Clinical and immunological study of Tofacitinib and Baricitinib in refractory Blau syndrome: case report and literature review

Blau syndrome (BS) is an autoinflammatory disorder characterized by non-caseating granulomatous dermatitis, arthritis, and uveitis. We present a case of refractory and severe BS that was treated with the Janus kinase inhibitors (JAKINIBS), Tofacitinib (TOFA) and then Baricitinib (BARI). Our aim was to describe the clinical and immunological outcomes after treatment with JAKINIBS. Blood tests and serum samples were obtained during follow-up with TOFA and BARI. We assessed their effects on clinical outcomes, acute phase reactants, absolute lymphocyte counts (ALCs), lymphocyte subset counts, immunoglobulins, and cytokine levels. A review of the literature on the use of JAKINIBS for the treatment of uveitis and sarcoidosis was also conducted. TOFA led to a rapid and maintained disease control and a steroid-sparing effect. A decrease from baseline was observed in ALC, CD3+, CD4+, CD8+, and natural killer (NK) cell counts. B-cells were stable. Serum levels of interleukin (IL)-4 and tumor necrosis factor alpha (TNF-α) increased, whereas IL-2, IL-6, IL-10, and IL-17 maintained stable. TOFA was discontinued after 19 months due to significant lymphopenia. The initiation of BARI allowed maintaining adequate control of disease activity with an adequate safety profile. The literature review showed seven patients with uveitis and five with sarcoidosis treated with JAKINIBS. No cases of BS treated with JAKINIBS were found. We report the successful use of JAKINIBS in a patient with refractory and severe BS.