Inverse correlation between serum complement component C1q levels and whole blood type-1 interferon signature in active tuberculosis and QuantiFERON-positive uveitis: implications for diagnosis.

Serum C1q is elevated in APTB, especially in those cases with uveitis. We propose that combined measurement of blood type-1 IFN signature and serum C1q may provide added value in the diagnosis of active TB disease. Combined measurement of type-1 IFN signature and serum C1q in QFT+ patients without signs of active TB disease, but suffering from uveitis of unknown cause, may be of help to identify cases with low or high likelihood of having active TB uveitis, which may facilitate clinical management decisions.