Inhibition of peripheral blood natural killer cell cytotoxicity in patients with myasthenia gravis treated with plasmapheresis.

BACKGROUND AND PURPOSE: Myasthenia gravis (MG) is an autoimmune disorder that may involve natural killer (NK) cells. Although NK cells are part of the innate immune system, they also influence adaptive immune responses. Double-filtration plasmapheresis (DFP) is an effective therapy for MG crisis. Thus, we examined the effects of DFP on the cytotoxicity of NK cells. METHODS: A total of 20 patients with MG and 16 healthy controls were recruited for the study. Ficoll-Paque-isolated peripheral blood mononuclear cells (PBMCs) and K562 cells were used as the effector and target cells, respectively. NK cell cytotoxicity was analyzed using flow cytometry immediately before and after DFP and upon course completion. RESULTS: Double-filtration plasmapheresis treatment decreased significantly the NK cell cytotoxicity in patients with MG, especially in good responders, those who were positive for acetylcholine receptor (AChR) antibodies, and those receiving immunosuppressants. CONCLUSIONS: The decrease in NK cell cytotoxicity after DFP and the decline of AChR antibody titer were observed in good responders indicating that this could benefit patients with MG.

Changes in serum cytokine levels during plasmapheresis in patients with myasthenia gravis.

BACKGROUND: The effect of plasmapheresis on cytokine levels in patients with myasthenia gravis (MG) has not been well established. METHODS: Cytokine levels were measured in 19 patients with MG before and after treatment with one course of double-filtration plasmapheresis (DFP). The control group comprised 6 age- and sex-matched healthy volunteers. RESULTS: At baseline, patients with MG had higher levels of IL-10 than normal controls. The levels of IL-2, IL-4, IL-5, and tumor necrosis factor-alpha were almost undetectable in MG patients. After a single session of DFP treatment, IL-10 levels were significantly increased. After three sessions, IL-10 levels were still higher than those at baseline. Elevated IL-10 level was significantly associated with use of immunosuppressant drugs, thymectomy, and good response to DFP treatment. CONCLUSIONS: Interleukin-10 might play a crucial role in the pathogenesis and perpetuation of MG.

Particle size reduction effectively enhances the intestinal health-promotion ability of an orange insoluble fiber in hamsters.

The effects of particle size changes by micronization on the intestinal health-promotion ability of orange insoluble fiber fraction (IFF) were investigated in a hamster model by feeding 3 diets, which contained unmicronized IFF (control), jet-milled IFF, and high-pressure micronized IFF as the sole fiber source in diet. The results showed that the micronization treatments significantly altered the physicochemical properties of insoluble fiber. The consumption of the micronized fibers (6.26 to 11.4 microm) at a level of 50 g/kg diet, especially those prepared by high-pressure micronization, resulted in significant (P < 0.05) improvements in cecal and fecal parameters such as reduced cecal ammonia concentration (-37.1%), increased fecal moisture (164%), and decreased activities of beta-D-glucuronidase (-68.3%) and mucinase (-28.5%) in feces. Both the particle size and treatment were important factors affecting the composition and physiological functions of fibers, and the consumption of micronized fiber might exert favorable effects on improving the intestinal health of hamsters. This study might give some hints for the potential applications of micron technology in food industry and provide opportunities to develop new formulations of fiber-rich functional foods.