Sequential Immune Modulation and Antigen-Specific Tolerance Induction for Disease Modification in Recent-Onset Type 1 Diabetes

Inclusion Criteria: * Age 18-45 years * Clinical diagnosis of Type 1 diabetes mellitus within 6 months of enrolment * Positive for at least one diabetes-related autoantibody (GAD65, IA-2, ZnT8, or IAA) * Detectable fasting or stimulated C-peptide ≥ 0.2 nmol/L * HbA1c ≤ 10% (86 mmol/mol) * Ability to provide written informed consent Exclusion Criteria: * Prior immunosuppressive therapy within 3 months * Active or chronic infection (HIV, hepatitis B/C, tuberculosis) * Current or prior malignancy within 5 years (except non-melanoma skin cancer) * Pregnancy or breastfeeding * Severe renal impairment (eGFR \< 30 mL/min/1.73m²) * Severe hepatic impairment (Child-Pugh C) * Known hypersensitivity to teplizumab or any excipient * Participation in another interventional trial within 30 days * Current systemic corticosteroid or immunomodulatory agent use * History of other autoimmune disease requiring immunosuppression * Absolute lymphocyte count \< 1.0 × 10⁹/L * ALT or AST \> 3× upper limit of normal * Haemoglobin \< 100 g/L * Unwillingness to use contraception during study period