The main objective of this study, Part 1, is to evaluate the safety characteristics of ADI-001 in three types of patients and determine its MTD/MAD to provide a basis for subsequent dose expansion studies (Part 2). Part 2: Aims to further characterize the safety characteristics of ADI-001 at the MTD/MAD levels determined in Part 1 in subjects with LN and SLE with extrarenal involvement (Cohort 1), SSc subjects (Cohort 2), and AAV subjects (Cohort 3), and confirm the RP2D of subsequent studies. Secondary objectives include: evaluating the cell dynamics of ADI-001 in each cohort, determining the preliminary efficacy in each cohort, evaluating the host B cell dynamics after ADI-001 administration in Cohort 1, and evaluating the dynamics of other host immune cells after ADI-001 administration. Exploratory studies are intended to: evaluate the relationship between pharmacodynamic biomarkers and toxicity and response; evaluate the association of safety biomarkers with dose and/or response; and evaluate the immunogenicity of ADI-001. Responses were assessed according to SLEDAI-2K and DORIS criteria in cohort 1; other efficacy measures of ADI-001 in SSc and AAV were characterized in cohorts 2 and 3.

1. Primary Objective: To evaluate the safety and tolerability of ADI-001 infusions in subjects with moderately to severely active, refractory rheumatoid arthritis (RA). 2. Secondary Objectives: To compare the degree of B cell depletion and the cellular kinetics of ADI-001 in RA subjects who received a lymphodepletion (LD) conditioning regimen of Cy + Flu or Cy alone prior to ADI-001 administration. Furthermore, to evaluate the efficacy of ADI-001 infusions in refractory RA not taking disease-modifying antirheumatic drugs (DMARDs). 3. Exploratory Objectives: To assess the relationship between pharmacodynamic biomarkers and toxicity and reactions, the immunogenicity of ADI-001, and the durability of remission achieved after ADI-001 infusions in refractory RA subjects not taking DMARDs.