Generalized Pustular Psoriasis: Divergence of Innate and Adaptive Immunity

Generalized pustular psoriasis (GPP) is a severe, relapsing, immune-mediated disease characterized by the presence of multiple sterile pustules all over the body. The exact pathomechanisms behind GPP remain elusive, although increased interest in the genetic basis and immunological disturbances have provided some revealing insights into the underlying signaling pathways and their mutual interaction. The genetic background of GPP has been thoroughly investigated over the past few years. The conducted studies have identified genetic variants that predispose to pustular forms of psoriasis. The loss-of-function mutation of the interleukin 36 receptor antagonist gene, along with rare gain-of-function mutations in the gene that encodes the keratinocyte signaling molecule (CARD14), are examples of the uncovered abnormalities. Interleukin 36 (IL-36), along with neutrophils, is now considered a central cytokine in GPP pathogenesis, with IL-36 signaling providing a link between innate and adaptive immune responses. More recently, a new concept of inflammation, caused by a predominantly genetically determined abnormal activation of innate immune response and leading to inflammatory keratinization, has arisen. GPP is currently considered a representative of this novel group of skin conditions, called autoinflammatory keratinization diseases. As no therapeutic agents have been approved for GPP to date in the United States and Europe, the novel anti-IL-36R antibodies are particularly promising and may revolutionize management of the disease.

Infliximab in Combination with Low-Dose Acitretin in Generalized Pustular Psoriasis: A Report of Two Cases and Review of the Literature

Generalized pustular psoriasis (GPP) is a severe, life-threatening disease that represents a major therapeutic challenge. There is a lack of randomized controlled trials assessing the efficacy of various treatment options for GPP. TNFα inhibitors have proven to be effective and are increasingly used in this indication. In the current paper, we present two patients with GPP treated with infliximab (Ifx) and a literature review appraising currently available data on the use of Ifx in GPP. Case 1 was a 73-year-old woman with GPP who exhibited lack of treatment response or primary intolerance to standard therapeutic options (high-dose acitretin, methotrexate, cyclosporine A, and methylprednisolone). However, Ifx therapy combined with low-dose acitretin resulted in rapid and sustained resolution of skin lesions. Case 2 was a 60-year-old man with GPP and numerous comorbidities who was initially treated with Ifx in combination with methotrexate, with good treatment response for 9 months. Following an infection-induced flare of GPP at week 38, methotrexate was discontinued in favor of low-dose acitretin and Ifx continued. This regimen again resulted in rapid resolution of pustules. We present these cases to highlight the advantage of long-term Ifx therapy with low-dose acitretin in GPP.

Cellular scars and local crosstalk in relapsing psoriasis: an example of a skin sticking disease

Psoriasis is an inflammatory disease that arises in genetically predisposed individuals. Chronic skin lesions that contain activated immune cells can persist for years. Systemic inhibition of TNF, IL‐17 and IL‐23 cytokines has revolutionized psoriasis care during the recent decades. Unfortunately, local relapse of disease is common at previously inflamed sites after cessation of treatment. This highlights that fundamental pathologic alterations of the affected tissues are not completely resolved during clinical remission. Here, we present arguments for a local disease memory located in both dermis and epidermis in psoriasis skin. We decipher different cellular components and intercellular crosstalk that sustain local disease memory and amplify disease relapse in human psoriasis. Decrypting the mechanisms underlying the establishment and persistence of pathogenic memory cells in resolved psoriasis may provide new therapeutic perspectives aimed at long‐term remission of psoriasis.

Biologics in the treatment of pustular psoriasis

INTRODUCTION

Pustular psoriasis is a group of skin diseases characterized by neutrophil infiltration in the epidermis and formation of sterile pustules. Conventional treatments, such as retinoids and immunosuppressive drugs, have improved the clinical manifestations; however, many patients suffer from drug-related toxicity or are resistant to therapy.

AREAS COVERED

In this review, the authors focus on the efficacy and safety of these biologics, including anti-IL-1β (gevokizumab and canakinumab), anti-IL-1 R (anakinra), anti-IL-36 R (BI 655130), anti-tumor necrosis factor-α (etanercept, infliximab, and adalimumab), anti-IL-12/23 (ustekinumab), anti-IL-17A (secukinumab and ixekizumab), anti-IL-17RA (brodalumab), anti-IL-2 R (basiliximab), anti-IL-6 R (tocilizumab), and anti-IL-23 (risankizumab and guselkumab), for treating pustular psoriasis.

EXPERT OPINION

Patients with pustular psoriasis treated with biologics demonstrated positive responses. Anti-TNF-α is the most available biologics for the treatment of pustular psoriasis, and anti-IL-12/23 and anti-IL-17A might be considered as the first- or second-line therapy for moderate-to-severe and refractory pustular psoriasis. Anti-IL-17A can be used in the pustular psoriasis patients who failed to respond to anti-TNF agents and anti-IL-12/23. Therapeutic efficacy of biologics in pustular psoriasis might have no association with IL-36 RN mutation status.

Retinoids as an Immunity-modulator in Dermatology Disorders

The skin is the largest epithelial surface protecting the body from invading microbes. Vitamin A plays vital roles in the host defence of the skin, including promoting epithelial cell integrity, proliferation, and differentiation and even mediating immune responses. Furthermore, vitamin A derivatives, retinoid drugs, are widely used to treat skin diseases, such as acne and psoriasis. However, the immunoregulatory mechanisms of retinoids in dermatology have not been systematically described. In this paper, we discuss the immunological functions of retinoids during disease treatment, especially in skin disorders caused by exogenous infections.

Cutaneous side effects of TNF-alpha inhibitors

Since the early 1990s, tumor necrosis factor alpha (TNF-alpha) inhibitors have been successfully used in the treatment of various immune-mediated inflammatory diseases. By now, comprehensive safety data has been compiled. While adverse reactions do occur, they are - in relation to the frequent use of these agents - rare and usually not serious. Cutaneous side effects include local injection site reactions, infections, immune-mediated reactions, and neoplasms. The most common serious adverse events are of an infectious nature. Mycobacteria but also non-mycobacterial pathogens, such as viruses and fungi, may cause serious, even lethal, systemic infections. The present article is meant to review current knowledge with respect to cutaneous side effects of TNF-alpha inhibitors.

Attenuation of Nitrogen Mustard-Induced Pulmonary Injury and Fibrosis by Anti-Tumor Necrosis Factor-α Antibody

Nitrogen mustard (NM) is a bifunctional alkylating agent that causes acute injury to the lung that progresses to fibrosis. This is accompanied by a prominent infiltration of macrophages into the lung and upregulation of proinflammatory/profibrotic cytokines including tumor necrosis factor (TNF)α. In these studies, we analyzed the ability of anti-TNFα antibody to mitigate NM-induced lung injury, inflammation, and fibrosis. Treatment of rats with anti-TNFα antibody (15 mg/kg, iv, every 9 days) beginning 30 min after intratracheal administration of NM (0.125 mg/kg) reduced progressive histopathologic alterations in the lung including perivascular and peribronchial edema, macrophage/monocyte infiltration, interstitial thickening, bronchiolization of alveolar walls, fibrin deposition, emphysema, and fibrosis. NM-induced damage to the alveolar-epithelial barrier, measured by bronchoalveolar lavage (BAL) protein and cell content, was also reduced by anti-TNFα antibody, along with expression of the oxidative stress marker, heme oxygenase-1. Whereas the accumulation of proinflammatory/cytotoxic M1 macrophages in the lung in response to NM was suppressed by anti-TNFα antibody, anti-inflammatory/profibrotic M2 macrophages were increased or unchanged. Treatment of rats with anti-TNFα antibody also reduced NM-induced increases in expression of the profibrotic mediator, transforming growth factor-β. This was associated with a reduction in NM-induced collagen deposition in the lung. These data suggest that inhibiting TNFα may represent an efficacious approach to mitigating lung injury induced by mustards.

Childhood generalized pustular psoriasis: longtime remission with combined infliximab and methotrexate treatment

An 8-year old boy with generalized pustular psoriasis unresponsive to several topical and systemic treatments responded dramatically with long-lasting remission to infliximab in combination with methotrexate. Combined therapy might offer a new therapeutic strategy yielding long-term remission.

Acrodermatitis continua of Hallopeau treated successfully with ustekinumab and acitretin after failure of tumour necrosis factor blockade and anakinra

Acrodermatitis continua of Hallopeau (ACH) is a rare form of chronic acral pustular eruption. Considered to be a variant of pustular psoriasis, it is a refractory condition that may not respond to conventional treatments. We report herein the case of a 53-year-old patient whose ACH was refractory to all conventional systemic treatment modalities and to anti-tumour necrosis factor. Because he had increased plasma levels of interleukin (IL)-1β, he received anakinra for 7 weeks, without further improvement however. Achievement of complete response was obtained with ustekinumab 90 mg s.c. every 12 weeks combined with acitretin; the plasma level of IL-1β concomitantly returned to normal. This case report is associated with a review on recent data on ACH treatment with biological agents, including anakinra and ustekinumab.