Rochalimaea antibodies in HIV‐associated neurologic disease

Rochalimaea henselae, a recently described pathogen thought to cause syndromes as varied as bacillary angiomatosis, parenchymal bacillary peliosis, fever with bacteremia, and cat-scratch disease, is associated with CNS diseases including cerebral and retinal bacillary angiomatosis, as well as cat-scratch-related encephalitis, myelitis, cerebral arteritis, and retinitis. We used a newly developed enzyme immunoassay and the polymerase chain reaction to investigate the association of R henselae infection with HIV-related CNS disease and found that whereas seroprevalence rates in HIV-positive patients unselected for neurologic disease were 4% to 5.5%, those with neurologic disease had seroprevalence rates of 32%. The ratio of organism-specific antibodies in CSF compared with serum suggested intra-blood-brain-barrier synthesis of these antibodies. CSF specimens containing only R henselae IgM had 16S rDNA specific for R henselae. Stored serum from one of these patients indicated he had developed R henselae-reactive IgM antibodies 10 months prior to the onset of neurologic disease. In the 14 patients for whom clinical data were available, evidence of CNS invasion by R henselae was accompanied by acute and subacute mental status changes including hallucinations, disorientation, and rapidly progressive dementia.