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The following is a summary of “Laminin β4 is a constituent of the cutaneous basement membrane zone and additional autoantigen of anti-p200 pemphigoid,” published in the April 2024 issue of Dermatology by Goletz, et al.

Anti-p200 pemphigoid is a subepidermal autoimmune blistering disease characterized by autoantibodies against a 200 kDa protein, with laminin γ1 identified as the target antigen in most patients. However, the diagnostic assay for anti-p200 pemphigoid remains limited, potentially due to uncertainty regarding the pathogenic relevance of anti-laminin γ1 autoantibodies. For a study, researchers sought to identify a target antigen with greater clinical and diagnostic significance in anti-p200 pemphigoid.

The analysis included skin extracts and sera from patients diagnosed with anti-p200 pemphigoid (n = 60), other autoimmune blistering diseases (AIBD) (n = 33), and healthy blood donors (n = 29). Techniques such as immunoprecipitation, mass spectrometry, and immunoblotting were utilized to examine the samples. Additionally, the localization of the newly identified antigen in the skin was investigated using cultured keratinocytes and fibroblasts. The localization process involved quantitative real-time polymerase chain reaction (PCR) and immunofluorescence microscopy to provide insights into the distribution and expression of the antigen within the skin tissue.

In all analyzed patients, laminin β4 was identified as the target antigen of anti-p200 pemphigoid. It was predominantly expressed in keratinocytes in the basement membrane zone of the skin. Further testing with more sera was required to confirm laminin β4 as the diagnostically relevant antigen of anti-p200 pemphigoid.

The discovery of laminin β4 as an additional target antigen in anti-p200 pemphigoid provides a means for differentiating this condition from other autoimmune blistering diseases, thereby enhancing disease management strategies for these rare disorders.

Reference: jaad.org/article/S0190-9622(23)03214-0/fulltext