Section 5 HA. Paroxysmal Nocturnal Hemoglobinuria (PNH). Definition Etiology and pathogenesis Characteristics of PNH （ clinical and lab ） Diagnostic process. Definition.
Paroxysmal Nocturnal Hemoglobinuria (PNH)
Etiology and pathogenesis
Characteristics of PNH （clinical and lab）
PNH is a clonal disorder of hematopoietic stem cells caused by a somatic mutation of the pig-A gene on the short arm of the X chromosome . And the patients with it may present either with a HA( with intravascular hemolysis and episodes of nocturnal hemoglobinuria) or pancytopeniawith a dysplastic or aplastic marrow morphology.
GPI - glycosylphosphatidylinositol glycan
complete or partial failure in the production of GPI anchor protein
Loss of several GPI-anchored membrane proteins
increased sensitivity to C-mediated lysis
complement-driven activation of platelets, impaired fibrinolysis
mutations of pig-A gene in HSC
CD59 : membrane inhibitor of reactive lysis,
CD55（decay accelerating factor
Severe anemia：fatigue, weakness, pallor, dyspnea
Clinical featuresof PNH
2. Dark urine : paroxysmal or on awakening or no.
(hemolysis episode after infection, transfusion, acid food or drugs, stress, fatigues or after aplastic or hypoplastic anemia.)
PNH I : GPI-negative cells(normal)
PNH II : Partial deficiency
PNH III:Complete deficiency
3. Splenomegaly in some patients
4. Venous thrombosis (hepatic, portal, splenic mesenteric veins) or DIC
5. Major bleeding or infection.
Some die of thrombotic diseases, some die of leukemia, some develop(or revert to AA.
Lab findings of PNH
A. intermittent hemoglobinuria
B. sideropenia (secondary to iron deficiency)
C. marrow insufficiency
3. Urine: sometimes hemoglobinuria，URO +
constanthemosiderinuria (Rous test +)
4. Specific tests
--- Sugar water test: screening test for PNH
--- Ham test: definitive test for PNH
5. Immunophenotype：decreased CD55, CD59
MA, IHA or some leukemia
SUGAR WATER TEST
Red cells suspension(patient)
control serum ( or same blood type)
【Principle】 The complement present in serum is responsible for lysis of PNH cells with sensitivity to acidifiction.
patient’s red cells suspension
acidified pH6.5 , 37℃1h
mixed with fresh complement
( same type control serum or patient’s own serum)
lysis: no lysis:
PNH normal orlack of PNH cells
Red cells suspension
inactivated serum(56℃, 30’)
pH6.5 , 37℃1h
1. kinetic studies with 51Cr labeled ,the red cells show a double population:
A. with a short half-life
B. with a subnormal survival
2. A cytometric assay of CD16 and CD66b on granulocytes in patients with equivocal red cell
3. GPI anchor protein and PIG-A gene.
two of the following or
one of the following
Sugar water test: (+)
Ham test: (+)
Rous test +
exclude AA.(exp. hypoplasia)
A 30-year-old male came to see the physician because of increasing fatigue over the previous few months.
PE : a pale but otherwise normal-appearing adult male, the liver and spleen slightly enlarged.
The patient reported noticing that his first urine of the morning was occasionally brown.
Hematocrit 0.25 l/L
1. What is the most probably diagnosis of this patient? List your evidence of the diagnosis.
2. If you want to have an exact diagnosis of this patient, which tests are supposed to be done and what are the expected results?
3. Can you explain the following results with the patient?
Serum iron: 8.1umol/L, TIBC: 66umol/L
AA and PNH:
Clinical features of AA
Ham test positive or Hburia,Rous test positive