Myelin Basic Protein-Induced Production of Tumor Necrosis Factor-α and Interleukin-6, and Presentation of the Immunodominant Peptide MBP85-99 by B Cells from Patients with Relapsing-Remitting Multiple Sclerosis

Intruders or protectors - the multifaceted role of B cells in CNS disorders

B lymphocytes are immune cells studied predominantly in the context of peripheral humoral immune responses against pathogens. Evidence has been accumulating in recent years on the diversity of immunomodulatory functions that B cells undertake, with particular relevance for pathologies of the central nervous system (CNS). This review summarizes current knowledge on B cell populations, localization, infiltration mechanisms, and function in the CNS and associated tissues. Acute and chronic neurodegenerative pathologies are examined in order to explore the complex, and sometimes conflicting, effects that B cells can have in each context, with implications for disease progression and treatment outcomes. Additional factors such as aging modulate the proportions and function of B cell subpopulations over time and are also discussed in the context of neuroinflammatory response and disease susceptibility. A better understanding of the multifactorial role of B cell populations in the CNS may ultimately lead to innovative therapeutic strategies for a variety of neurological conditions.

Transitional B cells involved in autoimmunity and their impact on neuroimmunological diseases

Transitional B cells (TrB cells) represent a crucial link between immature B cells in the bone marrow and mature peripheral B cells. Although TrB cells represent one of the regulatory B cell subpopulations in healthy individuals, the frequency of CD24hiCD38hi TrB cells in circulation may be altered in individuals with autoimmune diseases, such as multiple sclerosis, neuromyelitisoptica spectrum disorders, systemic lupus erythematosus, Sjögren's syndrome, rheumatoid arthritis, systemic sclerosis, and juvenile dermatomyositis. Although TrB cells play regulatory roles under inflammatory conditions, consequences of their functional impairment vary across autoimmune diseases. Since the origin, development, and function of TrB cells, especially in humans, remain unclear and controversial, this review aimed to discuss the characteristics of TrB cells at steady state and explore their role in various immune diseases, including autoimmune rheumatic diseases and neuroimmunological diseases.

Nanoimmunosensor based on atomic force spectroscopy to detect anti-myelin basic protein related to early-stage multiple sclerosis

Multiple Sclerosis (MS) is a chronic inflammatory disorder in the central nervous system for which biomarkers for diagnosis still remain unknown. One potential biomarker is the myelin basic protein. Here, a nanoimmunosensor based on atomic force spectroscopy (AFS) successfully detected autoantibodies against the MBP_85-99 peptide from myelin basic protein. The nanoimmunosensor consisted of an atomic force microscope tip functionalization with MBP_85-99 peptide, which was made to interact with a mica surface coated either with a layer of anti-MBP_85-99 (positive control) or samples of cerebrospinal fluid (CSF) from five multiple sclerosis (MS) patients at different stages of the disease and five non-MS subjects. The adhesion forces obtained from AFS pointed to a high concentration of anti-MBP_85-99 for the two patients at early stages of relapsing-remitting multiple sclerosis (RRMS), which were indistinguishable from the positive control. In contrast, considerably lower adhesion forces were measured for all the other eight subjects, including three MS patients with longer history of the disease and under treatment, without episodes of acute MS activity. We have also shown that the average adhesion force between MBP_85-99 and anti-MBP_85-99 is compatible with the value estimated using steered molecular dynamics. Though further tests will be required with a larger cohort of patients, the present results indicate that the nanoimmunosensor may be a simple tool to detect early-stage MS patients and be useful to understand the molecular mechanisms behind MS.

Non-Antibody-Secreting Functions of B Cells and Their Contribution to Autoimmune Disease

B cells play multiple important roles in the pathophysiology of autoimmune disease. Beyond producing pathogenic autoantibodies, B cells can act as antigen-presenting cells and producers of cytokines, including both proinflammatory and anti-inflammatory cytokines. Here we review our current understanding of the non-antibody-secreting roles that B cells may play during development of autoimmunity, as learned primarily from reductionist preclinical models. Attention is also given to concepts emerging from clinical studies using B cell depletion therapy, which shed light on the roles of these mechanisms in human autoimmune disease.

Multiplex ImmunoSpot® Assays for the Study of Functional B Cell Subpopulations

B cells mediate humoral immunity by producing antibody molecules, but they also participate in innate and acquired immune functions via the secretion of effector molecules such as cytokines, chemokines, and granzyme. B cell subpopulations releasing such effector molecules have been implicated in immunobiology and a number of diseases.Unlike antigen-specific T cells that can be identified by multimer staining, and then counter-stained to define T cell subpopulations, antigen-specific B cells cannot be detected by flow cytometry. Staining antigen-specific B cells with labeled antigen, in large, has been unsuccessful. Instead, antigen-specific B cells can be and are commonly studied by ELISPOT. In the ELISPOT approach, the B cell is identified via the antibody that it secretes being captured on a membrane by the antigen itself. Should it be feasible to measure simultaneously antibody production and the secretion of other secretory B cell products, it would then be possible to identify B cell subpopulations that co-express effector molecules. Here we introduce multiplex ELISPOT assays in which measurements of antibody secretion are combined with the detection of Granzyme B, IL-6, IL-10, IFN-γ, and TNF-α. Such multiplex assays will help define effector B cell subpopulations, as well as the understanding of their role in health and disease.

Effects of rituximab and dexamethasone on regulatory and proinflammatory B-cell subsets in patients with primary immune thrombocytopenia

OBJECTIVE

To investigate the cytokine production and surface marker composition of B cells in adult patients with newly diagnosed primary immune thrombocytopenia (ITP) before and 12 months after treatment with rituximab + dexamethasone (RTX+DXM) or dexamethasone (DXM).

METHODS

Peripheral blood mononuclear cells were isolated from nine patients treated with RTX+DXM, seven patients treated with DXM, and seven healthy donors. Expression of the cell-surface markers CD5, CD27, CD25, and CD19, and intracellular content of IL-6 and IL-10 were measured by flow cytometry.

RESULTS

PBMCs from ITP patients at baseline contained a lower proportion of IL-10⁺ B cells (P < .01) and IL-6⁺ B cells (P < .01) than healthy controls. All patients responded to therapy and levels were normalized at 12 months. The proportion of CD5⁺ B cells increased (P < .01) and CD27⁺ memory B cells decreased (P < .05) 12 months after treatment with RTX+DXM compared to baseline, with an inverse correlation between platelet numbers and the proportion of CD27⁺ B cells (R = -0.71; P < .05).

CONCLUSION

Both treatment regimens normalized the frequencies of cytokine-producing B cells. The additional increase in CD5⁺ B cells after RTX+DXM is compatible with induction of Bregs.

A Randomized Controlled Trial of the Effects of Mindfulness-Based Stress Reduction (MBSR[BC]) on Levels of Inflammatory Biomarkers Among Recovering Breast Cancer Survivors

PURPOSE

The purpose of this substudy of a large randomized controlled trial was to evaluate the efficacy of the Mindfulness-Based Stress Reduction (Breast Cancer) (MBSR[BC]) program compared to usual care (UC) in normalizing blood levels of pro-inflammatory cytokines among breast cancer survivors (BCS).

METHOD

A total of 322 BCS were randomized to either a 6-week MBSR(BC) program or a UC. At baseline and 6 and 12 weeks, 10 ml of venous blood and demographic and clinical data were collected and/or updated. Plasma cytokines (interleukin [IL]-1β, IL-6, IL-10, tumor necrosis factor [TNF] α, transforming growth factor [TGF] β1, soluble tumor necrosis factor receptor [sTNFR] 1) were assayed. Linear mixed models were used to assess cytokine levels across three time points (baseline and 6 and 12 weeks) by group (MBSR[BC] vs. UC).

RESULTS

Of the six measured cytokines, three were nondetectable at rates greater than 50% (IL-10, IL-1β, TGF-β1) and, because of overall low prevalence, were not analyzed further. For the remaining cytokines (TNFα, IL-6, sTNFR1), results showed that TNFα and IL-6 increased during the follow-up period (between 6 and 12 weeks) rather than during the MBSR(BC) training period (between baseline and 6 weeks), while sTNFR1 levels did not change significantly across the 12-week period.

CONCLUSIONS

Study results suggest that MBSR(BC) affects cytokine levels in BCS, mainly with increases in TNFα and IL-6. The data further suggest that B-cell modulation may be a part of immune recovery during breast cancer management and that increases in TNFα and IL-6 may be markers for MBSR(BC)-related recovery.