Single cell Ig VDJ sequencing (10X Genomics) of human blood B cells from SLE pateints and healthy controls

B cells positive for Ig kappa and Ig lambda are observed by flow cytometry in one fourth of patients with Systemic Lupus Erythematosus (SLE). Single cell Ig VDJ sequencing (10X Genomics) reveals that kappa/lambda B cells are at the same frequency (about 1.5%) in these SLE patients as in healthy controls. Cells observed by flow cytometry are instead decorated with VH4-34 IgM (kappa or lambda) autoantibodies that are present in some but not all SLE patients. B cells were enriched by magnetic cell sorting from PBMCs of 3 SLE adult patients (ABA-07; ABA-15; ABA-19) and 3 healthy controls (ABCtr-07; ABCtr-15; ABCtr-19); cells were processed for Ig VDJ libraries (10X Genomics).