Thrombocytopenia, Neonatal AlloimmuneAntigens, Human PlateletThrombocytopeniaHLA-DRB3 ChainsIsoantibodiesPlatelet TransfusionIsoantigensIntegrin alpha2Platelet CountMaternal-Fetal ExchangeIntegrin beta3Infant, NewbornPlatelet Membrane GlycoproteinsBlood PlateletsBlood Transfusion, IntrauterinePregnancyPurpura, ThrombocytopenicIntracranial HemorrhagesInfant, Newborn, DiseasesImmunoglobulins, Intravenous