🩸🧬 Terminal Complement Activation in PNH — By Prof. Talha Munir, KFSHRC 🔁 Root problem • ❌ Loss of CD55/CD59 → uncontrolled terminal complement • 💥 C5 cleavage → C5b–9 (MAC) + C5a 💥 Direct effects • 🩸 Intravascular hemolysis → ↑ LDH 📈 • 🧲 Free Hb → haptoglobin

🧬 PNH Complement Basics 🧪 Complement = classical, lectin & alternative pathways ⚡ All converge on C3 activation → amplification loop 🔥 C5 cleavage → C5a (inflammation) + MAC (C5b-9) 🩸 In PNH: loss of CD55/CD59 → unchecked MAC → hemolysis 🔑 Target the pathway,

@Doctors_GUILD C) Flow cytometry for CD55/CD59.. The best confirmatory test for paroxysmal nocturnal hemoglobinuria (PNH) is Flow cytometry for CD55/CD59. This is the gold standard for diagnosing PNH as it measures the absence or deficiency of glycosylphosphatidylinositol (GPI)-anchored

@Doctors_GUILD Best answer 👉 Flow cytometry for CD55/CD59 ✅ Let me break it down mentor-style, quick and crystal clear 👇 🧠 Why Flow Cytometry is the GOLD STANDARD? Paroxysmal Nocturnal Hemoglobinuria (PNH) is caused by absence of GPI-anchored proteins, mainly: •CD55 (DAF) •CD59 (MAC

@Doctors_GUILD The correct answer is: ✅ C) Flow cytometry for CD55/CD59 Why? Paroxysmal Nocturnal Hemoglobinuria (PNH) is caused by deficiency of GPI-anchored proteins, especially: CD55 (DAF) CD59 (MIRL) These normally protect red blood cells from complement-mediated destruction. 👉

HIV is known to recruit host complement inhibitors (eg factor H, CD55/CD59). The goal is the same - disable the first line of innate immunity to extend survival.

@Doctors_GUILD C) Flow cytometry for CD55 / CD59 ✅

@Doctors_GUILD C) Flow cytometry for CD55/CD59. • Paroxysmal Nocturnal Hemoglobinuria= acquired stem cell mutation→ deficient GPI-anchored proteins (CD55/CD59)→ unprotected RBCs→ complement lysis→ intravascular hemolysis. ∆ Classic triad: Nocturnal dark urine (hemoglobinuria),