Evaluation of Tuberculosis Activity in Patients with Anthracofibrosis by Use of Serum Levels of IL-2 $sR{\alpha}$, IFN-${\gamma}$ and TBGL(Tuberculous Glycolipid) Antibody

Anthracofibrosis의 결핵활동성 지표로서 혈청 IL-2 $sR{\alpha}$, IFN-${\gamma}$, 그리고 TBGL(tuberculous glycolipid) antibody 측정의 의의

Background : Anthracofibrosis, a descriptive term for multiple black pigmentation with fibrosis on bronchoscopic examination, has a close relationship with active tuberculosis (TB). However, TB activity is determined in the later stage by the TB culture results in some cases of anthracofibrosis. Therefore, it is necessary to identify early markers of TB activity in anthracofibrosis. There have been several reports investigating the serum levels of IL-2 $sR{\alpha}$, IFN-${\gamma}$ and TBGL antibody for the evaluation of TB activity. In the present study, we tried to measure the above mentioned serologic markers for the evaluation of TB activity in patients with anthracofibrosis. Methods : Anthracofibrosis was defined when there was deep pigmentation (in more than two lobar bronchi) and fibrotic stenosis of the bronchi on bronchoscopic examination. The serum of patients with anthracofibrosis was collected and stored under refrigeration before the start of anti-TB medication. The serum of healthy volunteers (N=16), patients with active TB prior to (N=22), and after (N=13), 6 month-medication was also collected and stored. Serum IL-2 $sR{\alpha}$, IFN-${\gamma}$ were measured with ELISA kit (R&D system, USA) and serum TBGL antibody was measured with TBGL EIA kit (Kyowa Inc, Japan). Results : Serum levels of IL-2 $sR{\alpha}$ in healthy volunteers, active TB patients before and after medication, and patients with anthracofibrosis were $640{\pm}174$, $1,611{\pm}2,423$, $953{\pm}562$, and $863{\pm}401$ pg/ml, respectively. The Serum IFN-${\gamma}$ levels were 0, $8.16{\pm}17.34$, $0.70{\pm}2.53$, and $2.33{\pm}6.67$ pg/ml, and TBGL antibody levels were $0.83{\pm}0.80$, $5.91{\pm}6.71$, $6.86{\pm}6.85$, and $3.22{\pm}2.59$ U/ml, respectively. The serum level of TBGL antibody was lower than of other groups (p<0.05). There was no significant difference of serum IL-2 $sR{\alpha}$ and IFN-${\gamma}$ levels among the four groups. Conclusion : The serum levels of IL-2 $sR{\alpha}$, IFN-${\gamma}$ and TBGL antibody were not useful in the evaluation of TB activity in patients with anthracofibrosis. More useful ways need to be developed for the differentiation of active TB in patients with anthracofibrosis.

연구배경 : 기관지내시경에서 관찰되는 anthracofibrosis가 활동성결핵과 연관이 있다는 보고가 있으나, 관찰 당시에 결핵의 활동성 여부가 확실하지 않아서 항결핵치료 시행여부를 결정하기 어려운 경우가 있다. 본 연구에서는 결핵의 활동성과 연관이 높은 IL-2 $sR{\alpha}$, IFN-${\gamma}$의 혈청 농도와 결핵의 혈청진단방법인 TBGL 항체의 농도가 anthracofibrosis 환자에서 결핵의 활동성 여부를 진단하는데 도움이 되는지를 알아보고자 하였다. 방 법 : 건강한 자원자(16명), 활동성결핵으로 진단되어 투약하기 직전의 환자(22명), 활동성결핵으로 진단되고 6개월간 항결핵제 투여를 마친 환자(13명), 그리고 anthracofibrosis 환자(15명)에서 혈청을 채취한 뒤, IL-2 $sR{\alpha}$, IFN-${\gamma}$ 그리고 TBGL 항체의 농도를 ELISA 방법으로 측정하였다. 결 과 : 건강한 자원자, 결핵치료전 환자, 결핵치료후 환자, 그리고 anthracofibrosis 환자의 IL-2 $sR{\alpha}$는 각각 $640{\pm}174$, $1,611{\pm}2,423$, $953{\pm}562$, $863{\pm}401$ pg/ml, IFN-${\gamma}$의 농도는 각각 0, $8.16{\pm}17.34$, $0.70{\pm}2.53$, $2.33{\pm}6.67$ pg/ml, 그리고 TBGL 항체 농도는 각각 $0.83{\pm}0.80$, $5.91{\pm}6.71$, $6.86{\pm}6.85$, $3.22{\pm}2.59$ U/ml였다. TBGL 항체 농도만이 건강한 자원자에서 다른 군에 비해 낮았을 뿐(p<0.05) IL-2 $sR{\alpha}$와 IFN-${\gamma}$ 농도는 네 군 사이에 차이가 없었다. Anthracofibrosis 환자 중에서 나중에 활동성 결핵으로 진단된 6명과 나머지 9명 사이에서도 상기한 지표의 농도 차이는 관찰되지 않았다. 결 론 : 1) Anthracofibrosis 환자의 40%에서 활동성 결핵이 동반되었다. 2) 혈청 IL-2 $sR{\alpha}$, IFN-${\gamma}$ 그리고 TBGL 항체 농도는 anthracofibrosis에서 결핵의 활동성 지표로 유용하지 않았다. 3) 혈청 TBGL 항체 농도는 건강한 자원자와 나머지 군 사이에 유의한 차이를 보였다.