CD55, CD59 결핍에 의한 발작성 야간 혈색소뇨증 2예

Abstract

Paroxymal nocturnal hemoglobinuria(PNH) is a rare, acquired hematologic disease characterized by marow hypoplasia, pancytopenia, recurrent venous thrombosis and chronic intravascular hemolysis. This disease shows marrow hypoplasia, during which a somatic mutation in a hematopoietic stem cell leads to an abnormal cell clone with degicient or absent membrane glycosylphosphatidylionsitol(GPI) anchor. In the disease, clone of abnormal, complement-sensitive blood cells(RBCs, platelets, granulocytes, lymphocytes and monocytes) coexist with normal blood cells(chimerism). We report two cases of PNH in all third decade of femal. Two cases with PNH was identified through positive Ham's test and sucrose lysis test. GPI-anchored Proteins CD55 and CD59 were studied by flow cytimetry. Case 1 showed slightly deficient CD55 on GBCs, severe deficint CD55 on neutrophils, CD59 on RBCs and neutrophils. Case 2 results nearly normal CD55 on RBCs and neutrophils, but severe deficient CD59 on RBCs and neutrophils. Immunophenotypic analysis of expression of GPI-anchored proteins is replacing the Ham's test as th standard diagnostic assay for PNH. Due to its relatively high sensitivity and specificity, it is particularly helpful in the early stages of disease, or when there is a small numbers or GPI-deficient cells present and also in quantitation of PNH type Ⅰ, Ⅱ, Ⅲ RBCs. In addition, with the recent commercial availability of CD59 analysis by flow cytometry, use of the Ham's test a a diagnostic assay is no linger recommended.