[Detection of C-reactive protein in patients with epidemic cerebrospinal meningitis by solid phase radioimmunoassay].

A modified solid phase RIA was developed for the quantification of C-reactive protein in human serum and CSF. The lowest measurable amount detected by this method was 5 ng/ml (0.25 ng/well). The serum levels in 68 healthy blood donors were with in the range from 0.028-3.4 micrograms/ml, with a median value of 0.166 micrograms/ml (mean = 1.57 micrograms/ml); whilst those in 63 patients with epidemic cerebrospinal meningitis were up to 520 micrograms/ml with a median value of 77.5 micrograms/ml (mean = 88.46 micrograms/ml). This is 400-500-fold higher than that of the normal. The levels of CRP in the sera collected during acute stage of the infection (ranged from 28.5-540 micrograms/ml, with a median value of 200 micrograms/ml, mean = 200.6 micrograms/ml) were 400-fold higher than that after recovery (ranged from 0.1-54 micrograms/ml, with a median value of 0.53 micrograms/ml). In addition, lower levels (0.07-150 micrograms/ml, median = 2.07 micrograms/ml) of CRP were detected in CSF. These results markedly revealed that the CRP reflected the characteristics of an acute phase protein in the infection, and would be usefull for the differential diagnosis of bacterial and nonbacterial meningitis, and in monitoring the clinical course of the illness.