Lymphocyte Profile Analysis in Lymph Node Puncture Fluid of Mediastinal Reactive Lymphadenopathy and Its Value in Differential Diagnosis with Tuberculous Lymphadenitis.

BACKGROUND

Lymphocyte profile (LP) analysis in mediastinal lymph nodes for differentiating reactive lymphadenopathy (RL) from tuberculous lymphadenitis (TBLA) remains understudied.

METHODS

Patients with intrathoracic lymphadenopathy undergoing endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) were enrolled. Lymph node puncture fluid (LNPF) was analyzed via flow cytometry to compare LP characteristics between TBLA and RL. Receiver operating characteristic (ROC) analysis identified optimal diagnostic cut-offs, and sensitivity, specificity, and accuracy were calculated.

RESULTS

A total of 41 TBLA cases and 45 RL cases were included. Compared with the TBLA group, the RL group exhibited increased proportions of CD4⁺ T cells and B cells, and decreased proportions of CD8⁺ T cells, natural killer (NK) cells, and natural killer T (NKT) cells in LNPF. Among single parameters, the CD4/CD8 ratio demonstrated the highest diagnostic performance for TBLA, with sensitivity of 88.89%, specificity of 70.73%, and accuracy of 80.23%. Among three-parameter combinations, the CD4⁺ T cell, CD8⁺ T cell, and NK cell ratio combination achieved optimal diagnostic performance, with sensitivity of 80.5%, specificity of 86.7%, and accuracy of 82.6%.