DISEASES OF THE IMMUNE SYSTEMDISEASES OF THE IMMUNE SYSTEM

Diseases

• Autoimmune diseases• Immunodeficiency diseases• And the dreaded AIDS

Autoimmune Diseases

• Occurs when the immune system loses self tolerance

• Systemic lupus erythematosus• Rheumatoid arthritis• Scleroderma

Systemic Lupus Erythematosus (SLE)

• Fundamental defect: failure of the mechanisms that maintain self-tolerance

• May be genetic or drug-induced• More common in young women (female:male

ratio 10:1)• Antibiotics such as those used to treat TB

Systemic Lupus Erythematosus (SLE)

• Clinical feature: butterfly rash

• Scleritis may also occur

Rheumatoid Arthritis

• chronic inflammatory disease that affects primarily the joints, but may also involve the skin, blood vessels, lungs, and heart

Scleroderma

• aka Progressive systemic sclerosis• abnormal accumulation of fibrous tissue in the

skin and multiple organs triggered by…• a combination of abnormal immune responses

and vascular damage, resulting in local accumulation of growth factors that act on fibroblasts and stimulate collagen production

Scleroderma

Immunodeficiency diseases

• Affects either humoral or cell-mediated pathway

• Severe combined immunodeficiency (SCID)- affects both

• DiGeorge Syndrome – affects T cells• Agammaglobulinemia – affect B cells

SCID

• Very much susceptible to infections• Infants oral yeast infection

DiGeorge Syndrome

• Thymus – underdeveloped or absent• Susceptible to viral infections

• Lateral Chest X-Ray

No thymus

heart

Agammaglobulinemia

• Susceptible to bacterial infections

AIDS

• Acquired Immunodeficiency syndrome• HIV- human immunodeficiency virus• Attacks the CD4 attached to the helper T-cell

– CD4 binds to MHC-II APC– CD4 T helper cell (CCR5)

HIV

Fetal hydropsErythroblastosis fetalis