TLR4 and autoimmune disease: Recently, a study unexpectedly found increased TLR4 surface expression on monocytes and enhanced pro-inflammatory cytokine (IL-8 and TNF-α) release after TLR stimulation (TLR1/2 heterodimer, TLR2/6 heterodimer, TLR4 and TLR5) in patients with autoimmune disease who were being treated with immunosuppressive medications, compared with patients not receiving immunosuppressive agents [31].