Association of clinical properties and compatibility of the QuantiFERON-TB Gold In-Tube test with the tuberculin skin test in patients with psoriasis.
BACKGROUND
Individuals with psoriasis show conflicting responses to the tuberculin skin test (TST), a commonly used screening test for latent tuberculosis infection. An alternative to TST is QuantiFERON-TB Gold In-Tube test (QFT-GIT), an in vitro interferon-gamma release assay. This study aimed to determine the effect of the clinical properties of psoriasis (disease severity and koebnerization status) on TST results and the agreement between the TST and QFT-GIT results in psoriatic patients.


METHODS
One hundred patients with mild to severe psoriasis were enrolled in this prospective cross-sectional study. Psoriasis properties, including disease severity (psoriasis area and severity index score and koebnerization status), latent tuberculosis infection risk factors, and bacillus Calmette-Guérin vaccination history, were recorded. All patients underwent a TST and QFT-GIT. TST positivity cut-off point was ≥10 mm for bacillus Calmette-Guérin-vaccinated patients and ≥5 mm for non-vaccinated patients.


RESULTS
Psoriasis area and severity index scores and koebnerization status did not correlate with TST diameters. Only one of the 23 koebnerization-positive patients developed koebnerization in response to TST. QFT-GIT positivity was prominently higher in the TST-positive group, and this was the only factor that differed between the TST-positive and TST-negative groups (P < 0.001).


CONCLUSIONS
Tuberculin skin test results were not affected by psoriasis severity or koebnerization status. QFT-GIT positivity was prominently higher in the TST-positive group (P < 0.001). Overall agreement between TST and QFT-GIT results was moderate (κ = 0.413). Concurrent negativity (44%) was higher than concurrent positivity (27%).
Department of Dermatology and Venereology, Ankara Education and Training Hospital, Ankara, Turkey.
Arzu
A
Karataş Toğral
Department of Dermatology and Venereology, Ankara Education and Training Hospital, Ankara, Turkey.
Özgül
Ö
Muştu Koryürek
Department of Dermatology and Venereology, Ankara Education and Training Hospital, Ankara, Turkey.
Muzaffer
M
Şahin
Department of Infectious Diseases, Ankara Education and Training Hospital, Ankara, Turkey.
Cemal
C
Bulut
Department of Microbiology, Ankara Education and Training Hospital, Ankara, Turkey.
Server
S
Yağci
Department of Dermatology and Venereology, Ankara Education and Training Hospital, Ankara, Turkey.
Hatice Meral
HM
Ekşioğlu
D000293:Adolescent; D000328:Adult; D000368:Aged; D001500:BCG Vaccine; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D059425:Interferon-gamma Release Tests; D055985:Latent Tuberculosis / Q000150:complications / Q000175:diagnosis* / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011565:Psoriasis / Q000150:complications / Q000473:pathology*; D012372:ROC Curve; D015203:Reproducibility of Results; D012307:Risk Factors; D012720:Severity of Illness Index; D014374:Tuberculin Test; D014611:Vaccination; D055815:Young Adult
D001500:BCG Vaccine