Abstract:

Objective: To investigate the related factors influencing interferon-gamma release assay (IGRA) results in patients having coexistent tuberculosis and acquired immune deficiency syndrome (AIDS). Methods: We enrolled 268 patients with coexistent tuberculosis and AIDS admitted to The Fourth People’s Hospital of Nanning from January 1, 2020 to June 30, 2023, including 141 cases with positive IGRA results showing a positivity rate of 52.6%, and the other 127 IGRA-negative patients. Clinical data and factors affecting the IGRA test results in patients were analyzed by establishing a multivariable logistic regression model. Results: The rate of concurrent other opportunistic infections was 42.6% (60/141) among the positive group, lower than that of the negative group at 65.4% (83/127), with a statistically significant difference (χ²=13.958, P<0.001). The incidence of extra-pulmonary tuberculosis in the positive group was 24.8% (35/141), lower than that of the negative group at 37.8%, with a statistically significant difference (χ²=5.260, P=0.022). The incidence of shortness of breath was 24.8% (35/141), lower than that of the negative group at 36.2% (46/127), with a statistically significant difference (χ²=4.116, P=0.042). The incidence of superficial lymph node enlargement was 31.9% (45/141), higher than that of the negative group at 21.3% (27/127), with a statistically significant difference (χ²=3.861, P=0.049). The rate of lactate dehydrogenase (LDH) >250U/L was 47.7% (63/141), lower than that of the negative group at 63.5% (75/127), with a statistically significant difference (χ²=6.162, P=0.013). The rate of lymphocyte count <1.1×10⁹/L was 52.5% (74/141), lower than that of the negative group at 71.7% (91/127), with a statistically significant difference (χ²=10.379, P=0.001). The rate of CD4⁺ T cell count ≤50 cells/μl was 25.5% (36/141), lower than that of the negative group at 59.1% (75/127), with a statistically significant difference (χ²=30.948, P<0.001). The rate of CD8⁺ T cell count <350 cells/μl was 34.8%(49/141), lower than that of the negative group at 49.6% (63/127), with a statistically significant difference (χ²=6.061, P=0.014). Multivariable logistic regression analysis showed that the presence of superficial lymph node enlargement (OR (95%CI)=0.359 (0.181-0.712)) was an independent protective factor for negative IGRA results in patients with co-morbid tuberculosis and AIDS, while concurrent other opportunistic infections (OR (95%CI)=0.359 (0.181-0.712)), the presence of extrapulmonary tuberculosis (OR (95%CI)=2.080 (1.105-3.916)), and CD4⁺ T cell count ≤50 cells/μl (OR (95%CI)=2.957 (1.466-5.966)) were independent risk factors for negative IGRA results in patients having coexistent tuberculosis and AIDS. Conclusion: Among patients having coexistent tuberculosis and AIDS, the positive rate of IGRA is low. For those with low CD4⁺ T-cell counts, concurrent other opportunistic infections, or having extra-pulmonary tuberculosis, when IGRA test results are negative, the possibility of false negative should be considered. In clinical application, when using IGRA to assist in the diagnosis of AIDS combined with tuberculosis, it is necessary to conduct a comprehensive analysis based on the patient’s condition.

Key words: Tuberculosis, Acquired immune deficiency syndrome, Interferon-gamma release assay, Factor analysis, statistical