title: Increased frequency of HLA-DR2 in patients with paroxysmal nocturnal hemoglobinuria and the PNH/aplastic anemia syndrome.
abstract: Many autoimmune diseases are associated with HLA alleles, and such a relationship also has been reported for aplastic anemia (AA). AA and paroxysmal nocturnal hemoglobinuria (PNH) are related clinically, and glycophosphoinositol (GPI)-anchored protein (AP)-deficient cells can be found in many patients with AA. The hypothesis was considered that expansion of a PNH clone may be a marker of immune-mediated disease and its association with HLA alleles was examined. The study involved patients with a primary diagnosis of AA, patients with myelodysplastic syndrome (MDS), and patients with primary PNH. Tests of proportions were used to compare allelic frequencies. For patients with a PNH clone (defined by the presence of GPI-AP-deficient granulocytes), regardless of clinical manifestations, there was a higher than normal incidence of HLA-DR2 (58% versus 28%; z = 4.05). The increased presence of HLA-DR2 was found in all frankly hemolytic PNH and in PNH associated with bone marrow failure (AA/PNH and MDS/PNH). HLA-DR2 was more frequent in AA/PNH (56%) than in AA without a PNH clone (37%; z = 3.36). Analysis of a second cohort of patients with bone marrow failure treated with immunosuppression showed that HLA-DR2 was associated with a hematologic response (50% of responders versus 34% of nonresponders; z = 2.69). Both the presence of HLA-DR2 and the PNH clone were independent predictors of response but the size of PNH clone did not correlate with improvement in blood count. The results suggest that clonal expansion of GPI-AP-deficient cells is linked to HLA and likely related to an immune mechanism.
authors.affiliation: Hematology Branch and Office of Biostatistics Research, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA. maciejej@nih.gov
authors.forename: J P
authors.initials: JP
authors.lastname: Maciejewski
authors.forename: D
authors.initials: D
authors.lastname: Follmann
authors.forename: R
authors.initials: R
authors.lastname: Nakamura
authors.forename: Y
authors.initials: Y
authors.lastname: Saunthararajah
authors.forename: C E
authors.initials: CE
authors.lastname: Rivera
authors.forename: T
authors.initials: T
authors.lastname: Simonis
authors.forename: K E
authors.initials: KE
authors.lastname: Brown
authors.forename: J A
authors.initials: JA
authors.lastname: Barrett
authors.forename: N S
authors.initials: NS
authors.lastname: Young
mesh_terms: D000483:Alleles; D000741:Anemia, Aplastic / Q000150:complications / Q000188:drug therapy / Q000276:immunology*; D001855:Bone Marrow Diseases / Q000276:immunology; D005787:Gene Frequency; D017261:Glycosylphosphatidylinositols / Q000172:deficiency; D006098:Granulocytes / Q000737:chemistry; D015802:HLA-DR2 Antigen / Q000235:genetics*; D006457:Hemoglobinuria, Paroxysmal / Q000150:complications / Q000188:drug therapy / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000235:genetics; D000949:Histocompatibility Antigens Class II / Q000235:genetics; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D009190:Myelodysplastic Syndromes / Q000150:complications / Q000188:drug therapy / Q000276:immunology; D013577:Syndrome
chemical_list: D017261:Glycosylphosphatidylinositols; D015802:HLA-DR2 Antigen; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D007166:Immunosuppressive Agents