Vascular Lesion Pattern as a Determinant of Neurological Phenotype in Endotheliotropic Bacterial Infection: A Compartmental Phenotypic-Bias Framework

Abstract Background Bartonella henselae, Rickettsia rickettsii/conorii, Treponema pallidum, and Borrelia burgdorferi are endotheliotropic bacteria with a demonstrated capacity to activate human vascular endothelium via NF-κB-dependent pathways [1-6]. All four also have published cases of vasculitis or vascular activation with projection to the central or peripheral nervous system. Yet their predominant clinical phenotypes differ markedly: acute vasculitic encephalopathy in rickettsiosis, an ischemic-occlusive picture in meningovascular neurosyphilis, focal radiculoneuropathy in neuroborreliosis, and a diagnostic overlap with multiple sclerosis (MS), acute disseminated encephalomyelitis (ADEM), and Guillain-Barré syndrome (GBS), documented through successive diagnoses in a single Bartonella henselae case [7,8]. Hypothesis We propose that the anatomical and pathophysiological pattern of the vascular lesion —not merely its existence— biases, in a partially falsifiable way, which tissue antigen pools become accessible for uptake and presentation, and in which territory, tilting the resulting neurological phenotype. Four candidate archetypes are distinguished: occlusive/chronic ischemic, diffuse/acute small-vessel, focal/perineural-radicular, and mixed/indeterminate —useful categories that are not mutually orthogonal, since each combines, unevenly, underlying dimensions such as hemodynamics, barrier integrity, distribution, caliber, territory, temporal course, and dominant mechanism (Section 3). This document does not replace the compartmental-access framework already established in [9]; it specializes that framework for endotheliotropic infections in which vascular injury or vascular activation may shape neurological compartmental access, adding lesion topology as a second-order causal variable. Conclusions The framework places four clinically and mechanistically relevant pathogens within a single comparative structure and proposes six prediction blocks —including three linked predictions concerning the cellular second hit and a negative prediction that delimits when the framework should be considered refuted—, distinguishing it from the anecdotal observation that "different bacteria produce different syndromes." The framework further predicts which pathogens should be more or less permissive for that cellular second hit by adjuvant aluminum particles carried by CCR2+ monocytes, extending the mechanism already proposed for Bartonella henselae [10] into a comparative question across pathogens; this extension is conceptually independent of the framework's vascular core and does not compromise it if refuted (Section 5).