Demographic characteristics of patients studied
| Variable | Study group | Control groups | ||
| TST and T-SPOT.TB negatives | TST and T-SPOT.TB positives | Microbiologically confirmed M. avium infection | ||
| Subjects | 21 | 11 | 10 | 6 |
| Sex | ||||
| Male | 10 (47.6) | 3 (27.3) | 6 (60) | 4 (66.7) |
| Female | 11 (52.4) | 8 (72.7) | 4 (40) | 2 (33.3) |
| Age yrs | 8.81±4.03 | 11.55±4.52 | 10±3.02 | 17.5±20.92 |
| BCG vaccinated | ||||
| Yes | 0 (0) | 5 (45.5) | 3 (30) | 0 (0) |
| No | 21 (100) | 6 (54.5) | 7 (70) | 6 (100) |
| Immunosupression | ||||
| Yes | 0 (0) | 0 (0) | 0 (0) | 0 (0) |
| No | 21 (100) | 11 (100) | 10 (100) | 6 (100) |
| Birth country | ||||
| Immigrants from countries with high prevalence of TB infection | 5 (23.8) | 6 (54.5) | 3(30) | 0 (0) |
| Residents in a non-epidemic TB country | 16 (76.2) | 5 (45.5) | 7 (70) | 6 (100) |
| Origin | ||||
| Contact tracing studies | 6 (28.6) | 8 (72.7) | 10 (100) | |
| Screening of LTBI at school | 15 (71.4) | 3 (27.3) | 0 (0) | |
| T-SPOT.TB | ||||
| Positive | 0 | 0 | 10 | 2# |
| Negative | 21 | 21 | 0 | 3 |
| Indeterminate | 0 | 0 | 0 | 1 |
| Ex vivo ELISPOT M. avium sensitin stimulation | ||||
| Positive | 10 | 0 | 5 | 4 |
| Negative | 6 | 11 | 3 | 1¶ |
| Indeterminate | 5 | 0 | 2 | 1 |
Data are presented as n, n (%) or mean±sd. TST: tuberculin skin test; M. avium: Mycobacterium avium; BCG: bacilli Calmette-Guérin; TB: tuberculosis; LTBI: latent TB infection. #: in one case, active TB was documented 8 yrs before; ¶: M. avium infection was reported 2 yrs before.