An increase in circulating IgA has been found in TB patients, but also in sera from both patients with other infectious respiratory diseases and patients with rheumatic and auto-immune diseases and persistent infections [16-19] Thus, the detection of IgA may increase the sensitivity of the detection of pulmonary TB, but it may also be the cause of the false-positive results obtained in the group of non-TB patients. The gene discussed is CD79A; the disease is tuberculosis.