ABSTRACT
<p><b>BACKGROUND</b>Th9 cells are a newly discovered CD4+ T helper cell subtype, characterized by high interleukin (IL)-9 secretion. Growing evidences suggest that Th9 cells are involved in the pathogenic mechanism of multiple sclerosis (MS). Mast cells are multifunctional innate immune cells, which are perhaps best known for their role as dominant effector cells in allergies and asthma. Several lines of evidence point to an important role for mast cells in MS and its animal models. Simultaneously, there is dynamic "cross-talk" between Th9 and mast cells. The aim of the present study was to examine the IL-9-mast cell axis in experimental autoimmune encephalomyelitis (EAE) and determine its interaction after neutralizing anti-IL-9 antibody treatment.</p><p><b>METHODS</b>Female C57BL/6 mice were randomly divided into three groups (n = 5 in each group): mice with myelin oligodendrocyte glycoprotein (MOG)-induced EAE (EAE group), EAE mice treated with anti-IL-9 antibody (anti-IL-9 Abs group), and EAE mice treated with IgG isotype control (IgG group). EAE clinical score was evaluated. Mast cells from central nervous system (CNS) were detected by flow cytometry. The production of chemokine recruiting mast cells in the CNS was explored by reverse transcription-polymerase chain reaction (RT-PCR). In mice with MOG-induced EAE, the expression of IL-9 receptor (IL-9R) complexes in CNS and spleen mast cells was also explored by RT-PCR, and then was repeating validated by immunocytochemistry. In vitro, spleen cells from EAE mice were cultured with anti-IL-9 antibody, and quantity of mast cells was counted by flow cytometry after co-culture.</p><p><b>RESULTS</b>Compared with IgG group, IL-9 blockade delayed clinical disease onset and ameliorated EAE severity (t = -2.217, P = 0.031), accompany with mast cells infiltration decreases (day 5: t = -8.005, P < 0.001; day 15: t = -11.857, P < 0.001; day 20: t = -5.243, P = 0.001) in anti-IL-9 Abs group. The messenger RNA expressions of C-C motif chemokine ligand 5 (t = -5.932, P = 0.003) and vascular cell adhesion molecule-1 (t = -4.029, P = 0.004) were significantly decreased after IL-9 neutralization in anti-IL-9 Abs group, compared with IgG group. In MOG-induced EAE, the IL-9R complexes were expressed in CNS and spleen mast cells. In vitro, splenocytes cultured with anti-IL-9 antibody showed significantly lower levels of mast cells in a dose-dependent manner, compared with splenocytes cultured with anti-mouse IgG (5 μg/ml: t = -0.894, P = 0.397; 10 μg/ml: t = -3.348, P = 0.019; 20 μg/ml: t = -7.639, P < 0.001).</p><p><b>CONCLUSIONS</b>This study revealed that IL-9 neutralization reduced mast cell infiltration in CNS and ameliorated EAE, which might be relate to the interaction between IL-9 and mast cells.</p>
Subject(s)
Animals , Female , Mice , Antibodies , Therapeutic Uses , Central Nervous System , Metabolism , Encephalomyelitis, Autoimmune, Experimental , Drug Therapy , Metabolism , Immunohistochemistry , Interleukin-9 , Allergy and Immunology , Metabolism , Mast Cells , Metabolism , Mice, Inbred C57BL , RNA, Messenger , Genetics , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
BACKGROUND AND PURPOSE: Myasthenia gravis (MG) is usually comorbid with thymoma. More accurate estimates of the incidence thymoma in MG will help inform patients and their physicians, facilitate health policy discussions, provide etiologic clues, and optimize the management of MG. METHODS: We conducted a systematic review search of relevant English-language studies published between 1960 and 2012 using MEDLINE and Embase. We identified additional studies by reviewing the bibliographies of the retrieved articles and hand searched the main neurology journals. Only incidence studies and case series of unselected MG patients in which information about thymoma were included. RESULTS: Out of 2206 potentially relevant studies, 49 met the inclusion criteria. Although there was a considerable degree of heterogeneity, the pooled estimate of the incidence of thymoma in MG was 21% (95% confidence interval, 20-22%). The pooled incidence was significantly higher for surgery-based studies than for population- and hospital-based studies. A large proportion of the reported thymomas were noninvasive. Furthermore, thymoma appears to occur significantly more frequently among male MG patients and those older than 40 years at the onset of MG. CONCLUSIONS: Thymoma is common in MG patients, but appears to be found more often in male MG patients and those older than 40 years at the onset of MG. Further research is needed to expand our understanding of these association conditions.