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A 42-year-man complains of several months of weight loss, night sweats, mild sputumproduction, and the spitting up of blood. You run a PPD (tuberculin skin test) and theresults are positive amounts of IL-2, IFN-Y, andTNF. The immune cell responsible for Patients with tuberculus granulomas that have elevated this pattern of cytokine production is the

A patient seeing a rheumatologist for the first time because of joint pain is asked to fill out forms that include questions about family history. She recalls many family members with arthritis, including her grandmother and great-aunt. Her mother has systemic lupus erythematosus (SLE) with arthritis symptoms andrenal disease. This family history is most suggestive of which of the following A. A microbial infection common to all afflicted family members B. X-linked Mendelian genetics C. An environmental exposure that her mother developed while growing up D. A genetic predisposition

#ImD #Immunity #Micro #L5 #L6 #L7 #L8 #Hypersensetivity_reactions #TBL1 #Asthma

👑 A patient develops a positive Mantoux test 48 hours after PPD injection. Which sequence BEST explains the reaction? 🔹A) Sensitized Th1 cells → Cytokine release → Macrophage recruitment → Tissue injury 🔹B) Sensitized Th1 cells → Perforin release → Direct killing of macrophages → Tissue injury 🔹C) Activated macrophages → Sensitization of Th1 cells → Cytokine release → Tissue injury 🔹D) Macrophage recruitment → Antigen exposure → Sensitization phase → Tissue injury

👑 TYPE IV HYPERSENSITIVITY ❌ No antibodies. ❌ No complement. ✅ T-cell mediated (Th1 ± CD8⁺). ✅ Delayed: 24–72 hours after re-exposure. ✅ IFN-γ activates macrophages. ✅ Macrophages are the main cause of tissue damage. 📌 Classic Type IV examples: 🔹Contact dermatitis (nickel, poison ivy). 🔹Mantoux (PPD) test. 🔹Granuloma formation (TB, Leishmaniasis, Sarcoidosis). 💎 Exam pearl: 🔹If the question says 48–72 hours + induration + T cells + macrophages → the answer is Type IV hypersensitivity. 🚨 MCQ ALERT: 🔹The major effector cell causing tissue injury in Type IV hypersensitivity is the activated macrophage, recruited by Th1-derived IFN-γ. 📚

👑 A patient develops hematuria, proteinuria, and hypertension two weeks after recovery from streptococcal pharyngitis. Laboratory testing shows low C3 levels and elevated ASO titers. 🔹Which finding, if present, would most strongly support the diagnosis of a Type III hypersensitivity reaction rather than a Type II hypersensitivity reaction? 🔹A) Antibody binding directly to glomerular basement membrane antigens 🔹B) Linear deposition of immunoglobulin along the basement membrane 🔹C) Granular deposition of antigen-antibody complexes within the glomerulus 🔹D) Complement-mediated lysis of intrinsic renal cells 🔹E) Opsonization of renal cells by IgG antibodies

👑 A 10-year-old boy develops severe pain, erythema, induration, and focal necrosis at the site of a tetanus booster vaccination 6 hours after injection. Laboratory studies reveal decreased serum C3 levels. Biopsy demonstrates immune complex deposition around small vessels with dense neutrophilic infiltration. 🔹Which of the following events is the most immediate cause of tissue injury in this patient? 🔹A) IgE-mediated mast cell degranulation causing histamine release 🔹B) Cytotoxic T-cell recognition of antigen-bearing endothelial cells 🔹C) Neutrophil release of lysosomal enzymes after Fc/complement receptor engagement with immune complexes 🔹D) Formation of membrane attack complex causing direct endothelial lysis 🔹E) Activation of macrophages by IFN-γ released from Th1 cells

👑 TYPE III HYPERSENSITIVITY — 10-SECOND REVISION 🔹Type III = Immune Complex (Ag-Ab) Disease 🔹IgG or IgM + Soluble Ag ⬇️ Immune Complexes ⬇️ Complement Activation (C3a, C5a) ⬇️ Neutrophil Recruitment ⬇️ Tissue Damage 🔹Local Type III = Arthus Reaction ▪️ Antibody excess ▪️ 4–8 hours after antigen injection ▪️ Redness + swelling + induration 🔹Systemic Type III = Antigen excess ▪️ Immune complexes circulate and deposit in tissues 🔹Favorite deposition sites: ▪️ Blood vessels → Vasculitis ▪️ Glomeruli → Glomerulonephritis ▪️ Synovium → Arthritis 🔹Classic examples: ▪️ Arthus reaction ▪️ Serum sickness ▪️ Post-streptococcal glomerulonephritis ▪️ SLE ▪️ Rheumatoid arthritis 🔹Exam clue: 🐎 Horse antivenom + Fever + Rash + Joint pain + Low C3 ➡️ Serum sickness 🔹Exam clue: 🦠 Recent Streptococcal pharyngitis + Hematuria + Periorbital edema + Low C3 ➡️ PSGN 🔹🧨 Ultimate Exam Trap: Type II = Antibody against a FIXED tissue antigen Type III = Antibody against a SOLUBLE antigen → Immune complexes deposit elsewhere 🔹🔪 Killer Memory: Type III = Immune Complexes + Complement + Neutrophils.

اكلج ضحى صدك هذا دواء اسمه forxiga نسيت اعدل اسمه لان من رجعت من المحاضره بوقتها بحثت عليه ف الدكتوره حجت عنه انو هو حيل زين ل علاج الDM type2 و كالت حتى يحمي الكلية و القلب بس الشركات ديحاربونه لان يريدون البشريه توصل ل مرحله حتى النوع الثاني يستخدم انسولين

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