Answer is D (Increased LAP scores) PNH is associated with a decreased Leukocyte Alkaline phosphase (LAP) score PNH: Paroxysmal Nuctunal haemoglobinuria: Review PNH is an Acquired Q Intracarpuscular (--) disorder, acquired at stern cell level (-) by loss characterised by undue sensitivity of red blood cell's membrane to complement (--) Common manifestations: PNH : Three common manifestation Hemolytic Anemia Venous Thrombosis Deficient Hematopoesis Probably due to defect at stem cell level Because of increased activation of Activation of complement indirectly Pancytopenia/Aplastic anemia complement and complement stimulates platelet aggregation and - Granulocytes mediated destruction hypercoagulability (thus thrombosis - Thrombocytes (thrombocytopenia) * despite thrombocytopenia) HemoglobinemiaQ Hemoglohinuriae HemosiderinuriaQ Elevated LDH Q Why is it called Paroxysmal Nocturnal haemoglobinuria? Basis : Acidification enhances activity of complement During night when one sleeps (noctunal) --> Relative Hypoxia --> Acidosis --> Enhanced complement activity Paroxysm of Haemoglobinuria identified by --> Complement mediated destruction of red blood cells passage of brown urine in morning. Red Cell Membrane is deficient in two factors which result in increased activation of complement 1. DAF Q :Decay accelerating factor that activates decay of complements 2. MIRL CD 59 : inhibits membrane attack complex