Direct fluorescent antibody assay and polimerase chain reaction for detection of Chlamydia trachomatis in patients with vernal keratoconjunctivitis

• Grant number: 11/18034-3
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: October 01, 2011
• End date: March 31, 2012
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Paulo Elias Correa Dantas
• Grantee: Paulo Elias Correa Dantas
• Host Institution: Faculdade de Ciências Médicas da Santa Casa de São Paulo (FCMSCSP). Fundação Arnaldo Vieira de Carvalho. São Paulo , SP, Brazil

Abstract

Objectives: To identify Chlamydia trachomatis via polymerase chainreaction and direct fluorescent antibody assay in patients with vernalkeratoconjunctivitis, comparing the efficacy of both tests in detectingChlamydia trachomatis in such condition.Methods: Conjunctival scraping samples were obtained from 177patients, divided into two groups (vernal keratoconjunctivitis andcontrol group). Polymerase chain reaction and direct fluorescent antibodyassay were performed. Sensitivity, specificity, ROC (receiver operating characteristic) curves and area under the curves were calculated for both tests in groups A and B. ROC curves were plotted using a categorical variable with only two possible outcomes (positive and negative)Results: Statistical analysis showed significant association between VKC and Chlamydia trachomatis infection detected by direct fluorescent antibody with high sensitivity and specificity. All patients in group A with positive polymerase chain reaction also presented with positive direct fluorescent antibody.Discussion: Association between vernal keratoconjunctivitis andChlamydia trachomatis infection was confirmed by positive directfluorescent antibody in 49.4% of vernal keratoconjunctivitis patientsand positive polymerase chain reaction in 20%. Direct fluorescentantibody detected Chlamydia trachomatis in a higher number ofpatients than polymerase chain reaction. Although the diagnosis oftrachoma is essentially clinical, the disease may not be detected invernal keratoconjunctivitis patients. Conclusion: Due to the high frequency of Chlamydial infection detected in patients with vernal keratoconjunctivitis, we suggest considering laboratorial tests to detect Chlamydia trachomatis as routine in patients with severe and refractory allergic disease. (AU)