Chronic relapsing experimental allergic encephalomyelitis: cerebrospinal fluid cytology and a comparison with meningeal and spinal cord pathology.

Cerebrospinal fluid (CSF) was taken from strain 13 guinea pigs in various stages of chronic relapsing experimental allergic encephalomyelitis, the spinal cords removed for histological examination and meningeal stretch preparations made. CSF cells were counted and characterized by morphological studies, anti-IgG and alpha-naphthyl acetate esterase (ANAE) staining. Approximately 65% of normal CSF lymphocytes were ANAE positive and 10% stained with anti-IgG. No polymorphonuclear leucocytes were seen. Five out of eight relapsing animals had raised cell counts (up to 152/microliters) as did three animals in remission. There was no change in the proportion of various types of CSF cells where increased numbers were recorded. Infiltrating cells in spinal cord sections and meningeal preparations were similarly characterized and the results compared with CSF cells findings. Animals in relapse which had, in addition, macroscopically visible cord plaques showed the most severe infiltrative changes in spinal cord tissue and in the meninges. There were differences between the proportion of various types of CSF cells and meningeal infiltrate cells on ANAE staining reaction. In general there were far more lymphocyte-type cells in the CSF but more monocyte-type cells in meningeal infiltrates.