B.16 Primary Immune Deficiencies + B17. Secondary immune deficiencies.

Question 1

Primary Immune Deficiencies

Answer 1

• Immune deficiency - decreased or missing reactivity.
• Forms: inherited (primary) or acquired (secondary).
• Consequence: increased susceptibility to infections.
• Primary immunodeficiencies are disorders in which part of the body’s immune system is missing or does not function normally.
• To be considered a primary immunodeficiency, the cause of the immune deficiency must not be secondary in nature (i.e., caused by other disease, drug treatment, or environmental exposure to toxins).
• Most primary immunodeficiencies are genetic disorders
• Starts with the stem cell, affecting myeloid cells (phagocytic problems) or lymphoid cells (combined deficiencies).
• Development deficiencies in the thymus will will cause T cell abnormalities (Th and Tc).
• Developmental deficiencies in the bursae will cause faulty atb production (hypo- and a-gamma globulinaemia)

Question 2

Phagocytic disorder

Answer 2

• ic killing, atg presentation.
• Chédiak-Higashi syndrome (mink, tiger, cat, killer whale, cattle)
o Bleedings, hair loss, de pigmentation of hair and eye.
o Abnormal granule size in every granulated cell (granulocytes, macorphage, melanocyte, pancreas)
• Pelger-Huet anomaly (dogs)
o Non segmented granulocyte nucleus (rounded), limited migration and damaged B activation.
• Leukocyte adherence disorder (LAD)
o Neutrophilia, decreased ic killing
o Dogs have no CD11b and CD18, cattle have no CD18

Question 3

Combined immunodeficiency

Answer 3

• Eq: pure bred and mixed arabic horses, 2-3% in foaosl (VDJ arrangement, inherited 5 bp deletion)
• Cattle: Angus, Danish red, 1-2% no Ig at all or no IgG in 15%
• Dog: Basset hound (pyoderma, normal IgM, decreased IgG and IgA levels, T activity, APC function disorders).

Question 4

Disorders of atb production

Answer 4

• A-gamma-globulinaemia (transient or long lasting) in eq and cattle.
• Selective IgM absence (normal IgG and IgA levels)
• Selective IgG shortage in eq

Question 5

T cell disorders

Answer 5

• Affects the humoral response, Zn needed for normal thymic hormone functions (high doses of Zn may help).
o Cattle: inherited parakeratosis at 4-8w. May result in death and infections of the skin. Ig response might be close to normal (disorders in Zn absorption).
o Dog: acrodermatitis (bull terrier), retarded growth, pustular dermatitis, pyoderma, diarrhoea (disorders of Zn absorption).

Question 6

Secondary immune deficiencies

Answer 6

• Secondary immunodeficiencies, also known as acquired immunodeficiencies, can result from various immunosuppressive agents, for example, malnutrition, aging and particular medications (e.g. chemotherapy, disease-modifying antirheumatic drugs, immunosuppressive drugs after organ transplants, glucocorticoids).
• Many specific diseases directly or indirectly cause immunosuppression. This includes many types of cancer, particularly those of the bone marrow and blood cells (leukemia, lymphoma, multiple myeloma), and certain chronic infections

Question 7

Viruses

Answer 7

• Killing of lymphoid cells o IBDV, CAV, NDV, panleukopenia, ASFV, BVD, herpes, retrovirus
• Lymphod over reacitons:
o Maedi-VIsna, Aleutian
• Lymphoid tumours o Leucosis/leukemia, retroviruses

Other like bacteria, yeast, parasites, toxins (fusarium T2, aflatoxin), GI disorders, age, environmental factors, tumours, injuries

Question 8

B18. Monoclonal antibodies

Answer 8

• Monoclonal atb = monospecific atb that are clones from one parent cell (hence polyclonal comes from
• several different immune cells).
• These atb have monovalent affinity, they will all bind to the same epitope.
• Usually one B cell or plasma cell is chosen and cloned in vitro —> monoclonal atb are produced.
• Note! Plasma cells will die without cytokines!