The process dynamics of viral and bacterial diseases of the central nervous system.

Several patients with herpes simplex encephalitis developed a prolonged humoral immune reaction within the central nervous system, which was evaluated by the measurement of locally synthesized immunoglobulin fractions in cerebrospinal fluid. Such phasic immune responses seem to occur predominantly in CNS infections with herpes and myxo/paramyxo viruses. In many cases the B-cell response follows a primary neutrophilic and a secondary mononuclear phase. Most benign viral encephalomeningitis cases lack this type of strong local B-cell activity. This is also true in most cases of bacterial meningitis, that recover after a strong neutrophilic attack and a minor mononuclear reaction. The initial phase of a purulent meningitis is characterized by a complete breakdown of the blood-CSF barrier. This occurs also in some cases of "apurulent bacterial meningitis", that are characterized by very low CSF-cell counts in spite of a totally broken barrier. The "compartmental leucopenia" is interpreted as an imbalance between the supply from the blood and an intense phagocytic consumption within the CSF space. The influence of the hydrodynamic size of viruses on the mode of entry into the central nervous system and on the dynamics of the inflammatory reactions is discussed.