Psoriasis--as an autoimmune disease caused by molecular mimicry

Trends Immunol. 2009 Oct;30(10):494-501. doi: 10.1016/j.it.2009.07.008. Epub 2009 Sep 24.

Abstract

Psoriasis is strongly associated with streptococcal throat infection, and patients have increased occurrence of such infections. Psoriatic lesional T cells are oligoclonal, and T cells recognizing determinants common to streptococcal M-protein and keratin have been detected in patients' blood. We propose that CD8(+) T cells in psoriatic epidermis respond mainly to such determinants, whereas CD4(+) T cells in the dermis preferentially recognize determinants on the streptococcal peptidoglycan that might itself act as an adjuvant. The streptococcal association might reflect the concurrence of superantigen production promoting skin-homing of tonsil T cells, M-protein mimicking keratin determinants, and adjuvant effects of the peptidoglycan. Accordingly, improvement of psoriasis after tonsillectomy should be associated with fewer T cells that recognize keratin and streptococcal determinants.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Antigens, Bacterial / blood
  • Antigens, Bacterial / immunology
  • Antigens, Bacterial / metabolism
  • Autoimmune Diseases / blood
  • Autoimmune Diseases / immunology*
  • Autoimmune Diseases / microbiology
  • Bacterial Outer Membrane Proteins / blood
  • Bacterial Outer Membrane Proteins / immunology
  • Bacterial Outer Membrane Proteins / metabolism
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / metabolism
  • CD8-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / metabolism
  • Carrier Proteins / blood
  • Carrier Proteins / immunology
  • Carrier Proteins / metabolism
  • Dermis / immunology
  • Epidermis / immunology
  • Humans
  • Keratins / immunology
  • Molecular Mimicry*
  • Palatine Tonsil / immunology
  • Peptidoglycan / immunology
  • Peptidoglycan / metabolism
  • Psoriasis / blood
  • Psoriasis / immunology*
  • Psoriasis / microbiology
  • Streptococcal Infections / complications*
  • Streptococcal Infections / immunology
  • Streptococcus / chemistry
  • Streptococcus / immunology*
  • Superantigens / immunology
  • Tonsillitis / complications*
  • Tonsillitis / immunology
  • Tonsillitis / microbiology

Substances

  • Antigens, Bacterial
  • Bacterial Outer Membrane Proteins
  • Carrier Proteins
  • Peptidoglycan
  • Superantigens
  • streptococcal M protein
  • Keratins