Latent tuberculosis screening before kidney transplantation in the South of Brazil

Abstract Background: Tuberculosis (TB) is a prevalent infection after kidney transplantation (KT) in high-burden countries. Latent tuberculosis infection (LTBI) screening includes previous TB history, chest radiograph findings, and tuberculin test (TST) and/or interferon-gamma release assays (IGRAs) results. We aimed to compare our routine LTBI screening of KT candidates and living donors (LD) with their IGRA results, and evaluate if this would improve isoniazid (INH) treatment referral. Methods: We evaluated adult KT candidates and LD with complete routine LTBI screening and QuantiFERON-TB® Gold In-Tube (QFT) testing. Blood samples were collected from April 4th, 2014 to October 31st, 2018, with follow-up until October 31st, 2019. Results: There were 116 KT recipients, with 30% QFT-positive results. Positive QFT was associated with past TB history (p=0.007), positive TST (p<0.0001), residual radiographic lesions (p=0.003), and diabetes (p=0.035). There were 25 LD, 40% had positive QFT. Positive QFT was associated with a positive TST (p=0.002). Positive QFT results increased INH referral in 80%. Post-transplant TB incidence was 2.6% in a median follow-up of 2 (1-33) months. No variables were associated with post-transplant TB. TB patients had inferior, although non-significant, 5-year graft survival (66.7% vs. 76.5%) (p = 0.402). Conclusion: In the present study, the association of QFT to our routine LTBI screening incremented INH treatment referral, but there was still a high incidence of post-transplant TB, possibly related to other forms of infection, such as new exposure and donor transmission.

【背景】在结核病高负担国家，结核（Tuberculosis, TB）是肾移植（Kidney Transplantation, KT）术后常见感染性疾病。潜伏性结核感染（Latent Tuberculosis Infection, LTBI）筛查通常涵盖既往结核病史、胸部影像学表现、结核菌素皮肤试验（Tuberculin Skin Test, TST）及/或γ干扰素释放试验（Interferon-Gamma Release Assays, IGRAs）结果。本研究旨在对比肾移植候选者与活体供者（Living Donor, LD）的常规LTBI筛查方案与其γ干扰素释放试验结果，并评估该方案是否可提升异烟肼（Isoniazid, INH）预防性治疗的转诊率。

【方法】本研究纳入完成全套常规LTBI筛查并接受QuantiFERON-TB® Gold In-Tube（QFT）检测的成年肾移植候选者及活体供者。血液样本采集时间为2014年4月4日至2018年10月31日，随访截止至2019年10月31日。

【结果】本研究共纳入116例肾移植受者，其中30%的QFT检测结果呈阳性。QFT阳性结果与既往结核病史（P=0.007）、TST阳性（P<0.0001）、残留影像学病灶（P=0.003）及糖尿病（P=0.035）显著相关。共纳入25例活体供者，其中40%的QFT检测结果呈阳性；该人群中QFT阳性仅与TST阳性显著相关（P=0.002）。将QFT检测纳入常规LTBI筛查后，异烟肼预防性治疗的转诊率提升了80%。中位随访2（1~33）个月期间，肾移植术后结核发生率为2.6%。未发现任何变量与肾移植术后结核发生相关。结核感染者的5年移植物存活率略低于未感染者（66.7% vs. 76.5%），但差异无统计学意义（P=0.402）。

【结论】本研究表明，将QFT检测纳入常规LTBI筛查可提升异烟肼预防性治疗的转诊率，但肾移植术后结核发生率仍处于较高水平，这可能与其他感染途径相关，例如新发结核暴露及供体传播。