NGN CASE STUDY CERTIFICATION
EVALUATION SCRIPT 2026 CLINICAL QANDA
VERIFIED
◉ Leukocyte Adhesion Deficiency (LAD) — CD18 Deficiency
Answer: 1. CD18 → forms LFA-1 adhesion integrin.
2. Neutrophils cannot exit bloodstream.
3. Delayed umbilical cord separation (>30 days)
4. Recurrent bacterial infections
5. NO pus formation (neutrophils can't enter tissues)
6. Neutrophilia (tons of them stuck in bloodstream)
7. "No pus + delayed cord separation" = CD18 / LAD.
◉ Complement Deficiencies Answer: 1. C8 (or C6/C7/C9) deficiency
- MAC defect
2. MAC can't form → cannot lyse bacteria.
3. Recurrent Neisseria infections (meningitidis or gonorrhoeae).
◉ Factor I Deficiency Answer: 1. Overactivation of complement →
consumption of C3.
2. Low C3
3. Recurrent pyogenic infections
, 4. Overactive alternative pathway
5. If C3 is missing but C4 normal → think Factor I.
◉ TLR3 Pathway Deficiency Answer: 1. TLR3 or associated signaling
(TRIF).
2. Viral dsRNA → induces type I interferons (IFN-α/β).
3. Recurrent herpes simplex encephalitis (HSV in the brain)Because
neurons rely heavily on type I interferon.
4. Isolated susceptibility to HSV encephalitis = TLR3 defect.
◉ SCID (Severe Combined Immunodeficiency) Answer: 1. Multiple
causes → same result: no T cells ± no B cells.
2. RAG1/2 deficiency → no T or B cells (recombination failure)
3. Common γ chain deficiency (X-linked) → failed cytokine signaling
4. ADA deficiency (not in your file but classically included)
◉ Common γ chain deficiency (IL2RG) — X-linked SCID Answer: 1.
IL-2, IL-4, IL-7, IL-9, IL-15, IL-21
2. Affects signaling, not ligand binding.
3. CD25 increases affinity, γ chain gives signal.
4. Most critical loss = IL-7 signaling → NO T cells
5. No T cells
6. B cells present but nonfunctional (need T help)
EVALUATION SCRIPT 2026 CLINICAL QANDA
VERIFIED
◉ Leukocyte Adhesion Deficiency (LAD) — CD18 Deficiency
Answer: 1. CD18 → forms LFA-1 adhesion integrin.
2. Neutrophils cannot exit bloodstream.
3. Delayed umbilical cord separation (>30 days)
4. Recurrent bacterial infections
5. NO pus formation (neutrophils can't enter tissues)
6. Neutrophilia (tons of them stuck in bloodstream)
7. "No pus + delayed cord separation" = CD18 / LAD.
◉ Complement Deficiencies Answer: 1. C8 (or C6/C7/C9) deficiency
- MAC defect
2. MAC can't form → cannot lyse bacteria.
3. Recurrent Neisseria infections (meningitidis or gonorrhoeae).
◉ Factor I Deficiency Answer: 1. Overactivation of complement →
consumption of C3.
2. Low C3
3. Recurrent pyogenic infections
, 4. Overactive alternative pathway
5. If C3 is missing but C4 normal → think Factor I.
◉ TLR3 Pathway Deficiency Answer: 1. TLR3 or associated signaling
(TRIF).
2. Viral dsRNA → induces type I interferons (IFN-α/β).
3. Recurrent herpes simplex encephalitis (HSV in the brain)Because
neurons rely heavily on type I interferon.
4. Isolated susceptibility to HSV encephalitis = TLR3 defect.
◉ SCID (Severe Combined Immunodeficiency) Answer: 1. Multiple
causes → same result: no T cells ± no B cells.
2. RAG1/2 deficiency → no T or B cells (recombination failure)
3. Common γ chain deficiency (X-linked) → failed cytokine signaling
4. ADA deficiency (not in your file but classically included)
◉ Common γ chain deficiency (IL2RG) — X-linked SCID Answer: 1.
IL-2, IL-4, IL-7, IL-9, IL-15, IL-21
2. Affects signaling, not ligand binding.
3. CD25 increases affinity, γ chain gives signal.
4. Most critical loss = IL-7 signaling → NO T cells
5. No T cells
6. B cells present but nonfunctional (need T help)
