Clinical, Histopathologic, and Immunohistochemical Features of Patients with IgG/IgA Pemphigus

Proteomic Profiling and Clinical Insights: The Role of MMP9 in Differentiating Psoriasis Vulgaris from Generalized Pustular Psoriasis

Background

Generalized pustular psoriasis (GPP) constitutes a rare, severe inflammatory disorder that differs from psoriasis vulgaris (PV). The IL-36 pathway has been identified as a key element in GPP pathogenesis.

Objective

To explore protein expression between PV and GPP, providing insights into potential mechanisms.

Methods

We performed proteomic analysis of tissue specimens from patients with PV and GPP to identify differentially expressed proteins. Comparative analysis of the proteomic data was performed and proteins with significant differences were further identified using immunofluorescence and Western blot techniques. Differential proteins were also explored by evaluating the efficacy of IL-36R inhibitors before and after GPP treatment, providing potential avenues for targeted therapeutic strategies.

Results

Tissue proteomic profiling showed that matrix metallopeptidase 9 (MMP9) increased significantly in the GPP as compared to PV. Immunofluorescence and Western blot analysis confirmed that MMP9 is higher expressed in GPP. And after therapy with IL-36 inhibitors showed that the level of MMP9 expression was markedly reduced.

Conclusion

MMP9 may be involved with the pathogenesis of GPP.

Uncommon and Unusual Variants of Autoimmune Bullous Diseases

Background

Autoimmune blistering diseases (AIBDs) are a type of dermatosis with antibodies produced against various structural proteins of the epidermis or dermoepidermal junction. AIBDs are broadly divided into intraepidermal and subepidermal types. Apart from the common AIBDs, there is an array of uncommon AIBDs.

Objective

To discuss uncommon variants of AIBDs so that the readers are updated about them.

Methods

In this review, we have discussed uncommon and unusual variants like pemphigus herpetiformis, IgA pemphigus, paraneoplastic pemphigus, induced pemphigus, IgG/IgA pemphigus, oral lichenoid pigmentation in pemphigus, pemphigus acanthoma, and follicular pemphigus. Rarer variants of the pemphigoid group of disorders include anti-laminin 332 pemphigoid, mixed linear IgA/IgG pemphigoid, anti-p200 pemphigoid, Brunsting-Perry pemphigoid, IgM pemphigoid, granular C3 pemphigoid, anti-p105 pemphigoid, ORF-induced anti-laminin 332 pemphigoid, and acral purpura in dermatitis herpetiformis.

Conclusion

This review will help in early diagnosis and treatment of uncommon and unusual variants of AIBDs.

TNF-α‒Mediated Keratinocyte Expression and Release of Matrix Metalloproteinase 9: Putative Mechanism of Pathogenesis in Stevens‒Johnson Syndrome/Toxic Epidermal Necrolysis

Stevens‒Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are severe cutaneous adverse drug reactions characterized by widespread keratinocyte cell death and epidermal detachment. At present, there is little understanding of how the detachment occurs or how it is abrogated by the TNF-α inhibitor etanercept, an effective SJS/TEN treatment. RNA sequencing was used to identify upregulated transcripts in formalin-fixed paraffin-embedded SJS/TEN skin biopsies. Epidermal matrix metalloproteinase 9 (MMP9) expression was assessed by immunohistochemistry in skin biopsies and cultured human skin explants exposed to serum from patients with cutaneous adverse drug reactions. TNF-α‒induced MMP9 expression and activity and its abrogation by etanercept were determined using the HaCaT immortalized keratinocyte cell line. Epidermal MMP9 expression was significantly higher in SJS/TEN skin (70.6%) than in healthy control skin (0%) (P = 0.0098) and nonbullous skin reactions (10.7%) (P = 0.0002). SJS/TEN serum induced significant MMP9 expression and collagenase activity in healthy skin explants, which was reduced by etanercept. Etanercept was also able to negate the TNF-α‒induced MMP9 expression in the HaCaT cell line. Data suggest that elevated epidermal MMP9 expression and collagenase activity are a putative pathogenic mechanism in SJS/TEN, which is limited by etanercept. Modulation of MMP9 expression and activity represents, to our knowledge, a previously unreported therapeutic target for the treatment of SJS/TEN.