Psoriasis--as an autoimmune disease caused by molecular mimicry.
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.
Valdimarsson
Helgi
H
Department of Immunology, Landspitali University Hospital, Reykjavik, Iceland. helgiv@landspitali.is
Thorleifsdottir
Ragna H
RH
Sigurdardottir
Sigrun L
SL
Gudjonsson
Johann E
JE
Johnston
Andrew
A
D000942:Antigens, Bacterial / Q000097:blood / Q000276:immunology / Q000378:metabolism; D001327:Autoimmune Diseases / Q000097:blood / Q000276:immunology* / Q000382:microbiology; D001425:Bacterial Outer Membrane Proteins / Q000097:blood / Q000276:immunology / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002352:Carrier Proteins / Q000097:blood / Q000276:immunology / Q000378:metabolism; D020405:Dermis / Q000276:immunology; D004817:Epidermis / Q000276:immunology; D006801:Humans; D007633:Keratins / Q000276:immunology; D018716:Molecular Mimicry; D014066:Palatine Tonsil / Q000276:immunology; D010457:Peptidoglycan / Q000276:immunology / Q000378:metabolism; D011565:Psoriasis / Q000097:blood / Q000276:immunology* / Q000382:microbiology; D013290:Streptococcal Infections / Q000150:complications* / Q000276:immunology; D013291:Streptococcus / Q000737:chemistry / Q000276:immunology*; D018089:Superantigens / Q000276:immunology; D014069:Tonsillitis / Q000150:complications* / Q000276:immunology / Q000382:microbiology
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D010457:Peptidoglycan; D018089:Superantigens; C014689:streptococcal M protein; D007633:Keratins