Chapter 10 Immunology vol.2

Chapter10 今日のメモ☆

Immunologyの二回目は4種類のHypersensitivity Reaction（過敏性反応；アレルギー）について。

Type I [IgE-mediated] hypersensitivity reaction
 (Anaphylaxy type immediate hypersensitivity)
 - reaction factor
    *IgE
    *histamine, serotonine, PG, LT = [early-phase reaction, 1~2 mins, peak 1~2 hrs]
    *eosinophils（好酸球） = [late-phase reaction（遅発反応）, 6~12 hrs]
    *inheritable（遺伝的素因）
    *Complement関与(－)

 - Common allergens
    *Respiratory allergens (pollen（花粉）, plants, fungi, animal fur etc)
    *Gastrointestinal allergens (shelfish, nuts, peanuts, egg, milk etc)
    *Skin and mouth allergen (topically applied drug such as procaine（局所麻酔薬） etc )
    *Intravenous allergen
      (insect venoms（昆虫毒）, drugs such as penicillin, cephalosporins, caccines etc)

 - Local symptoms of pathogenesis
    *urticaria（蕁麻疹）, pruritus（掻痒）, nasal congestion, bronchoconstriction（気管支収縮）,
      mucus and lachrymal hypersecretion, laryngeal edema（喉頭水腫）, vomiting and diarrhea
    *atopic dermatitis（アトピー性皮膚炎）
    *anaphylaxis

 - Diagnosis
    *scratch tests
    *Radioallergosorbent (RAST) & radioimmunosorbent (RIST) assays

 - Prophylazis
    *Hyposensitization (desensitization) （減感作療法）: アレルゲンを少量ずつ繰り返し与える（筋注）ことにより、アレルゲンに特異的なIgA,IgGの産生を促進させ、アレルギンとIgEとの結合を阻止する

 - Therapy
    *Competitive H1-antagonists of histamin for early-phase reaction
    *Glucocorticoids & Antileukotriene therapies for late-phase reaction
    *Epinephrine for anaphylaxis (α-agonist & β-agonist effect)
    *Clomolyn sodium（クロモグリク酸Na） (inhibitor of mast cell)
    *Topical steroids
    *Anti-IgE therapy, monoclonal antibody to the Fc region

Type II hypersensitivity reactions
  - reaction factor & pathogenesis
    *IgG, IgM
    *NK cells
    *Macrophage, eosinophils
    *Complement関与(+)

    *Cytotoxicity, Opsonization

 - Common allergens
    *º Foreign blood surface antigens
    *¹ transplanted tissue
    *² drug allergens such as penicillins, cephalosporins, quinidine
    *³ self-antigens : autoimmune diseases
         
 - Local symptoms of pathogenesis
    *º transfusion mismatches（輸血不適合）,
       Rh disease during pregnancy（Rh血液型不適合による新生児の溶血性黄疸）
    *¹ hyperacute graft rejection（急性移植拒絶反応）
    *² hemolytic anemia（溶血性貧血）, thrombocytopenia（血小板減少症） 
    *³ myathenia gravis(重症筋無力症）
       hemolytic amenia（自己免疫性溶血性貧血） by α-methyldopa

 - Prophylazis & Therapy
     *withdrawing the drug

Type III hypersensitivity reactions
 - reaction factor & pathogenesis
    *immune complexes（免疫複合体） activate complement, induce positive chemotaxis（走行性）
    *high concentration of antigen or antibody (e.g., after long-term & hy-dose therapy)
    *chronic formation of immune complexes
    *IgG, IgM, neutrophils
    *Complement関与(+)

 - Common allergens
    *¹Self-antigens in most non-organ-specific : autoimmune disorders
      e.g) lupus erythematosus（SLE; エリテマトーデス）, rheumatoid arthritis（関節リウマチ）
    *chronic infection by bacteria, protozoan or virus
    *² Fungal and bacterial spores（胞子）
    *Drugs such as penicillin, sulfonamides, thiouracil
    *Antisera（抗血清） from another species (e.g. horse)

 - Local symptoms of pathogenesis
    *Lmphadenopathy（リンパ節症）, splenomegaly（脾腫）, fever, rash (by drug-induced)
    *¹ Casculitis（血管炎）, glomerulonephritis（糸球体腎炎）, necrotizing（壊死）,
       arthralgia（関節症）, arthritis（関節炎）, joint pain
    *² pneumonitis（肺炎）

 - Prophylazis & Therapy
    *withdrawing the drug
    *antihistamines
    *corticosteroids

Type IV hypersensitivity (Delayed cutaneous hypersensitivity（遅延性過敏症）)
 - reaction factor & pathogenesis
    *antigen-specific T_H cells
    *Macrophages secrete cytokines
    *Complement関与(－), Antibody関与(－)

 - Common allergens
    *Infectious agents : Tuberculin reaction
    *antigen that induce a tuberculin reaction（ツベルクリン反応）
    *¹ Hapten allergens such as pentadecacatechols from poison ivy（漆）, poson oak,  antibiotic ointment :

 - Local symptoms of pathogenesis
    *¹ contact dermatitis（接触性皮膚炎）
    * Hashimoto thryoiditis
    * graft-versus-host reaction[GVHR]（移植片対宿主反応）

 - Prophylazis & Therapy
    *Topical corticosteroids
    *Oral corticosteroids : in severe cases


タイトル
Today's question
- type IV hypersensitivity reaction(遅延性過敏症)の問題
Q: In Which type IV hypersensitivity reaction is the tissue-damaging disorder considered an inappropriate response by the immune system?
(A) Poison ivy dermatitis
(B) Chronic tuberculosis
(C) Acute graft rejection
(D) Tuberculin test




A: (A) Poison ivy dermatitis
Poison ivy contains a hapten, pentadecyl catecholm which is not known to be toxic.  Therefore, its capacity to elicit an immute response is inappropriate because it serves no useful function.  In chronic tuberculosis, the immune response is attemptint, although unsuccessfully, to eliminate the mycobacterial pathogen.  Acute graft rejection is also appropriate, but unfortunate, because it is a response against foreign tissue.  A tuberculin test is an appropriate mainfestation of the existence of active immunity or memory to Mycobacterium.