2012 년 9 월 월례집담회 증례문제 풀이 여의도성모병원 진단검사의학과 임상강사 한상봉

증례 –F/51 –C.C : 건강검진상 발견된 고혈압과 단백뇨 (Dip stick 4+), 신기능이상 (Cr.: 1.5 mg/dL) 으로 입원 ( ) –4.21 Kidney Bx. : Congo red stain(+): apple-green birefringence  primary amyloidosis –4.26 serum & 24hr urine protein EP : M spike(+), serum & urine IFE : IgG, lambda type 의 monoclonal band –4.29 BM Bx. : Normocellular Marrow with Slightly Increased Plasma Cells (2.6%)

– 결핵균 특이항원 인터페론 - 감마 검사 (Quantiferon ® -TB Gold) 결핵감염 임상증상 (-), Chest X-ray : WNL  sputum AFB & culture, TB PCR 검사 시행 (X) – 치료 : Thalidomide/Dexamethasone 항암요법을 2 cycle 시행 – 결핵균 특이항원 인터페론 - 감마 검사에 대한 추적 검사 검사일자 NilTB AgMitogenTB Ag-NilMitogen-Nil 2011/5/ 약품명용량 및 용법투여기간 Thalidomide100mg po qd5/11 ~ 5/25, 6/8 ~ 6/13 Dexamethasone40mg IV5/12 ~ 5/14, 6/9 ~ 6/12 Aspirin100mg po qd 5/1 ~ 6/13 ( 계속 복용 ) Valsartan80mg po qd 5/1 ~ 6/13 ( 계속 복용 ) Atorvastatin10mg po qd 5/1 ~ 6/13 ( 계속 복용 ) Lansoprazole15mg po qd5/1 ~ 6/13 ( 계속 복용 ) 검사일자 NilTB AgMitogenTB Ag-NilMitogen-Nil 2011/6/

문제 1. 2 회에 걸쳐 시행된 이 환자의 Quantiferon ® -TB Gold 검사결과 를 해석하고 결과를 판정 (Negative/Indeterminate/Positive) 하시오. 만약 2 회의 검사결과에 차이가 있다면 그 원인은 무엇이겠는가 ? 문제 2. Quantiferon-TB Gold 를 포함한 interferon-gamma release assays (IGRAs) 에 영향을 미칠 수 있는 요인에 대해 고찰하시오.

Quantiferon ® -TB Gold In-Tube (QFT-GIT) –Principle Cell Mediated Immune (CMI) response test Latent or active TB infection 시 → Effector T-lymphocyte 가 MTB highly specific peptide Ag. 을 비롯한 여러 mycobacterial Ag. 에 감작됨 → QFT-GIT test : 감작된 Effector T-lymphocyte 를 MTB highly specific Ag. 으로 stimulation 시켜 IFN- Ƴ를 분비를 유도. → IFN- Ƴ를 검출

–MTB 의 highly specific peptide Ag. 종류 ① Early Secretory Antigenic Target-6 (ESAT-6) ② Culture Filtrate Protein-10 (CFP-10) ③ TB7.7 특징 –BCG vaccination 에 영향을 받지 않는다. –M. kansasii, M. szulgai, M. marinum 을 제외한 non tuberculosis mycobacteria 에 영향을 받지 않는다. –Induce IFN- Ƴ responses

–Procedure »Three collection tubes Nil tube : negative control 구성 : saline IFN- Ƴ, heterophile antibody effects, non specific IFN- Ƴ의 background level 을 측정 TB Antigen tube : test tube MTB highly specific peptide Ag. (ESAT-6, CFP-10, TB7.7) 가 포함 Mitogen tube : positive control Phytohemagglutinin : non-specific stimulator of T-cells. individual’s immune status 확인

Nil TB Antigen minus NilMitogen QFT [IU/mL] [IU/mL] minus Nil Result Report / Interpretation [IU/mL] ≤ 8.0 ≥ 0.35 and ≥ 25% of Nil valueAnyPositive 1 M. tuberculosis infection likely < 0.35 OR ≥ 0.35 and < 25% of Nil value ≥ 0.5Negative M. tuberculosis infection NOT likely < 0.5 Indeterminate Results are indeterminate for TB Antigen responsiveness > 8.0Any Guidelines for interpreting test result (recommended by CDC) 1 Where M. tuberculosis infection is not suspected, initially positive results can be confirmed by retesting the original plasma samples in duplicate in the QFT ELISA. if repeat testing of one or both replicates is positive, the test result is considered positive.

검사일자 NilTB AgMitogenTB Ag-NilMitogen-Nil 2011/5/ 검사일자 NilTB AgMitogenTB Ag-NilMitogen-Nil 2011/6/ Nil : 0.20 <8.0 TB Ag-Nil : 0.60 >0.35 and >0.05(25% of Nil)  Positive Nil : TB Ag-Nil : 0.04 <0.35  Negative

–Cut-off(0.35IU/mL) 주위 값의 변화 (cellestis FAQ) 검사 자체의 variability(<15% CV) 가 존재하기 때문에 infection status 가 변하지 않은 것으로 판단 Guidelines for interpreting test result : Where M. tuberculosis infection is not suspected, initially positive results can be confirmed by retesting the original plasma samples in duplicate in the QFT ELISA. 검사일자 NilTB AgMitogenTB Ag-NilMitogen-Nil 2011/5/

northern California households 의 63 명을 대상으로 3 개월 간격으로 두 번 방문 측정 결과 –QFT-GIT (+)  (-) : 5/15 (33%) –QFT-GIT (-)  (+) : 3/48 (6.3%) 8/63 (13%)

The Stanford Hospital and Clinics 에서 2011 년 11 월 10~20 일 사이의 QFT-GIT 양성률이 기존 평균인 10% 에서 31% 로 일시적 증가를 보임 (P<0.001, chi-squared test)

처음에 false-positive 결 과를 보인 81 명에 대해서 새 lot. 의 TB Ag tube 로 재검한 결과 91% 가 negative.  최근 tube 및 시약의 lot 변경여부 확인 및 최근 양성률 확인 필요

Cellestia FAQ –What is the attitude to a QFT positive response without information about a recent contact? Additionally, infections by other mycobacteria (eg. M. kansasii) can also potentially lead to positive results. –Incubation time 이 24h 을 넘어갈 경우, central memory T-cell 의 effector T-cell 로의 분화에 의해서 old/cured TB infection 이 있었던 환자에서 false-positive 가능

Quantiferon-TB Gold 를 포함한 interferon-gamma release assays (IGRAs) 에 영향을 미칠 수 있는 요인 –Indeterminate Low response to Mitogen (Mitogen-Nil<0.5 IU/mL) –Insufficient lymphocytes –reduced lymphocyte activity due to improper specimen handling, incorrect filling/mixing of the Mitogen tube –HIV infection, AIDS or immune suppressive treatment –may be transient  retesting the individual after a period of a few weeks

 High response to Nil (>8.0 IU/ml) -Longer than 16 hours from blood draw to incubation at 37 ℃ -Incomplete washing of the ELISA plate -Excessive levels of circulating IFN- Ƴ or presence of heterophile antibodies

PLoS One. 2011;6(8):e Epub 2011 Aug 19. Analysis of factors lowering sensitivity of interferon-γ release assay for tuberculosis. Hang NT, Lien LT, Kobayashi N, Shimbo T, Sakurada S, Thuong PH, Hong le T, Tam do B, Hijikata M, Matsushita I, Hung NV, Higuchi K, Harada N, Keicho N. NCGM-BMH Medical Collaboration Center, Hanoi, Viet Nam. PositiveNegativeIndeterminateP*P* n% (95% CI)n n All (n=504) (89.6–94.4)244.8 (3.1–7.0)153.0 (1.7–4.9) HIV positive (n=44) (45.5–75.6)511.4 (3.8–24.6) (15.0–42.8)<0.001 HIV negative (n=459) (92.8–97.0)194.1 (2.5–6.4)30.7 (0.1–1.9)

Allele nameNumber of alleles (% [95%CI])P*P* TotalIGRA positiveIGRA-negative 2n ‡ =1008 ‡2n=9302n=48 HLA-DRB (33.4 [30.5–36.4])318 (34.2 [31.1–37.3])11 (22.9 [12.0–37.3]) (12.8 [10.8–15.0])119 (12.8 [10.7–15.1])6 (12.5 [4.7–25.2])> (6.1 [4.7–7.7])44 (4.7 [3.5–6.3])11 (22.9 [12.0–37.3])< (5.9 [4.5–7.5])53 (5.7 [4.3–7.4])5 (10.4 [3.5–22.7]) (5.4 [4.0–6.9])49 (5.3 [3.9–6.9])4 (8.3 [2.3–20.0]) (5.3 [4.0–6.8])51 (5.5 [4.1–7.1])0 (0.0 [0.0–7.4]) (5.1 [3.8–6.6])49 (5.3 [3.9–6.9])2 (4.2 [0.5–14.3])>0.999 others264 (26.2 [23.5–29.0])247 (26.6 [23.7–29.5])9 (18.8 [8.9–32.6])0.312 HLA-DQB (38.0 [35.0–41.1])361 (38.8 [35.7–42.0])12 (25.0 [13.6–39.6]) (15.1 [12.9–17.4])138 (14.8 [12.6–17.3])9 (18.8 [8.9–32.6]) (9.3 [7.6–11.3])87 (9.4 [7.6–11.4])6 (12.5 [4.7–25.2]) (9.1 [7.4–11.1])74 (8.0 [6.3–9.9])12 (25.0 [13.6–39.6]) (8.0 [6.4–9.9])76 (8.2 [6.5–10.1])3 (6.3 [1.3–17.2])> (6.9 [5.5–8.7])68 (7.3 [5.7–9.2])0 (0.0 [0.0–7.4]) (4.2 [3.0–5.6])40 (4.3 [3.1–5.8])1 (2.1 [0.1–11.1])0.717 others94 (9.3 [7.6–11.3])86 (9.2 [7.5–11.3])5 (10.4 [3.5–22.7])0.797

Compared with the patients who had test-positive results, those with negative results were significantly –older (median age: 48.9 [IQR, 33.2–62.6] vs 39.0 [IQR, 29.1– 50.6], P=0.036) –lower BMI (median BMI: 16.6 [IQR, 13.9–17.9] vs 18.3 [16.9– 19.7] kg/m 2, P=0.0001)

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