Lacey, N. and Delaney, S. and Kavanagh, K. and Powell, F.C.
Mite-related bacterial antigens stimulate inflammatory
cells in rosacea.
British Journal of Dermatology.
Background Patients with papulopustular rosacea have a higher density of Demodex
folliculorum mites on their faces than normal subjects but the role, if any, of their
mites in initiating inflammation is disputed. Selective antibiotics are effective in
reducing the inflammatory changes of papulopustular rosacea, but their mode of
action is unknown.
Objectives To investigate whether a D. folliculorum-related bacterium was capable of
expressing antigens that could stimulate an inflammatory immune response in
patients with rosacea.
Methods A bacterium (Bacillus oleronius) was isolated from a D. folliculorum mite extracted
from the face of a patient with papulopustular rosacea, and was investigated
Results This bacterium produced antigens capable of stimulating peripheral blood
mononuclear cells proliferation in 16 of 22 (73%) patients with rosacea but only
five of 17 (29%) control subjects (P = 0Ã0105). This antigenic preparation was
fractionated into 70 subfractions and the proteins in each fraction were visualized
by sodium dodecyl sulphateâpolyacrylamide gel electrophoresis. Western blot
analysis revealed the presence of two antigenic proteins of size 62 and 83 kDa
in fractions when probing with sera from patients with rosacea. No immunoreactivity
to these proteins was recorded when probing with sera from control
patients. Two-dimensional electrophoretic separation was used to isolate these
proteins and matrix-assisted laser desorption âionization time-of-flight analysis
was employed to identify the relevant peptides. The 62-kDa immunoreactive protein
shared amino acid sequence homology with an enzyme involved in carbohydrate
metabolism and signal transduction while the 83-kDa protein was similar
to bacterial heat shock proteins.
Conclusions Antigenic proteins related to a bacterium (B. oleronius), isolated from a
D. folliculorum mite, have the potential to stimulate an inflammatory response in
patients with papulopustular rosacea.
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