Japanese guidelines for the management and treatment of generalized pustular psoriasis: The new pathogenesis and treatment of GPP

Generalized pustular psoriasis (GPP) is a rare disease characterized by recurrent fever and systemic flushing accompanied by extensive sterile pustules. The committee of the guidelines was founded as a collaborative project between the Japanese Dermatological Association and the Study Group for Rare Intractable Skin Diseases under the Ministry of Health, Labour, and Welfare Research Project on Overcoming Intractable Diseases. The aim of the guidelines was to provide current information to aid in the treatment of patients with GPP in Japan. Its contents include the diagnostic and severity classification criteria for GPP, its pathogenesis, and recommendations for the treatment of GPP. Since there are few clinical trial data with high levels of evidence for this rare disease, recommendations by the committee are described in the present guidelines.

Impact of ixekizumab treatment on skin-related personal relationship difficulties in moderate-to-severe psoriasis patients: 12-week results from two Phase 3 trials

BACKGROUND

Psoriasis symptoms may decrease quality of life for patients. Skin-related personal relationship difficulties in psoriasis patients are common, under-reported and poorly understood.

OBJECTIVE

To assess the effect of ixekizumab (IXE) treatment on skin-related personal relationship difficulties in patients with moderate-to-severe psoriasis.

METHODS

Pooled data (N = 2570) on skin-related relationship problems were obtained from two large phase 3 trials (UNCOVER-2 and UNCOVER-3) in patients with moderate-to-severe plaque psoriasis randomized to subcutaneous placebo (PBO, N = 361), etanercept (ETN; 50 mg twice weekly, N = 740), or 80 mg IXE as one injection every 4 (IXEQ4W, N = 733) or 2 weeks (IXEQ2W, N = 736) for 12 weeks, following a 160-mg initial dose. The Dermatology Life Quality Index (DLQI) Personal Relationships Domain (PRD) (Items 8 and 9) was used to assess how much the skin caused any personal relationship difficulties at weeks 0, 2, 4 and 12. Improvement was compared for IXE vs PBO and ETN using logistic models. Factors associated with improvement were assessed using multiple linear regressions. DLQI Item 9, assessing sexual difficulties, was also analysed separately.

RESULTS

PRD scores (mean ± standard deviation) at baseline were similar across all treatment groups (PBO: 1.8 ± 1.9; ETN: 1.7 ± 1.8; IXEQ4W: 1.6 ± 1.8; IXEQ2W: 1.7 ± 1.8). Treatment with IXE rapidly and significantly improved the mean PRD score compared to PBO and ETN (P < 0.001 at all time points). Baseline PRD score was the strongest negative predictor of improvement. IXE enabled significantly more patients with moderate-to-severe plaque psoriasis to reduce their skin-related sexual difficulties at Week 12 compared to PBO (P < 0.001) or ETN (P < 0.001).

CONCLUSION

Ixekizumab improves patient-reported skin-related PRD difficulties in patients with moderate-to-severe psoriasis.

Linear immunoglobulin A/G bullous dermatosis associated with ulcerative colitis

Linear immunoglobulin (Ig)A/G bullous dermatosis (LAGBD) is an autoimmune bullous disease characterized by formation of subepidermal blisters and linear deposition of IgA and IgG antibodies along the basement membrane zone (BMZ). The association between linear IgA bullous dermatosis and ulcerative colitis (UC) is well recognized, but reports of UC-associated LAGBD are lacking. We have reported a 24-year-old man suffering from LAGBD associated with UC, which occurred before exacerbations of skin rash. A skin biopsy indicated a subepidermal blister with an infiltration of primarily neutrophils and eosinophils in the dermis. Direct immunofluorescence (IF) studies showed a linear deposition of IgA, IgG and C3c. Indirect IF of human skin revealed IgA and IgG anti-BMZ autoantibodies. Indirect IF of 1 M NaCl-split human skin demonstrated reactivity of IgA and IgG antibodies at the epidermal side. Immunoblotting showed that IgG antibodies reacted to the BP180 NC16a domain and 120-kDa linear IgA dermatosis-1, and enzyme-linked immunoassay detected IgG anti-BP230 antibodies. Administration of prednisolone and diaminodiphenyl sulfone (DDS) via the p.o. route improved skin lesions and bowel conditions. These results suggest that the bowel inflammation observed in UC may have a causative effect of initiation of the immune response to the skin and development of the bullous skin lesions in LAGBD. A combination of DDS and corticosteroid could be a recommended therapeutic option for patients with LAGBD with UC.

Epidermal iron metabolism for iron salvage

BACKGROUND

The epidermis shows a reverse iron gradient from the basal layer to the stratum corneum and consequently, little epidermal intracellular iron is lost by desquamation.

OBJECTIVE

To clarify the underlying mechanism of iron salvage.

METHODS

We first used immunohistochemistry and mRNA quantification to demonstrate the distinctive expression pattern of iron metabolism molecules. The obtained results were confirmed using normal human epidermal keratinocytes (NHEKs) during in vitro differentiation. We next examined the effects of reducing ferroportin expression in vitro by ferroportin-specific siRNAs or hepcidin on the intracellular iron content of cultured NHEKs. Finally, we compared epidermal and systemic iron metabolism between Fpn^Epi-KO mice and control mice.

RESULTS

The results of both mRNA and protein expression analysis showed that most molecules participating in iron import and storage were expressed in the lower epidermis, while those involved in iron release from heme or iron transport were expressed in the upper epidermis. Consistent with their expression, keratinocyte differentiation reduced intracellular iron content. We next demonstrated that reducing ferroportin expression in vitro by ferroportin-specific siRNAs or hepcidin significantly increased the intracellular iron content. Finally, we showed that the iron content of the epidermis and squames was significantly greater in Fpn^Epi-KO mice than in control mice, and that Fpn^Epi-KO exhibited a more rapid decrease in blood hemoglobin concentration than control mice on a low iron diet.

CONCLUSION

These studies demonstrated that the epidermis is equipped with a machinery by which intracellular iron in differentiated keratinocytes is excreted to the extracellular space before reaching the stratum corneum.

Comparative study of cytokeratin and langerin expression in keratinized cystic lesions of the oral and maxillofacial regions

Dermoid cysts (DMCs) and epidermoid cysts (EDMCs) usually arise in soft tissues, whereas orthokeratinized odontogenic cysts (OOCs) and keratocystic odontogenic tumors (KCOTs) develop in the jaw. In this study, we performed immunohistochemical analysis of cytokeratins (CKs) to examine differences in the lining epithelium of DMCs, EDMCs, OOCs, and KCOTs. In addition, we carried out immunohistochemical examination of langerin to clarify the biological characteristics of the orthokeratinized lining epithelium of DMCs, EDMCs, and OOCs. Seven DMCs, 30 EDMCs, 11 OOCs, and 28 KCOTs were examined immunohistochemically using antibodies against CK10, 13, 14, 16, 17, 19, and langerin. Immunoreactivities for CKs and langerin in oral DMCs and EDMCs were similar to those of lesions affecting the skin. Positive reactivity for CK13 and 17 was evident in OOCs, but not in DMCs/EDMCs. CK10 was significantly positive in all layers except for the basal layer in OOCs, but was negative in KCOTs. CK17 was positive in all layers in KCOTs, and in all layers except for the basal layer in both OOCs and dentigerous cysts. CK19 was negative in OOCs. Langerhans cells were found mainly in OOCs, but were hardly evident in KCOTs. These results suggest that DMCs/EDMCs, OOCs and KCOTs are independent diseases.

Quantitative Analysis of Formaldehyde-induced Fluorescence in Paraffin-embedded Specimens of Malignant Melanomas and Other Melanocytic Lesions

Inter-observer agreement is problematic in the histopathological diagnosis of melanoma and melanocytic naevi, even among expert pathologists. Formaldehyde-induced fluorescence (FIF) has been used for histochemical demonstration of catecholamines, 5-hydroxytryptamine and their immediate precursors. FIF can detect melanogenic activity and may be useful in differentiating malignant melanoma from other melanocytic lesions. The fluorescence of various types of melanocytic lesions has been previously studied quantitatively in formalin-fixed and paraffin-embedded sections. This study compared 2 sets of excitation and emission bands: 450-490 nm excitation/510-560 nm absorption filters (filter unit A) and 480 nm excitation/510< nm absorption filters (filter unit B). Higher FIF was observed with filter unit A than with filter unit B. FIF intensity of central regions was found to be higher than that of the peripheral regions. Mean FIF was significantly higher in malignant melanomas than in naevi. Fluorescence imaging with filter unit A gave better diagnostic performance. In conclusion, quantitative measurement of FIF is a useful marker of malignant potential.

Autoantibodies Against Multiple Epitopes in Bp180 and Laminin Gamma-1 in Subepidermal Blistering Skin Disease Associated with Psoriatic Erythroderma

We report a 79-year-old Japanese man who developed subepidermal blistering skin disease after an 8-year history of psoriasis. Histology of a bullous lesion revealed a subepidermal blister with a mixed inflammatory cell infiltrate and fibrin nets. Indirect immunofluorescence using normal human skin sections revealed IgG and IgA autoantibodies in the patient serum, which bound to the epidermal side of 1M NaCl-split skin sections. Immunoblot analysis revealed that both IgA and IgG antibodies reacted with the BP180 NC16a domain and the 120-kDa LAD-1 and that IgG antibodies also reacted with the BP180 C-terminal domain and laminin gamma-1. These findings indicated that autoantibodies to laminin gamma-1 and multiple epitopes in BP180 ectodomain played a role in the pathogenesis of this unique autoimmune subepidermal blistering skin disease associated with psoriasis.

HLA-C*12:02 is a susceptibility factor in late-onset type of psoriasis in Japanese

Psoriasis is thought to be a multifactorial disease triggered by both genetic and environmental factors. The HLA-C locus on chromosome 6p21.33 remains the strongest susceptibility candidate locus in psoriasis. The strong association between psoriasis and the HLA-Cw6 allele has been well documented in various races. It is known that psoriatic patients with early onset are more likely to be familial and associated with HLA-Cw6. Familial occurrence of Japanese psoriasis is smaller than other populations. Furthermore, males are predominant over females in Japanese psoriasis. We investigated the relation between HLA-C alleles and age of onset, and in each gender for Japanese psoriasis, and discuss male predominance in the incidence of psoriasis in Japan. Four hundred forty six unrelated Japanese patients with psoriasis vulgaris and 557 sex- and age-matched unrelated Japanese healthy controls were investigated by genotyping. We confirmed the association between early-onset type of psoriasis with HLA-C*06:02 allele in Japanese. In addition, we detected the association between the late-onset type of psoriasis and the HLA-C*12:02 allele in Japanese. No significant differences in allele frequency were observed between females and males. Our results suggest that there is no genetic factor effect on male predominance in Japanese. In contract, the effect of environmental risk factors on the onset of Japanese psoriatic patients is stronger in males than in females. As a result, male predominant in psoriasis may occur in Japan.

Activation of LXRs using the synthetic agonist GW3965 represses the production of pro-inflammatory cytokines by murine mast cells

BACKGROUND

The activation of liver X receptor (LXR) α or LXRβ negatively regulates the expression of pro-inflammatory genes in mammalian cells. We recently reported that 25-hydroxycholesterol, a representative LXR-activating oxysterol, suppresses IL-6 production in mouse mast cells (MCs) following its engagement of the high-affinity IgE receptor (FcεRI). This finding suggests that murine MCs express functional LXRs; however, the mechanisms underlying the LXR-dependent repression of the MC-mediated production of pro-inflammatory cytokines, including IL-6, are poorly understood. Therefore, we employed the synthetic LXR ligand GW3965 to examine the functions of LXRα and LXRβ in the production of pro-inflammatory cytokines by murine bone marrow-derived MCs (BMMCs).

METHODS

We prepared BMMCs from wild-type (WT), LXRα(-/-), and LXRα/β(-/-) mice. Each group of BMMCs was pretreated with GW3965 and then stimulated with IgE+antigen (Ag) or lipopolysaccharide (LPS). Cytokine production was then analyzed using specific ELISA kits.

RESULTS

The activation of LXRs by GW3965 significantly attenuated the production of IL-1α and IL-1β, but not of IL-6, in the WT and LXRα(-/-) BMMCs stimulated with IgE+Ag. However, GW3965 treatment decreased the production of IL-1α, IL-1β, and IL-6 in WT and LXRα(-/-) BMMCs upon stimulation with LPS, while the GW3965-mediated suppression of cytokine production was nearly absent from the LXRα/β(-/-) BMMCs.

CONCLUSIONS

These findings demonstrate, for the first time, that the activation of LXRs by GW3965 attenuates the antigen- or LPS-induced production of pro-inflammatory cytokines, such as IL-1α and IL-1β, in murine MCs and that LXRβ plays an important role in the LXR-mediated repression of cytokine production.

Treatment of murine mast cells with IgEκ and protein L enhances apoptotic cell death induced by IL-3 withdrawal

Engagement of the high-affinity IgE receptor (FcεRI) can be either protective or non-protective against apoptotic cell death (ACD) in bone marrow-derived murine mast cells (BMMCs) after IL-3 withdrawal, depending on the avidity between IgE and its antigen. We recently reported that protein L (PpL), a bacterial Igκ-binding soluble protein, is able to stimulate intracellular signaling to induce activation of BMMCs by interacting with the IgEκ-FcεRI complex. However, it is unclear if cross-linking of FcεRI with IgEκ and PpL prevents or enhances IL-3-dependent ACD in BMMCs. In the present study, we found that IL-3-dependent ACD of BMMCs is accelerated by loading soluble PpL in the presence of IgEκ-occupied FcεRIα. For this purpose, soluble PpL was incorporated into the BMMCs. Unlike soluble PpL, immobilized PpL failed to enhance ACD, although both forms of PpL induced IL-6 production equally in BMMCs. In addition, we observed that DNS5-BSA protected anti-DNS IgE-sensitized BMMCs from IL-3 depletion-mediated ACD by inducing the production of autocrine IL-3. In contrast, DNS5-PpL enhanced IL-3 withdrawal-induced ACD of anti-DNS IgE-sensitized BMMCs and reduced the production of autocrine IL-3. These findings suggest that PpL increases IL-3 withdrawal-induced ACD of IgEκ-sensitized BMMCs by incorporating PpL into the BMMCs and that this internalized PpL may interfere with survival signals via FcεRI.

Japanese guidance for use of biologics for psoriasis (the 2013 version)

The clinical use of adalimumab and infliximab, human anti-tumor necrosis factor (TNF)-α monoclonal antibodies, for psoriasis began in January 2010. In January 2011, ustekinumab, a human anti-interleukin-12/23p40 (IL-12/23p40) monoclonal antibody, was newly approved as the third biologic with an indication for psoriasis. While all of these biologics are expected to exhibit excellent therapeutic effect for psoriasis and to contribute to the improvement of quality of life in patients, these drugs require careful safety measures to prevent adverse drug reactions, such as serious infections. The new guidance, an English version prepared by revising the Japanese Guidance/Safety Manual for Use of Biologics for Psoriasis 2011 (in Japanese), is intended to provide up-to-date, evidence-based recommendations and safety measures on the use of biologics, and describes the optimal use of the three biologics, medical requirements for facilities for using biologics, details of safety measures against reactivation of tuberculosis and hepatitis B virus infection, and recommendable combination therapies with biologics.