Most chilblains observed during the COVID‐19 outbreak occur in patients who are negative for COVID‐19 on polymerase chain reaction and serology testing

International audienceBackground: Acral lesions, mainly chilblains, are the most frequently reported cutaneous lesions associated with COVID-19. In more than 80% of patients tested, nasopharyngeal swabs were negative on reverse transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2 when performed, and serology was generally not performed.Methods: A national survey was launched on 30 March 2020 by the French Society of Dermatology asking physicians to report cases of skin manifestations in patients with suspected or confirmed COVID-19 by using a standardized questionnaire. We report the results for acral manifestations.Results: We collected 311 cases of acral manifestations [58.5% women, median age 25.7 years (range 18-39)]. The most frequent clinical presentation (65%) was typical chilblains. In total, 93 cases (30%) showed clinical suspicion of COVID-19, 67 (22%) had only less specific infectious symptoms and 151 (49%) had no clinical signs preceding or during the course of acral lesions. Histology of skin biopsies was consistent with chilblains. Overall, 12 patients showed significant immunological abnormalities. Of the 150 (48%) patients who were tested, 10 patients were positive. Seven of 121 (6%) RT-PCR-tested patients were positive for SARS-CoV-2, and five of 75 (7%) serology-tested patients had IgG anti-SARS-CoV-2. Tested/untested patients or those with/without confirmed COVID-19 did not differ in age, sex, history or acral lesion clinical characteristics.Conclusions: The results of this survey do not rule out that SARS-CoV-2 could be directly responsible for some cases of chilblains, but we found no evidence of SARS-CoV-2 infection in the large majority of patients with acral lesions during the COVID-19 lockdown period in France

Non‐acral skin manifestations during the COVID‐19 epidemic: COVIDSKIN study by the French Society of Dermatology

International audienceA variety of skin manifestations occurring during the COVID-19 pandemic have been reported since March 2020.1 The most reported were chilblain-like lesions, widespread urticaria, maculopapular eruptions, vesicular eruptions and vascular lesions such as livedo or necrosis.

Pivotal Advance: Kaposi’s sarcoma-associated herpesvirus (KSHV)-encoded microRNA specifically induce IL-6 and IL-10 secretion by macrophages and monocytes

Macrophages are an important source of inflammatory cytokines generated during the innate immune response, but in the microenvironment of certain tumors, macrophages promote tumor progression through their preferential secretion of cytokines that support tumor cell growth and suppress antitumoral immune responses. KSHV is the causative agent of KS and lymphomas preferentially arising in immunocompromised patients, and specific cytokines, including IL-6 and IL-10, have been implicated in KSHV-associated cancer pathogenesis. However, the contribution of KSHV-infected macrophages to the cytokine milieu within KSHV-related tumors is unclear. We found that individual KSHV-encoded miRNA induce IL-6 and IL-10 secretion independently and additively by murine macrophages and human myelomonocytic cells. Bioinformatics analysis identified KSHV miRNA binding sites for miR-K12-3 and miR-K12-7 within the 3′UTR of the basic region/leucine zipper motif transcription factor C/EBPβ, a known regulator of IL-6 and IL-10 transcriptional activation. Subsequent immunoblot analyses revealed that miR-K12-3 and miR-K12-7 preferentially reduce expression of C/EBPβ p20 (LIP), an isoform of C/EBPβ known to function as a negative transcription regulator. In addition, RNA interference specifically targeting LIP induced basal secretion of IL-6 and IL-10 by macrophages. Taken together, these data support a role for KSHV miRNA in the programming of macrophage cytokine responses in favor of KSHV-related tumor progression