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

Abstract: 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.

Malignant peripheral nerve sheath tumour: an elusive diagnosis.

Malignant peripheral nerve sheath tumour (MPNST) also termed as spindle cell malignancy of the peripheral nerve Schwann cells or neurogenic sarcoma, represents approximately 10% of all soft tissue sarcomas. This tumour is usually found in the lower extremities and only 10-12% of all lesions occur in the head and neck region, which makes it a rare entity. The diagnosis of MPNST has been described as one of the most difficult and elusive diagnosis in the soft tissue diseases because of its non-specific presentation both clinically and histopathologically. This was overcome by the use of immunohistochemistry. A case of MPNST of the left maxillary antrum in a 45 -year -old male patient is reported.

Increase of NK cells in decidua of women with recurrent spontaneous abortion

Various immunological mechanisms are known to be involved in maintenance of pregnancy but mechanisms underlying the failure of pregnancy in spontaneous abortion are poorly understood. Leukocytes consist a substantial percentage of endometrial stroma cells and classic natural killer cells have been proposed as immunological factor in spontaneous abortion. This study was performed to clarify the immunological role of classic NK cells in women with recurrent spontaneous abortion in the first trimester and of unknown etiology. This cell population was studied in 30 samples of decidua tissue of women with spontaneous abortion [test group] and compared with 30 samples of decidua of women undergoing elective pregnancy termination [control group]. Paraffin embedded sections were prepared from endometrial tissue samples of both groups and were dyed with specific monoclonal antibody against CD57 marker by using avidin-biotin-peroxides technique. NK cells positive for CD57 were then evaluated and counted under light microscopy with 400 magnification. Z-test was used to statistically compare NK population between test and control groups. Result showed that NK cells were scattered through stroma cells in both normal and abotion group. There was few NK cells observed in normal decidua tissue, where as this cell population was significantly increased in women with spontaneous abortion [P<0.003]. It seems that NK cells play key role in recurrent spontaneous abortion during the first trimester of pregnancy. Probably classic NK cells are activated by local cytokines and attack trophoblast cells of placenta and are thus involved in induction of spontaneous abortion