BioScience Trends. 2014;8(3):163-168. (DOI: 10.5582/ bst.2014.01032)

Relationship between T-SPOT.TB responses and numbers of circulating CD4+ T-cells in HIV infected patients with active tuberculosis.

Cai RT, Chen J, Guan LQ, Sun MY, Sun Y, Shen YZ, Zhang RF, Liu L, Lu HZ

This study sought to evaluate the performance of the T-SPOT.TB assay for the diagnosis of active tuberculosis (TB) in human immunodeficiency virus (HIV) infected patients. One hundred confirmed HIV-infected patients with active TB and known T-SPOT.TB and CD4+ T-cell counts were enrolled in this clinical retrospective study. We found that patients with lower CD4+ T-cell counts (11-50 cells/μL) had the lowest T-SPOT.TB positive rates (50%), and patients with higher CD4+ T-cell counts (50-100 cells/μL) had the highest T-SPOT.TB positive rates (75%). However, there were no significant differences between the T-SPOT.TB positive rates of patients with different CD4+ T-cell counts (< 10, 11-50, 51-100 and > 100 cells/μL) (χ² = 3.7747, p = 0.287). The patients with positive TB culture results had significantly higher T-SPOT.TB positive rates (78.9%) than patients that were culture-negative (44.3%) (χ² = 12.8303, p < 0.001). Other variables, including gender, age, TB disease classification, HIV RNA level, and highly reactive antiretroviral therapy (HAART), had no significant effects on T-SPOT.TB positive rates. The number of spot-forming cells (SFCs) reactive with ESAT-6, CFP-10 and ESAT-6/CFP-10-specific T cells detected by T-SPOT.TB were positively correlated with the number of circulating CD4+ T-cells (r_s = 0.3791, p = 0.0001; r_s = 0.2929, p = 0.0031; r_s = 0.3345, p = 0.0007, respectively). This study suggests that the number of SFCs is strongly related to the degree of immunodeficiency, while the T-SPOT.TB positive rates are less dependent on the level of CD4+ T-cell depletion in HIV infection and active TB.

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