Natural killer cells and alterations in collagen density: signs of periradicular herpesvirus infection?

Abstract

This study evaluated the presence and density of natural killer (NK) cells as well as collagen density in chronic apical periodontitis lesions and tried to find any correlations with concomitant herpesvirus infection or histopathological status of the lesion. Surgical specimens of chronic apical periodontitis lesions were surveyed for the presence and density of NK cells by immunohistochemical analysis. Collagen density in these lesions was quantified by means of histochemistry. All specimens were positive for the presence of CD57-positive cells. Topographically, CD57-positive cells were found singly or forming clusters in the granulomatous tissue, as well as subjacent and within the cystic epithelium. No significant differences in the density of CD57-positive cells were found between nonepithelialized and epithelialized lesions or between herpesvirus-positive and herpesvirus-negative lesions. Significant differences were found in volumetric density of collagen when comparing nonepithelialized and epithelialized lesions, with the latter demonstrating higher values. When no distinction of lesion type was made, there was no significant difference in collagen density between herpesvirus-positive and herpesvirus-negative lesions. When comparing the collagen density in herpesvirus-positive and herpesvirus-negative specimens from the same lesion type, a significant difference was found in nonepithelialized lesions, with herpesvirus-positive lesions showing lower values. The presence of CD57-positive cells in all chronic apical periodontitis specimens may indicate that activated NK cells play a role in the pathogenesis of this disease, possibly by participating in innate immunity events involved in the control of virus infection. Collagen density may vary in function of the type of lesion and presence of herpesvirus infection.

Cytomegalovirus‐infected inflammatory cells in dental periapical lesions

“…No periapical lesion revealed cytomegalovirus‐positive B lymphocytes. As shown elsewhere (14), cytomegalovirus may also infect natural killer cells in periapical lesions.…”

Evaluation of four clinical laboratory parameters for the diagnosis of myalgic encephalomyelitis

“…For instance, Blom et al reported that tick-borne encephalitis virus-induced NK cell activation is primarily limited to differentiated CD57 + /CD56 dim+ NK cells [ 45 ]. Additionally, CD57 + NK cells are routinely implicated in herpesvirus infections [ 46 , 47 ]. Therefore, including this parameter may be of utility when establishing or ruling out an initial diagnosis of ME.…”

Analysis of CD57+ natural killer cells and CD8+ T lymphocytes in periapical granulomas and radicular cysts

“…CD8 + /CD57 + T cells are considered senescent cells whose function is not fully understood, while in NK cells the acquisition of CD57 confers a greater cytotoxic potential to the cell. 2,10 In the present study, cells exhibiting immunostaining for CD57 associated with the cell morphology findings (large CD57 immunopositive cells with a cytoplasm containing several voluminous granules) were defined as NK cells. …”