Diagnostic sensitivity and related impact factors of T cell spot test of tuberculosis in acquired immunodeficiency syndrome/tuberculosis patients / 中华传染病杂志

ABSTRACT

Objective To analyze the diagnostic sensitivity and related impact factors of T cell spot test of tuberculosis (T‐SPOT .TB ) test in acquired immunodeficiency syndrome (AIDS )/tuberculosis (TB) patients .Methods Ninety‐two confirmed cases with AIDS/TB coinfection were tested by T‐SPOT . TB ,and the impact of CD4+ T cells counts on the diagnostic sensitivity was analyzed .Multivariate Logistic analysis was used for the analysis of impact factors of T‐SPOT .TB sensitivity .Blood samples of 19 cases with advanced stage AIDS/TB from January 2015 to January 2016 were collected ,and peripheral blood mononuclear cell (PBMC ) were isolated by Ficoll method , and lymphocytes were isolated by Percoll method .McNemar test was used for the comparison of these two methods .Results Among the 92 patients with AIDS/TB ,T‐SPOT .TB tests were positive in 51 cases ,with positive rate of 55 .4% .The sensitivity was 26 .3% (10/38) when CD4+ T cell count less than 20/μL ,and that was 92 .9% (13/14) when CD4+ T cell more than 200/μL .In Logistic analysis ,the sensitivity of T‐SPOT .TB test in patients with extra‐pulmonary tuberculosis was better than that in pulmonary tuberculosis patients (OR=3 .042 , P=0 .038) .The sensitivity of T‐SPOT .TB was positively correlated with CD4+ T cell count ,and the sensitivity increased by 2 .889 times when CD4+ T cells increasing 100/μL (OR=3 .889 ,P=0 .016) .The percentage of lymphocytes in PBMC was also positively correlated with T‐SPOT .TB positivity ,and the sensitivity increased by 1 .393 times when the percentage increasing 30% (OR=2 .393 ,P=0 .045) .When Percoll was used for lymphocytes isolation ,the T‐SPOT .TB sensitivity was 52 .6% (10/19) ,and when Ficoll was used for PBMC isolation ,the sensitivity was 36 .8% (7/19) .The difference was not statistically significant (P=0 .375) .Conclusion The sensitivity of T‐SPOT .TB test based on lymphocytes is higher than that based on PBMC .