Further studies of the fluorescent treponemal antibody-cerebrospinal fluid (FTA-CSF) test with a monospecific anti-IgM conjugate.

Recent studies have shown the fluorescent treponemal antibody-cerebrospinal fluid (FTA-CSF) test to be the most sensitive of the serological tests investigated for the detection of treponemal antibody in cerebro-specimens were obtained from humans with various stages of syphilis and from four chimpanzees before and at intervals after experimental infection with T. pallidum. However, the question of a priori significance of the reactive FTA results in CSF still remains. When an immunologically broad spectrum conjugate is used, there is a probability of detecting treponemal IgG antibody, the origin of which may involve: (1) An equilibrium of antibody between the serum and CSF; (2) A damaged blood-brain barrier; (3) Local (CNS) production of antibody; (4) A combination of these. Immunological studies of serum specimens by others have suggested that, since the IgM class of treponemal antibody supposedly appears earlier than that of the IgG class, the use of monospecific fluorescein labelled anti-IgM conjugate could result in earlier detection of the disease. Such a conjugate has been shown to be of value in differentiating passively transferred antibody from active syphilitic infection of the newborn (U.S. Department of Health, Education and Welfare, 1972). The IgM class of immunoglobulin is not considered to be a constituent of normal CSF (Schultze and Heremans 1966). Under pathological conditions, however, IgM has been found in CSF associated with conditions of increased capillary permeability or local immunoglobulin production, including fluorescent antibody (IFA) procedure and the specificity inherent in the use of a monospecific anti-IgM conjugate to detect a treponemal IgM antibody from within the CNS could be valuable in the early detection of neurosyphilis. The purpose of the present study was to survey the occurrence of treponemal IgM antibody detectable by an IFA procedure in CSF specimens from humans infected with syphilis and from chimpanzees used as animal models for the study of the human disease. Material and methods (1) Cerebrospinal fluid 370 CSF specimens were examined. A single CSF specimen was obtained from each of 29 humans in whom a diagnosis of neurosyphilis was made by the submitting physicians. Also, according to these physicians, nine of the individuals were thought to have been inadequately treated, twelve were thought to have been adequately treated, seven had received no antisyphilitic treatment, and on one no information was available. The remaining 341 CSF samples were collected from 39 chimpanzees: 264 specimens were obtained sequentially from 24 chimpanzees before and up to …