Which B-cell subset should we target in lupus?

New insights into the role of antinuclear antibodies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by antinuclear antibodies (ANAs) that form immune complexes that mediate pathogenesis by tissue deposition or cytokine induction. Some ANAs bind DNA or associated nucleosome proteins, whereas other ANAs bind protein components of complexes of RNA and RNA-binding proteins (RBPs). Levels of anti-DNA antibodies can fluctuate widely, unlike those of anti-RBP antibodies, which tend to be stable. Because anti-DNA antibody levels can reflect disease activity, repeat testing is common; by contrast, a single anti-RBP antibody determination is thought to suffice for clinical purposes. Experience from clinical trials of novel therapies has provided a new perspective on ANA expression during disease, as many patients with SLE are ANA negative at screening despite previously testing positive. Because trial results suggest that patients who are ANA negative might not respond to certain agents, screening strategies now involve ANA and anti-DNA antibody testing to identify patients with so-called 'active, autoantibody-positive SLE'. Evidence suggests that ANA responses can decrease over time because of the natural history of disease or the effects of therapy. Together, these findings suggest that, during established disease, more regular serological testing could illuminate changes relevant to pathogenesis and disease status.

Efficacy analysis of hydroxychloroquine therapy in systemic lupus erythematosus: a study on disease activity and immunological biomarkers

BACKGROUND

Hydroxychloroquine (HCQ) is a widely prescribed medication to patients with systemic lupus erythematosus (SLE), with potential anti-inflammatory effects. This study was performed to investigate the efficacy of HCQ therapy by serial assessment of disease activity and serum levels of proinflammatory cytokines in SLE patients.

METHODS

In this prospective cohort study, 41 newly diagnosed SLE patients receiving 400 mg HCQ per day were included. Patients requiring statins and immunosuppressive drugs except prednisolone at doses lower than 10 mg/day were excluded. Outcome measures were assessed before commencement of HCQ therapy (baseline visit) as well as in two follow-up visits (1 and 2 months after beginning the HCQ therapy). Serum samples of 41 age-matched healthy donors were used as controls.

RESULTS

Median levels of IL-1β (p < 0.001), IL-6 (p = 0.001), and TNF-α (p < 0.001) were significantly higher, whereas, median CH50 level was significantly lower (p < 0.001) in SLE patients compared with controls. Two-month treatment with HCQ resulted in significant decrease in SLEDAI-2K (p < 0.001), anti-dsDNA (p < 0.001), IL-1β (p = 0.003), IL-6 (p < 0.001) and TNF-α (p < 0.001) and a significant increase in CH50 levels (p = 0.012). The reductions in SLEDAI-2K and serum levels of IL-1β and TNF-α were significantly greater in the first month compared with the reductions in the second month.

CONCLUSION

HCQ therapy is effective on clinical improvement of SLE patients through interfering with inflammatory signaling pathways, reducing anti-DNA autoantibodies and normalizing the complement activity.

Intranuclear delivery of the transcription modulation domain of Tbet-improved lupus nephritis in (NZB/NZW) F1 lupus-prone mice

Excessive expression of Tbet and IFNγ is evidence of systemic lupus erythematosus (SLE) in lupus patients. In this study, the nucleus-transducible form of Transcription Modulation Domain (TMD) of Tbet (ntTbet-TMD), which is a fusion protein between Protein Transduction Domain Hph-1 (Hph-1-PTD) and the TMD of Tbet comprising DNA binding domain and isotype-specific domain, was generated to inhibit Tbet-mediated transcription in the interactomic manner. ntTbet-TMD was effectively delivered into the nucleus of the cells and specifically inhibited Tbet-mediated transcription without influencing the differentiation of other T cell subsets and signaling events for T cell activation. The severity of nephritis was significantly reduced by ntTbet-TMD as effectively as methylprednisolone in lupus-prone mice. The number of Th1, Th2 or Th17 cells and the secretion of their cytokines substantially decreased in the spleen and kidney of lupus-prone mice by ntTbet-TMD treatment. In contrast to methylprednisolone, the marked increase of Treg cells and the secretion of their immunosuppressive cytokine were detected in the spleen of (NZB/NZW) F1 mice treated with ntTbet-TMD. Thus, ntTbet-TMD can improve nephritis in lupus-prone mice by modulating the overall proinflammatory microenvironment and rebalancing T cell subsets, leading to new immune therapeutics for Th1-mediated autoimmune diseases.

[Modulating the survival and maturation system of B lymphocytes: Current and future new therapeutic strategies in systemic lupus erythematosus]

Systemic lupus erythematosus is an autoimmune disease associated with an aberrant production of autoantibodies by self-reactive B lymphocytes. The study of the phenotypic characteristics of B lymphocytes and the identification of their surface receptors such as BAFF-R, TACI and BCMA, which are responsible of their survival and maturation, have contributed to the development of new therapeutic strategies in recent years.

Long-lived plasma cells are early and constantly generated in New Zealand Black/New Zealand White F1 mice and their therapeutic depletion requires a combined targeting of autoreactive plasma cells and their precursors

Introduction

Autoantibodies contribute significantly to the pathogenesis of systemic lupus erythematosus (SLE). Unfortunately, the long-lived plasma cells (LLPCs) secreting such autoantibodies are refractory to conventional immunosuppressive treatments. Although generated long before the disease becomes clinically apparent, it remains rather unclear whether LLPC generation continues in the established disease. Here, we analyzed the generation of LLPCs, including autoreactive LLPCs, in SLE-prone New Zealand Black/New Zealand White F1 (NZB/W F1) mice over their lifetime, and their regeneration after depletion.

Methods

Bromodeoxyuridine pulse-chase experiments in mice of different ages were performed in order to analyze the generation of LLPCs during the development of SLE. LLPCs were enumerated by flow cytometry and autoreactive anti-double-stranded DNA (anti-dsDNA) plasma cells by enzyme-linked immunospot (ELISPOT). For analyzing the regeneration of LLPCs after depletion, mice were treated with bortezomib alone or in combination with cyclophosphamide and plasma cells were enumerated 12 hours, 3, 7, 11 and 15 days after the end of the bortezomib cycle.

Results

Autoreactive LLPCs are established in the spleen and bone marrow of SLE-prone mice very early in ontogeny, before week 4 and before the onset of symptoms. The generation of LLPCs then continues throughout life. LLPC counts in the spleen plateau by week 10, but continue to increase in the bone marrow and inflamed kidney. When LLPCs are depleted by the proteasome inhibitor bortezomib, their numbers regenerate within two weeks. Persistent depletion of LLPCs was achieved only by combining a cycle of bortezomib with maintenance therapy, for example cyclophosphamide, depleting the precursors of LLPCs or preventing their differentiation into LLPCs.

Conclusions

In SLE-prone NZB/W F1 mice, autoreactive LLPCs are generated throughout life. Their sustained therapeutic elimination requires both the depletion of LLPCs and the inhibition of their regeneration.