Immune-Deficiency Diseases Flashcards
Describe X-linked gammaglobulinaemia
- No antibodies (no B lymphocytes)
- Aetiology: very rare, affects boys
- Presentation: usually in 2nd 6 months of life with chest infections, sinusitis, otitis media and other bacterial infections
- Prognosis: if not treated will get worse and worse and will die in childhood/early adulthood
- Treatment: antibody replacement and antibiotics where needed, usually replacement IgG
Describe severe combined immune deficiency (SCID)
• Primary causes:
o Reticular dysgenesis - only red cells and platelets in the blood, These individuals only live a few days before dying of overwhelming infection
Describe common variable immune deficiency
- Aetiology: any gender, presents at any age
* Pathology: antibodies are low (two classes of antibodies must be low to fit diagnosis
Outline the causes of antibody deficiency
Primary = x-linked gammaglobulinaemia, SCID, CVID Secondary = infections (AIDs), malignant disease, trauma (burns, penetrating injury), loss of antibodies (nephrotic syndrome), drug-induced
Why may rituximab cause an antibody deficiency?
Anti-CD20 on B cells - depletion of B cells –> specific antibody deficiency may occur
What are the causes of T-lymphocyte deficiency?
Primary = DiGeorge syndrome, Nucleoside phosphorylase and adenine deaminase deficiency Secondary = AIDs, immunosuppressive drugs, cytotoxic drugs (methotrexate)
Describe DiGeorge syndrome
> Genetics: deletion of part of chromosome 22
Pathophysiology: defect in chromosome 22 defect in 3rd and 4th pharyngeal arches no thymus or parathyroid, facial abnormalities, great vessel abnormalities complete T cell absence
What are the causes of neutropenia?
Primary = cyclical neutropenia, Kostmann syndrome, chronic benign neutropenia Secondary = malignancy (leukaemia, lymphoma), drugs (cytotoxic therapy), infections
What infections are associated with neutropenia?
Frequently starts as oral soreness, gingivitis and then severe pharyngitis with upper and lower respiratory tract infections.
o Bacteria – Pseudomonas, E. Coli, enterobacteria (gram –ve rods), enterococci, staphylococci
o Fungi – candida, aspergillus
What are the causes of neutrophil function defects?
Chronic granulomatous disease, leukocyte adhesion deficiency (LAD), diabetes mellitus
Describe chronic granulomatous disease
♣ Genetics: X-linked only in boys
♣ Pathophysiology: inability to initiate respiratory burst in phagocytes can’t generate superoxide
♣ Presentation: before the age of 5 with pneumonia, osteomyelitis, infective arthritis, skin infections
♣ Tests: nitroblue tetrazolium test, (normal phagocytes can decolourise these dyes whereas a patient with this disease’s phagocytes cannot)
♣ Treatment: antibiotics, interferon, bone marrow transplant
Describe leukocyte adhesion deficiency (LAD)
♣ Genetics: very rare, autosomal recessive disease. Deficiency of CD18 (a part of neutrophil adhesion molecule)
♣ Pathophysiology: as a result of mutation, neutrophils cannot pass through post-capillary venule walls during inflammation
♣ Presentation: failure of umbilical cord to slough, pneumonia, gingivitis, peritonitis
♣ Treatment: antibiotics, bone marrow or stem cell transplant
Describe Wiskott-Aldrich syndrome
o Genetics: X-linked
o Pathophysiology: defective cytoskeletal protein found in haemopoetic cells . Thrombocytopenia causes bleeding and affects the B and T cells
o Presentation: infections (ears and sinuses) and lymphomas
Describe Chediak-Higashi syndrome
o Pathophysiology: defect in moving material into lysosomes mostly affects phagocytes but also affects the production of the cytolytic granules used by CD8+ T cells and natural killer cells
o Presentation: neutropenia, giant inclusion bodies in leukocytes, partial albinism, peripheral neurpathy
o Associated infections: bacterial infections
Describe how classical complement deficiency presents
Lupus-like picture due to poor handling of immune complexes. Low C3
