BACKGROUND: Suppressor of cytokine signalling 1 (SOCS1) insufficiency is an inborn error of immunity affecting the negative regulation of cytokine and growth factor signalling. We aimed to enhance the understanding of clinical manifestations, disease trajectories, disease penetrance, and the effect of Janus kinase (JAK) inhibition in individuals with SOCS1 insufficiency. METHODS: This study used data from two independent cohorts: the European Society for Immunodeficiencies (ESID) registry and the UK Biobank. Participants from the ESID registry were from nine European countries (Austria, Belgium, France, Germany, Ireland, Italy, Portugal, Sweden, and Ukraine), China, Taiwan, and the USA. Participants from the ESID registry were eligible if they had heterozygous, functionally validated SOCS1 variants
participants from the UK Biobank were included if they had any SOCS1 variant detected in the ESID registry cohort or any other SOCS1 variant that was classed as high-impact. Clinical manifestations of the underlying SOCS1 insufficiency were documented and summarised into nine subgroups, with ICD-10 diagnosis codes collected for participants from the UK Biobank. Participants from the ESID registry were tested for relevant autoantibodies in their local laboratory. Responses to JAK inhibitor treatment in participants from the ESID registry were assessed by the treating physician using a visual analogue scale. Descriptive statistics were used for analysis. People with lived experience were not involved in the study design. FINDINGS: We included 119 participants with SOCS1 insufficiency: 67 from the ESID registry, enrolled between Feb 15, 2021, and Dec 31, 2023, and 52 from the UK Biobank. Of the 67 participants from the ESID registry, 39 (58%) were female, 28 (42%) were male, and the median age was 28 years (IQR 15-44, range 2-85). 27 different monoallelic SOCS1 variants were identified in these participants. 62 (93%) of the 67 participants in the ESID registry cohort were symptomatic and five (7%) were asymptomatic family members
of the 62 participants with symptoms, allergy (33 [50%]), inflammatory gastrointestinal (22 [36%]) and skin (18 [29%]) manifestations, autoimmune cytopenia (24 [39%]), and lymphoproliferation (23 [37%]) were most frequent. Rheumatological manifestations (23 [37%]) included systemic lupus erythematosus, Sjögren's disease, and rheumatoid arthritis, with typical autoantibody profiles. 42 (68%) of the 62 symptomatic participants had at least three different manifestations. In the UK Biobank we found 52 participants carrying high-impact SOCS1 variants
29 (56%) were female, 23 (44%) were male, and the median age was 72 years (65-78, 57-86). Only 30 (58%) of these participants had developed manifestations that were potentially related to SOCS1 insufficiency. Allergy and rheumatological manifestations were more common in participants from the UK Biobank than the ESID registry. Female predominance (21 [70%] of 30 participants were female and nine [30%] were male) was also found among symptomatic participants from the UK Biobank. Treatment with JAK inhibitors showed promising results in 12 (92%) of 13 participants in the ESID registry. INTERPRETATION: SOCS1 insufficiency differs from other genetic autoimmune lymphoproliferative disorders by the presence of frequent atopic and rheumatological manifestations. Penetrance is incomplete and is higher in females than in males. JAK inhibition is a promising targeted therapy for patients with SOCS1 insufficiency. FUNDING: German Research Foundation (DFG).