A study evaluated a cohort of patients with rheumatoid arthritis on anti-TNF therapy in Southern California and the rate of seroconversion to a positive TB test.30 Goel et al found the conversion rate to be elevated at 9.4% at a median time of 31 months on therapy and there were no known risk factors, though Hispanics were at a higher risk (75%) compared to non-Hispanic whites (25%). The gene discussed is TNF; the disease is rheumatoid arthritis.