Type I interferon response and vascular alteration in chilblain-like lesions during the COVID-19 outbreak

Background

The outbreak of chilblain‐like lesions (CLL) during the COVID‐19 pandemic has been reported extensively, potentially related to SARS‐CoV‐2 infection, yet its underlying pathophysiology is unclear.

Objectives

To study skin and blood endothelial and immune system activation in CLL in comparison with healthy controls and seasonal chilblains (SC), defined as cold‐induced sporadic chilblains occurring during 2015 and 2019 with exclusion of chilblain lupus.

Methods

This observational study was conducted during 9–16 April 2020 at Saint‐Louis Hospital, Paris, France. All patients referred with CLL seen during this period of the COVID‐19 pandemic were included in this study. We excluded patients with a history of chilblains or chilblain lupus. Fifty patients were included.

Results

Histological patterns were similar and transcriptomic signatures overlapped in both the CLL and SC groups, with type I interferon polarization and a cytotoxic–natural killer gene signature. CLL were characterized by higher IgA tissue deposition and more significant transcriptomic activation of complement and angiogenesis factors compared with SC. We observed in CLL a systemic immune response associated with IgA antineutrophil cytoplasmic antibodies in 73% of patients, and elevated type I interferon blood signature in comparison with healthy controls. Finally, using blood biomarkers related to endothelial dysfunction and activation, and to angiogenesis or endothelial progenitor cell mobilization, we confirmed endothelial dysfunction in CLL.

Conclusions

Our findings support an activation loop in the skin in CLL associated with endothelial alteration and immune infiltration of cytotoxic and type I IFN‐polarized cells leading to clinical manifestations.

Activation endothéliale associée aux ANCA IgA au cours des lésions de lésions acrales pendant l’épidémie de COVID-19

Introduction

Matériel et méthodes

Résultats

Discussion

P10.06 Stiff limb syndrome associated to anti NMDA-R antibodies

BACKGROUND

Stiff person spectrum disorder is a group of rare conditions clinically characterized by the core symptoms of fluctuating muscular stiffness with superimposed spasms and an exaggerated startle response (hyperkplexia). It includes multiple variants amongst which are focal forms like stiff limb syndrome. Up to date, it was described in association with a spectrum of antibodies interfering with gabaergic transmission, most frequently antibodies targeting GAD, glycine receptor, amphiphysin and more rare dipeptidylpeptidase like protein 6, gephyrin, GABAAR and Glycine transporter 2.

MATERIAL AND METHODS

We report the case of a stiff limb syndrome associated to anti-NMDAR antibodies. The patient, a French 44-year male, with no antecedents presents with a 2-month history of painful spasms in his both legs resulting in a difficulty of walking and multiple falls. The diagnosis was supported by a stiff limb syndrome clinical pattern, a clinical response to treatment with benzodiazepines and baclofen and by the absence of other neurological finding that could have suggested an alternative diagnosis.

RESULTS

Anti NMDA-R antibodies were identified in blood and CSF samples using both immunofluorescence and cell-based assay. Any other intracellular and surface antibodies were negatives, GAD-ab included. Oncological evaluation was negative. The patient didn’t present encephalopathy signs and neuropsychological evaluation was normal. The patient received immunotherapy with one cure of intravenous immunoglobulins after an only partial improvement with symptomatic treatment.

CONCLUSION

This is the first case report of an association between the anti NMDA-R and stiff limb syndrome. Further investigations are needed to provide a better understanding of the pathophysiology of stiff person spectrum disorders.