Paroxysmal Nocturnal Hemoglobinuria (PNH)Section 5 HADefinitionEtiology and pathogenesisCharacteristics of PNH clinical and labDiagnostic process
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 pancytopenia with a dysplastic or aplastic marrow morphology.DefinitionGPI - glycosylphosphatidylinositol glycan
Etiology and pathogenesis of PNH
mutations of pig-A gene in HSC
CD59 : membrane inhibitor of reactive lysis, CD55 decay accelerating factor CD58CD16CD14
Clinical features of 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.)
Complement activation PNH I : GPI-negative cells(normal)PNH II : Partial deficiencyPNH III:Complete deficiency
3. Splenomegaly in some patientsClinical features of PNH Some die of thrombotic diseases, some die of leukemia, some develop(or revert to AA.4. Venous thrombosis (hepatic, portal, splenic mesenteric veins) or DIC 5. Major bleeding or infection.
WBC : neutropenia, low LAP score or absence. BPC: fall, abnormal platelet functionLab findings of PNH
Hypochromic anemia of PNH
2. Bone marrow hyperplasia or hypoplasia (aspiration site) hypochromic and normochromic erythrone
Iron stain is often absent.(iron deficiency) Lab findings of PNH
Bone marrow of PNH: erythroid hyperplasia
bone marrow of PNH
Hypochromic, polychromic, stippling
A. intermittent hemoglobinuria hemosiderinuriaB. sideropenia (secondary to iron deficiency)C. marrow insufficiencyWhy the patien with hypochromic anemia?
3. Urine: sometimes hemoglobinuriaURO + constant hemosiderinuria (Rous test +)
Lab findings of PNH5. Immunophenotypedecreased CD55, CD594. Specific tests --- Sugar water test: screening test for PNH --- Ham test: definitive test for PNH
Urine of PNH patient in the morning
3. Urine: URO +
SUGAR WATER TESTMethod control serum ( or same blood type)Red cells suspension(patient) sucrose
HAMS TESTPrinciple The complement present in serum is responsible for lysis of PNH cells with sensitivity to acidifiction. patients red cells suspension mixed with fresh complement ( same type control serum or patients own serum)acidified pH6.5 , 371hlysis: no lysis: PNH normal or lack of PNH cells
Red cells suspension + inactivated serum (56, 30) pH6.5 , 371h no lysis:
Control tubes for excluding false negative
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 cell3. GPI anchor protein and PIG-A gene.Progressive Studies
Diagnosis for PNH
Case assay: 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.
Case assay: CBC:Hb:85 g/LHematocrit 0.25 l/LRBC 2.61012/LWBC 4.4109/L
Bone marrow figure
Case assay: Rous test
Case assay: Questions: 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
Questions :What is the etioloy of PNH? How to diagnose PNH?3.How to differentiate PNH and AA?4. How to differentiate PNH and IDA?
AA and PNH:AA-PNH syndrome
AA crisisClinical features of AAHam test positive or Hburia,Rous test positive