Table 2.
IFN- γ ELISpot assay results during anti tuberculous treatment in HIV-infected children
| Antigen | Baseline | 1 month | 2 months | 6 months | |
|---|---|---|---|---|---|
| ESAT-6 (n = 15)* | |||||
| Median (IQR) IFN-γ response (SFCs/106 PBMC) | 110 (65-305) | 55 (20-267) | 35 (25-95) | 15 (10-115) | p = 0.04† |
| No (%) children with a positive ELISpot result | 15 (100) | 9/13 (69) | 13/15 (87) | 5/11 (45) | p = 0.006ϕ |
| No (%) children with a reduced IFN- γ response compared to baseline | 11/13 (85) | 12/15 (80) | 7/11 (64) | NA | |
| CFP-10 (n = 22)* | |||||
| Median (IQR) IFN-γ response (SFCs/106 PBMC) | 177 (48-508) | 185 (15-500) | 40 (27-327) | 20 (5-165) | p = 0.004† |
| No (%) children with a positive ELISpot result | 22 (100) | 13/19 (68) | 17/21 (81) | 8/17 (47) | p = 0.001ϕ |
| No (%) children with a reduced IFN-γ response compared to baseline | 11/19 (55) | 16/21 (76) | 14/17 (82) | NA | |
| ESAT-6 or CFP-10 (n = 22)* | |||||
| Median (IQR) IFN-γ response (highest response to either) | 250 (94-508) | 190 (20-500) | 95 (10-115) | 25 (10-165) | p = 0.004† |
| No (%) children with a positive ELISpot result | 22 (100) | 14/19 (74) | 19/21 (90) | 9/17 (53) | p = 0.002ϕ |
| No (%) children with a reduced IFN-γ response to either antigen compared to baseline | 14/19 (74) | 16/21 (76) | 14/17 (82) | NA | |
| PPD (n = 14)* | |||||
| Median (IQR) IFN-γ response | 155 (82-307) | 185 (27-242) | 177 (55-893) | 515 (45-1010) | p = 0.12† |
| No (%) children with a positive ELISpot result | 14 (100) | 10/13 (77) | 12 (86) | 10/11(91) | p = 0.56ϕ |
| No (%) children with a reduced IFN-γ response compared to baseline | 6/13 (46) | 7/14 (50) | 1/11 (9) | NA | |
* Children with definite TB or probable TB who had a positive IFN-γ ELISpot at presentation
† p value indicates difference in magnitude of the IFN-γ ELISpot responses at baseline vs. 6 months (Mann Whitney U test)
ϕ p value indicates difference in the proportion of children with a positive IFN-γ ELISpot assay (Chi Square test)