Relationships between alternative complement pathway activation, @entity1851 , and XXXX .

@entity1 @entity7706 @entity31156 @entity328 @entity221 @entity1851
In the absence of specific antibody, opsonization of @entity328 may be mediated by the alternative complement pathway (AP) or by @entity1851 (CRP) via C1 binding. To determine the role of these mechanisms in pneumococcal (PNC) disease, we studied 19 @entity1 with differing severities of @entity7706 . C4 and CRP levels and zymosan-induced consumption of 50% hemolytic complement (CH50) were measured in specimens obtained acutely and then weekly. In @entity1 with complicated illness, the modified mean CH50 in acute sera was 178 +/- 57 U/ml, significantly lower than the mean CH50 of 331 +/- 80 U/ml in @entity1 with @entity221 (P less than 0.05). The values of the two groups on a given day approximated each other on days 7, 14, and 23. Consumption of complement by zymosan was also lower in acute sera of @entity1 with complicated illness, with a mean value of 19 +/- 18 U/ml compared with 58 +/- 30 U/ml in those with @entity221 (P less than 0.05). This difference was also seen on day 7 (P less than 0.05). Disease involving lower-numbered PNC serotypes (less than 10) correlated with reduced availability of AP factors in acute sera, independent of illness severity. Mean CRP levels were inversely related to @entity31156 -induced complement activation in @entity1 with complicated illness. These data suggest that in vivo depletion of AP factors is significantly greater in @entity1 with complicated illness and is associated with high CRP levels. CRP may enhance AP activation via C3 convertase generation and function with it as a preantibody host defense mechanism.
