Recruitment of plasmacytoid dendritic cells in ultraviolet irradiation-induced lupus erythematosus tumidus

Lupus Erythematosus Tumidus Associated With Hemophagocytosis

ABSTRACT

A case of lupus erythematosus tumidus (LET), a subtype of chronic cutaneous lupus erythematosus, in an 85-year-old woman who presented with discrete indurated erythematous plaques over the face and upper chest is described. A skin biopsy showed features in keeping with a diagnosis of LET. Unusually however, the lymphocytic infiltrate contained frequent macrophages that demonstrated hemophagocytosis. Most of the phagocytosed cells were lymphocytes, but there was also evidence of erythrophagocytosis. The presence of conspicuous hemophagocytosis has only rarely been reported in skin biopsies of patients with autoimmune conditions. These include systemic lupus, neonatal lupus and dermatomyositis, and on 2 occasions in cases of nonspecified cutaneous lupus erythematosus. To the best of our knowledge, hemophagocytosis as a feature of LET has not been previously described in the literature.

Lupus Erythematosus Tumidus with Pseudolymphomatous Infiltrates: A Case Report

A 39-year-old Japanese woman presented with a pruritic infiltrated erythematous plaque on the right cheek. Histopathologic analysis of the erythema showed dermal edema, separation of collagen bundles, and nodular perivascular and periadnexal infiltration of lymphocytes in the whole dermis, without epidermal changes. Alcian blue staining intensity was elevated between the collagen bundles, indicating dermal mucinosis. The nodular infiltrates consisted of CD3+ T cell clusters and CD20+ B cell clusters (ratio, approximately 3:1) and included numerous CD123+ cells, indicative of plasmacytoid dendritic cells. Blood analysis revealed serum antinuclear antibody at a titer of 1:160 (homogeneous, speckled pattern). Lupus erythematosus tumidus with pseudolymphomatous infiltrates was diagnosed. Hydroxychloroquine treatment partially improved symptoms; however, the addition of prednisolone was required for complete resolution. Lupus erythematosus tumidus is sometimes accompanied by pseudolymphomatous infiltrates. Dermal mucinosis and the presence of numerous plasmacytoid dendritic cells are useful in differentiating lupus erythematosus tumidus from pseudolymphoma.

[Lupus erythematosus-a clinico-pathological heterogeneous disease]

Lupus erythematosus (LE) is an autoimmune disorder where immune tolerance towards nucleic acids is lost and a hyperactivated type I interferon system drives chronic immune activation. Typically, signs, symptoms, and clinical disease course are very variable between patients. Cutaneous LE can be associated with or precede systemic involvement or be limited to the skin, necessitating careful examination and follow-up of patients. LE skin disease includes a wide range of manifestations and precise classification for clinical studies is challenging. In this review article we discuss common and rare manifestations of cutaneous lupus with its clinical presentation and histopathological characteristics.

Lupus erythematosus tumidus: clinical perspectives

Lupus erythematosus tumidus (LET) is an uncommon and photosensitive inflammatory skin disorder which is characterised by erythematous urticarial plaques. In the last 20 years, extensive research on clinical and histological aspects of the disease have led to a better characterization of this nosological entity and to differentiate it from other similar or related diseases. Today, LET is considered as a separate subtype of cutaneous lupus erythematosus (CLE) with a benign, intermittent clinical course (intermittent CLE, ICLE) and only rarely associated with systemic lupus erythematosus (SLE).

Activation of type I interferon pathway in systemic lupus erythematosus: association with distinct clinical phenotypes

Growing evidence over the last few years suggests a central role of type I IFN pathway in the pathogenesis of systemic autoimmune disorders. Data from clinical and genetic studies in patients with systemic lupus erythematosus (SLE) and lupus-prone mouse models, indicates that the type I interferon system may play a pivotal role in the pathogenesis of several lupus and associated clinical features, such as nephritis, neuropsychiatric and cutaneous lupus, premature atherosclerosis as well as lupus-specific autoantibodies particularly against ribonucleoproteins. In the current paper, our aim is to summarize the latest findings supporting the association of type I IFN pathway with specific clinical manifestations in the setting of SLE providing insights on the potential use of type I IFN as a therapeutic target.

The type I interferon system in the development of lupus

The type I interferon (IFN) system induces inhibition of viral replication, but can also activate the innate and adaptive immune system. An important role of the type I IFN system in autoimmune diseases, including lupus, is suggested by the observation that these disorders display a prominent over-expression of type I IFN regulated genes. The development of autoimmune diseases in some individuals treated with IFN-α directly supports a pivotal role for this cytokine in breaking tolerance and inducing autoimmune reactions. A genetic setup that promotes type I IFN production and/or response and the presence of endogenous inducers of IFN-α production have been described in patients with lupus. Several known environmental risk factors for development of lupus or disease flares may contribute to the ongoing type I IFN production. In the present review we will describe the possible role of the type I IFN system in the lupus disease process. The possible connection between the type I IFN system and some environmental and genetic risk factors for lupus is also discussed.

The interferon-alpha signature of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic multisystem autoimmune disorder where interplay of environmental and genetic risk factors leads to progressive loss of tolerance to nuclear antigens over time, finally culminating in clinical disease. The heterogeneity of clinical manifestations and the disease's unpredictable course characterized by flares and remissions are very likely a reflection of heterogeneity at the origin of disease, with a final common pathway leading to loss of tolerance to nuclear antigens. Impaired clearance of immune complexes and apoptotic material and production of autoantibodies have long been recognized as major pathogenic events in this disease. Over the past decade the type I interferon cytokine family has been postulated to play a central role in SLE pathogenesis, by promoting feedback loops progressively disrupting peripheral immune tolerance and driving disease activity. The identification of key molecules involved in the pathogenesis of SLE will not only improve our understanding of this complex disease, but also help to identify novel targets for biological intervention.

Overview of common, rare and atypical manifestations of cutaneous lupus erythematosus and histopathological correlates

The skin is the second most frequently affected organ system in lupus erythematosus. Although only very rarely life threatening--an example is lupus erythematosus-associated toxic epidermal necrolysis--skin disease contributes disproportionally to disease burden in terms of personal and psychosocial wellbeing, vocational disability, and hence in medical and social costs. Since several manifestations are closely associated with the presence and activity of systemic lupus erythematosus, prompt and accurate diagnosis of cutaneous lupus erythematosus is essential. This review aims to cover common, rare, and atypical manifestations of lupus erythematosus-associated skin disease with a detailed discussion of histopathological correlates. Cutaneous lupus erythematosus covers a wide morphological spectrum well beyond acute, subacute and chronic cutaneous lupus erythematosus, which are commonly classified as lupus-specific skin disease. Other uncommon or less well-known manifestations include lupus erythematosus tumidus, lupus profundus, chilblain lupus, mucosal lupus erythematosus, and bullous lupus erythematosus. Vascular manifestations include leukocytoclastic and urticarial vasculitis, livedoid vasculopathy and livedo reticularis/ racemosa. Finally, we discuss rare presentations such as lupus erythematosus-related erythema exsudativum multiforme (Rowell syndrome), Kikuchi-Fujimoto disease, extravascular necrotizing palisaded granulomatous dermatitis (Winkelmann granuloma), and neutrophilic urticarial dermatosis.

Pathogenesis of cutaneous lupus erythematosus: common and different features in distinct subsets

The term 'cutaneous lupus erythematosus' (CLE) comprises several related autoimmune skin disorders, defined as 'specific' skin manifestations of lupus erythematosus (LE). The spectrum of clinical presentation of CLE is wide, reaching from mild erythema to disseminated scarring skin lesions. There is increasing knowledge concerning the pathogenesis of LE skin lesions and it has been shown that a complex network of cutaneous cytokines, chemokines and adhesion molecules orchestrate and promote tissue injury observed in LE skin lesions. However, a complete understanding of the diverse pathophysiological mechanisms in the different CLE subsets does not exist. Here we review the main pathological features described in CLE patients against the background of the clinical diversity of different CLE subtypes.

Phenotypic and functional abnormalities of bone marrow-derived dendritic cells in systemic lupus erythematosus

Introduction

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoreactive T and B cells, which are believed to be secondary to deficient dendritic cells (DCs). However, whether DC abnormalities occur during their development in the bone marrow (BM) or in the periphery is not known.

Methods

Thirteen patients with SLE and 16 normal controls were recruited. We studied the morphology, phenotype, and functional abilities of bone marrow-derived dendritic cells (BMDCs) generated by using two culture methods: FMS-like tyrosine kinase 3 (Flt3)-ligand (FL) and granulocyte-macrophage colony-stimulating factor (GM-CSF) plus interleukin-4 (IL-4), respectively.

Results

BMDCs induced by FL exhibited both myeloid (mDC) and plasmacytoid DC (pDC) features, whereas GM-CSF/IL-4 induced mDC generation. Substantial phenotypic and functional defects of BMDCs were found from patients with SLE at different stages of cell maturation. When compared with healthy controls, SLE immature BM FLDCs expressed higher levels of CCR7. Both immature and mature SLE BM FLDCs expressed higher levels of CD40 and CD86 and induced stronger T-cell proliferation. SLE BM mDCs expressed higher levels of CD40 and CD86 but lower levels of HLA-DR and a lower ability to stimulate T-cell proliferation when compared with control BM mDCs.

Conclusions

Our data are in accordance with previous reports that suggest that DCs have a potential pathogenic role in SLE. Defects of these cells are evident during their development in BM. BM mDCs are deficient, whereas BM pDCs, which are part of BM FLDCs, are the likely culprit in inducing autoimmunity in SLE.

Plasmacytoid dendritic cells and dermatological disorders: focus on their role in autoimmunity and cancer

Dendritic cells (DC), considered as immunological sentinels of the organism since they are antigen presenting cells, create the link between innate and adaptive immunity. DC include myeloid dendritic cells (MDC) and plasmacytoid dendritic cells (PDC). The presence of PDC, cells capable of producing large quantities of interferon alpha (IFN-alpha) in response to pathogenic agents or danger signals, seems to be closely related to pathological conditions. PDC have been observed in inflammatory immunoallergic dermatological disorders, in malignant cutaneous tumours and in cutaneous lesions of infectious origin. They seem to play a crucial role in the initiation of the pathological processes of autoimmune diseases such as lupus or psoriasis. Their function within a tumour context is not as well known and is controversial. They could have a tolerogenic role towards tumour cells in the absence of an activator but they also have the capacity to become activated in response to Toll-like receptor (TLR) ligands and could therefore be useful for therapeutic purposes.