TY - JOUR
T1 - The complexity of diagnosing latent tuberculosis infection in older adults in long-term care facilities
AU - Hochberg, Natasha S.
AU - Rekhtman, Sergey
AU - Burns, Julianne
AU - Ganley-Leal, Lisa
AU - Helbig, Sina
AU - Watts, Nathaniel S.
AU - Brandeis, Gary H.
AU - Ellner, Jerrold J.
AU - Horsburgh, C. Robert
PY - 2016/3/1
Y1 - 2016/3/1
N2 - Objectives: In the USA, tuberculosis disease rates are highest in older adults. Diagnostic testing for latent tuberculosis infection (LTBI) has not been evaluated carefully in this group. The aim of this study was to define the relationship between tuberculin skin test (TST) results, T-SPOT.TB results, and T-cell responses to Mycobacterium tuberculosis antigens. Methods: Long-term care facility residents with known prior TST results (positive or negative) were retested with TSTs and T-SPOT.TB. Prior exposure to M. tuberculosis was assessed by quantifying T-cell activation to mycobacterial antigens in vitro. Results: The median age of the 37 participants was 77 years (range 57-98 years). Among 18 participants with a prior positive TST, three (16.7%) had a negative TST when retested (TST reversion); two had a negative T-SPOT.TB. Of the 15 who were historically and currently TST-positive, four (26.7%) had a negative T-SPOT.TB and one (6.7%) had a borderline result. Percentages of CD4+ T-cells responding to mycobacterial antigens were higher in participants with positive TST and T-SPOT.TB (18.2%) compared to those with a positive TST but negative T-SPOT.TB (6.4%, p = 0.16) and negative TST and T-SPOT.TB (5.9%, p <0.001). Conclusions: LTBI testing in older adults is complicated by TST reversion and TST-positive/T-SPOT.TB-negative discordance, which may reflect clearance of infection or waning immunity.
AB - Objectives: In the USA, tuberculosis disease rates are highest in older adults. Diagnostic testing for latent tuberculosis infection (LTBI) has not been evaluated carefully in this group. The aim of this study was to define the relationship between tuberculin skin test (TST) results, T-SPOT.TB results, and T-cell responses to Mycobacterium tuberculosis antigens. Methods: Long-term care facility residents with known prior TST results (positive or negative) were retested with TSTs and T-SPOT.TB. Prior exposure to M. tuberculosis was assessed by quantifying T-cell activation to mycobacterial antigens in vitro. Results: The median age of the 37 participants was 77 years (range 57-98 years). Among 18 participants with a prior positive TST, three (16.7%) had a negative TST when retested (TST reversion); two had a negative T-SPOT.TB. Of the 15 who were historically and currently TST-positive, four (26.7%) had a negative T-SPOT.TB and one (6.7%) had a borderline result. Percentages of CD4+ T-cells responding to mycobacterial antigens were higher in participants with positive TST and T-SPOT.TB (18.2%) compared to those with a positive TST but negative T-SPOT.TB (6.4%, p = 0.16) and negative TST and T-SPOT.TB (5.9%, p <0.001). Conclusions: LTBI testing in older adults is complicated by TST reversion and TST-positive/T-SPOT.TB-negative discordance, which may reflect clearance of infection or waning immunity.
KW - Interferon-gamma release assays
KW - Latent tuberculosis
KW - Long-term care facility
KW - Nursing homes
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U2 - 10.1016/j.ijid.2016.01.007
DO - 10.1016/j.ijid.2016.01.007
M3 - Article
AN - SCOPUS:84958535015
SN - 1201-9712
VL - 44
SP - 37
EP - 43
JO - International Journal of Infectious Diseases
JF - International Journal of Infectious Diseases
ER -