Pathological interaction between CD4 + T cells and B cells is one of the important mechanisms of systemic autoimmune diseases. Follicular helper T cells (Tfh) and peripheral helper T cells (Tph) are key cells for assisting B cells. Tph cell is a newly discovered helper T cell subset, and their phenotype is PD-1 highCXCR5 -CD4 +. Tph cell and Tfh cell have certain differences in phenotype, function, and site of action. It interacts with B cells, promoting the differentiation of B cells into plasma cells and the production of autoantibodies, as well as promoting the formation of ELS to maintain local inflammation and antibody responses. Tph cells have recently been reported in various autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, Sjogren′s syndrome, and IgG4-related diseases. This review summarizes the progress in peripheral immune response of Tph cells in different systemic autoimmune diseases, aiming to explore the new mechanism of autoantibody production and help to develop new diagnostic and therapeutic targets in the future.

Objective:To analyze the characteristics of CD4 + T cell subsets and cytokines in patients with mixed connective tissue disease (MCTD) and the correlation of MCTD disease activity, laboratory data, and clinical symptoms with cytokines. Methods:A total of 48 MCTD patients (including 24 newly diagnosed patients and 24 treated patients) were enrolled from the Department of Rheumatology and Immunology, the Second Hospital of Shanxi Medical University from 2018 to 2021. Meanwhile, 49 healthy subjects who underwent physical examination were recruited (healthy control group). The absolute counts of CD4 + T cell subsets in peripheral blood samples were analyzed by flow cytometry. The levels of serum cytokines were detected by flow bead array. Analysis of variance and Mann-Whitney U test were used to compare the differences between groups. Pearson or Spearman correlation analysis was used for correlation analysis. Logistic regression analysis was used to analyze related factors. The receiver operating characteristic curve was used to detect the best cut-off value and effectiveness. Results:The absolute counts of Th1 ( P<0.01), Th2 ( P<0.01) and Treg cells ( P<0.01) in the newly diagnosed MCTD patients and the treated MCTD patients were lower than those in the healthy subjects. The levels of cytokines (IL-2, IL-4, IL-6, IL-10, IL-17, IFN-γ, and TNF-α) in the two MCTD groups were higher than those in the healthy control group ( P<0.01). Further analysis revealed that the cardiac enzymes in MCTD patients included creatine kinase, creatine kinase-MB, aspartate aminotransferase, α-hydroxybutyrate dehydrogenase, and lactate dehydrogenase were positively correlated with cytokines ( P<0.05). In addition, it was found that IL-2 was positively correlated with erythrocyte sedimentation rate ( r=0.477, P<0.001), but it was negatively correlated with complement C3 ( r=-0.546, P=0.002) and complement C4 ( r=-0.422, P=0.02). IL-10 was correlated with the myositis symptoms in MCTD patients and the area under the receiver operator characteristic curve was 0.745 (95% CI: 0.576-0.915, P<0.05). Conclusions:This study provides insights into the unique immunological characteristics of CD4 + T lymphocyte subsets and cytokines in patients with MCTD, and also reveals a close correlation between cytokines and cardiac enzymes in MCTD patients. IL-2 has been shown to be associated with disease activity in MCTD patients. The level of IL-10 may be related to the occurrence of myositis symptoms in MCTD.

Objective:To investigate the numbers of peripheral blood CD4 +T cell subpopulations in patients with elderly-onset rheumatoid arthritis (EORA) and its clinical significance. Methods:A total of 188 patients with newly diagnosed RA in the department of rheumatology and immunology of the Second Hospital of Shanxi Medical University from January 2020 to December 2023 were collected, including 48 cases of EORA (age of onset: ≥60 years old), 140 cases of young-onset rheumatoid arthritis (YORA) (18 years old ≤ age of onset < 60 years old). Meanwhile, 151 healthy controls (HC) were collected, of which 31 persons aged 60-85 years were included as HC group 1 (HC 1) and 120 individuals aged 18-59 years were included as HC group 2 (HC 2). Peripheral blood CD4 +T lymphocyte subsets of these participants were assessed by flow cytometry. Differences between groups were analyzed using independent-samples t test, Mann-Whitney U test or χ2 test. Results:Compared with healthy individuals, the absolute counts and percentages of peripheral blood Treg cells in patients with EORA were significantly decreased [absolute counts: 32.65 (23.04, 47.73) cells/μl vs. 23.03 (15.28, 32.12) cells/μl, Z=-3.35, P=0.001; percentages: 5.12%(4.13%, 6.16%) vs. 3.72% (2.79%, 4.82%), Z=-4.10, P<0.001], while the Th17/Treg cell ratio was increased [0.16 (0.12, 0.29) vs. 0.26 (0.18, 0.46), Z=-2.94, P=0.003], the differences are all significant. There was a tendency with higher absolute counts and percentages of Treg [absolute counts: 23.03 (15.28, 32.12) cells/μl vs. 20.97 (14.01, 30.64) cells/μl, Z=-0.58, P=0.561; percentages: 3.72%(2.79%, 4.82%) vs. 3.38% (2.39%, 4.71%), Z=-1.06, P=0.287] and lower Th17/Treg ratios [0.26 (0.18, 0.46) vs. 0.27 (0.19, 0.46), Z=-0.32, P=0.751] in EORA when compared to patients with YORA, but no significant differences were observed. Conclusion:Patients with EORA also have the reduced numbers of peripheral blood Treg cells and immune imbalance of Th17/Treg, suggesting that immune imbalance or dysfunction caused by defects in Treg cell counts and/or function contributes to the development of EORA, and that targeting Treg cells may be a promising therapeutic strategy for EORA.

Objective:To verify the causal relationship between tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-12 (IL-12) and gout using Mendelian randomization (MR) analysis. The findings are expected to provide insights into whether TNF-α, IL-6, IL-12 antagonists and other biological agents can be applied in the treatment of refractory gout (RG) in clinical practice.Methods:This study conducted a two-sample MR using publicly available summary statistics from an independent European ancestry cohort. For the data on TNF-α, IL-6, and IL-12, data were retrieved from the GWAS catalog database. For the gout data, to avoid confounding, the FinnGen database was used. The analysis was performed using R4.3.2 software. The statistical significance threshold was set at P<5×10 -5. Linkage disequilibrium (LDA was set to R2>0.001) was removed, and strongly correlated and independent single nucleotide polymorphism (SNP) loci were selected for analysis. Five methods were used for analysis: inverse variance weighting (IVW), MR Egger, weighted median, simple mode, and weighted mode. IVW was used as the main analysis method. When pleiotropy was present, MR-Egger estimates were considered more persuasive than IVW estimates, so MR-Egger was taken as the primary analysis method. Cochran′s Q test and MR-Egger intercept test were used to assess heterogeneity and pleiotropy. The leave-one-out method was used to test the stability of MR results by systematically excluding instrumental variables (IVs). Finally, a reverse MR analysis of gout and TNF-α, IL-6, IL-12 was conducted. Results:The IVW-MR, MR Egger, weighted median, simple mode, and weighted mode analyses showed no causal relationship between IL-6, IL-12, and gout (all P>0.05). Cochran′s Q test and MR-Egger intercept test results showed no significant heterogeneity or horizontal pleiotropy affecting causal estimates (all P>0.05). The leave-one-out test indicated stable results. MR-Egger analysis showed a weak causal relationship between TNF-α and gout [ OR(95% CI)=0.892 (0.812, 0.979), b=-0.113, P=0.021], while the other methods (IVW-MR, weighted median, simple mode, weighted mode) showed no causal relationship between TNF-α and gout (all P>0.05). Cochran′s Q test indicated no heterogeneity affecting causal estimates ( P>0.05), but MR-Egger intercept test suggested the presence of horizontal pleiotropy affecting causal estimates ( P<0.05). The reverse MR analysis of gout and TNF-α, IL-6, IL-12 showed no causal relationships (all P>0.05). No significant heterogeneity or horizontal pleiotropy affected causal estimates (all P>0.05), and the leave-one-out test indicated that the results were stable. Conclusion:MR analysis suggests that there is no causal relationship between IL-6, IL-12, and gout, but TNF-α may have a weak causal relationship with gout. More accurate and solid evidence are needed from further prospective randomized controlled trials.

Objective:The clinicalpathological features of TAFRO syndrome were analyzed to clarify the similarities and differences between TAFRO syndrome and autoimmune diseases and to establish differential diagnosis.Methods:Six patients diagnosed with TAFRO syndrome in Shanxi Bethune Hospital from January 2014 to March 2022 were collected. The clinical, examination, pathology and treatment of TAFRO syndrome were analyzed and compared with autoimmune diseases, especially systemic lupus erythematosus and Sj?gren′s syndrome.Results:Among the 6 patients, 4 were males and 2 were females, with an average age of (57.5 ±9.8) years. All the 6 patients had fever, edema (including chest and abdominal effusion and systemic edema), thrombocytopenia (3 main criteria) and more than 2 secondary criteria.ESR and CRP were significantly elevated in 6 patients. There were 1 case of elevated IgA and IgG (IgA 4.10 g/L, IgG19.05 g/L), 1 case of elevated igg (IgG 19.33 g/L), 3 cases of normal and 1 case of undetected. Serum IgG4 was negative in 4 cases and undetected in 2 cases. Autoantibodies: 4 cases were ANA positive, including 1 case with anti-SSA/Ro52(+), anti-SSA/Ro60(+), anti-SSB (+), 1 case with anti-SSA /Ro60(+), and 2 untested. Bone marrow cytological examination was performed in 6 cases, all of which showed active hyperplasia, 2 cases showed elevated megakaryocytes, and 1 case was accompanied by interstitial fibrosis. Pathological examination of lymph nodes: 5 cases were consistent with Castleman′s disease, and 1 case was suggestive of reactive hyperplasia of lymph nodes. Conclusion:Although the diagnostic criteria of TAFRO syndrome should exclude autoimmune diseases, TAFRO syndrome and autoimmune diseases can coexist, and the connective tissue disease complicated with TAFRO syndrome has its specific clinical characteristics and treatment plan, which needs to be identified clinically.

Objective:To explore the therapeutic effect of low-dose interleukin-2 (LdIL-2) on psoriasis and the regulatory role of peripheral blood Th17/Treg imbalance and cytokine disorder.Methods:45 psoriasis patients and 40 healthy individuals were collected from January 2021 to December 2022 in the Second Hospital of Shanxi Medical University. All patients were given with MTX (7.5 mg/week) for 12 weeks, followed by LdIL-2 (50×10 5 U/d×2 weeks×3 courses) until the 24 th week. PASI and ACR20 were collected at the 0, 12th and 24th weeks. Th17, Treg cell, IL-17 and IL-10 were detected. Statistical analysis included t-test, generalized estimating equations, Wilcoxon analysis, Chi-Square Test, Pearson linear correlation analysis, Spearman rank correlation analysis, etc. Results:①The number of patients who reached PASI50/75 in the 24 th week(31,10) was significantly higher than in the 12th week (14, 1), and the differences were statistically significant ( χ2=15.059, P<0.001; χ2=7.111, P=0.004). ②Compared the 0 week with the 24th week, Th17 cell was decreased [1.520%(0.985%, 2.005%) vs. 0.830%(0.675%, 1.125%), H=25.493, P<0.001], Treg cell was increased [3.010%(2.255%, 3.615%) vs.5.190%(4.605%, 6.030%), H=152.106, P<0.001], Th17/Treg ratio also was decreased [0.547(0.348, 0.712) vs. 0.170(0.105, 0.225), H=47.025, P<0.001], and the differences were statistically significant. ③Compared the 0 week with the 24th week, IL-17 was decreased [(19.7±8.7)pg/ml vs. (14.20±6.0)pg/ml, F=21.814, P<0.001], IL-10 was increased [(2.01±0.97)pg/ml vs. (2.62±0.92)pg/ml, F=11.230, P=0.004], IL-17/IL-10 ratio also was decreased [10.644(5.925, 14.705) vs. 5.410(3.455, 7.180), H=16.647, P<0.001], and the differences were statistically significant. ④The correlation analysis showed that PASI were significantly positively correlated with Th17 cells( r=0.598, P<0.001), Th17/Treg( r=0.772, P<0.001), IL-17( r=0.500, P<0.001) and IL-17/IL-10( r=0.776, P<0.001), and significantly negatively correlated with Treg cells( r=-0.822, P<0.001) and IL-10( r=-0.715, P<0.001). Conclusion:LdIL-2 can effectively reverse Th17/Treg imbalance and cytokine disorder in psoriasis patients, significantly alleviate the condition, and has good safety.

Objective:To explore the characteristics of blood lipid profile and its correlation with clinical features and cytokines in patients with active systemic sclerosis (SSc).Methods:In this study, from January 2018 to March 2023, a total of 102 SSc patients visited the Second Hospital of Shanxi Medical University and the First Hospital of Shanxi Medical University were enrolled, among which 57 cases were localized skin type, 25 cases were diffuse skin type, 20 cases were overlap syndrome. At the same time, 89 gender and age-matched health check-up subjects in the Second Hospital of Shanxi Medical University were selected as the healthy control group. The total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were compared between the two groups. According to the blood lipid level, they were grouped into normal blood lipid group and abnormal group, TG elevated group and normal group, HDL-C decreased group and normal group. The association between various lipid groups and organ involvement, modified Rodnan skin score (mRSS), laboratory examination and cytokines were analyzed. Continuous data were analyzed using t-test or Mann-Whitney U test, count data were tested with chi-square test, and Spearman correlation analysis was used for correlation analysis. Results:The level of TG [1.31 (1.04, 1.77) mmol/L vs. 1.05 (0.79, 1.35) mmol/L] and LDL-C [(2.33±0.69)mmol/L vs. (2.12±0.64) mmol/L] in active SSc patients were higher than that in HCs, and the level of TC [(4.27±1.11)mmol/L vs. (4.85±0.98)mmol/L] was lower than that in HCs ( Z=3.821, P<0.001; t=2.171, P=0.031; t=-3.791, P<0.001). Fifty-six (54.9%) SSc patients had dyslipidemia, the incidence of the TG increase and the HDL-C reduction was significantly higher. ESR, mRSS score and renal involvement in the dyslipidemia group were higher than that in normal blood lipid group. mRSS score and the incidence of cardiac and renal involvement were higher in the TG elevated group than that in normal group. TG was positively correlated with the mRSS scores ( r=0.321, P=0.001). The incidence of ESR increase and cardiac involvement was higher in HDL-C decreased group than that in normal group, while anti-Scl-70 positive rate was lower. HDL-C was negatively correlated with the ESR ( r=-0.411, P<0.001). In active SSc patients, levels of IL-2[2.78(2.04, 4.96)pg/ml], IL-6[14.71(7.74,28.38)pg/ml], IL-17[10.73(4.38, 26.62)pg/ml], and IFN-γ[5.40(3.11, 10.45)pg/ml] in the dyslipidemia group were higher than those in normal blood lipid group [IL-2:1.73(0.96, 3.75)pg/ml, Z=2.452, P=0.014; IL-6:6.78(4.38, 9.17)pg/ml, Z=3.726, P<0.001; IL-17:4.46(2.98, 12.53)pg/ml, Z=2.176, P=0.030;IFN-γ:3.76(2.20, 4.87)pg/ml, Z=2.960, P=0.003]. TG was positively associated with IL-2( r=0.358, P=0.002), IL-6( r=0.324, P=0.006), IL-10( r=0.270, P=0.024), IL-17( r=0.279, P=0.019), and IFN-γ( r=0.297, P=0.012)in patients with active SSc. HDL-C was negatively associated with levels of IL-2( r=-0.292, P=0.014), IL-6( r=-0.348, P=0.003), IL-10 ( r=-0.261, P=0.029)and TNF-α( r=-0.251, P=0.036). Conclusion:The incidence of dyslipidemia is higher in active SSc patients than that in HCs, the main manifestations are increased TG and LDL-C and decreased TC and HDL-C. Active SSc patients with dyslipidemia have higher levels of ESR and inflammatory cytokines, higher incidence of cardiac and renal involvement, and relatively severe skin fibrosis, which suggest that abnormal lipid metabolism plays an important role in the development of active SSc and organ involvement.

Pathological interaction between CD4 + T cells and B cells is one of the important mechanisms of systemic autoimmune diseases. Follicular helper T cells (Tfh) and peripheral helper T cells (Tph) are key cells for assisting B cells. Tph cell is a newly discovered helper T cell subset, and their phenotype is PD-1 highCXCR5 -CD4 +. Tph cell and Tfh cell have certain differences in phenotype, function, and site of action. It interacts with B cells, promoting the differentiation of B cells into plasma cells and the production of autoantibodies, as well as promoting the formation of ELS to maintain local inflammation and antibody responses. Tph cells have recently been reported in various autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, Sjogren′s syndrome, and IgG4-related diseases. This review summarizes the progress in peripheral immune response of Tph cells in different systemic autoimmune diseases, aiming to explore the new mechanism of autoantibody production and help to develop new diagnostic and therapeutic targets in the future.

Objective:To analyze the characteristics of CD4 + T cell subsets and cytokines in patients with mixed connective tissue disease (MCTD) and the correlation of MCTD disease activity, laboratory data, and clinical symptoms with cytokines. Methods:A total of 48 MCTD patients (including 24 newly diagnosed patients and 24 treated patients) were enrolled from the Department of Rheumatology and Immunology, the Second Hospital of Shanxi Medical University from 2018 to 2021. Meanwhile, 49 healthy subjects who underwent physical examination were recruited (healthy control group). The absolute counts of CD4 + T cell subsets in peripheral blood samples were analyzed by flow cytometry. The levels of serum cytokines were detected by flow bead array. Analysis of variance and Mann-Whitney U test were used to compare the differences between groups. Pearson or Spearman correlation analysis was used for correlation analysis. Logistic regression analysis was used to analyze related factors. The receiver operating characteristic curve was used to detect the best cut-off value and effectiveness. Results:The absolute counts of Th1 ( P<0.01), Th2 ( P<0.01) and Treg cells ( P<0.01) in the newly diagnosed MCTD patients and the treated MCTD patients were lower than those in the healthy subjects. The levels of cytokines (IL-2, IL-4, IL-6, IL-10, IL-17, IFN-γ, and TNF-α) in the two MCTD groups were higher than those in the healthy control group ( P<0.01). Further analysis revealed that the cardiac enzymes in MCTD patients included creatine kinase, creatine kinase-MB, aspartate aminotransferase, α-hydroxybutyrate dehydrogenase, and lactate dehydrogenase were positively correlated with cytokines ( P<0.05). In addition, it was found that IL-2 was positively correlated with erythrocyte sedimentation rate ( r=0.477, P<0.001), but it was negatively correlated with complement C3 ( r=-0.546, P=0.002) and complement C4 ( r=-0.422, P=0.02). IL-10 was correlated with the myositis symptoms in MCTD patients and the area under the receiver operator characteristic curve was 0.745 (95% CI: 0.576-0.915, P<0.05). Conclusions:This study provides insights into the unique immunological characteristics of CD4 + T lymphocyte subsets and cytokines in patients with MCTD, and also reveals a close correlation between cytokines and cardiac enzymes in MCTD patients. IL-2 has been shown to be associated with disease activity in MCTD patients. The level of IL-10 may be related to the occurrence of myositis symptoms in MCTD.

Objective:To verify the causal relationship between tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-12 (IL-12) and gout using Mendelian randomization (MR) analysis. The findings are expected to provide insights into whether TNF-α, IL-6, IL-12 antagonists and other biological agents can be applied in the treatment of refractory gout (RG) in clinical practice.Methods:This study conducted a two-sample MR using publicly available summary statistics from an independent European ancestry cohort. For the data on TNF-α, IL-6, and IL-12, data were retrieved from the GWAS catalog database. For the gout data, to avoid confounding, the FinnGen database was used. The analysis was performed using R4.3.2 software. The statistical significance threshold was set at P<5×10 -5. Linkage disequilibrium (LDA was set to R2>0.001) was removed, and strongly correlated and independent single nucleotide polymorphism (SNP) loci were selected for analysis. Five methods were used for analysis: inverse variance weighting (IVW), MR Egger, weighted median, simple mode, and weighted mode. IVW was used as the main analysis method. When pleiotropy was present, MR-Egger estimates were considered more persuasive than IVW estimates, so MR-Egger was taken as the primary analysis method. Cochran′s Q test and MR-Egger intercept test were used to assess heterogeneity and pleiotropy. The leave-one-out method was used to test the stability of MR results by systematically excluding instrumental variables (IVs). Finally, a reverse MR analysis of gout and TNF-α, IL-6, IL-12 was conducted. Results:The IVW-MR, MR Egger, weighted median, simple mode, and weighted mode analyses showed no causal relationship between IL-6, IL-12, and gout (all P>0.05). Cochran′s Q test and MR-Egger intercept test results showed no significant heterogeneity or horizontal pleiotropy affecting causal estimates (all P>0.05). The leave-one-out test indicated stable results. MR-Egger analysis showed a weak causal relationship between TNF-α and gout [ OR(95% CI)=0.892 (0.812, 0.979), b=-0.113, P=0.021], while the other methods (IVW-MR, weighted median, simple mode, weighted mode) showed no causal relationship between TNF-α and gout (all P>0.05). Cochran′s Q test indicated no heterogeneity affecting causal estimates ( P>0.05), but MR-Egger intercept test suggested the presence of horizontal pleiotropy affecting causal estimates ( P<0.05). The reverse MR analysis of gout and TNF-α, IL-6, IL-12 showed no causal relationships (all P>0.05). No significant heterogeneity or horizontal pleiotropy affected causal estimates (all P>0.05), and the leave-one-out test indicated that the results were stable. Conclusion:MR analysis suggests that there is no causal relationship between IL-6, IL-12, and gout, but TNF-α may have a weak causal relationship with gout. More accurate and solid evidence are needed from further prospective randomized controlled trials.