Background: Takayasu’s arteritis (TA) is a systemic vasculitis that primarily affects the aorta and major arteries. Despite aggressive treatment with glucocorticoids (GCs) and non-biological disease-modifying antirheumatic drugs (nbDMARDs), about 30% of patients experience resistance to therapy or relapse. This study aimed to identify risk factors associated with refractory and relapse TA in pediatric patients. Methods: A retrospective, open-label, case–control study was conducted with 56 pediatric patients with TA diagnosed between February 2011 and October 2022. Fourteen patients were excluded due to insufficient data in their medical records, leaving 42 for further analysis. The patients were divided into two groups: Group 1 (18 patients) with no evidence of relapse and Group 2 (24 patients) with relapse despite first-line treatment at the end of the follow-up period. Clinical, laboratory, and instrumental data were collected and analyzed using R v4.2 and Python v3.10. Results: The median time to relapse was 18 [IQR: 13; -] months according to the Kaplan–Meier curve. Patients with ITAS.A with a diagnosis of TA ≥ 12 had a higher probability of relapse, according to the log-rank criterion (p = 0.006). Symptoms of critical ischemia, such as limb claudication, were more common in Group 2 at diagnosis (p = 0.047), and a trend toward a longer diagnostic delay was observed (p = 0.067). Conclusions: Pediatric patients with an initial ITAS.A score above 12 have a higher risk of relapse when treated with a combination of GCs and nbDMARDs as first-line treatment. Further research is needed to identify high-risk patients more accurately and optimize therapeutic strategies.

Juvenile scleroderma (JS), comprising localized (JLSd) and systemic (JSSc) forms, is a rare autoimmune disorder. This study investigated associations of polymorphisms in extracellular matrix (MMP1, MMP9) and vascular homeostasis (NOS3) genes with JS risk and immunological phenotypes. A case–control study involved 215JS patients (194 JLSd, 21 JSSc) and 72 controls. SNPs (MMP1 rs1799750, MMP9 rs3918242, NOS3 rs1799983) were genotyped using real-time PCR followed by minisequencing and mass spectrometric analysis of reaction products. Associations with disease risk, subtypes, and immunological markers were analyzed statistically. The MMP9 (rs3918242) CT genotype was significantly associated with JLSd (OR = 2.23, 95% CI: 1.14–4.37, p = 0.022), showing a trend in linear facial forms. The NOS3 (rs1799983) GG genotype demonstrated a trend toward association with JSSc (OR = 2.61, 95% CI: 0.92–7.37, p = 0.065). No significant associations were found for rs1799750 MMP1 and risk of disease development. The MMP9 risk genotype did not correlate with scleroderma-specific autoantibodies, while the NOS3 GG genotype was associated with lower serum levels of anti-collagen IV antibodies (p = 0.039). Genetic associations differ for JS subtypes: MMP9 with JLSd and NOS3 with JSSc. Children with CT polymorphism MMP9 (rs3918242) and with NOS3 (rs1799983) GG genotype were found to be genetically predisposed for the development of JS.

Background/Objectives: Juvenile systemic sclerosis (jSSc) is a rare, chronic autoimmune disease with limited pediatric data. We aimed to characterize the demographic, clinical, immunological, and microvascular features of a Russian cohort of children with jSSc, and to evaluate treatment outcomes and predictors of escalation to biologic therapy. Methods: A retrospective single-center study of 40 children with jSSc (36 girls, 4 boys) followed over a 20-year period (2004–2024) was conducted. Clinical assessment included the modified Rodnan Skin Score (mRSS) and the Juvenile Systemic Sclerosis Severity Score (J4S). Nailfold capillaroscopy (NFC) was performed in 12 patients. Autoantibody profiling was available for 30 patients. Two first-line regimens were compared: glucocorticosteroids with penicillamine (PA, n = 19) versus glucocorticosteroids with DMARDs (methotrexate, mycophenolate mofetil, or cyclophosphamide; n = 21). Predictors of switching to biologic therapy were identified using binary logistic regression. Results: Median age at onset was 9.0 years (IQR 6.0–10.0), and diagnostic delay was 12.0 months (IQR 4.0–24.0). Diffuse cutaneous jSSc predominated (82.5%). Gastrointestinal involvement was detected in 82.5%, Raynaud’s phenomenon in 87.5%, and ILD in 37.5%. NFC revealed reduced capillary density (5.26 ± 1.33/mm). Giant capillaries were observed exclusively in males (4/4 vs. 0/8, p = 0.002). DMARD-based regimens were associated with better outcomes than PA, particularly for joint involvement. Eleven patients (27.5%) were switched to biologic therapy, primarily rituximab. ILD and J4S > 15 were the strongest predictors of switching (probability 60–61% vs. 8–15%, p < 0.001). The 5-year survival was 100%; the estimated 10-year survival was 71.4%, although the latter estimate should be interpreted cautiously because of the small number of events and loss to follow-up. Conclusions: In our cohort, children with jSSc present predominantly with diffuse cutaneous involvement. Male patients may be at risk for more severe microvascular changes, possibly related to diagnostic delay. ILD and J4S > 15 were associated with escalation to biologic therapy, and earlier switching to rituximab may be beneficial in refractory patients. Future prospective multicenter studies are needed to validate these findings.