Effect of acute experimental influenza A virus pneumonia on concentration of alpha 1-acid glycoprotein in mouse serum.

In mice, the mean serum concentration of the acute-phase reactant alpha 1-acid glycoprotein increased 34-48% over 14 days following experimental induction of pneumonitis by intranasal inoculation of influenza A virus. Inoculation of undiluted (hemagglutination titer 640) and 10(-1) dilution of virus was followed by development of maximum concentrations of alpha 1-acid glycoprotein in serum at seven days, of 334 micrograms/ml, compared to a concentration in control mice inoculated with irradiated inactivated virus of 225 micrograms/ml (P = 0.002). Infection with 10(-2) virus yielded a peak serum alpha 1-acid glycoprotein of 301 micrograms/ml at four days, 34% higher than in control mice at four days (P = 0.04). There were no differences in alpha 1-acid glycoprotein concentrations among virus-infected mice. Influenza A virus pneumonitis was confirmed histologically, by virus isolation, and by serologic testing, but no inoculum-dependent differences were observed. On day 7, there was a direct relationship demonstrated between the severity of pneumonitis evaluated histologically and the serum alpha 1-acid glycoprotein concentration (r = 0.50; P less than 0.02). Influenza A pneumonia in mice is associated with increased concentrations of alpha 1-acid glycoprotein in serum; the increase may be directly related to the severity of the pulmonary inflammation.