Evaluation of oral mucosal transudate for immunodiagnosis of Chagas´ disease

Abstract

The infectious diseases are diagnosed by the detection of specific immunoglobulins in serum, and the drawn blood with needlestick injuries makes this procedure somewhat unattractive. Oral mucosal transudate (OMT), a saliva component, is a serous fluid rich in IgG that comes from transudation at the gingival crevice and across oral mucosal surfaces. This biological fluid has been used as an alternative for detection of antibodies against a variety of viral agents including hepatitis A, B and C virus, HIV and S. mansoni antigens 2,3,10 . This alternative method have shown results as accurate as those obtained with serum samples.In the present communication we report the evaluation of oral mucosal transudate for the diagnosis of Trypanosoma cruzi infection using an immunoenzymatic assay.Twenty-one individuals proved (clinically, electrocardiographically, serologically and epidemiologically) to have chronic Chagas´ disease: 10 with cardiac form, 2 with digestive form, 6 with mixed form and 3 with asymptomatic form were studied. Seven individuals from endemic area, with negative serology, constituted the control group. Blood samples from these groups were taken by venopuncture and the sera obtained were stored at -20 o C. All individuals were tested for Chagas´ disease using two serological assay according to LUQUETTI et al. 5 .For the colection of the OMT from both groups, the collect device OraSure ® , Epitope Inc., Beaverton, OR, USA, was used. The paper pad was placed between the lower gum and cheek for 4 min. After collection, the pad was placed in a tube containing 1 ml of a bacteriostatic solution and stored at 4 o C by four days. The sample was recovered from the pad by centrifugation and stored at -20 o C until use.The Abbott Chagas antibody enzyme immunoassay (EIA) kit was used to detect anti-T. cruzi IgG. We used the 1:2 dilution for assaying OMT samples that were tested in duplicate. The cut-off was calculated on the basis of the optical density (OD) values from negative controls (oral samples from endemic area) plus two standard deviations (SD).The results of individual anti-T. cruzi specific IgG in OMT samples are shown in the Fig. 1. Twenty from twenty one chagasic patients presented the OD above the cut-off value (0.140) and were considered positive for Chagas´ disease. None of the OMT samples from the seronegative individuals were positive. The sensitivity and specificity were 95% and 100%, respectively. The confidence interval to sensitivity of 95% was 86% to 100%.Recently, a ELISA test, using whole saliva, was developed by PINHO et al. (1999) to detect specific IgG in a population of T. cruzi infected individuals. The sensitivity and specificity in this test were 90.4% and 95%, respectively. Whole saliva is a mixture of secretions from the parotid, submandibular, and minor salivary glands, and serum transudates from the capillaries beneath the bucal mucosae and from the gingival crevice as well as mucin, bacteria, leukocytes, and sloughed epithelial cells. The primary limitation of whole saliva as ...

Efficiency of oral fluid collection devices in extracting antibodies

“…Moreover, no significant differences in the sensitivity for anti‐hepatitis C IgG in oral fluid specimens collected by Salivette and saliva•sampler were reported (28). Despite their selective performance, oral fluids collected by the OraSure oral specimen collection device and/or saliva•sampler provided sufficient quantities of specific antibody concentrations for the detection of IgG against rubella virus, parvovirus B19 (29), HIV (12, 19), measles virus (27), and Trypanosoma cruzi (3).…”

TONGUE FUNCTION, SALIVARY FLOW RATE AND IgA, IgM AND IgG TOTAL SALIVARY LEVELS IN CHRONIC CHAGASIC PATIENTS

“…Although microscopic changes in the chagasic tongue have been described (Pereira et al, 2006;Pereira et al, 2007;Pereira et al 2009) and IgG antibodies anti-T. cruzi IgG have already been detected in infected patients (Barros et al, 1999), there are no studies evaluating lingual function and total antibody levels in the saliva of chagasic patients. Thus, the purpose of the present study was to evaluate the tongue function, salivary flow rate and total immunoglobulin A (IgA), immunoglobulin M (IgM) and immunoglobulin G (IgG) levels in the saliva of chronic chagasic patients in comparison with noninfected individuals.…”