Summaries of Articles Regarding NK Cells Absnormalities in Diseases
1. Abnormalities of quantities and functions of natural killer cells in severe aplastic anemia
Severe aplastic anaemia (SAA) is a rare autoimmune disease caused by bone marrow failure, where it is unable to produce sufficient blood cells for the body. Natural Killer (NK) cells are lymphocytes that play an important role in the pathogenesis of autoimmune disease, which host defence against malignancies, viruses and allogenic cells. They either kill target cells directly or encourage production of cytokines and chemokines. This study aims to investigate the quantitative and functional changes of NK cell subsets in peripheral blood of SAA patients before and after immunosuppressive therapy (IST). Results showed that the percentage of NK cells and its subsets in peripheral blood lymphocytes was decreased in SAA patients, but increased dramatically after IST. However, the ratio of NK cells increased and restored to normal levels in patients after intensive immunosuppressive therapy. This study also found that the median expression of NKp46 on NK cells of newly diagnosed SAA patients was higher than that of healthy individuals. Similar, the expression of perforin in newly diagnosed SAA patients was also higher than of controls. The expression of CD158b and the median expression of granzyme B in NK cells however, had no statistical difference between two groups. The highly expressed of NKp46 and perforin on the NK cells from these patients might be the cause of hematopoiesis failure in SAA.
2. Analysis of Natural Killer Cells in Patients with Aplastic Anemia
In humans, NK cells have been identified as large granular lymphocytes, and they bear the cell surface antigen markers Leu 7 and Leu 11. This study analysed NK cells in 43 patients with severe aplastic anemia using cytoxicity assays and microfluorometry with monoclonal antibodies, prior to and after treatment with antithymocyte globulin (ATG). Similar to the previous findings, the result also showed that the NK cells in the peripheral blood of patients with aplastic anemia is reduced compared to normal patients. NK cells in acute aplastic anemia patients was however not statically different to from chronic patients. Other than that, Nk cells in the bone marrow was also being measured in order to test the possibility of NK cells in mediating hematopoietic suppression in aplastic anemia. It is found that NK cells in aplastic bone marrow was decreased as compared with normal and to approximately the same degree as was observed in blood. These results indicated that high NK cells was not concentrated in the target organ of aplastic anemia. LGLs in aplastic anemia had defective NK cells. It is discussed that defective NK function is a consequences of the underlying bone marrow failure and therefore do not support the suggestion that hematopoietic suppression in aplastic anemia is mediated by NK cells.
3. NKG2A expression and impaired function of NK cells in patients with new onset of Graves' disease.
Graves’s disease (GD)is an organ-specific autoimmune disease. It was said that the role that NK cells play in the pathogenesis of Graves’s disease (GD) is still remain unclear. This study explored the presence of activated and inhibitory receptors if NK and NKT cells in the peripheral blood of patients with new GD onset. The result of this study showed the significant decrease of NK cells in the peripheral blood of untreated GD patients. It is concluded that a lower number of activated NK cells may participate in the pathogenesis of GD but whether impaired function of NK cells leads to the onset of GD or the onset of GD leads to impaired function of NK cells still remains unclear.
4. The characteristics of NK cells in Schistosoma japonicum-infected mouse spleens
Schistosomiasis japonica is an parasitic disease, where during infection the deposition of its eggs can lead to immunopathological reactions, such as granuloma and fibrosis formation, which are the main contributors to the host lesions. By using mice that are infected with Schistosoma japonicum , this study aim to study the charactheristics of NK cells in affected mice. The result showed no significant different in NK cell percentages between the normal and infected groups but NK cell numbers significantly increased after infection. It is found that NK cells from C57BL/6 mouse spleens were activated and produced more specific cytokines like IL-2, IL-4, IL-10 and IL-17 and less IFN- γ during the host defense process against S.japonicum infection.