ROCHESTER, N.Y., Jan. 28 (UPI) -- U.S. scientists have determined some drugs used to treat rheumatoid arthritis have profound, previously unrecognized positive effects on the immune system.

University of Rochester Medical Center researchers said they found drugs known as anti-tumor necrosis factor, or TNF, compounds -- including Enbrel, Humira and Remicade -- help eliminate abnormal cell activity in patients, raising the possibility the drugs improve health in a way no one has realized.

Dr. Ignacio Sanz and Dr. Jennifer Anolik found anti-TNF drugs disrupt the architecture of lymph system structures called germinal centers that produce "B cells" -- lymphocytes that help destroy bacteria and viruses.

In healthy people, once an infection is resolved, the germinal centers disappear. But in people with chronic autoimmune diseases such as rheumatoid arthritis or lupus, germinal centers persist and produce immune cells that wreak havoc by mistakenly attacking healthy tissues.

Anolik said he now will compare how two different anti-TNF compounds affect B cells in rheumatoid arthritis patients. The results could help explain why some patients respond well to some medications, while other patients do not.

The study is reported in the Journal of Immunology.

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