IL-10 production in multiple sclerosis patients, SLE patients and healthy controls: preliminary findings

Dual Role of Interleukin-10 in Murine NZB/W F1 Lupus

As a key anti-inflammatory cytokine, IL-10 is crucial in preventing inflammatory and autoimmune diseases. However, in human and murine lupus, its role remains controversial. Our aim was to understand regulation and immunologic effects of IL-10 on different immune functions in the setting of lupus. This was explored in lupus-prone NZB/W F1 mice in vitro and vivo to understand IL-10 effects on individual immune cells as well as in the complex in vivo setting. We found pleiotropic IL-10 expression that largely increased with progressing lupus, while IL-10 receptor (IL-10R) levels remained relatively stable. In vitro experiments revealed pro- and anti-inflammatory IL-10 effects. Particularly, IL-10 decreased pro-inflammatory cytokines and slowed B cell proliferation, thereby triggering plasma cell differentiation. The frequent co-expression of ICOS, IL-21 and cMAF suggests that IL-10-producing CD4 T cells are important B cell helpers in this context. In vitro and in vivo effects of IL-10 were not fully concordant. In vivo IL-10R blockade slightly accelerated clinical lupus manifestations and immune dysregulation. Altogether, our side-by-side in vitro and in vivo comparison of the influence of IL-10 on different aspects of immunity shows that IL-10 has dual effects. Our results further reveal that the overall outcome may depend on the interplay of different factors such as target cell, inflammatory and stimulatory microenvironment, disease model and state. A comprehensive understanding of such influences is important to exploit IL-10 as a therapeutic target.

Clinical associations of IL-10 and IL-37 in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by the development of autoantibodies to nuclear antigens and inflammatory responses mediated by multiple cytokines. Although previous studies have determined clinical associations between SLE and the anti-inflammatory cytokines IL-10 and IL-37, their role in the disease, or their potential as biomarkers, remains unclear. We examined serum levels of IL-10 and IL-37 in a large cohort of SLE patients, with detailed longitudinal clinical data. We demonstrate a statistically significant association of serum IL-10 with disease activity, with higher levels in active compared to inactive disease. High first visit IL-10 was predictive of high subsequent disease activity; patients with IL-10 in highest quartile at first visit were 3.6 times more likely to have active disease in subsequent visits. Serum IL-37 was also higher in SLE patients compared to control, and was strongly associated with Asian ethnicity. However, IL-37 was not statistically significantly associated with disease activity. IL-37 was significantly reduced in patients with organ damage but this association was attenuated in multivariable analysis. The data suggest that IL-10, but not IL-37, may have potential as a biomarker predictive for disease activity in SLE.

Role of interleukin-10 and interleukin-10 receptor in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by excessive production of a variety of autoantibodies, accumulation of immune complexes, and multiple organ systems involvement. Interleukin-10 (IL-10) has an important role in the growth, survival, differentiation, and function of B cells. Abnormally increased IL-10 synthesis seems contributing to the spontaneous hyperactivity of the B cell compartment, so that it can directly result in autoantibody production by committed plasma cells, circulating immune complexes formation, and eventually in tissue and organ damage, suggesting it might associate with the development of SLE. A better understanding of the regulation of IL-10 and its receptors (IL-10R) can likely provide more valuable clues to the pathogenic mechanisms underlying specific forms of SLE, so as to pave the way toward more effective therapeutics.

Interleukin-10 receptor expression and signalling were down-regulated in CD4⁺ T cells of lupus nephritis patients

Studies have indicated that interleukin (IL)-10 has a pathogenic role in systemic lupus erythematosus (SLE); however, a protective effect of IL-10 in SLE was also observed. Because the exact mechanism of IL-10 signalling in the pathogenesis of SLE is unclear, this study sought to assess the expression and signalling of interleukin-10 receptor (IL-10R) in peripheral leucocytes from patients with SLE. We used flow cytometry to examine the expression of IL-10R1 on different peripheral leucocytes from 28 SLE patients, of whom 14 had lupus nephritis (LN) and 14 were healthy controls. We also examined the effects of IL-10 on phosphorylation of signal transducer and activator of transcription (STAT)-3 and STAT-1 in peripheral blood mononuclear cells (PBMCs) obtained from 13 SLE patients and seven healthy controls. Plasma cytokines were detected by flow cytometric bead array (CBA) techniques. Although IL-10R1 expression levels on each peripheral leucocyte subset from 28 SLE patients and 14 healthy controls were similar, the expression levels on CD4(+) T cells from LN patients were significantly lower than on CD4(+) T cells from controls and SLE patients without nephritis (P < 0·01). IL-10R1 expression levels on CD4(+) and CD8(+) T cells were correlated negatively with the SLE disease activity index (P < 0·01). Additionally, the phosphorylation of STAT-3 was delayed and reduced in PBMCs from LN patients and active SLE patients. Plasma IL-10 levels were significantly higher in LN patients than controls. IL-10R1 expression on CD4(+) T cells and signalling in PBMCs were down-regulated in LN patients, indicating that IL-10 and its receptor may have a special role in LN pathogenesis.

The mechanism of action of methylprednisolone in the treatment of multiple sclerosis

Methylprednisolone plays an important role in the current treatment of multiple sclerosis (MS), particularly in the acute phase of relapse. It acts in various ways to decrease the inflammatory cycle including: dampening the inflammatory cytokine cascade, inhibiting the activation of T cells, decreasing the extravasation of immune cells into the central nervous system, facilitating the apoptosis of activated immune cells, and indirectly decreasing the cytotoxic effects of nitric oxide and tumor necrosis factor alpha. This paper reviews the most recent observations on these mechanisms both to understand the disease mechanism and its treatment. As more becomes known about these mechanisms, it may become possible to design treatment regimes that are more specific towards both the individual and the disease state.

Corticosteroids treatment

Corticosteroids (Cs) are widely used for treatment of multiple sclerosis (MS) acute relapses because of the potent immunosuppressive and anti-inflammatory properties. As for patients with relapsing-remitting (RR) MS, short-term administrations of Cs markedly less severity of symptoms and promote faster recovery of clinical attacks. Chronic administrations of Cs significantly diminish the formation of T1 hypointense lesions and the progression of brain atrophy. As for patients with secondary progressive MS treatment with Cs delays the time to onset of sustained disability. Finally the association between methylprednisolone and interferon beta (IFNbeta) leads the recovery of active lesions at greater extent and reduces the formation of neutralizing antibodies (NABs) against IFNbeta in patients with RRMS.

Investigation of cytokine (tumor necrosis factor-alpha, interleukin-6, interleukin-10) concentrations in the cerebrospinal fluid of female patients with multiple sclerosis and systemic lupus erythematosus

Humoral immune response seems to play a role in the pathogenesis of multiple sclerosis (MS) and in the central nervous system (CNS) complications of systemic lupus erythematosus (SLE). The aim of the present study was to compare the levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and IL-10 in the cerebrospinal fluid of female patients with several forms of MS (50 patients), and in female patients with several types of CNS complications in SLE (50 patients). Samples were investigated using an enzyme-linked immunosorbent assay technique. Involvement of CNS in SLE patients seems to be characterized with elevated concentrations of all three cytokines in CNS and intrathecal synthesis of IL-6. In MS patients, an intrathecal synthesis of TNF-alpha (relapsing-remitting form) and IL-6 (primary progressive form) were observed. Clinical forms of MS seem to be immunologically heterogeneous. The activation of cytokine network was observed in SLE patients with CNS complications, independent of the pathological process. Similarities between SLE and MS patients with the primary progressive form of the disease were demonstrated concerning the intrathecal synthesis of IL-6. Only MS patients with the relapsing-remitting clinical form showed intrathecal TNF-alpha synthesis.

The role of interleukin-10 in autoimmune disease: systemic lupus erythematosus (SLE) and multiple sclerosis (MS)

Interleukin-10 (IL-10) is an immunoregulatory cytokine that plays a crucial role in inflammatory and immune reactions. It has potent anti-inflammatory and immunosuppressive activities on myeloid cell functions which forms a solid basis for its use in acute and chronic inflammatory diseases. Here, we discuss the role of IL-10 in autoimmune diseases and examine its beneficial effects in cellular-based autoimmune diseases such as multiple sclerosis (MS) or its involvement in humoral-based autoimmune diseases such as systemic lupus erythematosus (SLE). Inhibition of the immune stimulatory activities of IL-10 may provide novel approaches in the treatment of humoral autoimmune diseases, infectious diseases and cancer.

IL-10 as a mediator in the HPA axis and brain

Certain functional interactions between the nervous, endocrine, and immune systems are mediated by cytokines. The pro-inflammatory cytokines, interleukin-1 (IL-1) and tumor necrosis factor (TNF) were among the first to be recognized in this regard. A modulator of these cytokines, IL-10, has been shown to have a wide range of activities in the immune system; in this review, we describe its production and actions in the hypothalamic-pituitary-adrenal (HPA) axis. IL-10 is produced in pituitary, hypothalamic, and neural tissues in addition to lymphocytes. IL-10 enhances corticotropin releasing factor (CRF) and corticotropin (ACTH) production in hypothalamic and pituitary tissues, respectively. Further downstream in the HPA axis endogenous IL-10 has the potential to contribute to regulation of glucocorticosteroid production both tonically and following stressors. Our studies and those of others reviewed here indicate that IL-10 may be an important endogenous regulator in HPA axis activity and in CNS pathologies such as multiple sclerosis. Thus, in addition to its more widely recognized role in immunity, IL-10's neuroendocrine activities described here point to its role as an important regulator in communication between the immune and neuroendocrine systems.