Antibody type specificity to trachoma in eye secretions of saudi arab children

Eradicating blinding trachoma: What is working?

Trachoma remains the leading cause of preventable corneal blindness in developing countries. The disease is contracted in early childhood by repeated infection of the ocular surface by C. trachomatis. Initial clinical manifestation is a follicular conjunctivitis which if not treated on timely basis, may lead to conjunctival and eyelid scarring that may eventually result in corneal scarring and loss of vision. Over the past two decades, a remarkable reduction in the prevalence of active trachoma has occurred due to the World Health Organization's (WHOs) program GET 2020 for the elimination of trachoma with adoption of the SAFE strategy incorporating Surgery, Antibiotic treatment, Facial cleanliness and Environmental hygiene. However, patients who already had infection at young age may present with adnexal-related complications of trachomatous scarring that may cause corneal scarring and visual loss. These patients may present with evidence of trichiasis/entropion as well as eyelid retraction. Lacrimal complications may include nasolacrimal-duct obstruction, dacryocystitis and canaliculitis requiring intervention. In addition to the increased risk for corneal scarring, trichiasis/entropion may further increase the risks for microbial keratitis in patients who may have unrecognized dacryocystitis and canaliculitis. Female patients may have more trachomtous-related complications and may present at an early age. Available evidence indicates that SAFE strategy may be effective and on the right track towards achieving GET 2020 goal for the eradication of trachoma.

The influence of local antichlamydial antibody on the acquisition and persistence of human ocular chlamydial infection: IgG antibodies are not protective

In order to study the effect of antichlamydial antibodies in ocular secretions on resistance to ocular chlamydial infection and clearance of this infection, we have performed linked longitudinal studies in a Gambian village in which trachoma is endemic. We have measured IgG and IgA antibody levels to a local serotype B isolate of Chlamydia trachomatis by amplified enzyme immunoassay, and chlamydial antigen levels in conjunctival swabs using a commercially available immunoassay which detects chlamydial glycolipid. Having previously demonstrated that sharing a bedroom with a case of active trachoma is a risk factor for acquisition of the disease, we have analyzed the effect of IgG and IgA antibody on the acquisition and persistence of clinical trachoma after controlling for age, sex, exposure to infection and for the presence of chlamydial antigen using a Poisson regression model. We have found that the presence of antichlamydial IgG in ocular secretions of disease-free subjects is associated with an increased incidence of trachoma. IgA antibody shows an opposite trend, but this is not statistically significant. One possible explanation of these findings is that antichlamydial IgG antibodies enhance the infectivity of C. trachomatis for the human eye; this could have major implications for the development of a chlamydial vaccine.

Antichlamydial antibody in tears and sera, and serotypes of Chlamydia trachomatis isolated from schoolchildren in Southern Tunisia

A predominance of TRIC serotype A has been isolated from schoolchildren in a population in Southern Tunisia with severe hyperendemic trachoma. The serotyping results correspond precisely with the serological findings in patients' tears and sera. Geometric mean titres of serum or tear antibody in defined populations or areas can thus give a useful indication of the prevalent serotypes. Collection of tear fluids on sponges is a more practical method than collection by filter paper strips and gives higher levels of antibody. The presence of antibody to Chlamydia trachomatis in tears correlates well with the presence of infectious agent in the eye and with the intensity of conjunctival inflammatory disease. The measurement of antichlamydial tear antibody can thus provide a meaningful index of the prevalence and intensity of active trachoma in a population. The role these antibodies may play in resistance to re-infection is not yet clear.

Trachoma in a rural Haitian community

We selected 43 patients, aged 15 days to 57 yesrs, for intensive study after screening 975 people for clinical evidence of trachoma in rural Haiti. Trachoma was present in Haiti with low endemicity and was followed by relatively mild sequelae. Laboratory studies confirmed the disease through demonstration of conjunctival inclusion bodies by immunofluoresence and serotyping of antibody in sera or eye secretions, or both. Of 23 patients (age 1 to 36 years) with active trachoma, all had serum antibody to chlamydia (range 1:10 to 1:640), nine had eye secretion antibody (range 1:10 to 1:1280), and one was inclusion positive. The remaining 20 patients (age 15 days to 57 years) had the following diagnosis: atypical follicles (eight), conjunctivitis with or without mucopurulent discharge (ten) innactive pannus only (one), and severe anemia (one). Only 16 of the 20 were tested for serum antibody and all were positive (1:10 to 1:5,120), 11 of 20 had eye secretion antibody (1:10 to less than or equal to 1:640), and one was inclusion positive. Serotyping attempted on 22 patients yielded 16 patients with antibodies specific for type A, one patient with type B, and five who were not typed.

Neutralization of Chlamydia trachomatis in cell culture

Neutralization of Chlamydia trachomatis was assayed by the decrease in inclusion-forming units in baby hamster kidney cells grown in culture. Five percent fresh guinea pig sera increased neutralization titers of rabbit antisera 100- to 1,000-fold but had no effect when normal rabbit sera were tested. Neutralization of a type A or B trachoma isolate was strain specific. Neutralization by human eye secretions and sera also was demonstrated when guinea pig sera were included in the test. All of the six human sera tested showed strain specificity against types A or B, in agreement with typing by the fluorescent antibody technique.