Case report: JAK1/2 inhibition with baricitinib in the treatment of STING-associated vasculopathy with onset in infancy.

Abstract

Gain-of-function mutations in STING1 (also known as TMEM173) which result in constitutive activation of STING, have been reported to cause STING-associated vasculopathy with onset in infancy (SAVI). Although a wider spectrum of associated manifestations and perturbations in disease onset have been observed since its description, the genotype-phenotype correlations are not definite, and there is no established treatment protocol for SAVI. Herein, we report a kindred, heterozygous STING mutation (p.V155M) in which the 2-year-old proband suffered from severe interstitial lung disease (ILD) while her father was initially misdiagnosed with connective tissue disease associated with ILD at an adult age. Baricitinib was initiated after the diagnosis of SAVI in the proband combined with steroids, and during the 14-month follow-up, the respiratory symptoms were improved. However, as the improvement of laboratory indicators was limited, especially in autoimmune indices, and the lung CT images remained unaltered, it seems that JAK1/2 inhibition was unsatisfactory in completely controlling the inflammation of the disease in our study. Baricitinib was shown to elicit some effect on the ILD but failed to control the inflammation of the disease completely. Further exploration of JAK inhibitors or other therapeutic strategies are needed to more optimally treat this inflammatory disease.