Disorder of Immune System (immune deficiency)

Immune system disorders (immunodeficiency)

cause abnormally low activity, over activity, or misguided activity of immune system; lead to a disfunctional immune system which can cause recurrent infections/tumors

Primary immunodeficiency

occur from intrinsic, inherited defects in the immune system; usually seen in infants and young children; caused by mutations, sometimes in a specific gene

Secondary immunodeficiency

any factor that interferes with the normal growth or expression of the immune system can lead to secondary immunodeficiency; can generally develop later in life; caused by an outside source like a toxic chemical or infection that attacks the body

Acquired Immuno-Deficiency Syndrome (AIDS)

Caused by HIV; breaks down the body’s immune system and the victim is vulnerable to infections, neurological disorders or AIDS-related tumors

HIV biology

contains RNA which can be reverse transcribed into DNA using reverse transcriptase then the resulting DNA integrates into human genome in cells; targets immune cells (CD4, macrophages, DCs)

Direct mechanisms for CD4 cell loss

Syncytia formation (cell-cell fusion) and direct viral cytopathic effect from HIV replication

Indirect mechanisms for CD4 cell loss

CD8+ attack of CD4+ cells expressing HIV antigens and viral proteins can activate Fas pathway; induces programmed cell death (apoptosis)

Mechanisms for immunodeficiency (AIDS)

Depletion of CD4 T cells in the GI tract of AIDS patients

Avian leukosis virus (ALV)

avian retrovirus which is oncogenic: infection causes tumor in liver, spleen, bursa, and the most common of which are lymphomas; ALV-J mainly infected the bone marrow cells and its precursor cells, and thus formed myelocytome and Lymphocytoma; can integrate genomic information into host genome

ALV symptoms

Loss of appetite, weakness, diarrhea, dehydration, weight loss, depression, enlarged bursa and sometimes an enlarged liver, and hermangioma in the skin

Severe Combined Immunodeficiency (SCID)

rare potentially fatal syndrome of diverse genetic causes in which there is combined absence T and B cell function and sometimes NK cells; lack the ability to produce an immune system (T and B cell production); genetic-primary immunodeficiency; SCID-X1 (X-linked serve combined immunodeficiency)

SCID management & treatment

antibody infusions, bone marrow transplants, and gene therapy