Goals Brief review of Immunology and immunodeficiency When to suspect an immunodeficiency - some specific criteria Initial laboratory evaluation - specific recommendations Some illustrative, confidence-building cases Complement T Cells Host Defense Phagocytes B Cells Bacteria handles Attract the good guys Direct the immune response Kill infected cells Make Immunoglobulins Eat everything and show the digested pieces to their friends. Innate Immunity Adaptive Immunity 4 Compartments of the Immune System Cellular Immunodeficiency (7%) Combined Immunodeficiency (23%) Complement deficiency (1%) PMN dysfuction (14%) Other (2%) Antibody Deficiency (53%) Relative Incidence of Primary Immunodeficiencies Skoda-Smith and Barrett, Contemporary Pediatrics 17:156-165 Complement Recurrent disseminated Neisserial infections. Autoimmune symptoms (Lupus). Pyogenic bacterial infections. Angioedema of face, hands, feet, or GI tract. Hisory suggestive of autosomal dominant inheritance. C1 C3(H2O), Bb C4 C2 C3b, Bb C4b, 2a C3b, Bb, P C3 C3a C3b C5 C5a C5b, 6, 7, 8, 9 Membrane Attack Complex Bactericidal Activity Classical Alternative Y Y Y Y Immune Complex Microbes Anaphylotoxin Opsonin Chemotactic Factor Phagocytes Soft tissue abscesses or lymphadenitis. Infection with catalase + organisms (Staph aureus, Serratia, E. coli, Aspergillus). Poor wound healing. Delayed separation of the umbilical cord. Chronic gingivitis and periodontal disease. Mucosal ulcerations. Delves and Roitt, NEJM 343:37-49 B Cells B Cells Recurrent bacterial sino- pulmonary infections or sepsis, particularly with encapsulated organisms. Chronic or recurrent gastroenteritis (Giardia and Enterovirus common). Chronic enteroviral menigo- encephalitis. Arthritis Unexplained bronchiectasis. Delves and Roitt, NEJM 343:37-49 T Cells Pneumocystis carinii pneumonia. Fungal infections. GVHD (rash, abnormal LFT’s, and chronic diarrhea. Recurrent, severe, or unusual viral infections. Failure to thrive. Delves and Roitt, NEJM 343:108-117 7 Red Flags: . Recurrent Infections: In 1 year - OM x 8; Sinusitis x 2; Pneumonia x 2; or any 2 deep-seated infections (meningitis, pneumonia, osteo, etc.) 2; or any 2 deep-seated infections (meningitis, pneumonia, osteo, etc.) Other Causes of Recurrent Infections Foreign Bodies - Lines, VP shunts, Artificial valves, Aspirated foreign bodies. Barrier Problems - Atopic dermatitis, Burns, Basilar skull Fx, Abnormal sinus tracts. Clearance Problems - Hypotonia, Aspiration, Ciliary dysfunction, CF. Obstructions - CF, Eustachian tube dysfunction, UPJ obstruction. Secondary immunodeficiencies - Immaturity, Malignancy, Malnutrition, Functional asplenia, Protein loss, Collagen vascular diseases, Immunosuppresives. Tough bugs - TB, MRSA, Multiply resistant organisms. Skoda-Smith and Barrett, Contemporary Pediatrics 17:156-165 Complement Phagocytic B Cell T Cell Recurrent disseminated Neisserial infections. Pyogenic bacterial infections. Angioedema of face, hands, feet, or GI tract. Autoimmune symptoms (Lupus). Hisory suggestive of autosomal dominant inheritance. Soft tissue abscesses or lymphadenitis. Infection with catalase + organisms (Staph aureus, Serratia, E. coli, Aspergillus). Poor wound healing. Delayed separation of the umbilical cord. Chronic gingivitis and periodontal disease. Mucosal ulcerations. Recurrent bacterial sino- pulmonary infections or sepsis, particularly with encapsulated organisms. Chronic or recurrent gastroenteritis (Giardia and Enterovirus common). Chronic enteroviral menigo- encephalitis. Arthritis Unexplained bronchiectasis. Pneumocystis carinii pneumonia. Fungal infections. GVHD (rash, abnormal LFT’s, and chronic diarrhea. Recurrent, severe, or unusual viral infections. Failure to thrive. D E F E C T T Y P E Combined CH50 - tests entire complement cascade ($83) CBC/Differential ($40) T & B cell subset analysis ($202) DTH reaction to Candida & Tetanus CBC/Differential ($40) Quantitative IgM, IgG, IgA, & IgE ($127) Anti-tetanus titers ($57) Anti-pneumococcal titers pre- & 4 wks post immunization CBC/Differential ($40) Neutrophil oxidative burst assay - AKA NBT assay ($86) . Recurrent infections: In 1 year - OM x 8; Sinusitis x 2, Pneumonia x 2; or any 2 deep-seated infections (osteo, CNS, etc.) Recurrent deep skin or organ abscesses Persistent thrush (mouth or other skin sites) after 1y/o . Family history of Primary Immunodeficiency . Classic clinical presentation: Ex. DiGeorge or Ataxia Telangactasia . Failure to Thrive . Poor response to antibiotics: Need for IV or prolonged course (>2 mo) to clear infections . Infection with signature organisms - PCP, Serratia, Aspergillus, Nocardia, Pseudomonas L A B S Immunodeficiency Algorithm C1 C3(H2O), Bb C4 C2 C3b, Bb C4b, 2a C3b, Bb, P C3 C3a C3b C5 C5a C5b, 6, 7, 8, 9 Membrane Attack Complex - Cell Lysis Classical Alternative Immune Complex Microbes Y Y Y Y Y Y Y CH50 The amount of complement (serum dilution) that causes lysis of 50% of antibody coated Sheep RBC’s. Tests only the Classical pathway. NBT Oxidative Burst Assay The soluble yellow dye nitroblue tetrazolium is taken up by phagocytosis into neutrophils. In normal neutrophils, the dye is reduced to dark blue, insoluble formazan crystals within the cell. This process requires the generation of superoxide by the neutrophil. Normal Control CGD Lekstrom-Himes and Gallin, NEJM 343:1703-1714 DHR, the New NBT Test Weakly fluorescent Dihydrorhodamine is taken up by phagocytosis into neutrophils. In normal neutrophils, the dye is reduced causing it to fluoresce brightly. Like the NBT test, this process requires the generation of superoxide by the neutrophil. Rich Clinical Immunology (2002), Harcourt - 123_05 Complement Phagocytic B Cell T Cell Recurrent disseminated Neisserial infections. Pyogenic bacterial infections. Angioedema of face, hands, feet, or GI tract. Autoimmune symptoms (Lupus). Hisory suggestive of autosomal dominant inheritance. Soft tissue abscesses or lymphadenitis. Infection with catalase + organisms (Staph aureus, Serratia, E. coli, Aspergillus). Poor wound healing. Delayed separation of the umbilical cord. Chronic gingivitis and periodontal disease. Mucosal ulcerations. Recurrent bacterial sino- pulmonary infections or sepsis, particularly with encapsulated organisms. Chronic or recurrent gastroenteritis (Giardia and Enterovirus common). Chronic enteroviral menigo- encephalitis. Arthritis Unexplained bronchiectasis. Pneumocystis carinii pneumonia. Fungal infections. GVHD (rash, abnormal LFT’s, and chronic diarrhea. Recurrent, severe, or unusual viral infections. Failure to thrive. D E F E C T T Y P E Combined CH50 - tests entire complement cascade ($83) CBC/Differential ($40) T & B cell subset analysis ($202) DTH reaction to Candida & Tetanus CBC/Differential ($40) Quantitative IgM, IgG, IgA, & IgE ($127) Anti-tetanus titers ($57) Anti-pneumococcal titers pre- & 4 wks post immunization CBC/Differential ($40) Neutrophil oxidative burst assay - AKA NBT assay ($86) . Recurrent infections: In 1 year - OM x 8; Sinusitis x 2, Pneumonia x 2; or any 2 deep-seated infections (osteo, CNS, etc.) Recurrent deep skin or organ abscesses Persistent thrush (mouth or other skin sites) after 1y/o . Family history of Primary Immunodeficiency . Classic clinical presentation: Ex. DiGeorge or Ataxia Telangactasia . Failure to Thrive . Poor response to antibiotics: Need for IV or prolonged course (>2 mo) to clear infections . Infection with signature organisms - PCP, Serratia, Aspergillus, Nocardia, Pseudomonas L A B S Immunodeficiency Algorithm A Few Notes on Quantitative Ig’s 1. Immunoglobulin levels vary by age so be sure to check age specific reference values. (Harriet Lane pp. 339-340). 2. DON’T check IgG subclasses in children under age 2 y/o. Complement Phagocytic B Cell T Cell Recurrent disseminated Neisserial infections. Pyogenic bacterial infections. Angioedema of face, hands, feet, or GI tract. Autoimmune symptoms (Lupus). Hisory suggestive of autosomal dominant inheritance. Soft tissue abscesses or lymphadenitis. Infection with catalase + organisms (Staph aureus, Serratia, E. coli, Aspergillus). Poor wound healing. Delayed separation of the umbilical cord. Chronic gingivitis and periodontal disease. Mucosal ulcerations. Recurrent bacterial sino- pulmonary infections or sepsis, particularly with encapsulated organisms. Chronic or recurrent gastroenteritis (Giardia and Enterovirus common). Chronic enteroviral menigo- encephalitis. Arthritis Unexplained bronchiectasis. Pneumocystis carinii pneumonia. Fungal infections. GVHD (rash, abnormal LFT’s, and chronic diarrhea. Recurrent, severe, or unusual viral infections. Failure to thrive. D E F E C T T Y P E Combined CH50 - tests entire complement cascade ($83) CBC/Differential ($40) T & B cell subset analysis ($202) DTH reaction to Candida & Tetanus CBC/Differential ($40) Quantitative IgM, IgG, IgA, & IgE ($127) Anti-tetanus titers ($57) Anti-pneumococcal titers pre- & 4 wks post immunization CBC/Differential ($40) Neutrophil oxidative burst assay - AKA NBT assay ($86) . Recurrent infections: In 1 year - OM x 8; Sinusitis x 2, Pneumonia x 2; or any 2 deep-seated infections (osteo, CNS, etc.) Recurrent deep skin or organ abscesses Persistent thrush (mouth or other skin sites) after 1y/o . Family history of Primary Immunodeficiency . Classic clinical presentation: Ex. DiGeorge or Ataxia Telangactasia . Failure to Thrive . Poor response to antibiotics: Need for IV or prolonged course (>2 mo) to clear infections . Infection with signature organisms - PCP, Serratia, Aspergillus, Nocardia, Pseudomonas L A B S Immunodeficiency Algorithm A Few Notes on T & B Cell Subsets 1. Test is performed by labelling patient’s cells with fluorescently labelled antibodies to various cell surface proteins present on T and B cells. The cells that become labelled with a specific antibody are then counted by laser activated fluorescence as they flow through a chamber. The most important markers are: CD3 - a protein present on the surface of all normal T cells CD4 - a protein present on the surface of “helper” T cells CD8 - a protein present on the surface of “cytotoxic T cells CD19 or CD20 - proteins present on the surface of all mature B cells Complement Phagocytic B Cell T Cell Recurrent disseminated Neisserial infections. Pyogenic bacterial infections. Angioedema of face, hands, feet, or GI tract. Autoimmune symptoms (Lupus). Hisory suggestive of autosomal dominant inheritance. Soft tissue abscesses or lymphadenitis. Infection with catalase + organisms (Staph aureus, Serratia, E. coli, Aspergillus). Poor wound healing. Delayed separation of the umbilical cord. Chronic gingivitis and periodontal disease. Mucosal ulcerations. Recurrent bacterial sino- pulmonary infections or sepsis, particularly with encapsulated organisms. Chronic or recurrent gastroenteritis (Giardia and Enterovirus common). Chronic enteroviral menigo- encephalitis. Arthritis Unexplained bronchiectasis. Pneumocystis carinii pneumonia. Fungal infections. GVHD (rash, abnormal LFT’s, and chronic diarrhea. Recurrent, severe, or unusual viral infections. Failure to thrive. D E F E C T T Y P E Combined CH50 - tests entire complement cascade ($83) CBC/Differential ($40) T & B cell subset analysis ($202) DTH reaction to Candida & Tetanus CBC/Differential ($40) Quantitative IgM, IgG, IgA, & IgE ($127) Anti-tetanus titers ($57) Anti-pneumococcal titers pre- & 4 wks post immunization CBC/Differential ($40) Neutrophil oxidative burst assay - AKA NBT assay ($86) . Recurrent infections: In 1 year - OM x 8; Sinusitis x 2, Pneumonia x 2; or any 2 deep-seated infections (osteo, CNS, etc.) Recurrent deep skin or organ abscesses