Peripheral blood CD4+ T cells in systemic lupus erythematosus

Higher CD4+CD40+ T cells (Th40 cells) associate with systemic lupus erythematosus activity

The aim of this study was to investigate the characteristics of CD4⁺CD40⁺ T cells (Th40 cells) in Chinese systemic lupus erythematosus (SLE) patients. Flow cytometry was used to identify the percentage of Th40 cells in peripheral blood from 24 SLE patients and 24 healthy individuals and the level of IL-2, IL-4, IL-6, IL-10, IFN-r, and TNF-α in serum (22 cases) from the SLE patients. Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2000) was used to assess the SLE disease active state. The percentage of Th40 cells in T cells from SLE patients (19.37 ± 17.43) (%) was significantly higher than that from healthy individuals (4.52 ± 3.16) (%) (P < 0.001). The percentage of Th40 cells was also positively associated with SLEDAI-2000 (P = 0.001) and negatively associated with complement C3 (P = 0.007). The Th40 cell percentage was different in SLE patients with different organs involved. The Th40 cell percentage in SLE patients with lupus serositis (29.29 ± 22.19) was significantly higher than that in patients without serositis (13.41 ± 10.79; P = 0.040), and the percentage in SLE patients with lupus pneumonia involvement (29.11 ± 11.88) was significantly higher than that in patients without lupus pneumonia (16.80 ± 17.99; P = 0.043). After 4 weeks treatment, the Th40 cell percentage decreased significantly (P = 0.005). However, Th40 cell expression was not related to cytokines (IL-2, IL-4, IL-6, IL-10, IFN-r, and TNF-α; P > 0.05). A significantly higher percentage of Th40 cells was found in SLE patients, and the Th40 cell percentage was associated with SLE activity. Thus, Th40 cells may be used as a predictor for SLE disease activity and severity and therapeutic efficacy.

Role of MiR-98 and Its Underlying Mechanisms in Systemic Lupus Erythematosus

Objective.

T-lymphocyte apoptosis plays a critical role in the pathogenesis of systemic lupus erythematosus (SLE). However, the underlying regulatory mechanisms of apoptosis in SLE remain unclear. The aim of this study was to explore the role of miR-98 in SLE and its underlying mechanisms.

Methods.

Western blotting and quantitative reverse transcription PCR (qRT-PCR) were used to analyze miR-98 and Fas expression. Luciferase reporter assays were performed to identify miR-98 targets. To modify miRNA levels, miR-98 mimics and inhibitor were transfected into cells. A lentiviral construct was used to overexpress the level of Fas in SLE CD4+ T cells. Gene and protein expression were determined by qRT-PCR and Western blotting. Apoptosis levels were evaluated by annexin V staining and flow cytometry.

Results.

Compared to those of healthy donors, miR-98 was downregulated in SLE CD4+ T cells, whereas Fas mRNA and protein expression were upregulated. Upregulation of miR-98 by mimic transfection protected Jurkat cells against Fas-mediated apoptosis at both mRNA and protein levels, while miR-98 inhibitor induced the completely opposite effect. Luciferase reporter assays demonstrated that miR-98 directly targeted Fas mRNA. Further, miR-98 inhibitor induced apoptosis in primary healthy CD4+ T cells through the Fas-caspase axis, while upregulation of miR-98 in SLE CD4+ T cells led to the opposite effect.

Conclusion.

The current study revealed that downregulation of miR-98 induces apoptosis by modulating the Fas-mediated apoptotic signaling pathway in SLE CD4+ T cells. These results suggest that miR-98 might serve as a potential target for SLE treatment.

Urinary mononuclear cell and disease activity of systemic lupus erythematosus

Mononuclear cells play a cardinal role in the pathogenesis of systemic lupus erythematosus (SLE). A high urine cytology score has been reported to be associated with lupus nephritis in relapse. The objective of this study was to examine the urinary mononuclear cell population of patients with lupus nephritis, and explore its correlation with lupus disease activity. We studied 12 patients with active lupus nephritis, 17 patients with lupus nephritis in remission, 12 SLE patients with no history of renal disease and 13 healthy subjects. Clinical disease activity was quantified by the SLE Disease Activity Index (SLEDAI). Mononuclear cell species in the urinary sediment were examined by immunocytochemistry. Patients with active lupus nephritis had significantly more mononuclear cells in the urinary sediment. The number of CD3+ cell was significantly elevated in the active lupus nephritis than the others (P < 0.001), while there was no significant difference in the number of CD20+ and CD56+ cell among patient groups. The total urinary mononuclear cell correlated significantly with the overall SLEDAI score (r = 0.58, P < 0.001) as well as the renal score (r = 0.57, P < 0.001). The number of urinary CD3+, but not CD20+ or CD56+, cell significantly correlated with the overall SLEDAI score (r = 0.46, P = 0.003) as well as the renal score (r = 0.40, p = 0.011). In nine patients with renal biopsy, the histological activity index correlated with the total urinary mononuclear cell (r = 0.75, P = 0.02), CD3+ (r = 0.69, P = 0.04) and CD20+ cell (r = 0.69, P = 0.04). We conclude that urinary mononuclear cell was markedly elevated in patients with active lupus, and the urinary mononuclear cell count correlated significantly with the SLEDAI score and histological activity. CD3+ and CD20+ cells are the major component of urinary mononuclear cell in SLE patients and their number correlates with lupus disease activity.