Clonal Hematopoiesis as Defined by Polymorphic X-Linked Loci Occurs Infrequently in Aplastic Anemia

• Published in: Blood Vol. 86; no. 8; pp. 2938 - 2947
• Main Authors: Raghavachar, Aruna, Janssen, Johannes W.G., Schrezenmeier, Hubert, Wagner, Bettina, Bartram, Claus R., Schulz, Ansgar S., Hein, Christian, Cowling, Graham, Mubarik, Ashad, Testa, Nydia G., Dexter, T.Michael, Hows, Jill M., Marsh, Judith C.W.
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 15-10-1995; The Americain Society of Hematology
• Subjects: Adolescent; Adult; Aged; Anemia, Aplastic - pathology; Anemias. Hemoglobinopathies; Base Sequence; Biological and medical sciences; Clone Cells - pathology; Diseases of red blood cells; Dosage Compensation, Genetic; Female; Genetic Markers; Hematologic and hematopoietic diseases; Hematopoiesis; Humans; Medical sciences; Methylation; Middle Aged; Molecular Sequence Data; Phosphoglycerate Kinase - genetics; Polymorphism, Genetic; X Chromosome; Human; Exploration; Hemopathy; Hematopoiesis; Aplastic anemia; Clone
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V86.8.2938.2938

We evaluated the methylation status of the X-linked gene phosphoglycerate kinase (PGK1) and the DXS 255 locus detected by probe M27β to study clonality in acquired aplastic anemia (AA). A total of 30 females were suitable for clonal analysis of peripheral blood polymorphonuclear cells (PMN) and mononuclear cells using a polymerase chain reaction-based procedure in 24 patients and Southern blotting in 9. Overall, 10 of 30 patients exhibited an imbalanced X-inactivation pattern. However, in 4 patients, analysis of constitutional DNA suggested a skewed methylation pattern and 2 further cases had to be excluded because of the lack of an appropriate control. A truly clonal pattern was thus established in 4 of 30 (13%) patients. In 7 patients who later developed clonal disorders of hematopoiesis, X-inactivation analysis did not predict this event in any case. In patients with a paroxysmal nocturnal hemoglobinuria phenotype, there was no correlation between the proportion of phosphatidyl-inositol glycan anchored protein (PIG-AP)–deficient blood cells and the corresponding X-inactivation pattern. X-inactivation analysis detected clonal hematopoiesis in only 3 of 10 patients with a deficiency in PIG-AP in the cell population under study, but sorting of nucleated cells on the basis of PIG-AP expression showed the clonal nature of PIG-AP-deficient cells. We conclude that the majority of patients with AA show polyclonal hematopoiesis using X-linked clonal analysis, but that minor clonal populations, such as PIG-AP–deficient cells, may not be detected unless sorted cell populations are separately analyzed.