IL6 and bacterial infectious disease: Other anti-cytokine autoantibodies, such as anti-IL-2 autoantibodies, have been found in human immunodeficiency virus (HIV)-infected patients (14); anti-G-CSF autoantibodies were identified in Felty’s syndrome (FS), in which neutropenia is associated with bacterial infections (15); and anti-IL-6 autoantibodies have been confirmed to be associated with severe bacterial infections, including Escherichia coli, Streptococcus intermedius, and Staphylococcus aureusinfections (14).