In inflamed joints of rheumatoid arthritis (RA), ∼10% of effector memory CD4+ alpha/beta T cells produce CXCL13 without the expression of IFN‐γ, IL‐4, IL‐17, or B‐cell lymphoma 6 (BCL6) and express low levels of CXCR5 and ICOS 9, 10. The gene discussed is IL4; the disease is rheumatoid arthritis.