(A) PBMCs were isolated from age-matched, epidemiological risk–matched, healthy (no comorbid conditions and no immunosuppressive drugs) nonconverters (n = 3) and converters (n = 3) at baseline (during study enrollment, when all participants were LTBI^–) and after 24 months. Freshly isolated PBMCs were cultured with or without ESAT-6 and CFP-10 (10 μg/mL each), as described in the Methods section. After 96 hours, RNA was extracted, cDNA libraries were prepared, and whole-transcriptome sequencing was performed. The numbers of unique and relative transcript changes in unstimulated and ESAT-6 + CFP-10–stimulated PBMCs of converters and nonconverters at baseline and follow-up are shown. (B) A representative heatmap is shown. Transcripts differentially expressed in the PBMCs of LTBI^– compared with LTBI⁺ and active TB (P < 0.05, ANOVA). Diagram showing differentially expressed transcripts in nonconverters compared with converters. (C) PBMCs were obtained from nonconverters (n = 10) and converters (n = 10) at baseline and follow-up and from unexposed healthy controls (n = 10) and cultured in the presence of ESAT-6 + CFP-10 (10 μg/mL each), as described in the Methods section. After 96 hours, RNA was extracted, and the mRNA expression levels of Siglec-14, CES1, RPS-26, ANXA1, and RGCC1 were determined by quantitative real-time PCR. (D) PBMCs were obtained from healthy donors (n = 5) and cultured in the presence or absence of γ-M. tuberculosis (10 μg/mL). After 96 hours, various immune cell populations were sorted, and the relative mRNA expression levels of Siglec-14, CES1, RPS-26, ANXA1, and RGCC1 were determined by quantitative real-time PCR. (E) PBMCs were obtained from healthy donors (n = 3) and cultured in the presence or absence of γ-M. tuberculosis (10 μg/mL). After 96 hours, the expression of Siglec-14 in various immune populations was determined by flow cytometry. The P values were determined by 1-way ANOVA with Tukey’s multiple comparisons test. Mean values, SDs, and P values are shown.