Gene expression based molecular test as diagnostic aid for the differential diagnosis of psoriasis and eczema in formalin fixed and paraffin embedded tissue, microbiopsies and tape strips

J Invest Dermatol. 2023 Mar 6:S0022-202X(23)00156-2. doi: 10.1016/j.jid.2023.02.015. Online ahead of print.

ABSTRACT

Highly effective targeted therapies are available to treat non-communicable chronic inflammatory skin diseases (ncISD). In contrast, the exact diagnosis of ncISD is complicated by their complex pathogenesis and clinical and histological overlap. Particularly, differential diagnosis of psoriasis and eczema can be challenging in special cases and molecular diagnostic tools need to be developed to support gold standard diagnosis. Aim of this work was to develop a real-time PCR based molecular classifier to distinguish psoriasis from eczema in FFPE-fixed skin samples and to evaluate the use of minimally invasive microbiopsies and tape strips for molecular diagnosis. Here, we present a FFPE-based molecular classifier (MC) that determines the probability for psoriasis with a sensitivity/specificity of 92%/100%, respectively, and an AUC of 0.97 delivering comparable results to our previous published RNAprotect-based MC. The psoriasis probability, as well as levels of NOS2 expression positively correlated with disease hallmarks of psoriasis and negatively with eczema hallmarks. Furthermore, minimally invasive tape strips and microbiopsies were effectively used to differentiate psoriasis from eczema. In summary, the MC offers broad usage in pathology laboratories as well as outpatient settings and can support the differential diagnosis of ncISD on a molecular level FFPE tissue, microbiopsies and tape strips.

PMID:36889660 | DOI:10.1016/j.jid.2023.02.015