Clinical and pathological differences between polymorphonuclear-rich and lymphocyte-rich tuberculous pleural effusion

OBJECTIVE: Analysis of the occurrence factors and disease characteristics of tuberculous (TB) pleural effusion (TPE) dominated by neutrophils. METHODS: We retrospectively analyzed the clinical data of 304 patients with two types of TB pleurisy. The clinical, laboratory, and pathological features of TB pleurisy separately dominated by lymphocytes and neutrophils were analyzed. RESULTS: Neutrophil-predominant effusion was observed in 33 (10.9%) patients. The patients with TPE with polymorphonuclear leukocytes (PMNLs) had higher fever rates and higher decortication rates than those with lymphocyte-predominant TPE. Otherwise, they had lower chest distress rates and lower positive rates of pulmonary TB and lower biopsy tissue culture-positive rates than patients with lymphocyte-predominant TPE. PMNL TPE patients had higher lactic acid dehydrogenase (LDH) (1297 vs. 410 U/l, P < 0.001) and adenosine deaminase (ADA) levels (54.1 vs. 42.9 U/l, P = 0.043) and lower pleural fluid glucose (1.92 vs. 4.70 mmol/L, P < 0.001) and protein (47.4 vs. 48.4 g/L, P = 0.024) levels than that of lymphocyte-predominant TPE. Otherwise, they had lower blood ALB levels and higher C-reactive protein levels than lymphocyte-predominant TPE. Finally, PMNL TPE patients had lower rates of granuloma formation (27.2% vs. 75.2%, P < 0.001) and pleural nodules than patients with lymphocyte-predominant TPE and more frequent findings of pus, caseous exudate, and necrosis. CONCLUSION: The TB pleurisy patients dominated by neutrophils show strong inflammatory reactions and higher ADA levels in pleural effusion. These findings can significantly improve the positive rate of Mycobacterium tuberculosis in neutrophil-predominant TPE under thoracoscopy.