Inclusion Criteria:

• * Signed informed consent must be obtained before any assessment is performed.
• * Male and female patients aged 18 years to 70 years (inclusive).
• * Body weight at least 35 kg and not more than 150 kg and must have a body mass index (BMI) within the range of 18 - 35 kg/m2. BMI = Body weight (kg) / \[Height (m)\]2 at screening.
• * Diagnosed with RA, SjD and/or SLE as determined by the investigator.
• * Have active disease (RA, SjD or SLE) that may benefit from B-cell depletion therapy, as determined by the investigator.
• * Participants currently receiving protocol-allowed SoC should be on stable doses of SoC medications for 4 weeks prior to first dosing of study treatment.
• * Ability to communicate well with the investigator, understand and agree to comply with the requirements of the study.

Exclusion Criteria:

• * Use of prohibited therapies.
• * Active viral, bacterial or other infections requiring systemic treatment at the time of screening or baseline or history of recurrent clinically significant infection.
• * Plans for administration of live vaccines during the study period.
• * Uncontrolled co-existing serious disease.
• * Pregnant or nursing (lactating) women.
• * Women of child-bearing potential (WOCBP), defined as all women physiologically capable of becoming pregnant, refusing or unable to use highly effective methods of contraception while on study treatment and for 6 months after stopping of study drug.
• * US (and other countries, if locally required): sexually active males unless using barrier protection during intercourse with women of child-bearing potential while taking study treatment.
• Other protocol-defined inclusion/exclusion criteria may apply.