Abstract:

Objective: To investigate the distribution characteristics of peripheral blood lymphocyte subsets in patients with pulmonary tuberculosis complicated with osteoarticular tuberculosis (PTB-OTB) and to analyze the correlations of B lymphocytes with inflammatory markers and nutritional status. Methods: A retrospective study was conducted on 96 patients with pulmonary tuberculosis (PTB group), 75 patients with osteoarticular tuberculosis (OTB group), and 90 patients with PTB-OTB who were admitted to the Eighth Medical Center of Chinese PLA General Hospital from January 2022 to July 2025. Flow cytometry was used to detect the absolute counts of peripheral blood T lymphocyte subsets. Meanwhile, laboratory indicators were collected, including body mass index (BMI), hemoglobin (Hb), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), prealbumin (PA), and albumin (Alb). Differences in various indicators among the three groups were compared, and Spearman correlation analysis was performed to explore the associations between B lymphocytes and clinical indicators in the PTB-OTB group. Results: The proportion of sputum smear-positive patients in the PTB-OTB group (41.1%, 37/90) was significantly lower than that in the PTB group (67.7%, 65/96)(χ²=13.268, P<0.001). The BMI (18.92 (17.43, 21.05) kg/m²) and Hb (103 (92, 129) g/L) in the PTB-OTB group were significantly lower than those in the OTB group (20.74 (18.21, 21.60)) kg/m², (125 (105,141) g/L) and the PTB group (20.48 (18.04, 21.85) kg/m², 126 (113, 135) g/L)(Z=4.220, P<0.001; Z=2.512, P=0.036; Z=2.677, P=0.022; Z=3.708, P=0.010). The ESR ((30 (20, 52) mm/1 h and 34 (27, 74) mm/1 h) and CRP (22.61 (10.54, 50.07) mg/L and 18.66 (6.76, 40.29) mg/L) levels in the PTB-OTB and OTB groups were significantly higher than those in the PTB group (17 (7, 38) mm/1 h and 4.61 (1.55, 26.74) mg/L)(Z=3.322, P=0.003; Z=3.815, P<0.001; Z=3.885, P<0.001; Z=3.028, P=0.007). In contrast, Alb levels of the two above groups (37.7 (33.0, 41.5) g/L and 36.2 (33.8, 40.0) g/L) were significantly lower than those in the PTB group (40.3 (37.5, 44.0) g/L)(Z=2.982, P=0.009; Z=3.254, P=0.003). The PA level in the PTB-OTB group (19.34 (18.27, 21.54) mg/dl) was lower than that in the PTB group (21.51 (19.27, 24.60) mg/dl)(Z=3.242, P=0.004). After adjusting for potential factors via analysis of covariance, no significant differences were observed in the absolute counts of CD3⁺ T cells, CD4⁺ T cells, CD8⁺ T cells, NK cells, and NKT cells among the three groups. However, the B lymphocyte count in the PTB-OTB group ((99 (52, 198) cells/μl) was significantly lower than that in the OTB group (156 (85, 294) cells/μl) and the PTB group (177 (90, 254) cells/μl)(Z=2.667, P=0.023; Z=4.255, P<0.001). Spearman correlation analysis showed that in the PTB-OTB group, B lymphocyte count was significantly positively correlated with BMI (r=0.251, P=0.020), Hb (r=0.342, P=0.001), Alb (r=0.310, P=0.004), and PA (r=0.254, P=0.018), but showed no significant correlation with ESR (r=―0.138, P=0.211) or CRP (r=―0.191, P=0.078). Conclusion: Patients with PTB-OTB present with specific decreased absolute count of peripheral blood B lymphocytes, which is closely associated with poor nutritional status. These findings suggest that B lymphocytes may serve as a potential biomarker for assessing the dissemination risk of Mycobacterium tuberculosis. This study may provide a theoretical basis for the early identification of high-risk TB patients with disseminated disease, guiding clinical nutritional interventions, and evaluating immune reconstitution in the future.

Key words: Tuberculosis, pulmonary, Tuberculosis, osteoarticular, B-lymphocytes, Nutritional status