This is an investigator-initiated, open-label, single-arm, dose-escalation and dose-expansion study to evaluate the safety, tolerability, PK, PD, and preliminary efficacy of MTM-H-001 in adult participants with B-cell-related autoimmune diseases.

Inclusion Criteria:

• Key inclusion criteria include：

  1. Male or female, aged 18 - 75 years old (inclusive);
  2. The participant or his/her legally acceptable representative gives consent to this clinical study participation and signs an Informed Consent Form (ICF) indicating their understanding of the objectives and procedures of the clinical study and willingness to participate in the study;
  3. Confirmed diagnosis of the target autoimmune disease per international classification criteria;
  4. Adequate organ function to tolerate treatment;
  5. Women of childbearing potential (WOCBP) must have a negative serum pregnancy test at screening and agree to use at least one effective contraceptive method throughout the study and within 6 months after the last treatment cycle.

Exclusion Criteria:

• Key exclusion criteria include:

  1. Active, severe, uncontrolled infection;
  2. Pregnancy or breastfeeding women;
  3. History of malignancy within the protocol-defined period, except adequately treated low-risk cancers;
  4. Any condition that, in the investigator's opinion, would compromise safety, compliance, or interpretability of study data.