Notes by dott. Claudio Italiano
Synonym: immunodeficit
It means lack of immunity, that is the process by which a subject is able to
defend himself from pathogens, ie infectious agents carrying diseases and / or
neoplastic processes, so that degenerated cells can no longer be eliminated
through the process of cytotoxicity.
The causes of immunodeficiency are multiple, both primitive, ie the etiology of
which is not known or secondary, ie acquired, which means that a healthy born
subject then becomes immunodeficiencies for example for exposure to viruses such
as HIV, AIDS virus , or radiation.
They are divided into:
- B lymphocyte defects with antibody deficiency syndrome:
• Bruton agammaglobulinemia:
hereditary transmission linked to the X chromosome: women are carriers and the
male children are sick. Lack of maturation from precursors to mature B
lymphocytes. The disease manifests itself in the absence of plasma cells and B
lymphocytes
• common variable immunodeficiency (CVID):
antibody deficiency syndrome clinically similar to Bruton's agammaglobulinemia,
but not hereditary.
• transient hypogammaglobulinemia:
Occasionally appears in young children up to the end of the 2nd year of age
• selective IgA deficiency:
is the most frequent immunodeficiency (1: 500)
• IgG subclass deficiency (especially IgG: and IgG4).
- T cell defects:
• Di George syndrome:
aplasia of the thymus and parathyroids with absence of cell-mediated immunity,
corrected by fetal thymus transplantation
- Combined B and T cell defects:
isolated T cell defects are very rare. T-B cellular cooperation also usually
reduces the production of immunoglobulins.
• severe combined immunodeficiency (SCID):
hypoplasia of all lymphatic tissues, including the thymus. There are numerous
variations, e.g. a variant with defect of the adenosine-deaminase gene (ADA). In
the case of SCID with hereditary transmission bound to the X chromosome (X-SCID)
there is also a defect of the IL-2R-y gene.
• Nezeloff syndrome: particular form of SCID with B cell normality
• ataxia-telangiectasia (Louis-Bar syndrome):
autosomal recessive inheritance; association with ataxia + telangiectasia
• Wiskott-Aldrich syndrome:
recessive inheritance linked to the X chromosome; association with
thrombocytopenia + eczema
• chronic mucocutaneous candidiasis: defect of T lymphocytes and macrophages in
the production of lymphokines.
They are divided into:
- B cell defects (antibody deficiency syndrome): e.g.
• protido-dispersing syndrome due to enteric or renal causes
• non-Hodgkin type B lymphomas, in particular plasmacytoma and LLC
• splenectomy, radiotherapy - T cell defects:
• viral infections: HIV, CMV, EBV and measles virus • tuberculous mycobacterium
or leprosy bacterial infections
• protein deficiency (malnutrition)
• Hodgkin's and non-Hodgkin's T-type lymphomas
•treatment with corticosteroids, immunosuppressants
- Combined defects of B and T cells: •
• e.g. cytostatic therapy, uremia, burns, polytrauma.
A person suffering from immunodeficiency will have an increased susceptibility
to bacterial infections, (in particular the respiratory tract) in the case of
B-cell defects, or to viral and fungal infections in case of T-cell defects;
moreover, an increased susceptibility to autoimmune tumors and affections
appears.
It makes use of the history, the clinic and laboratory investigations, including
the protidogramma and the dosage of the gamma globulins. The matrix shows a
lymphocyte count characterized by deficiency of the same, so the phenotypic
characterization of the T, B, T-helper and T-suppressor lymphocytes, T / L ratio
and the immunoglobulin dosage are required: IgG with their subclasses, IgA , IgM.
Some authors use skin tests with so-called "booster" antigens to evaluate T cell
function. Finally, analysis of the complement system. Specific researches: e.g.
biopsy with histology of the bone marrow and lymph nodes.
• Prophylaxis of infections: hygienic measures, possibly aseptic localization,
selective decontamination measures, prophylaxis targeted at particular diseases
(eg prophylaxis of Pneumocystis carinii pneumonia, by administration of
cotrimoxazole), etc.
• in case of infections: antimicrobial chemotherapy
• in case of antibody deficiency syndrome, substitution therapy with y-globulins
(immunoglobulins), possibly also with virus-specific hyperimmune preparations.
Chronic substitution treatment e.v. with polyvalent IgG preparations (200-300 mg
/ kg body weight every 4 weeks) is higher than i.m. In case of IgA deficiency
the indication for the administration of immunoglobulins should be carefully
evaluated, as it may cause anaphylactic reactions. A test for the detection of
anti-IgA autoantibodies must first be performed and it is advisable to use IgA
depleted IgA preparations. In case of need for blood transfusion, use only
washed erythrocyte concentrates
• administration of cytokines in controlled studies.