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Primary Immune Deficiency Diseases (Harrison Ch351) - Coggle Diagram
Primary Immune Deficiency Diseases (Harrison Ch351)
Immune System Overview
Innate Immunity (先天免疫)
Phagocytes:
Neutrophils, Macrophages, Dendritic Cells
Complement System
Toll-like Receptors (TLRs)
Adaptive Immunity (適應性免疫)
T Cells:
CD4+ (Helper), CD8+ (Cytotoxic)
B Cells → Antibody Production
IgG, IgA, IgM, IgE, IgD
Diagnosis & Screening
10 Warning Signs of PID
≥ 4 Ear Infections/year
≥ 2 Sinus Infections/year (without allergy)
≥ 2 Pneumonias/year
Recurrent Skin Abscesses
Chronic Fungal Infections (Candida)
Failure to Thrive (FTT)
Severe Infection after Live Vaccines (BCG, Polio)
Family History of PID
Key Lab Tests
CBC
: Neutropenia (SCN), Lymphopenia (SCID)
Immunoglobulin Levels
: Low IgG, IgA, IgM (XLA, CVID)
DHR Test
: CGD (↓ ROS production)
CH50/AP50
: Complement Deficiencies
Flow Cytometry
: T/B/NK Cell Deficiencies
Genetic Testing
: Confirm PID (SCID, CGD, LAD, WAS)
Key Primary Immunodeficiency Diseases
Innate Immunity Defects
Chronic Granulomatous Disease (CGD)
Defect:
NADPH Oxidase → ↓ ROS → No Bacterial Killing
Pathogens:
Staphylococcus aureus, Aspergillus, Serratia marcescens
Diagnosis
DHR Test:
↓ ROS production
Treatment
Antibiotics:
Trimethoprim/Sulfamethoxazole
Antifungal:
Itraconazole
Immunotherapy:
Interferon-γ
Curative:
HSCT
Leukocyte Adhesion Deficiency (LAD)
Defect:
β2-Integrin (LAD-1) → No Neutrophil Adhesion
Clinical Features
No Pus Formation
Delayed Umbilical Cord Separation (>30 days)
Diagnosis
Flow Cytometry:
↓ CD18
Treatment
Curative:
HSCT
Complement Deficiencies
Pathogens:
Recurrent Neisseria infections
(C5-C9 Deficiency)
Diagnosis
CH50/AP50 Test:
↓ Complement Activity
Treatment
Vaccination
Penicillin Prophylaxis
Adaptive Immunity Defects
Severe Combined Immunodeficiency (SCID)
Defect:
No T Cells (± B/NK cells) → Life-threatening Infections
Pathogens:
Pneumocystis jirovecii, Candida, Viruses
Diagnosis
Newborn TREC Screening
Flow Cytometry:
Absent T Cells
Treatment
Curative:
HSCT, Gene Therapy
X-linked Agammaglobulinemia (XLA)
Defect:
BTK Mutation
→ No B Cells → No Antibodies
Pathogens:
Encapsulated Bacteria (S. pneumoniae, H. influenzae)
Diagnosis
Absent B Cells (CD19-)
Low IgG, IgA, IgM
Treatment
IVIG (Lifelong)
Avoid Live Vaccines
Common Variable Immunodeficiency (CVID)
Defect:
Low IgG, IgA, IgM (B-cell Dysfunction)
Diagnosis
↓ IgG, ↓ IgA ± IgM
Treatment
IVIG
Monitor for Autoimmune Diseases & Lymphoma
Wiskott-Aldrich Syndrome (WAS)
Defect:
WASP Mutation → T-cell Dysfunction, Small Platelets
Triad
Thrombocytopenia
Eczema
Recurrent Infections
Diagnosis
Low Platelet Size (MPV↓)
↓ IgM, ↑ IgA/IgE
Treatment
HSCT (Curative)
IVIG
Rituximab (Autoimmune Issues)
Clinical Considerations
How to Differentiate PID from Other Diseases?
HIV/AIDS:
CD4+ T Cell Depletion → HIV PCR
Cystic Fibrosis:
Chronic Lung Infections → Sweat Chloride Test
SLE (Lupus):
Autoimmune Features → ANA, Complement Levels (C3/C4↓)
Transient Hypogammaglobulinemia:
Resolves after Age 3
Clinical Red Flags for PID
Severe Opportunistic Infections (
Pneumocystis, Candida
)
Recurrent Infections that do NOT respond to standard antibiotics
Failure to Thrive (FTT) in infants
Family History of Early Childhood Deaths due to Infections
Post-vaccine complications (
BCG dissemination
)
Treatment Strategies
IVIG (Intravenous Immunoglobulin)
→ XLA, CVID, WAS
Antibiotic Prophylaxis
→ CGD (
Trimethoprim/Sulfamethoxazole, Itraconazole
)
HSCT (Hematopoietic Stem Cell Transplantation)
→ SCID, CGD, LAD, WAS
Gene Therapy (Experimental)
→ SCID, CGD
Exam Tips & High-Yield Facts
DHR Test
→ CGD Diagnosis
CH50/AP50 Test
→ Complement Deficiencies
Low IgG, IgA, IgM
→ Think CVID, XLA
Thrombocytopenia + Eczema + Infections
→ WAS
Cold Staph Abscesses + High IgE
→ Job’s Syndrome