A Study to Assess Adverse Events, How the Drug Moves Through the Body and Effectiveness of Intravenous Infusions of ABBV-319 in Adult Participants With Systemic Lupus Erythematosus (SLE), Sjogren's Disease (SjD) and Rheumatoid Arthritis (RA)

Inclusion Criteria: * Systemic Lupus Erythematosus (SLE) Population - Clinical diagnosis of SLE at least 6 months prior to Screening as defined by the 2019 European Alliance of Associations for Rheumatology (EULAR)/American College Of Rheumatology (ACR) classification criteria for SLE and a positive antinuclear antibody (ANA) \>= 1:80 drawn at Screening. * SLE Population - Anti-double stranded DNA (dsDNA), anti-Smith (Sm), anti-ribonucleoprotein (RNP), or anti-Sjogren's syndrome Ag A (SSA) Abs above the upper limit of normal (ULN). * Sjogren's Disease (SjD) Population - Primary diagnosis of SjD at least 6 months prior to Screening as defined by the ACR/EULAR 2016 Criteria. * SjD Population - EULAR Sjogren's Syndrome Disease Activity Index (ESSDAI) \>= 5 at Screening. * SjD Population - EULAR Sjogren's Syndrome Patient Reported Index (ESSPRI) \>= 5 at Screening. * Rheumatoid Arthritis (RA) Population - Clinical diagnosis of RA and fulfilling the 2010 ACR/EULAR classification criteria for RA. * RA Population - Rheumatoid Factor (RF) or ACPA above the ULN at Screening. * RA Population - Confirmation of at least moderate disease activity at Screening, defined by both of the following disease activity criteria: * Presence of at least 6 swollen and 6 tender joints at Screening using the 68 (tender)/66 (swollen) joint count. * hs-CRP ≥3 mg/L. Exclusion Criteria: * History of infection as defined in the protocol. * Any of the medical diseases or disorders listed in the protocol. * History of clinically significant (per investigator's judgment) drug or alcohol abuse within the 6 months prior to Screening. * Any planned elective surgery that would impact study procedures or assessments through the completion of the Day 365 assessments. * Any clinically significant ECG abnormalities at Screening. * RA-Specific Exclusion Criteria - History of RA overlap syndromes, including but not limited to, SLE, SjD, scleroderma, mixed connective tissue disease, or polymyositis.