Introduction

Sjögren’s syndrome is an autoimmune, chronic exocrinopathy, of slow progression and unknown etiology. It is characterized by dryness in the mucosa, mainly oral mucosa (xerostomia) and ocular mucosa (xerophthalmia) although it can frequently elicit symptoms due to nasal, dermal or vaginal dryness. Even though in most patients the disease can be located in exocrine glands (glandular manifestations),^1,2 due to its systemic characteristics, it frequently exhibits extra-glandular manifestations.³ Approach for SS diagnosis can be difficult, controversial and late. Diagnosis encompasses two different objectives: evaluation of systemic, salivary and ocular components and determination of whether it represents a primary or secondary disease. Some diagnostic criteria are not accurate and patients can be erroneously evaluated especially at initial stages of the disease.⁴ Within evaluation criteria the following is assessed: dryness of eye and mouth, antibody determination and biopsy of minor salivary glands.^2,5

Some studies incorporate image-supported diagnoses, nevertheless they are non-specific, thus, classification criteria grant diagnostic value to determination of anti Ro and anti La antibodies, which can be found in other autoimmune diseases.⁵

Biopsy of labial minor salivary glands is an invasive technique that can leave sequels in the oral mucosa.⁵

Exfoliative cytology is a simple, non-invasive procedure to study epithelial cells in the mucosae, this technique has been used to diagnose certain types of oral lesions, most of them related to viral and fungal diseases.⁶

The term impression cytology was first introduced by Egbert et al in 1977,^7,8 it was first used in conjunctiva mucosa. Later on, several authors have conducted modifications according to their needs, describing the use of this technique to study mucus purity on conjunctiva surface⁹ as well as changes in nuclear chromatin of epithelial cells in Sjögren’s syndrome.

The conventional method is the most frequently used, this could be due to scarcity of studies on impression cytology to examine oral mucosa.

The aim of the present project was to compare two cytology techniques: exfoliative and impression cytology in a study of oral mucosa of patients afflicted with sicca and Sjögren’s syndrome, which might allow diagnosis with a non-invasive technique.

Materials and methods

Results

Patients’ average age was 50 years, 86% of them were female.

Both techniques allowed us to observe in C regular-shaped isolated one-layered epithelial cells, basophils, normal shaped and sized, central and picnotic nuclei (Figure 1 A); in ME group folded and grouped isolated cells with predominantly eosinophilic cytoplasm and lacking nucleus alterations were observed (Figure 2 B); in SS patients, smaller sized cytoplasmatic area and increased nucleus area with denser chromatin was observed (Figure 3 C).

Figure 1 A) Patient relation (N/C) 1: 8 image 200 x, scale = 100 microns. 

Figure 2 B) Patient relation (N/C) 1: 4 image 200 x, scale = 100 microns. 

Figure 3 C) Patient relation (N/C) 1: 2 image 200 x, scale = 100 microns. 

Histophormometric study of both techniques revealed the following: in group C a cell amount reaching 40 per mm² area, in correspondence to C p<0.01, nucleus-cytoplasm relationship N/C 1:4, and in SS patients a N/C 1:2 relationship of 400 cells per mm², with statistically significant increase p < 0.001 with respect to ME and C (Figures 4 and 5).

Figure 4 Nucleus/cytoplasm relationship in different experimental groups p < 0.01. 

Figure 5 Number of cells in different experimental groups p < 0.01. 

Discussion

The procedure of exfoliative cytology of the oral mucosa is increasingly becoming more important in the early diagnosis of different local and systemic conditions, it is considered a procedure for the procurement of cell samples that can later be analyzed though sophisticated diagnostic techniques such as cytomorphometry, AND cytometry and molecular analyses.¹⁰

Use of sophisticated computer programs has changed the scenario and rendered result interpretation more reliable.

The technique of exfoliative cytology for cells of the mouth is non-aggressive, simple and expedite; it is therefore well accepted by patients and suitable for routine application in population screening programs for early analysis of suspicious lesions as well as for pre- and post-monitoring of oral lesion treatments.^10-12

Impression cytology used in conjunctiva of the eye has enabled to easily recognize squamous metaplasia in severe and moderate dry eyes found in SS patients, thus contributing to clinical diagnosis confirmation and disease follow-up.^13-16 It is worth mentioning that there is no present evidence supporting use of this procedure in the mouth.

Both cytology techniques allowed us to identify similar parameters, such as type, color size and amount of cells. In the case of autoimmune diseases such as SS, although both techniques were efficient to establish diagnosis, perception of cell grouping was better characterized in impression cytology preparations.

Our study established comparison of both techniques, exfoliative and impression cytology, measuring fit of the sample and diagnosis coincidence in the aforementioned groups.

Sample analysis revealed that cytologies processed with the impression technique exhibited certain advantages, since the thin and uniform distribution of cell material allowed more accurate observation of nuclei and cells’ shape, moreover, cell superposition was decreased and presence of polymorphonuclear cells was observed.

In histomorphometric studies, impression cytology also exhibited advantages over conventional techniques, because it allowed for a better observation of studied parameters such as changes in nucleus-cytoplasm relationship of different experimental groups.

In the present study, results associated to biochemical and clinical observations suggest that SS can cause morphological and functional alterations in epithelial oral cells which can be detected through microscopic analysis and cytometry using cytology techniques.

Conclusion

Preliminary data of histological description evidenced greater detail when using impression technique as compared to the exfoliativetechnique. Form this we might infer that impression cytology can be used in the diagnosis of oral and systemic lesions in patients afflicted with hyposalivation.