Splenic abscess caused by in a patient with multiple tooth extractions.

A woman in her 40s with a history of dental abscess presenting with a 3-month history of nightly fevers, malaise, fatigue and acutely worsening left flank pain was found to have a splenic abscess replacing almost the entire splenic parenchyma on abdominal CT. Abscess aspirate showed Gram-positive rods, and both aerobic and anaerobic cultures grew (previously Propionibacterium acnes), a common member of the skin microbiome. Prior case reports of splenic abscess all involved parental inoculation via needle use.

Multiple sclerosis, the microbiome, TLR2, and the hygiene hypothesis.

The pathophysiology of autoimmune diseases such as Multiple Sclerosis (MS) involves a complex interaction between genetic and environmental factors. Studies of monozygotic twins suggest a significant role for environmental factors in susceptibility to MS. Numerous studies, driven by the "Hygiene Hypothesis," have focused on the role of environmental factors in allergic and autoimmune diseases.

Systemic TLR2 tolerance enhances central nervous system remyelination.

Background: Multiple sclerosis (MS) is a central nervous system (CNS) autoimmune disease characterized by both inflammatory demyelination and impaired remyelination. Studies indicate that Toll-like receptor 2 (TLR2) signaling contributes to both the inflammatory component and the defective remyelination in MS. While most MS therapeutics target adaptive immunity, we recently reported that reducing TLR2 signaling in innate immune cells by inducing TLR2 tolerance attenuates adoptively transferred experimental autoimmune encephalomyelitis.

TLR Tolerance as a Treatment for Central Nervous System Autoimmunity.

The role of TLR signaling in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE) is unclear. This role is especially controversial in models of adoptive transfer EAE in which no adjuvant and no TLR ligands are administered. We recently reported that a microbiome-derived TLR2 ligand, Lipid 654 (L654), is present in healthy human serum but significantly decreased in the serum of MS patients.