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Regulatory B cells (Bregs), a newly described subset of B cells, have been proved to play a suppressive role in immune system. Bregs can inhibit other immune cells through cytokines secretion and antigen presentation, which give them the role in the pathogenesis of autoimmune diseases and cancers. There are no clear criteria to identify Bregs; different markers were used in the different experimental conditions. Massive researches had described the functions of immune cells such as regulatory T cells (Tregs), dendritic cells (DCs), and B cells in the autoimmune disorder diseases and cancers. More and more researches focused on the roles of Bregs and the cytokines such as Interleukin-10 (IL-10) and transforming growth factor beta (TGF-β) secreted by Bregs. The aim of this review is to summarize the characteristics of Bregs and the roles of Bregs in cancer.

Alzheimer's disease (AD) is generally defined as the aberrant production of β-amyloid protein (Aβ) and hyperphosphorylated tau protein, which are deposited in β-amyloid plaques (APs) and neurofibrillary tangles (NFTs), respectively. Decreased levels of brain-derived neurotrophic factor (BDNF) have been detected in patients with AD compared to control subjects. However, the underlying molecular mechanisms driving the downregulation of the BDNF remain unknown. Therefore, we explored the mechanisms underlying the regulation of BDNF in the neurons of APP/PS1 transgenic (Tg) mice, an AD experimental model. Using the APP/PS1 Tg mice, we found that BDNF expression was markedly downregualted at the age of 3- and 9-month-old. After cerebroventricular injection (i.c.v) of Aβ1−42 oligomers into the mice, BDNF was also found to be decreased, which demonstrated the critical roles of the Aβ1−42 oligomers in regulating the expression of BDNF. In neuronal culture, peroxisome proliferators-activated receptor γ coactivator 1α (PGC-1α) and fibronectin type III domain-containing 5 (FNDC5) were found to be downregulated by treatment with the Aβ1−42 oligomers. In addition, overexpression of either PGC-1α or FNDC5 reversed the suppressive effects of the Aβ1−42 oligomers on the expression of BDNF in neuroblastoma 2a (n2a) cells. More importantly, elevating the levels of PGC-1α, FNDC5 or BDNF in the n2a cells counteracted the effects of the Aβ1−42 oligomers on neuronal apoptosis. Additionally, intranasal administration BDNF in the APP/PS1 Tg mice decreased the Aβ deposition and reduced the cognitive decline of the mice.

To clarify clinical characteristics of immune thrombocytopenia (ITP) subsets associated with autoimmune diseases (AIDs).Five thousand five hundred twenty patients were reviewed retrospectively. One hundred four ITP patients were included for analysis. Clinical manifestations at first thrombocytopenic episode were recorded.Systemic lupus erythematosus (SLE) and primary Sjogren syndrome (pSS) accounted for a large part in AIDs associated with secondary ITP. SLE-ITP, pSS-ITP, and primary ITP (pITP) patients were different in several aspects in clinical and immunological characteristics. A subgroup of patients in pITP patients with some obvious autoimmune features (defined as AIF-ITP) such as positive ANA but failing to meet the diagnosis criteria now used for a specific kind of connective tissue diseases were also different with other pITP patients in some immunological features, indicating the difference in the pathogenesis mechanism of those autoimmune featured ITP patients.ITP patients were heterogeneous in clinical characteristics. Further study about the different pathogenesis of ITP subsets especially those AIF-ITP patients who only presented with thrombocytopenia will help us have a better understanding of pathogenesis of ITP and a better management of ITP patients.

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