Abnormalities of Peripheral Lymphocyte Subsets in Rheumatoid Arthritis Patients Complicated with Osteoporosis.

INTRODUCTION: Osteoporosis (OP) is one of the major comorbidities of rheumatoid arthritis (RA). Recent studies have shown that immune cells modulate bone health and regulate bone remodeling. However, the alterations of lymphocyte subsets in RA patients with OP are unclear. Here, we assessed the absolute numbers and proportions of the subsets in RA sufferers with OP and investigated the clinical significance. METHODS: A total of 777 RA patients and 117 gender- and age-matched healthy controls (HCs) were enrolled in this study. Patients were divided into RA-non-OP and RA-OP group according to their bone mineral density (BMD) and the history of fragility fracture. Peripheral lymphocyte subsets of participants were assessed by flow cytometry. RESULTS: Among 220 (28.31%) RA-OP patients, there were higher levels of erythrocyte sedimentation rate (ESR) (P = 0.011), C-reactive protein (CRP) (P = 0.028), rheumatoid factor (RF) (P = 0.013) and anti-cyclic citrullinated peptide antibody (ACPA) (P = 0.010), while red blood cells (RBC) (P = 0.039) were lower than those in RA-non-OP group. Compared with those of HCs and RA-non-OP group, the level of circulating Th17 cells in RA-OP patients was significantly increased (P < 0.05), while those of Tregs decreased (P < 0.01), leading to a higher ratio of Th17/Treg (P < 0.01). Notably, the level of B cells in both RA-non-OP and RA-OP group was reduced, this alteration was more obvious in patients with OP (P < 0.05). CONCLUSIONS: Immune disorders characterized by peripheral Th17/Treg imbalance and reduced B cells may contribute directly or indirectly to OP in RA, and this deserves more clinical attention.

Low-Dose Interleukin-2 Altered Gut Microbiota and Ameliorated Collagen-Induced Arthritis.

PURPOSE: Low-dose interleukin-2 (ld-IL-2) has been shown to regulate the balance between effector T and regulatory T (Treg) cells and has been used in several clinical trials to treat autoimmune diseases including rheumatoid arthritis (RA). In this study, we investigated the effects of ld-IL-2 on collagen-induced arthritis (CIA) in mice. METHODS: Arthritis severity in CIA mice was measured using the arthritis index (AI), radiographs, and hematoxylin and eosin staining. Cytokines were detected using enzyme-linked immunosorbent assay. Gut microbiota alterations and short-chain fatty acid production were analyzed through 16S rRNA sequencing and gas chromatography. RESULTS: The AI scores of CIA mice treated with ld-IL-2 were significantly lower compared to the model group, which significantly reduced the severity of arthritis. Ld-IL-2 also altered the gut microbiota in CIA mice. The diversity, composition, and dominant species of gut microbiota were altered by ld-IL-2 treatment. Ld-IL-2 also increased short-chain fatty acid levels. There was a strong correlation between ld-IL-2 treatment and improved gut microbiota. CONCLUSION: Ld-IL-2 significantly ameliorated joint inflammation and bone damage and improved gut microbial dysbiosis in CIA, indicating that it may be a promising therapy for RA patients.

Decreased numbers and sex-based differences of circulating regulatory T cells in patients with seropositive undifferentiated arthritis.

AIMS: CD4+ T cells play crucial roles as both mediators and regulators of the pathogenesis of rheumatoid arthritis (RA). However, the characteristics of CD4+ T cell subpopulations in the earliest stage of RA development remain unclear. Hence, we determined the proportions and absolute counts of circulating CD4+ T cell subsets in patients with seropositive undifferentiated arthritis (SUA), the early and preclinical stage of RA. METHODS: Peripheral blood samples and clinical information were collected from 177 patients with SUA, 104 patients with RA, and 120 healthy controls. All patients were newly diagnosed and untreated. Proportions and absolute counts of CD4+ T cell subpopulations were determined by flow cytometric analysis. RESULTS: In patients with SUA, percentages and absolute counts of circulating regulatory T (Treg) cells were decreased significantly and Th17/Treg cell ratios were abnormally increased, whereas Th17 cell numbers were similar to those in healthy controls. In addition, sex-based differences in circulating Treg cells were observed, with female SUA patients having lower proportions and absolute counts of Treg cells than those in males. Moreover, female patients with SUA had higher erythrocyte sedimentation rates and 28-joint Disease Activity Scores than those in males. CONCLUSION: Immune tolerance deficiency resulting from an abnormal reduction in circulating Treg cells might be the most crucial immunological event in the earliest stage of RA. The sex-specific disparity in Treg cells should also be considered for immunoregulatory and preventive strategies targeting early RA.

Characteristics and reference ranges of CD4+T cell subpopulations among healthy adult Han Chinese in Shanxi Province, North China.

BACKGROUND: Immunophenotyping of blood lymphocytes is an essential tool to evaluate the immune function of patients with immunodeficiency or autoimmunity. Predominately identified CD4+T cell subsets, Th1, Th2, Th17, as well as regulatory T (Treg) cells, play crucial roles in several immunological and pathological conditions. Considering the variations in cell counts among populations and ethnicities, specific CD4+T cell subset reference values need to be locally established to enable meaningful comparisons and accurate data interpretation in clinical and research settings. Therefore, the aim of this study was to establish distributions and reference ranges for blood CD4+T cell subpopulations in age- and sex-balanced healthy adults of a Han Chinese population in Shanxi Province, North China. METHODS: Peripheral blood CD4+T cell subsets were examined in 150 healthy volunteers (75 males, 75 females) aged 20-70 years with a four-color FACSCalibur flow cytometer. RESULTS: Reference value percentages (absolute counts, cells/µl) were defined as 95% of the population for cell types as follows: CD4+T, 23.78-51.07 (360-1127); Th1, 0.43-39.62 (2.64-276.21); Th2, 0.27-3.57 (1.80-27.14); Th17, 0.22-2.62 (1.10-19.54); and Treg, 2.17-7.94 (13.47-64.58). The ranges for the Th1:Th2 and Th17:Treg ratios were 0.59-52.37 and 0.04-0.76, respectively. Notably, a significant increase was observed in the values of Treg cells in older individuals, and the numbers of Treg cells in females also tended to decrease when compared to those in males. Therefore, we established the distribution and reference range of CD4+T cell subsets based on age and sex, demonstrating the lowest values of Treg cells in younger females. CONCLUSIONS: Collectively, our data provide population-, age-, and sex-specific distributions and reference ranges of circulating CD4+T cell subpopulations, which can be adopted to guide clinical decisions and interpretation of immunophenotyping data in the Han Chinese population in Taiyuan, Shanxi Province, China. In addition, the low expression of peripheral Treg cells in younger females may be associated with the predisposition of females to autoimmune diseases.

Sirolimus selectively increases circulating Treg cell numbers and restores the Th17/Treg balance in rheumatoid arthritis patients with low disease activity or in DAS28 remission who previously received conventional disease-modifying anti-rheumatic drugs.

OBJECTIVES: Regulatory T (Treg) cells are crucial players in the prevention of autoimmunity. Mechanistic target of rapamycin (mTOR) signalling negatively controls the development and function of Treg cells. The aim of the present study was to evaluate the effects of rapamycin, under the generic name sirolimus, on CD4+CD25+FoxP3+ Treg cells in rheumatoid arthritis (RA) patients with low disease activity or in DAS28 remission. METHODS: Fifty-five RA patients and 60 healthy controls were enrolled in this study. All patients had previously received conventional disease-modifying anti-rheumatic drugs (DMARDs) and were considered to have a low DAS28 score (≤3.2). Peripheral blood samples and clinical information were obtained at baseline and following 6 and 12 weeks of sirolimus treatment, or after 12 weeks of conventional treatment. Peripheral blood samples were also obtained from the healthy controls. The circulating levels of lymphocyte subpopulations were assessed by flow cytometry. RESULTS: Thirty-five patients received sirolimus and 20 patients continued treatment with conventional DMARDs. The absolute counts and proportions of CD4+CD25+FoxP3+ Treg cells were significantly lower in all RA patients with DAS28 ≤ 3.2 as compared with those in healthy controls. By contrast, the difference in circulating Th17 cell numbers was not significant. Sirolimus administration resulted in elevations in circulating Treg cell numbers and significant reductions in the Th17/Treg cell ratio, whereas the circulating level of Treg cells and the Th17/Treg cell ratio in patients under conventional treatment both showed a tendency of reduction. Furthermore, a greater proportion of patients under sirolimus treatment achieved DAS28-based remission at 12 weeks. CONCLUSIONS: Sirolimus can favourably expand Treg cells in RA patients with DAS28 ≤3.2, consequently restoring a healthy balance of Th17/Treg cells, which might improve the likelihood of long-term and sustained clinical remission and reduce the probability of disease flare-ups in RA.

Low-Dose Sirolimus Immunoregulation Therapy in Patients with Active Rheumatoid Arthritis: A 24-Week Follow-Up of the Randomized, Open-Label, Parallel-Controlled Trial.

BACKGROUND: We have reported previously the insufficient absolute number or functional defects of regulatory T cells (Tregs) in patients with rheumatoid arthritis (RA), challenging conventional unspecific immunosuppressive therapy. Sirolimus, a mTOR inhibitor, is reported to allow growth of functional Tregs; here, we investigated the efficacy of low-dose sirolimus combined with conventional immunosuppressants (sirolimus immunoregulation therapy) for RA treatment with lower side effects and better tolerance. METHODS: In this nonblinded and parallel-group trial, we randomly assigned 62 patients to receive conventional glucocorticoids and immunosuppressants with or without sirolimus at a dosage of 0.5 mg on alternate days for 24 weeks in a 2 : 1 ratio. The demographic features, clinical manifestations, and laboratory indicators including peripheral blood lymphocyte subgroups and CD4+T subsets were compared before and after the treatment. RESULTS: Finally, 37 patients in the sirolimus group and 18 in the conventional treated group completed the 6-month study. By 24 weeks, the patients with sirolimus experienced significant reduction in disease activity indicators including DAS28, ESR, and the number of tender joints and swollen joints (p < 0.001). Notably, they had a higher level of Tregs as compared with those with conventional therapy alone (p < 0.05), indicating that sirolimus could partly restore the reduced Tregs. Concomitantly, their usage of immunosuppressants for controlling disease activity was decreased as compared with the conventional group with no difference in blood routine, and liver and renal functions both before and after the treatment of sirolimus and between the two groups (p > 0.05). CONCLUSIONS: Low-dose sirolimus immunoregulatory therapy selectively upregulated Tregs and partly replaced the usage of immunosuppressants to control disease activity without overtreatment and evaluable side effect. Further study is required using a large sample of RA patients treated with sirolimus for a longer period. This trial is registered at the Chinese Clinical Trial Registry (http://www.chictr.org.cn/showproj.aspx?proj=17245).

Combination of 4-hydroperoxy cyclophosphamide and methotrexate inhibits IL-6/sIL-6R-induced RANKL expression in fibroblast-like synoviocytes via suppression of the JAK2/STAT3 and p38MAPK signaling pathway.

Although conventional combination therapy is effective for most patients with rheumatoid arthritis (RA), many still do not respond to current therapies. Therefore, novel combination regimens that better target cellular processes involved in RA pathogenesis are required. Preliminary studies have demonstrated the beneficial effects of a combination of cyclophosphamide (CTX) and methotrexate (MTX) in models of RA. Using western blotting, real-time polymerase chain reaction, enzyme-linked immunosorbent assays, and immunofluorescent staining, we demonstrated that the combination of 4-hydroperoxy CTX (4-H-CTX) and MTX inhibited the expression of receptor activator of nuclear factor-κB ligand (RANKL) in fibroblast-like synoviocytes (FLS) treated with the interleukin (IL)-6/soluble IL-6 receptor (sIL-6R) complex. To elucidate the mechanisms underlying this effect, we treated RA-FLS with the JAK2/STAT3 inhibitor AG490 or p38MAPK inhibitor SB203580. The results showed that IL-6/sIL-6R-induced RANKL upregulation required phosphorylation-mediated activation of STAT3 and p38 signaling, and that 4-H-CTX and/or MTX inhibited RANKL expression in IL-6/sIL-6R-stimulated FLS by suppressing JAK2/STAT3 and p38MAPK signaling. This study demonstrated for the first time the inhibitory effects of 4-H-CTX and MTX on RANKL expression in IL-6/sIL-6R-stimulated FLS via suppression of STAT3 and p38MAPK phosphorylation. These results identify promising therapeutic agents that might have clinical applications in patients with RA who are at high risk of bone erosion or do not respond well to conventional therapy.