1. PhD. student kefah F.Hasson 2014 Hypersensitivity Reactions type III

2. Type III Reactions:  other name : Immune Complex.  Involve reactions against soluble antigens circulating.  Usually involve IgA antibodies.  Antibody-Antigen immune complexes are deposited in organs, activate complement, and cause inflammatory damage.

3. Mechanism of type III hypersensitivity  Formation of the intermediate immune complex  Deposition of the intermediate immune complex  Tissue injury by the immune complex.

4. Immune Complex Mediated Hypersensitivity.

5. Common Disease of type III Hypersensitivity Arthus reaction : local immune complex reaction may cause Necrotic vasculitis, Ulcer.

6. 1.Complement initiates mast cell degranulation 2.Neutrophils are chemotactically attracted to the site 3.Neutrophils release lytic enzyme after failed attempts to endocytose the immune complex

7. Serum Sickness Disease: (SSD) Acute systemic immune complex in tissue may cause fever, skin rash,erhythema. due to Penicillin 、 Sulfanilamide Acute immune complex glomerulonephritis (locally) : due to Streptococcus infection. Glomerulonephritis: Inflammatory kidney damage. Occurs with slightly high antigen-antibody ratio is present.

8. Serum sickness

9. Chronic immune complex disease Systemic Lupus Erythematosus (SLE): Auto -antibodies react against DNA, blood cells, neurons, and other tissues. When cells die, immune complexes form and deposit under skin, joints, in kidneys, blood vessels, and central nervous system. Rheumatoid Arthritis: auto -antibodies (rheumatoid factors) against IgG form complexes in joint, leading to inflammation and cartilage damage. Often causes finger and joint deformities.

10. Systemic Lupus Erythematosus

11. THANK YOU