Abstract
We conducted a long-term follow-up study in patients with rheumatic diseases who were candidates for biologics treatment to evaluate the effects of biologic agents on the risk of tuberculosis infection and the effect of prophylactic treatment on tuberculosis activation. One hundred one patients with rheumatic diseases who were candidates for biologics treatment were recruited, and 57 healthy subjects were recruited as controls. Tuberculin skin test (TST) and the T-SPOT.TB test were performed for all subjects at baseline. Follow-up testing by the T-SPOT.TB assay was performed every 6 months in patients with rheumatic diseases and at 2 years of recruitment in the healthy controls. In patients with rheumatic diseases and healthy controls, the TST-positive (induration, ≥10 mm) rates were 37.6% (38/101) and 34.0% (18/53), respectively (P > 0.05), while the T-SPOT.TB-positive rates were 46.5% (47/101) and 21.1 (12/57), respectively (P = 0.0019). Fifty-two patients were followed up at month 6 with a T-SPOT.TB-positive rate of 40.4%, and 49 were followed up for ≥12 months with a T-SPOT.TB-positive rate of 36.7%, with no significant difference in the positive rate at different time points including baseline (P > 0.05). Long-term follow-up revealed that conversion to T-SPOT.TB positivity occurred only in the biologics treatment group, with a positive conversion rate of 11.2% (4/38). Most importantly, no latent tuberculosis developed into active tuberculosis during follow-up with T-SPOT.TB screening and preemptive treatment with isoniazid. Biologics treatment appears to increase the risk of tuberculosis infection. However, tuberculosis activation could be prevented by preemptive isoniazid treatment in patients with latent tuberculosis infection while receiving biologics therapy.