Abstract
Aim:
To asses morphological and morphometrical alterations of oral squamous epithelial cells in HIV infected individuals, and determine its diagnostic significance for HIV infection.
Materials and Methods:
Informed Consent was obtained from all study subjects. 40 adult HIV infected patients (experimental group) and 40 adult non-infected volunteers (control group) participated. Age, occupation, and relevant medical history were recorded. The following laboratory tests reports were recorded: complete blood cell counts, blood glucose levels, serum iron and erythrocyte sedimentation rate. Oral smears were collected from normal appearing tongue and buccal mucosa of the individuals by exfoliative cytology. The cells were morphologically analysed and the nuclear area (NA), the cytoplasmic area (CA) and the nucleus-to-cytoplasm area ratio (NA/CA) were calculated. Cell yield, cell cohesion, presence/absence of inflammatory cells and candida were observed.
Results:
The cytological smears of HIV patients showed abundant cell yield and the epithelial cells were found to be in close cohesive clusters and both findings were found to be statistically significant. Nuclear cytoplasmic ratio was seen to be increased in 93.8% of HIV positive patientsand Mild to moderate pleomorphism was observed in 17.9% of HIV positive patients. HIV positive patients had a diminished inflammatory response and this was found to be statistically significant.
Conclusion:
Statistically significant deviations from normal oral epithelium were found in the study conducted. With further research, oral exfoliative cytology may form a new, painless, inexpensive diagnostic method for HIV infections.
Introduction
Oral manifestations of HIV infections are numerous and some of these are acknowledged as being of great importance in the early diagnosis of the disease. Although nearly all oral disorders associated with HIV infection also occur in other conditions characterized by immune suppression, a wide and significant spectrum of oral disease is associated only with HIV infection. 1 Many HIV-associated oral disorders occur early in HIV infection, not infrequently as the presenting sign or symptom. Thus, early detection of associated oral disease should, in many cases, result in earlier diagnosis of HIV infection. 2 Cytology, a simple, painless, and inexpensive method, has become a preferred method for early diagnosis of certain lesions. HIV affects primarily the immune cells, but there are studies 3 that have concentrated on the cervical and gastrointestinal epithelia when investigating the various mechanisms of HIV infection across mucosal surfaces. Through this study, we aimed at assessing the morphological and morphometrical alterations in oral squamous epithelial cells of HIV-infected individuals.
Ethics Committee
Ethical approval for the study was obtained from Institutional Ethics Committee of Manipal College of Dental Sciences, Mangalore. Informed consent was obtained from all study participants before obtaining oral smears.
Patients and Methods
In all, 40 adult HIV-infected patients (experimental group) and 40 adult noninfected volunteers (control group) participated in this study. These patients were diagnosed for HIV infection at the teaching hospital attached to the dental college. Age, occupation, and relevant medical history were recorded. The following laboratory test reports were recorded: complete blood cell counts, blood glucose levels, serum iron, and erythrocyte sedimentation rate. The alcohol, tobacco, and mouth rinse regular users, as well as those individuals who had oral mucosa injuries, were not included in this study.
Oral smears were collected from normal appearing tongue and buccal mucosa of 40 HIV-infected (study patients) and 40 noninfected (control) individuals by exfoliative cytology. The cells were morphologically analyzed and the nuclear area (NA), the cytoplasmic area (CA), and the nucleus area– cytoplasm area ratio (NA–CA) were calculated. Cell yield, cell cohesion, presence/absence of inflammatory cells, and candida were observed.
Results
The cytological smears obtained from the HIV-positive patients as well as age- and gender-matched controls were compared based on factors like cell yield, cell cohesion, atypical features (increased nuclear–cytoplasmic ratio and pleomorphism), presence of fungal organisms, bacterial colonies, the degree of inflammation, and the type of inflammatory cells seen (Table 1). The cytological smears of HIV-infected patients showed abundant cell yield, and the epithelial cells were found to be in close cohesive clusters when compared to the normal smears. Both these findings were found to be statistically significant with P values of .028 and .006, respectively. Nuclear–cytoplasmic ratio was seen to be increased in 93.8% of HIV-positive patients when compared to 6.2% of controls (P < .001). Mild to moderate pleomorphism was observed in 17.9% and 5.1% of the HIV-positive patients and controls, respectively (P = .001). Candida hyphae were observed only in 5.1% of the HIV-positive patients. No significant difference was observed in the presence of bacterial colonies between HIV-positive patients and controls. On comparing the inflammatory component, it was seen that the HIV-positive patients had a diminished inflammatory response consisting mainly of mixed inflammatory cells when compared to the chronic inflammation in the controls, and this was found to be statistically significant with a P value of <.001.
Morphometrical Changes in the Oral Epithelial Cells of HIV-Infected and Noninfected Individuals.
Abbreviation: NC, nuclear–cytoplasmic ratio.
Discussion
The oral mucosa is covered by epithelial cells arranged in layers, and the integrity of this mucosa membrane is important for the maintenance of oral health. 4 Several studies have concentrated on the cervical and gastrointestinal epithelia when investigating the various mechanisms of HIV infection across mucosal surfaces, but very few studies have concentrated on HIV disease and oral mucosal alterations. Our study comprised 40 retro-positive study patients and 40 controls. We found statistically significant morphological differences between the groups. The cytological smears of HIV-infected patients showed abundant cell yield, and the epithelial cells were found to be in close cohesive clusters when compared to the normal smears. Both these findings were found to be statistically significant with P values of .028 and .006, respectively. HIV-1 infection of the oral mucosa may also be restricted by the stratified squamous structure of the oral epithelium.
Oral epithelium contains differentiated layers of cells that can be 20 or more layers of thickness. 5 Many squamous mucosal sites show high cell turnover rates, which may encourage the shedding and swallowing of any associated virus. During exposure to HIV-1, the stage of keratinocyte differentiation may affect susceptibility to capture virus or cooperate with immature dendritic cells to transfer virus. Keratinized mucosa may be relatively resistant to virus uptake. Conversely, nonkeratinized mucosa which lines the buccal mucosa, the floor of the mouth, the oropharynx, the soft palate, and the gingival sulcus often appears ulcerated during the disease process and show lot of changes like candidiasis and periodontitis. This probably explains the increased cell yield and lack of cohesion between the cells.
The presence of candida growth among the retro-positive patients is a common finding. Oral candidiasis is the most common opportunistic infection in patients living with AIDS. This disease occurs in 80% to 90% of these patients, generally when the CD4 counts are less than 200 cells/mm3. The resultant decrease in systemic and mucosal immune integrity is, in turn, associated with an increased frequency of oral lesions. 6 The degree of immunodeficiency determines the recurrence and severity of this mycotic infection. 7 –9 Inflammatory changes were evident in most of our study patients with no dysplastic and/or neoplastic changes observed, this study revealed that HIV infection was able to induce morphometrical changes in the oral epithelial cells.
Much progress has been made in recent years in the investigation of the interplay between HIV-1 and its host cells. As all viruses, HIV depends heavily on the host-cell factors that enable the virus to enter cells and manifest the infection. These interactions are complex and are not yet fully understood. The real understanding of oral HIV infection remains elementary. Moreover, there is a lack of understanding of the fundamental mechanisms by which HIV directly and indirectly affects the oral mucosal epithelium. 10
The present study is a pilot study; the results suggest a change in the cytopathological pattern of the oral epithelium in retro-positive patients. Meanwhile, additional studies and studies with large study population should be performed to find the real mechanisms involved in the oral mucosa changes induced by this disease.
Conclusion
This study strengthens the argument that HIV is able to induce significant changes in oral epithelium, detectable by microscopy and cytomorphometry. In summary, there were obvious changes in the oral mucosa, explaining the fact that HIV affects oral mucosa as much as it affects the other mucosal cells, including host immune cells.
Footnotes
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.