Role of Interleukin-18 and T-helper Type 1 Cytokines in the Development of Mycoplasma pneumoniae Pneumonia in Adults

• Published in: Chest Vol. 121; no. 5; pp. 1493 - 1497
• Main Authors: Tanaka, Hiroshi, Narita, Mitsuo, Teramoto, Shin, Saikai, Toyohiro, Oashi, Kensuke, Igarashi, Tomofumi, Abe, Shosaku
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Northbrook, IL Elsevier Inc 01.05.2002; American College of Chest Physicians
• Subjects: Adult; Bacterial diseases; Bacterial diseases of the respiratory system; Biological and medical sciences; Cytokines; Disease; Female; Hospitals; Human bacterial diseases; Humans; Infections; Infectious diseases; Interferon; Interferon-gamma - blood; interferon-γ; interleukin-12; Interleukin-12 - blood; Interleukin-12 Subunit p40; interleukin-18; Interleukin-18 - blood; Interleukin-18 - immunology; interleulin-2; Lymphocytes; Male; Medical imaging; Medical sciences; Middle Aged; Mycoplasma pneumonia; pleuritis; Pneumonia; Pneumonia, Mycoplasma - blood; Pneumonia, Mycoplasma - immunology; Protein Subunits; Receptors, Interleukin-2 - blood; Th1 Cells - immunology; Th1 Cells - metabolism; Japan; interferon-γ; IL; MP; interleukin-12; IFN; sIL-2R; interleulin-2; interleukin-18; pleuritis; DTH; Mycoplasma pneumonia; Th1; NK; Human; Lung disease; Pneumonia; Pathophysiology; Respiratory disease; Pathogenesis; Cytokine; Mycoplasma pneumoniae; Exploration; Mycoplasmataceae; Interleukin 18; Infection; Mollicutes; Mycoplasmatales; Interleukin 2; T-Lymphocyte; Bacteriosis; Bacteria; Adult; Mycoplasmal infection; Gamma interferon; Biological receptor
• ISSN: 0012-3692; 1931-3543
• DOI: 10.1378/chest.121.5.1493

Interleukin (IL)-18 is a proinflammatory cytokine, originally termed interferon (IFN)-γ-inducing factor, which promotes T-helper type 1 (Th1) cytokine responses. We recently reported that serum IL-18 levels were elevated in children with Mycoplasma pneumoniae pneumonia (MP). In this study, we investigated the contribution of IL-18 to the infection and assessed the Th1 cytokine response to pulmonary involvement in adults. We investigated the clinical course, pulmonary involvement, and serum levels of IL-18, IFN-γ, IL-12p40, and soluble IL-2 receptor (sIL-2R) in 21 patients with acute-stage MP and in 21 age- and sex-matched control subjects. Significantly (p < 0.001) increased serum IL-18 (median, 248 pg/mL [range, 89 to 441 pg/mL] vs median, 126 pg/mL [range, 47 to 217 pg/mL]) and sIL-2R (median, 617 U/mL [range, 410 to 1,032 U/mL] vs median, 425 U/mL [range, 268 to 601 U/mL]) were found in patients with MP as compared with healthy control subjects, and there was a tendency toward increased serum IFN-γ and IL-12p40. Circulating IL-18 values had a positive correlation with serum sIL-2R levels (r = 0.62, p = 0.028) and the number of affected pulmonary lobes (σ = 0.61, p = 0.024), but not with the serum levels of antibodies to M pneumoniae, IFN-γ, or IL-12p40. Serum IL-18 and sIL-2R values in severe cases were significantly higher (p < 0.03) than those in mild cases. IFN-γ and sIL-2R levels in four patients with pleural effusion were significantly (p < 0.05) higher than those in the other 17 subjects. Serum levels of IL-18 were raised during the acute phase of MP. We suggest IL-18 and Th1 cytokines may play a significant role in the immunopathologic responses in MP.