Successful Therapy of Severe and Refractory Cutaneous Sarcoidosis with Baricitinib

Abstract is missing (Short communication)

Advance in pathogenesis of sarcoidosis: Triggers and progression

Sarcoidosis, a multisystemic immune disease, significantly impacts patients' quality of life. The complexity and diversity of its pathogenesis, coupled with limited comprehensive research, had hampered both diagnosis and treatment, resulting in an unsatisfactory prognosis for many patients. In recent years, the research had made surprising progress in the triggers of sarcoidosis (genetic inheritance, infection and environmental factors) and the abnormal regulations on immunity during the formation of granuloma. This review consolidated the latest findings on sarcoidosis research, providing a systematic exploration of advanced studies on triggers, immune-related regulatory mechanisms, and clinical applications. By synthesizing previous discoveries, we aimed to offer valuable insights for future research directions and the development of clinical diagnosis and treatment strategies.

Anti-inflammatory Therapy for Sarcoidosis

Over 50% of patients with sarcoidosis will require anti-inflammatory therapy at some point in their disease course. Indications for therapy are to improve health-related quality of life, prevent or arrest organ dysfunction (or organ failure) or avoid death. Recently published treatment guidelines recommended a stepwise approach to therapy however there are some patients for whom up front combination or more intense therapy maybe reasonable. The last decade has seen an explosion of studies and trials evaluating novel therapeutic agents and treatment strategies. Currently available anti-inflammatory therapies and several novel therapies are discussed here.

The inflammatory spectrum of cardiomyopathies

Infiltration of the myocardium with various cell types, cytokines and chemokines plays a crucial role in the pathogenesis of cardiomyopathies including inflammatory cardiomyopathies and myocarditis. A more comprehensive understanding of the precise immune mechanisms involved in acute and chronic myocarditis is essential to develop novel therapeutic approaches. This review offers a comprehensive overview of the current knowledge of the immune landscape in cardiomyopathies based on etiology. It identifies gaps in our knowledge about cardiac inflammation and emphasizes the need for new translational approaches to improve our understanding thus enabling development of novel early detection methods and more effective treatments.

Partial IL-10 Inhibition of the Cell-Mediated Immune Response in Chronic Beryllium Disease

Chronic beryllium disease (CBD) provides a human disorder in which to study the delayed type IV hypersensitivity response to persistent Ag that leads to noncaseating pulmonary granuloma formation. We hypothesized that, in CBD, failure of IL-10 to modulate the beryllium-specific, cell-mediated immune response would result in persistent, maximal cytokine production and T lymphocyte proliferation, thus contributing to the development of granulomatous lung disease. To test this hypothesis, we used bronchoalveolar lavage cells from control and CBD subjects to evaluate the beryllium salt-specific production of endogenous IL-10 and the effects of exogenous human rIL-10 (rhIL-10) on HLA expression, on the production of IL-2, IFN-γ, and TNF-α, and on T lymphocyte proliferation. Our data demonstrate that beryllium-stimulated bronchoalveolar lavage cells produce IL-10, and the neutralization of endogenous IL-10 does not increase significantly cytokine production, HLA expression, or T lymphocyte proliferation. Second, the addition of excess exogenous rhIL-10 partially inhibited the beryllium-stimulated production of IL-2, IFN-γ, and TNF-α; however, we measured no change in T lymphocyte proliferation or in the percentage of alveolar macrophages expressing HLA-DP. Interestingly, beryllium salts interfered with an IL-10-stimulated decrease in the percentage of alveolar macrophages expressing HLA-DR. We conclude that, in the CBD-derived, beryllium-stimulated cell-mediated immune response, low levels of endogenous IL-10 have no appreciable effect; exogenous rhIL-10 has a limited effect on cytokine production and no effect on T lymphocyte proliferation or HLA expression.

Antibodies to the IL-12 Receptor β2 Chain Mark Human Th1 But Not Th2 Cells In Vitro and In Vivo

Great attention has been placed on the possibility of distinguishing Th1 from Th2 cells on the basis of differential expression of surface receptors. We have recently shown that the differential expression of the IL-12Rβ2 chain in Th1 and Th2 cells, as measured at the mRNA level, accounts for an important regulatory mechanism in the differentiation of the two cell subsets. In this study, we identify IL-12R expression at the protein level. We have generated an anti-IL-12Rβ2-specific mAb and analyzed IL-12Rβ2 expression on polarized Th cell populations generated in vitro and on T cells derived from patients with Th1- or Th2-mediated inflammatory conditions. Although IL-12Rβ2 was absent in freshly isolated PBMC and in cord blood cells, we were able to detect IL-12Rβ2 expression selectively in differentiated Th1 and T cytotoxic 1, but not Th2 or T cytotoxic 2 cells. In the presence of IL-12, cell surface expression of the IL-12Rβ2 subunit was readily detected on T cells after 24 h, reached the maximum at day 5, and declined thereafter. Most importantly, the anti-IL-12Rβ2 mAb recognizes lung T cells from patients with sarcoidosis, a disease characterized by a typical cell-mediated, Th1-type inflammatory response. In contrast, IL-12Rβ2 was absent in lung T cells from patients with allergic asthma, a disease characterized by a Th2-type inflammatory response. The mAb reported in this study should represent a powerful tool to investigate the role of Th1 and Th2 cells in inflammatory conditions and to monitor therapies aimed at altering the balance of Th cell subsets.

Involvement of the IP-10 Chemokine in Sarcoid Granulomatous Reactions

The accumulation of T cells and monocytes at sites of ongoing inflammation represents the earliest step in the series of events that lead to granuloma formation in sarcoidosis. In this study, we evaluated the pulmonary production of IFN-inducible protein 10 (IP-10), a CXC chemokine that stimulates the directional migration of activated T cells. Striking levels of IP-10 were demonstrated in the bronchoalveolar lavage (BAL) fluid of 24 patients with pulmonary sarcoidosis and lymphocytic alveolitis, as compared with patients with inactive disease or control subjects. A positive correlation was demonstrated between IP-10 levels and the number of sarcoid CD45R0+/CD4+ cells in the BAL. Immunochemistry, performed with an anti-human IP-10 polyclonal Ab in lymph nodes displaying prominent sarcoid granulomas, showed that cells bearing IP-10 were mainly epithelioid cells and CD68+ macrophages located inside granulomatous areas. Macrophages recovered from the BAL of sarcoid patients stained positive for IP-10 protein. Furthermore, alveolar macrophages isolated from sarcoid patients with T cell alveolitis and cultured for 24 h in presence of IFN-γ secreted definite levels of IP-10 capable of inducing T cell chemiotaxis. Interestingly, alveolar lymphocytes recovered from patients with active sarcoidosis were CD4+ T cells expressing Th1 cytokines (IL-2 and IFN-γ) and high levels of CXCR3. Taken together, these data suggest the potential role of IP-10 in regulating the migration and activation of T cells toward sites of sarcoid inflammatory process and the consequent granuloma formation.

Active Wegener’s Granulomatosis Is Associated with HLA-DR+ CD4+ T Cells Exhibiting an Unbalanced Th1-Type T Cell Cytokine Pattern: Reversal with IL-10

Wegener’s granulomatosis (WG) is a granulomatous vasculitis that affects the upper respiratory tract, lung, and kidney. Since T cells make up a significant proportion of cells infiltrating granulomatous lesions in WG, we investigated the proliferative response and cytokine profile of T cells from these patients. PBMCs were isolated from 12 patients with active WG, 7 patients with inactive disease, and 12 healthy normal donors. PBMCs from clinically active WG patients exhibited increased proliferation following stimulation with either PMA/ionomycin or anti-CD2 and anti-CD28, when compared with normal donors. In addition, these PBMCs exhibited increased secretion of IFN-γ, but not of IL-4, IL-5, or IL-10. Furthermore, TNF-α production from PBMCs and CD4+ T cells isolated from patients with WG was elevated, when compared with healthy donors. In further studies, we investigated the ability of WG patients’ monocytes to produce IL-12 and showed that both inactive and active patients produced increased amounts of IL-12. Finally, the in vitro IFN-γ production by WG PBMC is inhibited in a dose-dependent manner by exogenous IL-10. These data suggest that T cells from WG patients overproduce IFN-γ and TNF-α, probably due to dysregulated IL-12 secretion, and that IL-10 may therefore have therapeutic implications for this disease.

Induction of Granulomatous Experimental Autoimmune Thyroiditis in IL-4 Gene-Disrupted Mice

To study the role of IL-4 in development of granulomatous experimental autoimmune thyroiditis (EAT), IL-4 gene-disrupted mice expressing the EAT-susceptible H-2k haplotype were generated and used for EAT induction. Spleen cells from mouse thyroglobulin (MTg) and LPS-primed IL-4+/+ and IL-4−/− donors could induce severe granulomatous EAT when spleen cells were activated with MTg and anti-IL-2R mAb in the presence of IL-12. Thyroid lesions had extensive follicular cell proliferation, large numbers of histiocytes, polymorphonuclear leukocytes, and multinucleated giant cells, in addition to lymphocytes and other mononuclear cells. Expression of IFN-γ gene mRNA and production of IFN-γ by effector spleen cells stimulated with MTg and IL-12 were similar for both IL-4+/+ and IL-4−/− mice. Although IL-4 was undetectable in IL-4−/− mice, expression of mRNA for IL-5, IL-10, and IL-13 and production of IL-5 by both MTg-activated spleen cells and anti-CD3-activated CD4+ T cells were comparable for cells from IL-4+/+ and IL-4−/− mice, indicating that the absence of IL-4 did not prevent production of other Th2 cytokines. Production of MTg-specific IgG1 was very low or undetectable in IL-4−/− mice. IL-4 gene mRNA and MTg-specific IgG1 could be detected in IL-4+/+ or IL-4−/− recipients only when they received effector cells from IL-4+/+ donor mice, indicating that IL-4- and IgG1-secreting cells are of donor origin. These results demonstrate that IL-4 is not essential for development of granulomatous EAT.