Major Histocompatibility Complex- Large genomic family of membrane-bound glycoproteins that play important role in immune system and autoimmunity; main role to present protein antigen to T cells
| | | | | | Remember: (MHC) 1 × 8 (CD8 T cell) = (MHC) 2 × 4 (CD4 T cell) | | | | | |
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- MHC I:
- Process/bind intracellular antigens
- Antigens are taken up and degraded in cytosol of cell
- MHC I recognized by CD8 T cells
- Main types of MHC I genes: HLA-A, HLA-B, and HLA-C
• MHC II - Process/bind extracellular proteins via degradation in endocytic vesicles (of APCs)
- MHC II recognized by CD4 T cells
- MHC II genes: HLA-DP, DLA-DQ, and HLA-DR
• Know following diseases with HLA associations (Table 1-17)
| | | | | | | Table 1-17 MHC I-Associated Diseases | | | HLA | | Associated Diseases | | | HLA-B8 | | Oral lichen planus, dermatitis herpetiformis | | | HLA-B13 | | Guttate psoriasis, erythrodermic psoriasis | | | HLA-B17 | | Guttate psoriasis, erythrodermic psoriasis | | | HLA-B27 | | Psoriasis vulgaris, psoriatic arthritis, ankylosing spondylitis, reactive arthritis (Reiter disease), acrodermatitis continua of Hallopeau, lichen planus | | | HLA-B51 | | Behcet’s disease, lichen planus | | | HLA-B57 (Bw57) | | Oral lichen planus (in English patients) | | | HLA-Cw6
(Most definitive for psoriasis) | | Psoriasis (influences early onset) | | | | | |
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| | | | | | | Table 1-18 MHC II-Associated Diseases | | | HLA | | Associated Diseases | | | HLA-DR1 | | Lichen planus (oral and cutaneous) | | | HLA-DR2 | | Lupus | | | HLA-DR3 (DRw3) | | Dermatitis herpetiformis, pemphigus gestationis, lupus erythematosus, lichen planus | | | HLA-DR4 (DRw4) | | Pemphigus vulgaris, idiopathic chronic urticaria, pemphigoid gestationis, rheumatoid arthritis | | | HLA-DR6 (DRw6) | | Pemphigus vulgaris | | | HLA-DR10 | | Lichen planus | | | HLA-DQ2 (DQw2) | | Dermatitis herpetiformis (strongest association) | | | HLA-DQ8 | | Dermatitis herpetiformis, chronic urticaria | | | | | |
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