John Libbey Eurotext

European Journal of Dermatology

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Chilblains observed during the COVID-19 pandemic cannot be distinguished from classic, cold-related chilblains Volume 32, numéro 3, May-June 2022

Figure 1.

Patient 26. A) Clinical presentation of chilblain lesions observed during the pandemic with purplish-erythematous macules located on the toes. B-D) Histopathological features showing a very dense and deep inflammatory lymphohistiocytic infiltrate in the dermis (B), essentially peri-eccrine (C) (yellow arrow) and perivascular with a lymphocytic vasculitis (C) (black arrow) as well as microthrombosis (D) (black arrow) (haematoxylin and eosin; original magnification: [B] x3, [C] x20, [D] x20).

Figure 2.

Interferon signature in patients with CL. A-D) PBMCs from healthy controls (HC, n=8) and CL patients (n=21) were cultured without stimulation (NS) or with PHA+IL-2 stimulation for 72 hours. RNA was then isolated and qPCR to determine MX1, IRF7 and EF1 mRNA expression was performed. MX1 and IRF7 expression was normalized against EF1. B, D) Induction was calculated by comparing the expression of MX1 and IRF7 in stimulated PBMCs versus unstimulated PBMCs. E-F) Skin biopsies were performed on healthy skin of HC (n=12) and skin lesions of CL patients (n=7). RNA isolation and qPCR to determine MX1, IRF7 and EF1 mRNA expression were performed as described for PBMCs. G) IFNα2 concentration in serum of HC (n=8), CL patients (n=23) and SARS-CoV-2 infected patients (n=29) was measured by ELISA. The cut-off for detection of IFNα2 was 12.5 pg/mL. Data are shown as mean ±SD.*p ≤ 0.05 and **p ≤ 0.01 ([A], [C], [G]: Kruskal-Wallis test with Dunn’s multiple comparisons test; [B], [D], [E], [F]: Mann-Whitney test).

Figure 3.

Immunohistochemistry for antiviral myxovirus resistance protein 1 (MX1) showing weak non-specific staining of the basal layer of keratinocytes from healthy skin (A), and diffuse positive staining of the epidermis and a lymphohistiocytic infiltrate from a pre-pandemic idiopathic chilblain (B) and a chilblain during the pandemic (C) (haematoxylin and eosin; magnification: x20 for all images).