Identification of gene profiles of CD4~ and CD8~ T lymphocyte in systemic lupus erythematosus by generation of longer cDNA fragments from serial analysis of gene expression tags for gene identification

Objective To identify LongSAGE Tags in systemic lupus erythematosus (SLE) by generation of longer cDNA fragments from serial analysis of gene expression (SAGE) tags for gene identification (GLGI). Methods CD4 and CD8 T lymphocytes were collected from the PBMCs of 25 patients with SLE and 10 healthy controls. Then the total RNA was extracted and reversely     

系统性红斑狼疮初发患者外周血T细胞免疫球蛋白及黏蛋白域蛋白-3及其配体半乳糖凝集素-9表达水平和意义

Objective To investigate the expression of T cell immunoglobulin domain and mucin domain (TIM)-3 and its ligand Galectin-9 in the peripheral blood of initial systemic lupus erythematosus (SLE)patients,and explore their effects on SLE.Methods The percentages of CD4+TIM-3+,CD8+TIM-3+cells from 33 SLE patients and 26 normal controls were detected by flow cytometry,and the Galectin-9 gene expression of PBMCs was determined by real-time PCR The SLE Disease Activity Index(SLEDAI),C3 level and lymphocyte count were evaluated.Mann-Whitney U test was used for independent samples analysis and Spearmen's test was used for correlation analysis.Results The percentages of CD4+TIM-3+ and CD8+TIM-3+ cells were markedly increased in SLE group than those of the control group(P<0.01).In particular,the CD4+TIM-3+,CD8+TIM-3+ level Was positively correlated with SLEDAI (r=0.517,P＜0.01;r=0.400,P＜0.05);but negatively correlated with C3(r=0.487,P＜0.05;r=0.395,P＜0.05).The Galectin-9 mRNA in SLE PBMCs was higher than that of the controls(P<0.05).Conclusion TIM-3-Galectin-9 pathway may be involved in T cell immune regulation of SLE,and is related to disease activity.     

干扰素诱导蛋白44基因与系统性红斑狼疮的相关性研究

目的 探讨系统性红斑狼疮(SLE)患者外周血白细胞干扰素诱导蛋白 44(IFI44)基因实时定量表达水平与SLE临床表现及病情活动的相关性.方法 收集100例SLE患者,40例非SLE其他自身免疫性疾病患者,40名健康对照人群的临床资料,抽提外周血总RNA并逆转录成eDNA,运用SYBRgreen dve Ⅰ实时定量聚合酶链反应(RT-PCR)检测患者和对照组的IFI44基因定量表达水平,并对其与各临床指标及病情活动度的相关性进行分析.数据分析采用方差分析,采用Pearson及Spearman检验进行相关性分析.结果 ①SLE患者组的IFI44拷贝数26.8±5.3明显高于非SLE组7.4±2.7(P=0.0012)和健康对照组5.2±2.0(P=0.005);而非SLE患者组与健康对照组差异无统计学意义.②SLE重度活动组患者IFI44表达量63.1±22.4明显高于非活动组9.2±1.8(P=0.000)和轻度活动组患者28.0±7.2(P=0.015).③SLE患者组的IFI44拷贝数与SLEDAI积分之间呈正相关(r=0.38,P=0.000),与尿蛋白定量(24 h)也呈正相关(r=0.42,P=0.000).结论 IFI44基因在SLE患者中有明显表达上调现象;检测IFI44的表达水平有助于判断SLE患者病情活动状况.

Abstract：

Objective To investigate the expression of interferon-induced protein 44 (IFI44) gene in the leukocytes of the peripheral blood samples from patients with systemic lupus erythematosus (SLE), and to evaluate the relationship between the expression level and disease activity. Methods Mononuclear cells in the peripheral blood samples from 100 SLE patients were compared with those of 40 disease controls and 40 healthy donors (HD) and the expression of the IFI44 was evaluated by quantitative real-time PCR.Comparisons between groups were performed with ANOVA, and the correlation analysis between the level of expression was higher in SLE patients than disease controls and healthy donors (26.8±5.3, 7.4±2.7, 5.2±2.0,respectively) (P=0.0012, P=0.005), but no difference was found between disease controls and healthy donors. Mild disease activity and the SLE patients with stable disease (63.1±22.4, 28.0±7.2, 9.2±1.8, respectively)and 24 hours urine protein level (r=0.42, P=0.000). Conclusion IFI44 is demonstrated to be highly expressed in SLE patients. The level of IFI44 may be a promising candidate biomarker for identifying SLE activity.     

系统性红斑狼疮患者外周血CD4+CXCR5+滤泡辅助性T细胞样细胞的变化及糖皮质激素对其的影响

Objective To investigate the frequencies of CD4+CXCR5+T cells in the CD4+T cells of peripheral blood of patients with systemic lupus erythematosus (SLE) and the effect of glucocorticoid on it.Methods Frequencies of CD4+CXCR5+T cell were analyzed by flow cytometry in 45 active,20 inactive SLE patients and 20 healthy controls.Differences between groups and the effect of glucocorticoid were analyzed.Meanwhile, the expression of CXCR5 on CDI9+B cells was analyzed. Independent sample t test was used for statistical analysis between twogroups, ANOVA was applied for data analysis between 3 groups,,nonparameterical Spearman's analysis was used for correlation analysis and repeated measurement ANOVA were used to compare the parameters before and after treatment. Results The percentage of CD4+CXCR5+ in CD4+T cells was increased in patients with SLE compared with healthy controls[(16±7)% vs (12±3)%, P＜0.01].It was increased in patients with active SLE [(18±7)%] compared with healthy controls (P＜0.05) but there was no significant difference between inactive SLE[(11±4)%] and healthy controls(P＞0.05). The percentage in patients with LN was higher than that in patients without LN, but without significant difference[(18±7)%vs (14±7)%, P=0.05 ]. The percentage of CD4+CXCR5+T cells was positively correlated with SLEDAI,the titer of ANA and level of ESR but negatively correlated with the level of C3 (P<0.05 for each).No correlation was found between duration and the levels of CRP and immunoglobulin.. The percentage in patients with high anti-dsDNA group was also higher than that of the low group, but no differences were found between anti-Sm antibody positive and negative groups neither between anti-SSA/SSB antibody positive and negative groups(P＞0.05 for each).The expression level of CXCR5 on CD19+B cells in active SLE patients was lower than that of healthy controls[(85±11)% vs (94±3)%, P＜0.05 ]. The percentages of CD4+CXCR5+T cells in 10 untreated active SLE patients were decreased at day 1,day 3 and day 7 after being treated with dexamethasone (20mg/d) when compared with those before the treatment (P＜0.05 for each), but the percentages of CD19+CXCR5+B cells had no significant change (P＞0.05 for each).Conclusion These results demonstrate that the abnormality of CD4+CXCR5+T cells may play an important role in the pathogenesis of SLE.     

Effect of Hejie decoction on T cell immune state of chronic hepatitis B patients

AIM: To explore the effect of Hejie decoction (HJD) (mediation decoction) on T cellular immune state of chronic hepatitis B patients.METHODS: Sixty-five patients with chronic hepatitis B were randomly divided into 2 groups. Forty patients in the treatment group were treated by HJD, and 25 patients in the control group were treated by routine Western medicine. The TCRVβ7 gene expression, T lymphocyte subsets (CD3^+, CD4^+, CD8^+,CD4^+/CD8^+) levels were observed before and after treatment.RESULTS: The level of CD4^+ cells was lower whereas the level of CD8^+ cells was higher in patients than in the normal group. There was no significant difference between the levels of CD3^+ cells in patients and normal persons. After 6 months of treatment, ALT, AST, TB levels of the 2 groups were obviously decreased, and the level of CD4^+ cells was increased whereas the level of CD8^+ cells was decreased in the treatment group. However, the level of CD4^+ cells and CD8^+ cells had no significant difference in the control group. TCRVβ7 expressions were detected in 6 patients of the treatment group, whose HBV-DNA and HBeAg turned negative and ALT became normal. HBeAg in another 3 patients turned negative while HBV-DNA did not, and TCRVβ7 expressions were not detectable. TCRVβ7 expression could not be detected in the control group, HBV-DNA of the control group did not turn negative. HBeAg in 1 patient turned negative while HBV-DNA did not, and TCRVβ7 expressions were not detectable. The total effective rate was not significantly different between the 2 groups and the markedly effective rate was significantly different(P&lt;0.01).CONCLUSION: H3D is effective for treating chronic hepatitis B, and its effect seems to relate with the improvement of the TCRVβ7 expression of chronic hepatitis B patients, thus activating T cells and eliminating HBV. T cellular immune function plays an important role in HBV infection and virus elimination.     

系统性红斑狼疮初发患者外周血T细胞免疫球蛋白及黏蛋白域蛋白-3及其配体半乳糖凝集素-9表达水平和意义

目的 通过检测T细胞免疫球蛋白及黏蛋白域蛋白(TIM)-3及其配体半乳糖凝集素-9在系统性红斑狼疮(SLE)初发患者外周血的表达水平,探讨其在SLE发病中的可能作用.方法 选取SLE初发患者33例,健康对照组26名,采用流式细胞术检测2组CD4+TIM-3+、CD8+TIM-3+细胞表达水平;实时荧光定量聚合酶链反应(PCR)技术比较2组外周血单个核细胞(PBMCs)半乳糖凝集素-9 mRNA表达水平;同时记录SLE组SLE疾病活动指数(SLEDAI)、补体C3水平和外周血淋巴细胞计数.两独立样本比较采用Mann-Whitney U检验;相关关系采用Spearman等级相关分析.结果 SLE组CD4+TIM-3+、CD8+TIM-3+细胞比率显著高于对照组(P＜0.01);其中CD4+TIM-3+、CD8+TIM-3+细胞数目与SLEDAI呈正相关(r=0.517,P＜0.01;=400,P＜0.05);与补体C3水平呈负相关(r=-0.487,P＜0.05;r=-0.395,P＜0.05).SLE组PBMCs半乳糖凝集素-9 mRNA表达较对照组显著上调(P＜0.05).结论 TIM-3-半乳糖凝集素-9通路可能参与了SLET细胞免疫调节,并与疾病活动性相关.

Abstract：

Objective To investigate the expression of T cell immunoglobulin domain and mucin domain (TIM)-3 and its ligand Galectin-9 in the peripheral blood of initial systemic lupus erythematosus (SLE)patients,and explore their effects on SLE.Methods The percentages of CD4+TIM-3+,CD8+TIM-3+cells from 33 SLE patients and 26 normal controls were detected by flow cytometry,and the Galectin-9 gene expression of PBMCs was determined by real-time PCR The SLE Disease Activity Index(SLEDAI),C3 level and lymphocyte count were evaluated.Mann-Whitney U test was used for independent samples analysis and Spearmen's test was used for correlation analysis.Results The percentages of CD4+TIM-3+ and CD8+TIM-3+ cells were markedly increased in SLE group than those of the control group(P<0.01).In particular,the CD4+TIM-3+,CD8+TIM-3+ level Was positively correlated with SLEDAI (r=0.517,P＜0.01;r=0.400,P＜0.05);but negatively correlated with C3(r=0.487,P＜0.05;r=0.395,P＜0.05).The Galectin-9 mRNA in SLE PBMCs was higher than that of the controls(P<0.05).Conclusion TIM-3-Galectin-9 pathway may be involved in T cell immune regulation of SLE,and is related to disease activity.     

系统性红斑狼疮外周血B淋巴细胞激活及TOLL样受体9表达

目的探讨系统性红斑狼疮(SLE)外周血单个核细胞(PBMCs)中B淋巴细胞的激活状态及TOLL样受体9(TLR9)表达水平。方法用流式细胞术测定25例SLE患者PBMC中CD19 B细胞及CD19 CD38 B细胞的比例。用反转录-聚合酶链反应(RT-PCR)半定量方法检测38例SLE患者PBMCs中TLR9mRNA的表达水平。分析TLR9mRNA的表达水平与SLE活动性指数(SLEDAI)的相关性。结果SLE患者PBMCs中CD19 B细胞和CD19 CD38 B细胞的百分数均高于正常对照组(P<0.01)。活动期SLE患者PBMCs的TLR9mRNA表达低于缓解组(P<0.01)及正常对照(P<0.01),缓解期和正常对照组相比,差异无统计学意义(P>0.05)。TLR9mRNA的表达与SLEDAI评分呈负相关。结论SLE患者PBMC中激活B细胞增多。活动期SLE患者PBMC的TLR9的表达水平降低,与SLEDAI呈负相关。TLR9可能参与SLE的病理发病过程。     

系统性红斑狼疮外周血单个核细胞DcR3 mRNA表达研究

目的研究凋亡相关基因诱骗受体3(DcR3)在系统性红斑狼疮患者(SLE)外周血单个核细胞(PBMCs)中的mRNA表达水平。方法应用半定量逆转录-聚合酶链反应(RT-PCR)检测38例SLE患者(21例活动期,17例缓解期)和15例正常人PBMCs中DcR3 mRNA的表达水平,分析其与狼疮活动指数(SLEDAI)的相关性。结果SLE患者PBMCs中,DcR3mRNA表达水平明显高于正常人(P<0.01),但疾病不同病期(活动期与缓解期)其表达水平无统计学差异(P>0.05);DcR3 mRNA表达与SLEDAI不相关(r=-0.024,P>0.05)。结论SLE患者PBMCs DcR3 mRNA表达增加,提示DcR3可能与SLE免疫细胞凋亡异常和免疫调节的紊乱有关,参与了SLE的发病过程。     

干扰素调节因子5在系统性红斑狼疮的表达及临床相关性研究

目的 比较干扰素调节因子5(IRF5)mRNA在系统性红斑狼疮(SLE)患者和健康对照组的表达水平,分析IRF5表达与SLE疾病活动性及自身抗体和临床症状的相关性.方法 Ficoll密度梯度离心法分离SLE患者及健康对照外周血单个核细胞(PBMC),Trizol法分离提取总RNA,反转录mRNA为eDNA;实时定量聚合酶链反应(PCR)法测定SLE患者和正常对照组IRF5表达量;并分析SLE患者IRF5表达量与疾病活动性及临床症状的相关性.结果 SLE组IRF5表达量(2.1+2.2)高于正常对照组(1.5±1.2),但差异无统计学意义(P=0.161);SLE患者IRF5表达量与其疾病活动指数(SLEDAI)显著相关(r=0.616,P<0.01);SLE患者中抗dsDNA抗体阳性组IRF5表达量(3.2±2.8)明显高于抗体阴性组(1.3±1.6).差异有统计学意义(P=0.018);SLE患者有发热、神经精神症状者IRF5表达量明显高于无此类临床症状者.结论 IRF5在SLE患者中表达偏高,且与SLEDAI显著相关,其可能通过调节下游基因的转录表达诱一导免疫失调,并由此参与SLE的发病过程.     

Dysfunction of TRIM21 in interferon signature of systemic lupus erythematosus

Abstract

Objectives: TRIM21 is an E3 ubiquitin ligase for interferon regulatory factors (IRFs) that are involved in innate and acquired immunity. Here, we evaluated the role of TRIM21 in the interferon (IFN) signature of systemic lupus erythematosus (SLE).

Methods: Twenty SLE patients and 24 healthy controls were enrolled in this study. We analyzed mRNA expression of TRIM21, type I IFN, and IFN-inducible genes in peripheral blood mononuclear cell (PBMC). The protein levels of IRFs were assessed by Western blotting in PBMCs cultured with or without MG-132.

Results: The expression of TRIM21 mRNA and protein was significantly higher in SLE PBMCs as compared to healthy controls. There was a correlation between TRIM21 mRNA expression and SLE activities. In contrast to a negative correlation between mRNA expression level of TRIM21 and those of type I IFNs in healthy controls, we found a positive correlation between them in anti-TRIM21 antibody-positive SLE patients. Neither positive nor negative correlation was observed in the autoantibody-negative SLE patients. Western-blotting analysis revealed impaired ubiquitin-dependent proteasomal degradation of IRFs in SLE PBMCs.

Conclusion: Our study showed ubiquitin-dependent proteasomal degradation of IRFs was impaired in anti-TRIM21 antibody-dependent and -independent fashions, leading to amplification of IFN signature in SLE.     

系统性红斑狼疮患者外周血单个核细胞端粒保护蛋白TPP1及POT1基因表达的研究

目的 研究端粒保护蛋白TPP1及POT1基因在系统性红斑狼疮(SEE)患者与健康人外周血单个核细胞(PBMCs)的表达及其与SEE肾损、疾病活动度的相关性.方法 应用实时荧光定量聚合酶链反应检测SEE患者活动组28例、缓解组20例及健康对照组30例PBMCs TPP1、POT1 mRNA表达水平,并且与SEE患者临床指标进行相关性分析.结果 SLE组与健康对照组相比,TPP1及POT1基因表达明显降低(P均<0.01),活动组与缓解组均显著低于健康对照组(P均<0.05);POT1基因在活动组的表达显著低于缓解组(P<0.05);TPP1及POT1基因在肾损组的表达低于无肾损组(P<0.01),在SLE肾损患者中,尿蛋白定量与TPP1及POT1基因的表达水平呈负相关(P<0.05),尿白细胞与POT1基因呈负相关(P<0.05);红细胞沉降率、C反应蛋白、抗核抗体与TPP1、POT1基因的表达及SLE疾病活动指数(SLEDAI)评分没有相关性;POT1 mRNA的表达与血清IsG、SLEDAI评分呈负相关(P<0.05,P<0.01),与补体C3呈正相关(P<0.01);TPP1 mRNA的表达与血清IgG、SLEDAI评分及C3没有相关性.结论 端粒保护蛋白TPP1和POT1基因在SLE的发病中发挥重要作用,其参与了SLE肾脏损害的病理过程,POT1可作为SEE疾病活动的有效的评判指标.     

Activation of the interferon‐γ signaling pathway in systemic lupus erythematosus peripheral blood mononuclear cells

Objective

To investigate interferon‐γ (IFNγ) signaling in peripheral blood mononuclear cells (PBMCs) from patients with systemic lupus erythematosus (SLE) by analyzing IFNγ receptor (IFNγR) expression, STAT‐1 expression and phosphorylation, and the regulation of IFNγ‐inducible genes.

Methods

Fluorocytometry was used to investigate expression of STAT‐1, pSTAT‐1, CD95, HLA–DR, class I major histocompatibility complex (MHC), IFNγ‐inducible 10‐kd protein (IP‐10), monokine induced by IFNγ (Mig), and IFNγR in PBMCs from SLE patients and healthy individuals. STAT‐1 phosphorylation was determined by fluorocytometry and Western blotting after stimulation with IFNα or IFNγ. Quantitative polymerase chain reaction was used to assess messenger RNA (mRNA) expression of the IFNγ‐inducible genes IP‐10 and Mig shortly after preparation or after stimulation with IFNγ in monocytes.

Results

STAT‐1 expression was increased in PBMCs from SLE patients and correlated significantly with disease activity and with the IFN‐inducible expression of CD95 and HLA–DR. STAT‐1 expression also showed a trend toward association with class I MHC expression. In addition, the expression of other IFNγ‐inducible genes, such as IP‐10 or Mig, was increased in SLE monocytes. While STAT‐1 phosphorylation in SLE PBMCs and PBMCs from healthy individuals was similar after IFNα stimulation, incubation with IFNγ induced STAT‐1 phosphorylation only in SLE lymphocytes. Moreover, SLE monocytes showed a considerably higher increase in pSTAT‐1 expression upon IFNγ stimulation than monocytes from healthy individuals. Increased responsiveness of SLE monocytes to IFNγ was also confirmed on the mRNA level, where expression of the IFN‐inducible, STAT‐1–dependent genes IP‐10 and Mig was more efficiently increased in SLE cells. However, IFNγR was similarly expressed on SLE lymphocytes and monocytes and those from healthy individuals.

Conclusion

In addition to supporting the role of IFNs in SLE immunopathogenesis in general, the findings of the present study support a role of IFNγ in this disease.

     

系统性红斑狼疮患者外周血单个核细胞B细胞刺激因子的异常表达及其临床意义

目的研究系统性红斑狼疮(SLE)患者外周血单个核细胞中B淋巴细胞刺激因子(Blys)的表达情况,并探讨Blys的转录水平与狼疮活动性和狼疮肾炎(LN)的关系,分析Blys在狼疮发病中的作用。方法应用半定量反转录-聚合酶链反应(RT-PCR)法检测活动期组(26例)和缓解期组(22例)SLE患者外周血单个核细胞(PBMCs)BlysmRNA的表达水平,以健康志愿者(20例)作为对照;同时将BlysmRNA的表达水平与患者临床检验指标进行相关分析;采用流式细胞仪技术检测20例SLE患者和16例健康对照膜结合型Blys蛋白水平。结果SLE患者PBMCsB1ysmRNA的表达明显高于正常人(P<0.01),活动期患者的表达高于缓解期(P<0.05);BlysmRNA的表达与狼疮活动指数(SLEDAl)和蛋白尿呈正相关,与补体C3、C4水平呈负相关;抗dsDNA抗体阳性和尿蛋白阳性的SLE患者BlysmRNA的表达高于阴性患者(P<0.05);而且SLE患者PBMCs中Blys的平均荧光强度也显著增加(P<0.05)。结论SLE患者PBMC的膜Blys和BlysmRNA表达均增强,且与狼疮活动性及尿蛋白呈正相关,提示Blys可能参与SLE及狼疮肾炎的发病过程,且有望成为临床观察和疗效评价的新指标。     

Expression of human tumor necrosis factor-like weak inducer of apoptosis in patients with systemic lupus erythematosus

The aim of this study was to compare the mRNA and serum expression of tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) in patients with systemic lupus erythematosus (SLE) and healthy controls. Sixty-two SLE patients and 15 healthy controls were recruited in the study. TWEAK messenger RNA (mRNA) expression in peripheral blood mononuclear cells (PBMCs) from 33 of 62 patients was detected by relative quantification RT-PCR. TWEAK concentrations in the sera of all 62 patients were measured by ELISA. TWEAK mRNA expressions in PBMCs were decreased in SLE patients compared with healthy controls. Lower TWEAK mRNA expression was also found in the active SLE patients when compared to inactive ones. However, there was no significant difference between patients with lupus nephritis (LN) and those without. The level of serum TWEAK (sTWEAK) in SLE patients was increased when compared to healthy controls. In addition, the sTWEAK level was higher in SLE patients with vasculitis than those without vasculitis, and so was in comparison between patients with and without headache. Nevertheless, no significant differences were found between active SLE patients and inactive patients, or between LN patients and non-LN SLE patients. In this study, patients with SLE express low levels of TWEAK mRNA but high levels of sTWEAK. Additionally, sTWEAK level was associated with several clinical manifestations of SLE, indicating that TWEAK may play a complex role in SLE.     

Expression feature of CD3, FcεRIγ, and Zap-70 in patients with chronic lymphocytic leukemia

In leukemia patients, T-cell function has been suppressed with the disease progress. Patients with chronic lymphocytic leukemia (CLL) are all to a degree immunodeficient. In order to elucidate the feature of T-cell receptor signal transduction in CLL, the expression levels of CD3γ, δ, ε, and ζ chain, FcεRIγ, and Zap-70 genes in peripheral blood mononuclear cells (PBMCs) were analyzed. Real-time polymerase chain reaction with SYBR Green technique was used for detecting the gene expression level in PBMCs from 13 patients with CLL, 13 healthy individuals, and 10 B-cell acute lymphocytic leukemia (B-ALL) served as control. The β2-microglobulin gene was used as an endogenous reference. Relative mRNA expression level of genes was analyzed by using the 2(-ΔCt) × 100% method. Significant lower expression levels of CD3γ, ε, and ζ chain genes, as well as FcεRIγ gene were found in CLL samples. Moreover, there was lost the negative correlation of the expression levels between CD3ζ and FcεRIγ genes. The expression level of Zap-70 in CLL was lower than those from healthy controls, while higher than those from B-ALL group. There was no significant correlation between the expression levels of CD3ζ and Zap-70 genes neither in the healthy group nor in the CLL group. In conclusion, the results provide a global gene expression profile of CD3γ, δ, ε, and ζ chains, and the CD3ζ-related genes FcεRIγ and Zap-70 in CLL. Deficiency of these gene expression levels might represent the feature related to T-cell immunodeficiency. The study might contribute to better understand the cellular immune features in CLL patients.     

Relations between surface expression of the interleukin-2 receptor and release of the soluble form of the receptor in cultured mononuclear cells from patients with rheumatoid arthritis or systemic lupus erythematosus

The relationship between surface expression of the interleukin-2 receptor (IL-2R) and release of the soluble form of the receptor (sIL-2R or sCD25) was investigated with peripheral blood mononuclear cells (PBMCs) from individuals with rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE). The spontaneous release of sCD25 was significantly increased in PBMCs from RA patients and decreased in cells from SLE patients, compared with normal controls. However, the extent of sCD25 release from phytohaemagglutinin (PHA)-stimulated PBMCs did not differ between RA or SLE patients and normal controls. The serum concentration of sCD25 was significantly increased in SLE or RA patients compared with the normal controls. Whereas the surface expression of CD25 by unstimulated PBMCs did not differ among the three groups of subjects, this parameter was significantly reduced for PHA-stimulated PBMCs from RA patients relative to those from normal controls. The surface expression of CD25 showed a positive correlation with sCD25 release for PBMMCs from SLE patients under either basal or stimulated conditions. No such relation was apparent for cells from RA patients. The surface expression of IL-2R (CD122) under basal or stimulated conditions was significantly reduced in PBMCs from RA or SLE patients, compared with cells from normal controls. Thus, the increased concentration of sCD25 in the serum of individuals with these autoimmune rheumatic diseases may result from two different mechanisms: an increase in the spontaneous release of sCD25 in RA, and reduced clearance of this protein in SLE.