Immunological Basis of Endocrine Disorders PDF

Nahla Elsherbiny Immunological basis of some endocrine disorders Immunological Basis of Some Endocrine Disorders Nahla Elsherbiny Professor of Medical Microbiology & Immunology...

Nahla Elsherbiny Immunological basis of some endocrine disorders Immunological Basis of Some Endocrine Disorders Nahla Elsherbiny Professor of Medical Microbiology & Immunology ILOs: Recall the Immunological basis of Hashimotos , Graves’ diseases and type I diabetes mellitus State the clinical picture of Hashimotos, Graves’ diseases and type I diabetes mellitus Interpret the clinical pictures and laboratory test results to identify Hashimoto thyroiditis, Graves’ diseases and type I diabetes mellitus Hashimoto thyroiditis (Chronic lymphocytic thyroiditis- chronic autoimmune thyroiditis) It is the most common cause of goitrous hypothyroidism It is the most common cause of hypothyroidism in iodine- sufficient regions. Age of onset Commonly seen in middle-aged women Immunological mechanisms: Association with certain HLA (e.g. HLA-DR3) Associations: increased risk for other autoimmune disease (eg Graves’ disease, type 1 diabetes, SLE, etc) and non-Hodgkin lymphoma The target antigen is to an unknown antigen in the thyroid The main underlying mechanism is Type IV hypersensitivity reaction (CD8 cells directly destroy thyroid tissue and CD4-attracted macrophages destroy thyroid tissue), which releases the contents into the blood stream (e.g., thyroglobulin and thyroid peroxidase). The components were usually never seen by the immune system, so auto- antibodies are made against them. § The net result is destruction of the thyroid tissue 1 Nahla Elsherbiny Immunological basis of some endocrine disorders Triggers: Genetic and environmental factors likely play a role. Clinical picture: Early stage Asymptomatic Goiter (painless – nontoxic) Transient hyperthyroidism due to follicular rupture of hormone containing thyroid tissue (“Hashitoxicosis”) Late stage Thyroid gland may be normal or small if fibrosis occurs Hypothyroidism (clinical manifestations) Laboratory diagnosis Immunological Antithyroid peroxidase (TPO) positive Antithyroglobulin (Tg) antibody positive Others Thyroid functions (early: normal values in early stages, then ↓ TSH, ↑ T3, ↑T4, then upon progression: ↑TSH, ↓ T3, ↓T4). Lipid profile CBC 2 Nahla Elsherbiny Immunological basis of some endocrine disorders Graves’ disease (Toxic diffuse goiter) It is the most common cause of hyperthyroidism Age of onset Sex: ♀ > ♂ (8:1) Typical Commonly affects patients age