Editorial
Authors
1 Department of Medicine and Clinical Immunology, faculty of medicine, Al-Azhar University
2 Department of Clinical Pathology, faculty of medicine, Al-Azhar University
Prof. Ahmed Elghobary2 and prof. Mohamed Aref1
1 Department of Clinical Pathology, faculty of medicine, Al-Azhar University
2 Department of Medicine and Clinical Immunology, faculty of medicine, Al-Azhar University
Von Pirquet (1874-1929) introduced the term "allergy" in 1906. He described a change to the reactivity of the organism namely in time, quantity and quality . In contrast to the widely accepted use of the "allergy" today, it is restricted to specific immunologic hypersensitivity reactions against harmless foreign antigens. He wanted to describe in general a change in reactivity of the organism, namely in word "allergy" today, when it is restricted to specific immunologic hypersensitivity reactions against harmless foreign antigens. Allergy in Pirquets sense comprised a general term indicating increases and decreases of the reactivity, and so both hypersensitive and hyposensitive reactions. With the expansion of understanding sunstones (so called allergens) it also on endogenous factors of the organism itself.(Stanford 2016).
Although the postulation of Pirquet that he described over 100 years, ago , the theory still valid. The present work was a trial to discuss the strength and week points of this theory.
Type 1: It is IgE mediated hypersensitivity . This type gives a positive reaction within 15 minutes. The woard allergy is usually applie1d to type one hypersensitivity
Type 2 : It is Cytotoxic or Cytolytic through an antibody mediated reaction in target organ through an inflammation reaction of the target organs. Transfusion reaction, Hemolytic diseases of the newborn autoimmune hemolytic anemia best are examples .
Type 3 : It is antibody and complement mediated inflammation . Both.type 2 and 3 gives positive skin reaction after 8 hours . Serum sickness is the best example
Type 4 :It is cell mediated mediate hypersensitivity .This type gives a positive skin reaction after 24 hours . Activated lymphocyte is mediating the pathological reaction. Allergic contact dermatitis, tuberculin type of hypersensitivity, allograft transplantation reaction are the best examples.
Allergy / hypersensitive is an unusual response in an individual to a substance or a condition which is harmless to others. It is an over reaction. The word allergy applied to type 1 hypersensitivity is substances that the immune system consider it harmful even if they are not.
A normal reaction should be the developments of immunity. The antibodies involves in allergies are known as IgE. People who usually are affected to allergy produce large quantities of IgE. These IgE antibodies lunch back against a perfectly harmless substances such as rasp pollen, and cat dander ( dDandruff) drug like penicillin etc. .
Other main components to allergies are mast cells. A mast cell has about 1000 histamine containing granules in its cytoplasm and on its surface it has up to 1 million receptors for IgE antibodies. IgE encounters allergens when it activated the mast cells to release histamine and other chemicals.
Type II Hypersensitivity:1 cytotoxic Compatibility in newborns (Erythroblastosisfetalis) . 2.Rheumatic heart disease 3.Blood transfusion reaction 4.Drug induced hemolytic anemia 5.Thrombocytopenia
According to definition of allergy, all types are due to non self antigens .Types 2,3 are precipited by self antigen. IuType 2 definition of allergy, all types are due to non self antigen. in fact, type 3 and type 2 was overlabing.
Type III hypersensitivity: immune complex :
Examples areSerum sickness, Lupus erythematosus Rheumatoid arthritis and allergic stomatitis
Although IgE in Type 1 hypersensitivity is the cornerstone , its absence has many explanations, but lack of approve . However skin test is sensitive but lack of specificity.
Our suggestion depends on evaluation of serum histamine .If is high , patients are considered type 1 , which can be vaccinated, and anti-histamine is ahelpful therapy.
On the others hand, if serum histamine levels is normal , total IgG and IgM were estimated. If high , this could be type 2 or type 3 hypersensitivity. They could be differentiated by estimation of complement C3.
According to Perqute theory for patients of type 2,3 the clinician dealing ith active diseases not with disease itself. So, ESR and CRP are the most value to folly up for disease activity. .
References:
Huber B. Wien KlinWochenschr. (2006 )[100 years of allergy: Clemens von Pirquet - his idea of allergy and its immanent concept of disease]. Oct;118(19-20):573-9. doi: 10.1007/s00508-006-0701-3. PMID: 17136331 German.
Stanford T Shulman https://pubmed.ncbi.nlm.nih.gov/27794078/-full-view-affiliation-1 (2016)
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