This study will evaluate the safety and efficacy of MSC303 in patients with Immune glomerular diseases.

The primary endpoint of Phase Ib：Evaluate the safety of MSC303 in patients with Lupus Nephritis (LN）and ANCA-associated glomerulonephritis (ANCA-GN).

The primary endpoint of Phase II：Evaluate the change of Urine Protein/Creatinine Ratio (UPCR) in Week 12 compared with the baseline of MSC303 in patients with Lupus Nephritis(LN） and ANCA-associated glomerulonephritis (ANCA-GN).

Inclusion Criteria:

1. Aged 18 to 65 years (including boundary values), gender unspecified；

2. Willing to participate voluntarily in this clinical study and with good compliance；

3. Regarding the criteria for the study diseases, meet the diagnostic criteria for any of the following diseases:

   1. Diagnosed with lupus nephritis(LN);
   2. diagnosed with ANCA-associated glomerulonephritis (ANCA-GN);

4. Sufficient organ function;

Exclusion Criteria:

1. History of severe allergic reaction to humanized monoclonal antibodies, or known allergy to any component of MSC303；
2. Active infection requiring antibiotic treatment；
3. Concomitant with other serious diseases；
4. Patients with congenital immunoglobulin deficiency；
5. Infection with human immunodeficiency virus (Human immunodeficiency virus (HIV)), hepatitis B or hepatitis C (including HBsAg, HBcAb positive with abnormal Hepatitis B Virus DNA (HBV DNA) or Hepatitis C virus RNA (HCV RNA ));
6. Other exclusion criteria may apply.

Due to concerns regarding the security of patient personal information.