Delayed tuberculin reactivity in persons of Indochinese origin: implications for preventive therapy
Department of Quantitative Health Sciences
Medical Subject Headings
Adult; Aged; Cross-Sectional Studies; Female; Humans; Hypersensitivity, Delayed; Lymphocyte Activation; Male; Middle Aged; Radiography, Thoracic; Refugees; Risk Factors; *Tuberculin Test; Tuberculosis; Vietnam
Bioinformatics | Biostatistics | Epidemiology | Health Services Research
OBJECTIVES: To 1) study a variant delayed reaction to tuberculin testing as a way to enhance screening for tuberculosis among high-risk persons and 2) correlate the delayed reaction with lymphocyte blastogenesis.
DESIGN: Cross-sectional study.
SETTING: 2 public health department clinics in North Carolina. Participants: 121 adults who had recently emigrated from Vietnam to North Carolina and who were ethnic Vietnamese and ethnic Dega, a minority population group from the central highlands region of Vietnam.
MEASUREMENTS: Medical history, physical examination, laboratory evaluation, and standard purified protein derivative (PPD) testing (Mantoux method). Skin test results were read at 72 hours and again at 6 days. Variant reactivity was defined as induration of less than 10 mm at 72 hours that, when reassessed at 6 days, had increased in size to 10 mm or greater. Persons with negative (n=54) and variant (n=32) PPD results also had booster testing at 10 to 12 weeks. Serum samples were obtained from 57 participants for lymphocyte blastogenesis studies.
RESULTS: 26% of participants had variant tuberculin reactivity. Variant reactivity was strongly associated with booster positivity: Sixty-five percent of persons with variant PPD results had booster positivity compared with 16% of persons with negative PPD results (P<0.001). The lymphocyte blastogenesis response of persons with variant PPD results was between the response of persons with negative PPD results and that of persons with positive PPD results.
CONCLUSION: Variant reactivity in this high-risk group was a predictor of booster positivity. Together with the blastogenic response pattern, this association strongly suggests that variant reactivity has a high positive predictive value for tuberculous infection. Clinicians should incorporate these findings into their approach for choosing candidates for preventive therapy.
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Citation: Ann Intern Med. 1996 May 1;124(9):779-84.
Robertson, John M.; Burtt, Dawn S.; Edmonds, Kay L.; Molina, Paul L.; Kiefe, Catarina I.; and Ellner, Jerrold J., "Delayed tuberculin reactivity in persons of Indochinese origin: implications for preventive therapy" (1996). Quantitative Health Sciences Publications and Presentations. 150.