C-reactive protein in acute viral infections.

A sensitive solid-phase enzyme immunoassay procedure was used to determine the concentrations of C-reactive protein (CPR) in the acute and convalescent phase sera of patients with verified rubella, herpes simplex, cytomegalo, influenza A or B, enterovirus, or mycoplasma infection. In all infection groups about 90% (80% for influenza) elevated CRP values were observed in the acute phase sera (mean values in the different groups 16-57 micrograms/ml), the highest values exceeding or approaching 100 micrograms/ml. The serum CRP values were highest in all groups before the specific serum antibodies were detectable and decreased approaching the upper limit or normal controls (2 microgram/ml) within 2 weeks. Notable individual variation in the CRP production was seen. We conclude tha serum CRP determination should not be used as a reliable criterion to distinguish bacterial and viral infections.