Total IgE, PPD-reactive IgE and prostaglandin D2 in active pulmonary tuberculosis with and without pre-existing asthma

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Background Pulmonary TB and asthma can co-exist, but immunological characteristics in both conditions remain incompletely understood. The study designed to compare total immunoglobulin E, IgE reactivity to purified protein derivatives (PPD), and prostaglandin D2 (PGD2) in patients with active pulmonary tuberculosis infection with and without a documented pre-existing asthma who presented with exacerbated respiratory manifestations. Methods This study included 200 participants were categorized into two groups: Group I ( n = 100): Patients with pulmonary tuberculosis with pre-existing diagnosis of asthma. Group II ( n = 100): Patients with pulmonary tuberculosis alone. TB was investigated by using sputum Ziehl-Neelsen (AFB) staining, Lowenstein-Jensen (LJ) culture, and GeneXpert MTB/RIF ULTRA. Serum Total IgE, PPD-reactive IgE identified by an in-house ELISA, and Prostaglandin D2 (PGD2) were estimated for both groups. Receiver Operating Characteristic (ROC) analysis assessed for all biomarkers. Results Pulmonary TB and previous documented asthmatic patients showed a significantly higher values of total IgE (mean ± SD = 478.953 ± 628.420 vs. 36.540 ± 24.730; P = 0.0001). 88% of Group I higher than the cut-off value, while 0% of Group II. PPD-reactive IgE positive values were 8% in Group I and 0% in Group II. Group I showed higher mean values of serum PGD2 than Group II (95.724 ± 227.725 versus 39.064 ± 24.305 pg/mL; P = 0.014). The Area Under the Curve (AUC) of total IgE was 0.963, PPD-reactive IgE was 0.645, while the PGD2 was 0.555. Conclusion The study revealed that was potential association between active pulmonary tuberculosis and asthma. Patients with concomitant TB and history of asthma can produce higher values of total IgE, greater IgE reactivity against mycobacterial antigens, and release PGD2. Total IgE can discriminate between the predefined groups well. Whereas PPD-reactive IgE and PGD2 showed limited discrimination.