L5 - Immunopathology (Filariasis) Flashcards
Lymphatic filariasis (Species and symptoms)
Brugia malayi, Wuchereria bancrofti)
Due to adult worm
Filarial fever
Acute lymphangitis (fever, inflammation of lymph nodes/vessels)
Dermatolymphangioadenitis (bacterial infection, fever, cutaneous inflammation)
Lymphoedema/hydrocoele (genital damage) /elephantiasis
Elephantiasis of arms and legs
Onchocerciasis (Species and symptoms)
Onchocerca volvulus
Due to microfilariae
Chronic dermatitis
Blindness
Host parasite interaction
Infected human exposed to multiple life cycle stages each interacting with different parts of the immune system
Disease Spectrum
1) Immunity
2) Tolerance
3) Inappropriate immune response
Wolbachia endosymbiotic bacteria of filarial nematodes
Pathogenesis
o Acute inflammation
o Adverse drug reaction
o Chronic pathology
Wolbachia
An obligate intracellular bacteria
Present in all developmental stages
Nematodes rely on bacterial metabolites essential for their survival
Worm needs its for reproduction
Presence of Wolbachia in all stages of filariae suggest host will be exposed to Wolbachia following death of parasite or through release of bacterial products
Wolbachia exposure (Acute and Chronic)
Acute exposure : death due to chemotherapy
Chronic exposure : natural attrition of parasite, constant turnover of mf
Pro-Inflammatory activity in filarial nematodes
induce pro-inflammatory cytokines in vitro
TNFalpha, IL-1, NO from macrophages
Wolbachia (receptor and cytokines)
induce the pathology and inflammatory responses seen in both lymphatic filariasis and onchocerciasis
Dependent on TLR2 and the co receptor TLR6, not TLR4
Adverse reactions correlated with IL-6
Wolbachia pathogenesis
Wolbachia DNA found in sera of onchocerciasis patients post drug treatment – correlates with post treatment reactions
causes neutrophil mediated keratitis
development of chronic pathology
bacteria occur in hydrocoele fluid
