Is schizophrenia caused by excessive production of interleukin-2 and interleukin-2 receptors by gastrointestinal lymphocytes?

Excessive production of interleukin-2 (IL-2) and IL-2 receptors (IL-2R) by gastrointestinal (GI) T-lymphocytes is hypothesized as the cause of schizophrenia. It is based on: 1) IL-2 given to human volunteers can cause all the symptoms of schizophrenia; 2) GI lymphocytes in nonhuman primates produce much more IL-2 and IL-2R when stimulated than peripheral blood lymphocytes; 3) the GI tract is the largest lymphoid 'organ' in the body. The hypothesis appears to: 1) explain the protective effect of rheumatoid arthritis on schizophrenia; 2) make mechanistically plausible the findings on wheat and schizophrenia; 3) be consistent with and explain many of the known immunological abnormalities in schizophrenia.