In Reply.—We agree with Dr Dalens, and we reemphasize the importance of processing CSF samples quickly for several reasons. First, neutrophils degenerate rapidly, and they can alter the total and differential cell counts. Second, the delay in processing may result in degenerative, as well as artifactual, changes in monocytes. Third, the bacteria can be identified before disintegration.
The definition of macrophages in CSF is not universal. A review of the literature shows that various investigators1-5 have used different terms for the cells of the mononuclear phagocytic system. In our article, we followed the nomenclature in which a nonactivated monocyte in CSF was identified morphologically as a monocyte, whereas the activated monocyte and macrophage were considered identical, because we believe that except for minor variations they are similar cell types.6,7
Observations of a relationship between psychomotor handicaps and a greater percentage of histiomonocytic cells in CSF on serial