The Leukocyte Response During Viral Respiratory Illness in Man

Abstract

Serial peripheral leukocyte counts were performed in 113 normal adult male volunteers who were inoculated with one of four respiratory viruses. Changes in leukocyte counts were observed in ill volunteers, but not in those infected who were not ill. Common colds developed after inoculation with rhinovirus NTH 1734 and were associated with moderate increase in circulating neutrophils. Similar neutrophil increase occurred during illness with influenza virus A2/Bethesda/10/63 and this change was accompanied by a decrease in lymphocytes. Cox-sackievirus A-21 illness was also associated with neutrophil rise and lymphocyte fall. In addition, neutrophil decrease occurred later. Adeno-virus type 4 illness which was moderately severe was associated with moderate neutropenia. A rise in lymphocytes occurred prior to illness in more severely ill volunteers, a rise not seen in less severely ill volunteers, regardless of virus inoculum. Thus, illness with different respiratory viruses is associated with different white blood cell changes, although the illnesses caused by these agents are similar. The frequent occurrence of mild leukocytosis with neutrophilia at the onset of illness suggests that this finding is not helpful in differentiating viral from bacterial respiratory illnesses. Leukopenia due to neutropenia occurring later in illness would, however, suggest that the illness was viral in nature, whereas leukocytosis occurring later in illness would suggest a respiratory illness of a non-viral origin.