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

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

Background

Myalgic encephalomyelitis (ME) is a complex and debilitating disease that often initially presents with flu-like symptoms, accompanied by incapacitating fatigue. Currently, there are no objective biomarkers or laboratory tests that can be used to unequivocally diagnosis ME; therefore, a diagnosis is made when a patient meets series of a costly and subjective inclusion and exclusion criteria. The purpose of the present study was to evaluate the utility of four clinical parameters in diagnosing ME.

Methods

In the present study, we utilized logistic regression and classification and regression tree analysis to conduct a retrospective investigation of four clinical laboratory in 140 ME cases and 140 healthy controls.

Results

Correlations between the covariates ranged between [− 0.26, 0.61]. The best model included the serum levels of the soluble form of CD14 (sCD14), serum levels of prostaglandin E2 (PGE₂), and serum levels of interleukin 8, with coefficients 0.002, 0.249, and 0.005, respectively, and p-values of 3 × 10⁻⁷, 1 × 10⁻⁵, and 3 × 10⁻³, respectively.

Conclusions

Our findings show that these parameters may help physicians in their diagnosis of ME and may additionally shed light on the pathophysiology of this disease.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1696-z) contains supplementary material, which is available to authorized users.

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

The aim of this study was to compare the number of CD57+ natural killer (NK) cells and CD8+ T lymphocytes between periapical granulomas (PGs) and radicular cysts (RCs). Twenty-fives cases of PGs and 25 of RCs were submitted to histological analysis and immunohistochemistry using anti-CD57 and anti-CD8 biomarkers. Positive cells were counted in 10 fields (400× magnification) and the median value was calculated for each case. Statistical tests were used to evaluate differences in the number of CD57+ NK cells and CD8+ T lymphocytes according to type of lesion, intensity of the infiltrate and thickness of the lining epithelium. The number of CD57+ NK cells and CD8+ T lymphocytes was higher in PGs than in RCs (p = 0.129 and p = 0.541, respectively). Comparison of the number of CD57+ NK cells in atrophic and hyperplastic epithelium revealed a larger number of cells in the atrophic epithelium (p = 0.042). A larger number of CD57+ NK cells and CD8+ T lymphocytes were observed in grade III infiltrates compared to grade I/II (p = 0.145 and p = 0.725, respectively). CD8+ T lymphocytes were more prevalent than CD57+ NK cells in most cases when PGs and RCs were analyzed separately or in combination (p < 0.0001). CD57+ NK cells and CD8+ T lymphocytes play a key role in antiviral defense and the presence of these cells supports evidence suggesting the participation of these microorganisms in the pathogenesis of PGs and RCs. The response mediated by CD8+ T lymphocytes was more frequent, indicating greater participation of the adaptive immunity in these chronic lesions.

Analysis of CD15, CD57 and HIF-1α in biopsies of patients with peri-implantitis

Peri-implantitis is an infectious disease characterized by inflammation of the tissues surrounding the implant, bleeding on probing with or without suppuration, and bone loss. Peri-implant lesions contain a leukocyte infiltrate of plasma cells, lymphocytes, macrophages and neutrophils. A survey of the literature did not show any studies reporting an association between hypoxia and peri-implantitis. The aim of the present cross-sectional study was to evaluate histological changes and immunostaining for CD15, CD57 and HIF-1α in the peri-implant mucosa of patients with and without peri-implantitis. Mucosal biopsies were obtained from 18 patients with peri-implantitis and 10 control subjects without peri-implantitis at a private health care center between 2010 and 2012. The sections were fixed in 10% buffered formalin, processed and embedded in paraffin for histopathological and immunohistochemical study. Acanthosis, spongiosis and exocytosis were observed in both groups, with no significant difference between them. The peri-implantitis group showed increased immunostaining for CD15, a neutrophil marker, and HIF-1α, a tissue hypoxia marker, but no significant difference in immunostaining for CD57, a Natural Killer cell marker. The increase in neutrophil (CD15) and hypoxia (HIF-1α) markers in patients with peri-implantitis suggests an active participation of neutrophils and hypoxia in the pathogenesis of this disease. Since the present study was the first to evaluate the expression of CD15, CD57 and HIF-1α in peri-implant tissues, further studies should be performed to better understand the role of these molecules in peri-implantitis.