Attenuation of influenza-like symptomatology and improvement of cell-mediated immunity with long-term N-acetylcysteine treatment.
N-acetylcysteine (NAC), an analogue and precursor of reduced glutathione, has been in clinical use for more than 30 yrs as a mucolytic drug. It has also been proposed for and/or used in the therapy and/or prevention of several respiratory diseases and of diseases involving an oxidative stress, in general. The objective of the present study was to evaluate the effect of long-term treatment with NAC on influenza and influenza-like episodes. A total of 262 subjects of both sexes (78% > or = 65 yrs, and 62% suffering from nonrespiratory chronic degenerative diseases) were enrolled in a randomized, double-blind trial involving 20 Italian Centres. They were randomized to receive either placebo or NAC tablets (600 mg) twice daily for 6 months. Patients suffering from chronic respiratory diseases were not eligible, to avoid possible confounding by an effect of NAC on respiratory symptoms. NAC treatment was well tolerated and resulted in a significant decrease in the frequency of influenza-like episodes, severity, and length of time confined to bed. Both local and systemic symptoms were sharply and significantly reduced in the NAC group. Frequency of seroconversion towards A/H1N1 Singapore 6/86 influenza virus was similar in the two groups, but only 25% of virus-infected subjects under NAC treatment developed a symptomatic form, versus 79% in the placebo group. Evaluation of cell-mediated immunity showed a progressive, significant shift from anergy to normoergy following NAC treatment. Administration of N-acetylcysteine during the winter, thus, appears to provide a significant attenuation of influenza and influenza-like episodes, especially in elderly high-risk individuals. N-acetylcysteine did not prevent A/H1N1 virus influenza infection but significantly reduced the incidence of clinically apparent disease.
De Flora
S
S
Institute of Hygiene and Preventive Medicine, University of Genoa, Italy.
Grassi
C
C
Carati
L
L
D000111:Acetylcysteine / Q000008:administration & dosage / Q000627:therapeutic use*; D000284:Administration, Oral; D000368:Aged; D000998:Antiviral Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects; D015994:Incidence; D009980:Influenza A virus; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D007558:Italy / Q000453:epidemiology; D008297:Male; D012621:Seasons; D013997:Time Factors
D000998:Antiviral Agents; D000111:Acetylcysteine