not aware of their infection, and this silent infection can subsequently result in severe reproductive tract complications and sequelae. The current review paper provides all background, evidence base and discussions for the 2015 European guideline on the management of Chlamydia trachomatis infections (Lanjouw E, et al. Int J STD AIDS 2015). Comprehensive information and recommendations are included regarding the diagnosis, treatment and prevention of anogenital, pharyngeal and conjunctival Chlamydia trachomatis infections in European countries. However, Chlamydia trachomatis also causes the eye infection trachoma, which is not a sexually transmitted infection. The 2015 European Chlamydia trachomatis guideline provides up-to-date guidance regarding broader indications for testing and treatment of Chlamydia trachomatis infections; clearer recommendation of using validated nucleic acid amplification tests only for diagnosis; advice on (repeated) Chlamydia trachomatis testing; recommendation of increased testing to reduce the incidence of pelvic inflammatory disease and prevent exposure to infection and recommendations to identify, verify and report Chlamydia trachomatis variants. Improvement of access to testing, test performance, diagnostics, antimicrobial treatment and follow-up of Chlamydia trachomatis patients are crucial to control its spread.

2015 European guideline on the management of Chlamydia trachomatis infections

Chlamydia trachomatis infections, which most frequently are asymptomatic, are major public health concerns globally. The 2015 European C. trachomatis guideline provides: up-to-date guidance regarding broader indications for testing and treatment of C. trachomatis infections; a clearer recommendation of using exclusively-validated nucleic acid amplification tests for diagnosis; advice on (repeated) C. trachomatis testing; the recommendation of increased testing to reduce the incidence of pelvic inflammatory disease and prevent exposure to infection; and recommendations to identify, verify and report C. trachomatis variants. Improvement of access to testing, test performance, diagnostics, antimicrobial treatment and follow-up of C. trachomatis patients are crucial to control its spread. For detailed background, evidence base and discussions, see the background review for the present 2015 European guideline on the management of Chlamydia trachomatis infections (Lanjouw E, et al. Int J STD AIDS. 2015).

Prevalence and diagnostic significance of specific IgA and anti-heat shock protein 60 Chlamydia trachomatis antibodies in subfertile women

The objective of the present study was to evaluate the clinical usefulness of the simultaneous measurement of three serological markers of chlamydial infection in women with tubal factor infertility (TFI) and spontaneous miscarriage. Serum was collected from 87 patients (33 with TFI and 54 with spontaneous miscarriage) and analyzed for the presence of IgG and IgA antibodies against Chlamydia trachomatis MOMP antigen (Dia.Pro) and IgG antibodies to chlamydial heat shock protein 60 (cHSP60) antigen (Medac). We determined a high degree (64.5 %) of seropositivity against chlamydial antigens in our study population. The prevalence of persistent chlamydial infection has tended to be higher in the group of patients with TFI (41.4 %) than in patients with spontaneous miscarriage (21.3 %). The serum level of IgA, as a marker of active infection, was statistically higher in the TFI group with persistent infection than in the corresponding spontaneous miscarriage group (p = 0.008), while the serum level of IgG showed no statistically significant differences compared with the spontaneous miscarriage group with persistent infection (p = 0.227). Also, using the receiver operating characteristic (ROC) curve, we found that the serum level of IgA has the ability to discriminate patients with persistent chlamydial infection between the TFI and miscarriage groups, with a sensitivity and specificity of 74.3 % and 71.4 %, respectively. To the best of our knowledge, the present study is the first study which, besides the already confirmed linkage between serologic evidence of persistent chlamydial infection and TFI, also confirmed associations between spontaneous miscarriage and serologic evidence of persistent chlamydial infection.

Chlamydia trachomatis infections of the female genital tract: state of the art

Chlamydia trachomatis (CT) is the most common bacterial cause of sexually transmitted infections. CT infections are strongly associated with risk-taking behavior. Recommendations for testing have been implemented in many countries. The effectiveness of the screening programs has been questioned since chlamydia rates have increased. However, the complication rates including pelvic inflammatory disease, tubal factor infertility, and tubal pregnancy have been decreasing, which is good news. The complication rates associated with CT infection have clearly been over-estimated. Genetic predisposition and host immune response play important roles in the pathogenesis of long-term complications. CT plays a co-factor role in the development of cervical neoplasia caused by high-risk human papillomavirus (HPV) types. The evidence linking CT and other adverse pregnancy outcomes is weak. The current nucleic acid amplification tests perform well. A new genetic variant of CT was discovered in Sweden but has only rarely been detected elsewhere. Single-dose azithromycin remains effective against CT. Secondary prevention by screening is still the most important intervention to limit the adverse effects of CT on reproductive health.

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.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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%.

CONCLUSION

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.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Role of activins and inducible nitric oxide in the pathogenesis of ectopic pregnancy in patients with or without Chlamydia trachomatis infection

Chlamydia trachomatis infection can lead to pelvic inflammatory disease, ectopic pregnancy (EP), infertility, and chronic pelvic pain in women. Activins and inducible nitric oxide synthase (iNOS) are produced by the human fallopian tube, and we speculate that tubal activins and iNOS may be involved in the immune response to C. trachomatis in humans and their pathological alteration may result in tubal pathology and the development of EP. Blood and fallopian tubes were collected from 14 women with EP. Sera were analyzed by enzyme-linked immunosorbent assay to detect antibodies against chlamydial heat shock protein 60 (chsp60) and the major outer membrane protein of C. trachomatis. Confirmation of C. trachomatis serology was made using the microimmunofluorescence test. The patients were classified into three groups according to their serological results, and immunohistochemistry and quantitative reverse transcription-PCR were performed to investigate the expression of candidate molecules by tubal epithelial cells among the three groups. This is the first study to show an increase in the expression of activin betaA subunit, type II receptors, follistatin, and iNOS within the human fallopian tube of EP patients who were serologically positive for C. trachomatis. A similar expression profile was observed in the fallopian tubes with detectable antibodies only against chsp60. These results were shown at the mRNA and protein levels. We suggest that tubal activin A, its type II receptors, follistatin, and NO could be involved in the microbial-mediated immune response within the fallopian tube, and their pathological expression may lead to tubal damage and the development of EP.

Chlamydia trachomatis serology in women with and without ovarian cancer

Pelvic inflammation has been implicated in the genesis of ovarian cancer. We conducted serologic measurements of Chlamydia trachomatis antibodies as a surrogate marker of chlamydial pelvic inflammatory disease. Women with ovarian cancer (n = 521) and population-based controls (n = 766) were tested. IgG antibodies to serovar D of chlamydia elementary bodies (EBs) were detected using an ELISA assay. The odds of having ovarian cancer among women with the highest titers (>or=0.40 OD units) were 0.6 (95% CI 0.4-0.9). These data do not support our earlier finding of elevated titers for antibodies to C. trachomatis among women with ovarian cancer.

Seroprevalences of herpes simplex virus type 2, five oncogenic human papillomaviruses, and Chlamydia trachomatis in Katowice, Poland

Herpes simplex virus type 2 (HSV-2), human papillomaviruses (HPVs), and Chlamydia trachomatis are the most common pathogens causing sexually transmitted infections (STIs). There is limited information about the prevalences of these STIs in Poland. Here, we estimated the occurrence of immunoglobulin G (IgG) antibodies against HSV-2, HPV, and C. trachomatis in 199 blood donors and 110 patients of both genders attending an STI clinic in Katowice in southern Poland. The seroprevalences of HSV-2 were 5% for blood donors and 14% in the STI cohort. The seroprevalences of the five potentially oncogenic HPV types 16, 18, 31, 35, and 51 were 15%, 7%, 5%, 5%, and 17%, respectively, in blood donors and 37%, 8%, 12%, 5%, and 21%, respectively, in the STI cohort. The majority of HPV-infected individuals showed antibodies against more than one type, i.e., had been infected with multiple HPV types. Anti-C. trachomatis IgG antibodies were detected in 6% of blood donors and 13% of individuals attending the STI clinic. The relatively high prevalence of HPV-51 may have implications for future vaccine programs, as the newly introduced HPV vaccines are based on the potentially oncogenic HPV types 16 and 18.

Chlamydia trachomatis-associated tubal factor subfertility: Immunogenetic aspects and serological screening

Chlamydia (C.) trachomatis female genital tract infections usually remain asymptomatic and untreated. Therefore, an adequate immune response, rather than antibiotic treatment, is essential to clear the pathogen. Most women will effectively clear C. trachomatis infections, but some will have persistent C. trachomatis infections, which may ascend to the upper genital tract and increase the risk of tubal factor subfertility. Pattern recognition receptors (PRRs) of the toll-like receptor (TLR) and nucleotide-binding oligomerization domain (NOD) families recognize C. trachomatis and initiate the immune response. Host immune factors are determinants of the course of C. trachomatis infections. Genetic variations in TLR and NOD genes may affect receptor function, leading to inadequate recognition of C. trachomatis, an inadequate immune response, and consequently an increased risk of persistence and late sequelae. For the risk assessment of tubal pathology in subfertile women, C. trachomatis immunoglobulin (Ig) G antibody testing (CAT) in serum is widely used. A positive CAT is indicative of a previous infection but not of a persistent infection. Measuring serological markers of persistence, of which C-reactive protein (CRP) seems promising, in CAT-positive women may identify a subgroup of subfertile women with persistent C. trachomatis infections and the highest risk of tubal pathology.

Chlamydia trachomatis and chlamydial heat shock protein 60-specific antibody and cell-mediated responses predict tubal factor infertility

BACKGROUND

To evaluate the role of Chlamydia trachomatis-induced humoral and cell-mediated immune (CMI) responses in predicting tubal factor infertility (TFI).

METHODS

Blood samples were taken from 88 women with TFI and 163 control women. C. trachomatis and chlamydial heat shock protein 60 (CHSP60)-specific immunoglobulin G (IgG) antibodies were analysed using enzyme-linked immunosorbent assay (ELISA) kits. Proliferative reactivity of peripheral blood mononuclear cells was studied in vitro against Chlamydia elementary body (EB) and recombinant CHSP60 antigens.

RESULTS

C. trachomatis-specific IgG antibodies were found more frequently (43.2 versus 13.5%), and the antibody levels were higher in the TFI cases than in the controls (P < 0.001). C. trachomatis EB-induced lymphocyte responses were positive in 81.8% of the TFI cases and 58.9% of the controls (P < 0.001). Similarly, CHSP60-induced lymphocyte responses were found in 45.5% of the TFI cases and 30.7% of the controls (P < 0.001). CHSP60 antibody test was the best single test predicting TFI. Compared to cases with all four markers negative, the estimated risk for TFI was 4.1 (95% CI 1.4-11.9) among those with one positive marker and 19.9 (95% CI 6.9-57.4) among those with three to four positive markers.

CONCLUSION

Our results show that TFI prediction model can be improved by combining tests for humoral and CMI response to chlamydial antigens.

Prevalence of antibodies against feline coronavirus and Chlamydophila felis in Swedish cats

Serum samples from 214 Swedish cats with no signs of infectious disease were analysed for the presence of antibodies against Chlamydophila felis (Cp felis), while 209 of these were also analysed for feline coronavirus (FCoV) antibodies. The prevalence of antibodies against Cp felis was 11%, with no significant difference between purebred and mixed breed cats. The overall prevalence of antibodies against FCoV was 31%, significantly higher among pure breed cats (65%) than among mixed breed cats (17%). A high proportion of cats with antibodies against FCoV had relatively high antibody titres, and was therefore likely to be shedding FCoV in faeces. For Cp felis, the majority of seropositive animals had relatively low antibody titres, and the risk of these animals infecting others is not known.

Tubal factor infertility, with special regard to chlamydial salpingitis

PURPOSE OF REVIEW

This article will highlight recent research into tubal factor infertility as one of the main causes of involuntary childlessness in women. There will be a focus on chlamydial infections.

RECENT FINDINGS

The most common cause of tubal factor infertility is occlusion of the fallopian tubes due to an infection by a sexually transmitted agent, by Chlamydia trachomatis or Neisseria gonorrhoeae. The prevalence of diagnosed cases of tubal factor infertility (TFI) can be correlated to the epidemiological situation regarding these agents that was prevailing several years ago. This is partly due to the trend seen in many Western countries that women often postpone to try to get pregnant. Therefore, there is often a time lag between the acute primary pelvic inflammatory disease (PID) and when women first consult because of fertility problems. Sub-clinical salpingitis is today regarded as even more common than symptomatic PID. Persistent tubal infections by C. trachomatis are also a common feature, even despite courses of antibiotic therapy. The current focus on TFI has been on the immunopathology of tubal chlamydial infections, for which differences in host factors, such as genetic polymorphism in cytokine response and human leukocyte antigen type, may play a role in the outcome of pelvic inflammatory disease. Hysterosonography is a more convenient mode for diagnosing tubal occlusion than hysterosalpingography. The use of new species-specific antibody tests for C. trachomatis has decreased previous specificity problems found when used to detect tubal occlusion in work-up of women consulting because of infertility.

SUMMARY

Infection by C. trachomatis is a major cause of TFI. Many cases of chlamydial salpingitis have a more or less subclinical course. The tubal infection may become chronic in spite of antibiotic therapy. Immunological processes may continue after microbiological cure, which stresses the importance of screening for C. trachomatis in order to detect and treat carriers to hinder spread to still uninfected women.

Chlamydia infection and subfertility

In the majority of women chlamydia infections remain asymptomatic but they may increase the risk for tubal factor subfertility. Pelvic inflammatory disease (PID) and its chronic sequelae are associated with chlamydial IgG antibody formation in serum, and a correlation between the height of antibody titres and the presence of tubal factor subfertility has been established. The predictive value of chlamydia antibody testing (CAT) is limited however. Several factors affecting sensitivity and specificity of CAT have been identified. Because it is assumed that the presence of chlamydial heat shock proteins (HSPs) may be indicative of chronic inflammation, chlamydial HSP60 antibody testing has been evaluated in its prediction of tubal factor subfertility.