This high frequency of 9G4+ B cells in some of the HIV patients may result from measuring both the B cells actually expressing VH4-34-encoded BCR, and also the indirect binding of the 9G4 reagent to serum VH4-34-encoded autoreactive antibody bound to B220 on the B cell, as previously described in SLE patients and not HC subjects [21], [26] and heretofore referred to as painting. This evidence concerns the gene PTPRC and systemic lupus erythematosus.