[Regulatory B cell and autoimmune disease]

Phenotypic identification of CD19+CD5+CD1d+ regulatory B cells that produce interleukin 10 and transforming growth factor β1 in human peripheral blood

INTRODUCTION

Regulatory B cells (Bregs), a novel subpopulation of B cells, are a significant area of research due to their immune regulatory function in the immunological response. Bregs have been reported to regulate acute inflammation and immunity through the production of anti-inflammatory cytokines.

MATERIAL AND METHODS

A B cell subpopulation was identified using flow cytometric analysis in two different processes: 1) after preparation and storage of peripheral blood mononuclear cells (PBMCs) using Ficoll density gradient centrifugation from a human blood sample, 2) followed by isolation and storage of B cells through magnetic separation using a B cell isolation kit and MS column. ELISA assays were performed to observe the cytokine production of interkleukin 10 (IL-10) and transforming growth factor β₁ (TGF-β₁) by this novel B cell subpopulation.

RESULTS

Double positive staining of CD5+CD1d+ Bregs represents (19.27 ±1.52) from PBMCs, (33.32 ±2.95) from B cells accordingly (n = 40). Through ELISA assays, it has been found that B cell subpopulation produces IL-10 (0.56 ±0.08) and TGF-β₁ (0.90 ±0.12) (n = 40).

CONCLUSIONS

These methods should be able to facilitate progress in research on Bregs through the following steps: 1) the regulatory role may be observed in comparison with particular autoimmune diseases, inflammation, cancer, and immunologic responses to find out whether Breg alteration and/or cytokine production is altered as well in these disorders or conditions. 2) If the alteration of Bregs and cytokine production is significant along with the clinical correlation, a further in vitro study can be initiated with exposure of certain drugs to overcome the alteration of the cytokine production; then, an in vivo study can be initiated.

Anti-IL-10 antibody in systemic lupus erythematosus

Purpose

IL-10 is a cytokine known to inhibit inflammatory cytokines. To determine its role in the pathogenesis of systemic lupus erythematosus (SLE), the presence of anti-IL-10 antibody is required to be examined. Although antibodies against cytokines are known to be present in SLE, no studies have determined the role of IL-10, particularly in Japanese patients. We assayed anti-IL-10 antibody in SLE and examined the clinical significance.

Patients and methods

We performed a retrospective study of 80 Japanese patients with SLE. Sixteen scleroderma patients, 19 rheumatoid arthritis (RA) patients, 23 Behcet’s disease patients, and 23 healthy subjects were selected as control groups. Clinical information was abstracted from medical records. Anti-IL-10 antibody level was determined with an ELISA.

Results

With the cutoff established as serum absorbance +2 SDs (OD 0.729) in healthy subjects, we defined any sample above this cutoff as anti-IL-10 antibody-positive. Fourteen patients with SLE (17.5%) were found to be anti-IL-10 antibody positive. Absorbance was significantly higher in serum from patients with SLE and RA than in healthy individuals. In SLE, patients with low complement values were significantly more common in the antibody-positive group. Serum IgG levels were significantly higher in the antibody-positive group. In multivariable analysis, high level of serum IgG is associated with anti-IL-10 antibody positive.

Conclusion

The present study found that anti-IL-10 antibody is present in SLE and related to clinical parameters. These results suggest that the presence of anti-IL-10 antibody was associated with high level of serum IgG, but is not associated with disease activity in patients with SLE.

Regulatory B Cells in Seropositive Myasthenia Gravis versus Healthy Controls

OBJECTIVE

To find out if the failure in immunotolerance of myasthenia gravis (MG) is a possible aspect of deduction in Breg cells and to characterize B cell subsets in MG.

METHODS

Flow cytometry detection and enzyme-linked immunosorbent assays in peripheral blood films of 10 MG patients and 10 healthy controls (HCs) were performed after isolation of B cells. The CD19⁺CD5⁺CD1d⁺ Breg cells percentages were measured to complement a B cell phenotype assay and frequencies of B cell subsets. The clinical outcome measures and immunological variables of patients with MG were compared with HCs.

RESULTS

Patients with MG had relatively lowered percentages of CD19⁺CD5⁺CD1d⁺ Breg cells as compared to HCs. The production of interleukin (IL)-10 and transforming growth factor (TGF)-β1 was relatively lesser in patients with MG than HCs, which were linked with more severe of MG disease status according to Myasthenia Gravis Foundation of America (MGFA) clinical classification. The reduction of cytokine production was more significant for IL-10 than TGF-β1 when compared to HCs.

CONCLUSION

It has been observed that the reduced number of B cells is able to produce IL-10 in MG patients but lesser than compared to HCs. The Bregs reduction mainly was regarded by the severity of disease status, which was highly significant and also by disease duration which was statistically significant as well. The findings of the measurement of B cell phenotype assay and frequencies of B cell subsets between MGs and HCs give us new ideas to develop B cell-mediated therapies of MG such as (1) isolated B cells of MGs could be cultured with steroids, e.g., dexamethasone in vitro to see if it induces the CD19⁺CD5⁺CD1d⁺ Breg cells, (2) it may observe whether induced CD19⁺CD5⁺CD1d⁺ Bregs have higher production of IL-10 and TGF-β1, as both are linked with disease severity, and (3) after completion in vitro steps, through further research in vivo to observe whether it improves the function of MG disease status.

B-Cell Depletion with CD20 Antibodies as New Approach in the Treatment of Inflammatory and Immunological Events Associated with Spinal Cord Injury

Spinal cord injury (SCI) is a highly debilitating pathology that has irreversible impacts and results in functional loss. We evaluated the anti-inflammatory and immunologic role of antibody-mediated depletion of B cells through the glycoengineered anti-muCD20 antibody (18B12) in an experimental model of spinal cord compression, in vivo and ex vivo. Intraperitoneal 18B12 was administered at a dose of 30 mg/kg, 1 h and 6 h after SCI, and mice were sacrificed 24 h after trauma. We demonstrated, in vivo, that 18B12 slowed severe hindlimb motor dysfunction (Basso Mouse Scale score) and neuronal death by histological evaluation in SCI mice, as well as decreased expression of nuclear factor-kB, inducible nitric oxide synthase, cytokines, and glial fibrillary acidic protein. Also, 18B12 reduced expression of microglia, just as it lowered the expression of B and T lymphocytes. Moreover, in spinal cord organotypic cultures, pretreatment with 18B12 significantly reduced nitric oxide expression and protected cells from cell death [3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay]. In this study, we showed that 18B12 treatment reduces the development of inflammation and tissue injury by alteration of the immune system associated with SCI. This study increases the current knowledge that B-cell depletion is able to exert immunomodulating actions in damaged spinal cords.

Characterization and Clinical Implication of Th1/Th2/Th17 Cytokines Produced from Three-Dimensionally Cultured Tumor Tissues Resected from Breast Cancer Patients

OBJECTIVES: Several cytokines secreted from breast cancer tissues are suggested to be related to disease prognosis. We examined Th1/Th2/Th17 cytokines produced from three-dimensionally cultured breast cancer tissues and related them with patient clinical profiles. METHODS: 21 tumor tissues and 9 normal tissues surgically resected from breast cancer patients were cultured in thermoreversible gelatin polymer–containing medium. Tissue growth and Th1/Th2/Th17 cytokine concentrations in the culture medium were analyzed and were related with hormone receptor expressions and patient clinical profiles. RESULTS: IL-6 and IL-10 were expressed highly in culture medium of both cancer and normal tissues. However, IFN-γ, TNF-α, IL-2, and IL-17A were not detected in the supernatant of the three-dimensionally cultured normal mammary gland and are seemed to be specific to breast cancer tissues. The growth abilities of hormone receptor–negative cancer tissues were significantly higher than those of receptor-positive tissues (P = 0.0383). Cancer tissues of stage ≥ IIB patients expressed significantly higher TNF-α levels as compared with those of patients with stage < IIB (P = 0.0096). CONCLUSIONS: The tumor tissues resected from breast cancer patients can grow in the three-dimensional thermoreversible gelatin polymer culture system and produce Th1/Th2/Th17 cytokines. Hormone receptor–positive cancer tissues showed less growth ability. TNF-α is suggested to be a biomarker for the cancer stage.

CD1d(hi)CD5+ B cells expanded by GM-CSF in vivo suppress experimental autoimmune myasthenia gravis

IL-10-competent subset within CD1d(hi)CD5(+) B cells, also known as B10 cells, has been shown to regulate autoimmune diseases. Whether B10 cells can prevent or suppress the development of experimental autoimmune myasthenia gravis (EAMG) has not been studied. In this study, we investigated whether low-dose GM-CSF, which suppresses EAMG, can expand B10 cells in vivo, and whether adoptive transfer of CD1d(hi)CD5(+) B cells would prevent or suppress EAMG. We found that treatment of EAMG mice with low-dose GM-CSF increased the proportion of CD1d(hi)CD5(+) B cells and B10 cells. In vitro coculture studies revealed that CD1d(hi)CD5(+) B cells altered T cell cytokine profile but did not directly inhibit T cell proliferation. In contrast, CD1d(hi)CD5(+) B cells inhibited B cell proliferation and its autoantibody production in an IL-10-dependent manner. Adoptive transfer of CD1d(hi)CD5(+) B cells to mice could prevent disease, as well as suppress EAMG after disease onset. This was associated with downregulation of mature dendritic cell markers and expansion of regulatory T cells resulting in the suppression of acetylcholine receptor-specific T cell and B cell responses. Thus, our data have provided significant insight into the mechanisms underlying the tolerogenic effects of B10 cells in EAMG. These observations suggest that in vivo or in vitro expansion of CD1d(hi)CD5(+) B cells or B10 cells may represent an effective strategy in the treatment of human myasthenia gravis.