Sandfly Fever: Sequential Changes in Neutrophil Biochemical and Bactericidal Functions

Neutrophil function was evaluated during the course of experimental infection with sandfly fever virus in volunteers by in vitro assay of quantitative nitroblue tetrazolium (NBT) dye reduction, leukocyte glucose-6-phosphate dehydrogenase (G-6-PD), 6-phosphogluconic dehydrogenase (6-PGD) activities and by a bactericidal assay utilizing a strain of Staphylococcus aureus as a test organism. In the first study group in six infected subjects, leukocyte G-6-PD activity was reduced to as low as 5 to 6% and quantitative NBT dye reduction was depressed to 20 to 30% of baseline values in comparison to two uninfected subjects who did not show these changes. No changes were detected in leukocyte 6-PGD in control or infected subjects. These impairments in leukocyte function occurred between the 4th and the 7th day after infection and returned to normal between the 19th and 25th days. In a second study group of nine men, in each of seven infected subjects, bactericidal activity was diminished by as much as 45% of baseline values, usually by the 7th to the 25th day in comparison to two uninfected subjects who did not show these changes. The changes in bactericidal capacity of earliest onset and of greatest amplitude occurred between the 3rd and the 7th day in two subjects who presented with the most severe clinical illness. By 32 days postinfection, bactericidal activity had returned to baseline values. These changes in leukocyte function were unrelated to total leukocyte count and occurred following the neutropenia characteristic of the disease.