It is therefore mechanistically plausible that antibodies to alpha-synuclein (or additional disease relevant proteins) could contribute to CNS swelling associated with disease progression

It is therefore mechanistically plausible that antibodies to alpha-synuclein (or additional disease relevant proteins) could contribute to CNS swelling associated with disease progression. subsets. There is also evidence that regulatory B cells are protecting in PD. There is evidence for a role played by antibodies to alpha-synuclein in PD having a possible increase in early disease. There are numerous exciting potential future avenues for further exploration of the part of B lymphocytes including improving our understanding of the role of meningeal and calvarial (skull bone marrow) based B cells in health and disease, the use of larger, well phenotyped clinical cohorts to understand changes in peripheral and cerebrospinal fluid B cells over time and the potential application of B cell targeted therapies in PD. Keywords:Parkinsons disease, inflammation, B lymphocytes, alpha-synuclein antibodies == AN INTRODUCTION TO B LYMPHOCYTES == B lymphocytes Felbamate perform a variety of roles as part of the adaptive immune system with complex interactions with other branches of the innate and adaptive immune systems. Felbamate Recent evidence suggests that immune cells including B lymphocytes are likely to interact with the central nervous system in complex ways via the meningeal lymphatic [1, 2] system and via more recently described channels in the skull bone marrow that allow egress of calvarial immune cells including B lymphocytes [3, 4]. These discoveries suggest that B lymphocytes are likely to be involved with the inflammation in Parkinsons disease (PD) in complex ways, both centrally and peripherally, and are potentially a relevant target for disease modifying therapies. Felbamate It is now relatively well established that B lymphocytes are reduced in PD [58], as this has been replicated across a number of studies (although not in all) but the mechanism behind this observation remains unclear. Scott et al. showed that B cells were also reduced in transgenic alpha-synuclein mouse models of PD suggesting that this may be related to alpha-synuclein pathology [9]. It is also possible that this represents migration of B cells to other compartments (e.g., the cerebrospinal fluid (CSF) or meninges) or alternatively the end result of chronic stimulation. To get a clearer understanding of these and other observations, it is necessary to first review B cell development and function to appreciate that their role in PD is likely to be complex as their functions are diverse. == B LYMPHOCYTE DEVELOPMENT == B lymphocytes are derived from a common lymphoid progenitor in the bone marrow. At the pre-B cell stage, the nascent IgM molecule is only found in the cytoplasm, moving to the cell surface in the immature B lymphocyte to form the B cell receptor (BCR). These cells then leave the bone marrow as transitional B lymphocytes to circulate in the blood to secondary lymphoid tissues (the spleen and lymph nodes mainly but also mucosal tissues, Peyers patches and possibly the meninges) where they differentiate into naive, follicular (circulating or in lymph nodes) or marginal zone B cells (in the spleen) [10]. Chemokine and cytokine gradients drive subsequent movement of B cells back into circulation (e.g., sphingosine-1-phosphate) or back into lymph nodes or germinal centers (e.g., CXCL13).Physique 1gives a Alas2 broad overview of this process, showing the major developmental points, from an immature B cell to a transitional B cell (which is also one of the B cell subsets that produces the regulatory cytokine IL10) (physique and summary modified from Clatworthy et al. [11]). Subsequently, the B cell may become a follicular B cell, where upon encountering antigen and costimulatory signals from follicular T Felbamate helper cells (Tfh) (including CD40L/CD40, ICOS/ICOSL, and CD28/CD86), it can enter the germinal center reaction where, via a process of clonal selection and somatic hypermutation, more specific high affinity antibodies are generated to the antigen.

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