Regulatory T cell frequency, but not plasma IL-33 levels, represents potential immunological biomarker to predict clinical response to intravenous immunoglobulin therapy.

BACKGROUND: Intravenous immunoglobulin (IVIG) is a polyspecific pooled immunoglobulin G preparation and one of the commonly used therapeutics for autoimmune diseases including those of neurological origin. A recent report in murine model proposed that IVIG expands regulatory T (Treg) cells via induction of interleukin 33 (IL-33). However, translational insight on these observations is lacking. METHODS: Ten newly diagnosed Guillain-Barré syndrome (GBS) patients were treated with IVIG at the rate of 0.4 g/kg for three to five consecutive days. Clinical evaluation for muscular weakness was performed by Medical Research Council (MRC) and modified Rankin scoring (MRS) system. Heparinized blood samples were collected before and 1, 2, and 4-5 weeks post-IVIG therapy. Peripheral blood mononuclear cells were stained for surface CD4 and intracellular Foxp3, IFN-γ, and tumor necrosis factor alpha (TNF-α) and were analyzed by flow cytometry. IL-33 and prostaglandin E2 in the plasma were measured by ELISA. RESULTS: The fold changes in plasma IL-33 at week 1 showed no correlation with the MRC and MRS scores at weeks 1, 2, and ≥4 post-IVIG therapy. Clinical recovery following IVIG therapy appears to be associated with Treg cell response. Contrary to murine study, there was no association between the fold changes in IL-33 at week 1 and Treg cell frequency at weeks 1, 2, and ≥4 post-IVIG therapy. Treg cell-mediated clinical response to IVIG therapy in GBS patients was associated with reciprocal regulation of effector T cells-expressing TNF-α. CONCLUSION: Treg cell expansion by IVIG in patients with autoimmune diseases lack correlation with IL-33. Treg cell frequency, but not plasma IL-33 levels, represents potential immunological biomarker to predict clinical response to IVIG therapy.

[An atypical case of lipoid proteinosis]. / Un cas atypique de protéinose lipoïde.

The lipoid proteinosis is a rare autosomic recessive genodermatosis characterized histologically by deposits of hyaline-like eosinophilic material of characteristic distribution. We herein report the case of a 56-year-old man admitted for progressive aggravated dementia associated with a late-onset dysphonia. Histologic examination of cutaneous and laryngeal biopsies showed deposits of an amorphous and eosinophilic material arranged around vessels, and adnexal structures, stained by PAS and congo red negative. The detection of a mutation in the ECM1 gene confirmed the diagnosis of lipoid proteinosis of atypical clinical presentation.

Intravenous immunoglobulin expands regulatory T cells via induction of cyclooxygenase-2-dependent prostaglandin E2 in human dendritic cells.

CD4(+)CD25(+)FoxP3(+) regulatory T cells (Tregs) play a critical role in the maintenance of immune tolerance. Intravenous immunoglobulin (IVIg), a therapeutic preparation of normal pooled human IgG, expands Tregs in various experimental models and in patients. However, the cellular and molecular mechanisms by which IVIg expands Tregs are relatively unknown. As Treg expansion in the periphery requires signaling by antigen-presenting cells such as dendritic cells (DCs) and IVIg has been demonstrated to modulate DC functions, we hypothesized that IVIg induces distinct signaling events in DCs that subsequently mediate Treg expansion. We demonstrate that IVIg expands Tregs via induction of cyclooxygenase (COX)-2-dependent prostaglandin E2 (PGE2) in human DCs. However, costimulatory molecules of DCs such as programmed death ligands, OX40 ligand, and inducible T-cell costimulator ligands were not implicated. Inhibition of PGE2 synthesis by COX-2 inhibitors prevented IVIg-mediated Treg expansion in vitro and significantly diminished IVIg-mediated Treg expansion in vivo and protection from disease in experimental autoimmune encephalomyelitis model. IVIg-mediated COX-2 expression, PGE2 production, and Treg expansion were mediated in part via interaction of IVIg and F(ab')2 fragments of IVIg with DC-specific intercellular adhesion molecule-3-grabbing nonintegrin. Our results thus uncover novel cellular and molecular mechanism by which IVIg expands Tregs.

Chronic inflammatory demyelinating polyradiculoneuropathy: search for factors associated with treatment dependence or successful withdrawal.

BACKGROUND: About 40% of responders to treatment for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) remain treatment dependent and have a relapse if treatment is interrupted. OBJECTIVE: To look for factors associated with treatment dependence or successful withdrawal in CIDP patients. METHODS: We retrospectively studied 70 responder CIDP patients comprising 34 patients who remained treatment dependent (treatment-dependent group) and 36 patients whose treatment could be discontinued (treatment withdrawal group). Clinical, biological, electrophysiological and therapeutic features were compared between these groups. RESULTS: A multifocal deficit was more frequent in the treatment-dependent group (35%) than in the treatment withdrawal group (8%) (p<0.01). The most frequent effective treatment was intravenous immunoglobulin (IVIG) for the treatment-dependent group (79%). In this group, more patients were resistant to corticosteroids in first-line therapy (93%) than in the treatment withdrawal group (40%) (p=0.002). The delay to effective treatment was significantly shorter for the treatment withdrawal group than for the treatment-dependent group (mean 11.1 vs 31.2 months; p<0.01). The rate of successful withdrawal was lower with IVIG (29%) than with corticosteroids (83%) (p<0.001). CONCLUSIONS: When compared with the treatment withdrawal group, the treatment-dependent group was more frequently responsive to IVIG, more frequently resistant to corticosteroids in first-line treatment, had a longer delay to effective treatment and was more likely to present a multifocal deficit. The rate of successful withdrawal seems to be higher with corticosteroids, but a prospective study with a long-term follow-up is needed to confirm these features.

Intravenous immunoglobulin exerts reciprocal regulation of Th1/Th17 cells and regulatory T cells in Guillain-Barré syndrome patients.

Guillain-Barré syndrome (GBS) is an acute, autoimmune inflammatory disorder of peripheral nervous system characterized by a severe functional motor weakness. Treatment with intravenous immunoglobulin (IVIg) is one of the approved and preferred therapeutic strategies for GBS. However, the mechanisms underlying the therapeutic benefit with IVIg in GBS are not completely understood. In the present study, we observed that GBS patients have increased frequencies of Th1 and Th17 cells, but reduced number of Foxp3(+) regulatory T cells (Treg cells) with defective functions. We show that IVIg treatment in GBS patients results in a marked reduction in the frequency of Th1 and Th17 cells with a concomitant expansion of Treg cells. Importantly, IVIg-expanded Treg cells exhibited an increased T cell suppressive function. Together our results demonstrate that therapeutic benefit of IVIg in GBS patients implicates the reciprocal regulation of Th1/Th17 and Treg cells.

Peripheral neuropathies in rheumatic disease--a guide to diagnosis.

Peripheral neuropathy is a common neurological disorder that can be associated with a wide range of conditions, including rheumatic disease. Although the association of the two disorders can be coincidental, an underlying pathogenic link can occur in many instances, which can affect treatment options. The presentation of peripheral neuropathy can be multifaceted, an important consideration when recognizing the condition and optimizing diagnosis. Furthermore, understanding the diagnostic strategy will help physicians treating patients with rheumatic disease who develop peripheral neuropathy. Finally, although available treatment options have greatly reduced the risk of patients with inflammatory disorders developing systemic complications, among which includes peripheral neuropathy, new therapeutic agents can trigger toxic or immune-mediated neuropathies and treatment will need to be adjusted accordingly. In this Review, we will discuss the general approach for diagnosing patients with peripheral neuropathy, and detail the presentation, pathophysiological features and general rules of treatment of patients with peripheral neuropathy in the context of rheumatic disease.