Circulating TNF-α, TGF-β, and IL-10 in tuberculosis patients and healthy contacts

Levels of tumour necrosis factor (TNF)-α, transforming growth factor (TGF)-β, and interleukin (IL)-10 in plasma of pulmonary tuberculosis (TB) patients and healthy contacts and plasma and pleural fluid of patients with tuberculous pleuritis were examined by enzyme immunoassay. Plasma TNF-α and IL-10 were elevated to significant levels in healthy contacts. High levels of TGF-β and IL-10 were also detected in plasma from TB patients and healthy contacts. Pleural fluid contained all three cytokines with the level of IL-10 being highest followed by TGF-β and TNF-α. Plasma of tuberculous pleuritis patients also had detectable levels of the three cytokines. Increased levels of TNF-α in plasma of contacts and to some extent pleural fluid of pleuritis patients, is perhaps to limit the infection, while elevated IL-10 in plasma of TB patients and contacts and pleural fluid would perhaps modulate excess proinflammation. Elevated TGF-β in TB patients suggests its role in the immunopathogenesis.