title: First example of familial posttransfusion purpura in two PlA1-negative sisters.
abstract: Posttransfusion purpura (PTP) (platelet count 5000/microliter) was diagnosed in a female patient (never transfused, gravida IV, para IV) 1 week after transfusion for hysterectomy in 1978. She did not respond to pooled random-donor platelets but recovered following a single plasma exchange. Her platelets were PlA1 negative, and her plasma contained potent anti-PlA1. In 1986, her sister (never transfused, gravida III, para III) developed PTP (platelet counts 5-15,000/microliter) following surgery-associated transfusion. She did not respond to pooled random-donor platelets. Platelet-associated IgG was markedly elevated (5365) molecules/platelet; normal, less than 660); her plasma contained a potent platelet antibody with anti-PlA1 specificity. Her platelets were subsequently shown to be PlA1 negative. The platelet count did not rise above 30,000 per microliter, despite 3 days of high-dose methylprednisolone sodium succinate and 2 weeks of prednisone (80 mg/day). Later, her platelet count increased and remained normal after steroids were discontinued. The two sisters proved to be HLA-identical, and each possessed one haplotype carrying the DR3 marker, which has been implicated as a risk factor in neonatal alloimmune thrombocytopenia associated with anti-PlA1.
authors.affiliation: Department of Medicine, Washington University Medical School, St. Louis, Missouri.
authors.forename: H
authors.initials: H
authors.lastname: Chaplin
authors.forename: R H
authors.initials: RH
authors.lastname: Aster
authors.forename: L K
authors.initials: LK
authors.lastname: Morgan
authors.forename: B
authors.initials: B
authors.lastname: Horn
authors.forename: K T
authors.initials: KT
authors.lastname: McDonagh
authors.forename: R
authors.initials: R
authors.lastname: Baskin
mesh_terms: D016824:Antigens, Human Platelet; D001788:Blood Grouping and Crossmatching; D001792:Blood Platelets / Q000276:immunology; D005260:Female; D006680:HLA Antigens / Q000032:analysis; D006801:Humans; D039661:Integrin beta3; D007519:Isoantigens / Q000032:analysis*; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic; D011693:Purpura / Q000139:chemically induced*; D065227:Transfusion Reaction
chemical_list: D016824:Antigens, Human Platelet; D006680:HLA Antigens; C061248:ITGB3 protein, human; D039661:Integrin beta3; D007519:Isoantigens