Amravati, India (special for SIIC)

Oral fluids are advocated as painless, noninvasive alternative to serum for detection of antibodies to a number of specific bacterial, viral, fungal, and parasitic agents. GCF and saliva are distinct body fluids. Whole saliva and GCF differs by the fact that the Immunoglobulin G (IgG) content of the GCF is several times greater than that of saliva.

Comparative studies of whole saliva and gingival crevicular transudate or GCF will be necessary to determine true sensitivity of ELISA.

Thus the present study was carried out to detect the anti-HIV antibodies in GCF by ELISA with respect to their CD4 counts.

With permission of the ethical committee, the study was carried out between 37 HIV+ve (37-GCF, 10-saliva) and 37 HIV-ve individuals for a period of 7-8 months in 2006 in GDC Nagpur. HIV+ve individuals were the persons visiting the antiretroviral therapy (ART) clinic of Government dental and hospital, Nagpur. The persons visiting voluntary councelling and testing (VCTC) of Indira Gandhi Government medical college (IGGMC), Nagpur were included as the control (seronegative individuals), who were the suspected individuals but were negative for serum. All the clinically suspicious patients were subjected to serum analysis for HIV and were found.

The HIV+ patients were classified as: a) stage I: b) stage II: c) stage III: and d) stage IV.

Total 74 GCF samples were collected using Kimble disposable microcapillaries with expirator.

Disposable microcapillaries, ELISA kit, sterile bottles, cotton pellets, gloves, and masks were required.

Patients were seated with head slightly reclined. The site was dried and isolated. White colour coded 1-5 µl volumetric microcapillary was placed in the crevice for approximately 20-25 min and 5 µl of GCF was collected.

GCF and whole saliva samples were collected from the same patient. Saliva was collected by asking the patient to bend forward. The drooling saliva was collected in a sterile bottle. The collected samples were stored at -20 °C.

HIV-CheX ELISA kit was used according to manufacture’s instructions for processing of the samples. The samples were processed and were read under ELISA reader at 450 nm/650 nm within one hour.

Samples and reagents handled as potentially infectious agents and decontaminated in 5% sodium hypochlorite for 30-60 min before disposal.

Significant difference in the CD4 counts of stage I when compared with stage III and IV was noted.

Significant difference in the CD4 counts when stages II and IV, stage III and stage IV were compared respectively.

When mean Ab titres were compared were nonsignificant. The mean Ab titer of seropositive group (1.72 ± 0.595) was more. Unpaired “t” test and the “p” value was < 0.05 and showed significant differences between groups. Whole saliva and GCF when compared, the mean Ab titres were 1.737 and 1.780. Ab titre of GCF and mean OD (optical density) of GCF was higher than saliva. Paired ‘t” test was applied and “p” value was less than 0.05 (p = 0.008). This was statistically significant. Mean CD4 count of seropositive patients with oral manifestations and without oral manifestations was statistically significant (p = 0.011). Only 12 patients (32%) from study group showed oral manifestations. Ab titer of GCF when compared with serum the sensitivity, specificity, positive, negative predictive value of GCF was 100%.

In 1983 the virus first recognized by Barre-Sinoussi et al. Montagnier et al. in 1984 called it as human T cell leukemia/lymphoma virus (HTLV-III). Grassly et al. in 2001 discovered that HIV is transmitted by sexual contact, infectious blood or blood products. Scarlatti in 2004 focused on vertical transmission of this disease. The above mentioned conditions are prevented by public health measures like screening of donated blood and plasma for antibody to HIV, screening for HIV associated p24 antigen, Heat treatment of clotting factor concentrates, and screening of donors on the basis of history, with all these measures the risk of HIV transmission is reduced. However AIDS still remains the fifth most common cause of death in adults age between 25 and 44 years.

The primary target of HIV is CD4 subset of “T” cells resulting in the decrease in the CD4:CD8 cell ratio.

The enzyme labeled conjugates were first introduced in 1966 for localization of antigens in the tissues.

ELISA is the most commonly used test to screen HIV infection because of its relatively simple methodology, inherent high sensitivity, and suitability for testing large numbers of samples, particularly blood testing.

As newer advancement in technology, alternatives to the classic tests arise. Each offers more attractive features which simplify collection, testing or interpretation of results. Although generally referred to as “saliva” the fluid used for testing is actually crevicular fluid from gingival crevice, which is a transudate of blood and is therefore similar to the samples used in serum based tests.

Mortimer and Parry painted out that only 0.5 mg/l of IgG is required to have a very sensitive test for HIV.

In our study, HIV antibodies in GCF were detected with the new device which can be a promising screening procedure in diagnosis.

In 2003, Goodson stated that substance from outside do not penetrate the periodontal pocket that means the GCF inside the crevice uncontaminated, so the concentration of IgG is approximately 100 times more than saliva. It is now appreciated that GCF is formed as a blood ultrafiltrate.

Soto-Ramirez et al. studied gingival crevicular transudate and obtained sensitivity, specificity, and positive and negative predictive values of 99.5%, 100%, 100%, and 99.9% respectively. Whereas, in our study the sensitivity, specificity, and positive and negative predictive values of GCF were found to be 100%. The specificity, and positive and negative predictive values were comparable with our study. The sensitivity and negative predictive values were high in our study. The variation in these may be due to difference in the collection devices and method.

However GCF can be medium of choice instead of serum because of its non-invasive, painless, cost effectiveness, easy collection and less sample size. Samples Can be disposed off easily. The above findings are suggestive of GCF being a better diagnostic medium than saliva.