title: An increased HLA DR2 frequency is seen in aplastic anemia patients.
abstract: The underlying etiology of aplastic anemia is unknown in the majority of patients, although medications, chemical exposure, or viral infections can be implicated in some. Genetic susceptibility to a variety of diseases has been shown and it has recently been suggested that aplastic anemia is more common in individuals who are HLA DR2+ than in the general population. To examine this question, we retrospectively analyzed the results of HLA-DR typing in 75 aplastic anemia patients who received antithymocyte globulin (ATG) therapy or an HLA-matched sibling bone marrow transplant at UCLA between 1978 and 1989. Thirty-one patients were DR2+, a 1.9-fold higher incidence than the expected number of 16.6 patients (P < .0005). Of the 37 patients who received ATG, 33 were evaluable for a response; 14 patients had either a complete (4 patients) or partial (10 patients) response, for an overall response rate of 42.4%. Of the 14 DR2+ patients who received ATG, 7 responded, for a 50% response rate, which is not significantly higher than the response rate for the DR2- patients (7 of 19 [36.8%]; P = .50). The median survival of patients who are DR2+ was slightly, but not significantly, longer than that of the DR2- patients in the ATG group (P = .19). Although the incidence of HLA DR2 was clearly increased in these patients with aplastic anemia, response rates to ATG were not significantly different in the DR2+ and DR2- patients.
authors.affiliation: UCLA School of Medicine.
authors.forename: S D
authors.initials: SD
authors.lastname: Nimer
authors.forename: P
authors.initials: P
authors.lastname: Ireland
authors.forename: A
authors.initials: A
authors.lastname: Meshkinpour
authors.forename: M
authors.initials: M
authors.lastname: Frane
mesh_terms: D000293:Adolescent; D000328:Adult; D000741:Anemia, Aplastic / Q000276:immunology* / Q000628:therapy; D002675:Child, Preschool; D005260:Female; D005787:Gene Frequency; D015802:HLA-DR2 Antigen / Q000235:genetics*; D006801:Humans; D007165:Immunosuppression Therapy; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012044:Regression Analysis; D012189:Retrospective Studies
chemical_list: D015802:HLA-DR2 Antigen