CD19 and polycystic ovary syndrome: We also quantified TNF-α expression in B cells after stimulation with B cell-targeted activator (CpG, CD40L plus anti-IgM/IgA/IgG) by flow cytometry and found that the percentage of TNF-α+ cells in CD19+ B cells was notably higher in women with PCOS than that in control subjects (Figure 1C).