A screening and intervention program aimed to reduce mortality and serious morbidity associated with severe neonatal alloimmune thrombocytopenia

Abstract

The study's objective was to identify HPA 1a-negative women and to offer them an intervention program aimed to reduce morbidity and mortality of neonatal alloimmune thrombocytopenia (NAIT). HPA 1 typing was performed in 100 448 pregnant women. The HPA 1a-negative women were screened for anti-HPA 1a. In immunized women, delivery was performed by Cesarean section 2 to 4 weeks prior to term, with platelets from HPA 1a-negative donors reserved for immediate transfusion if petechiae were present and/or if platelet count was less than 35 ؋ 10 9 /L. Of the women screened, 2.1% were HPA 1a negative, and anti-HPA 1a was detected in 10.6% of these. One hundred seventy pregnancies were managed according to the intervention program, resulting in 161 HPA 1a-positive children. Of these, 55 had severe thrombocytopenia (< 50 ؋ 10 9 /L), including 2 with intracranial hemorrhage (ICH). One woman with a twin pregnancy missed the follow-up and had one stillborn and one severely thrombocytope-

Incidence and Consequences of Neonatal Alloimmune Thrombocytopenia: A Systematic Review

“…Alternatively, as has been advocated recently by several investigators, pregnant women could be screenedfor HPA-type and tested foralloantibodies. [5][6][7] The debate on screening for NAIT is complicated by the lack of a good population data on incidence of severe thrombocytopenia and bleeding complications.…”

“…Several groups have published calculations of costs and potential benefits of screening and intervention, all coming to the same conclusion that such programs are likely cost-effective. [5][6][7][20][21][22] The main reason for cost-effectiveness, despite large-scale testing and, in the case of IVIG, expensive treatment, is the fact that the disease burden and costs for a child with lifelong severe neurologic damage from ICH is excessive.…”

Maternal HLA genotyping is not useful for predicting severity of fetal and neonatal alloimmune thrombocytopenia

“…As the HPA1a antigen is most commonly implicated in severe FNAIT, a number of studies investigating the association between a particular human leucocyte antigen (HLA) type and the risk of developing an immune response in HPA-1a-negative women have been carried out over the last 20 years. A strong association between the HLA class-II DRB3*01:01 (DRw52a) or DQB1*02:01 and FNAIT was originally described in groups of clinically diagnosed cases (Valentin et al, 1990;L Abbe et al, 1992) and later confirmed in screening studies (Williamson et al, 1998;Maslanka et al, 2003;Turner et al, 2005;Kjeldsen-Kragh et al, 2007). Although the negative predictive value of HLA-DRB3*01:01 in these studies was high (90-99%), indicating that HPA-1a-alloimmunisation is rare in women who lack the allele, the positive predictive value was much lower (26-35%), reducing the clinical usefulness of testing for this allele.…”

Et nyfødt barn med petekkier

“…I litteraturen angis insidensen til én per 1 000-2 000 (8,9). Dette innebaerer at i Norge blir 30-60 nyfødte rammet hvert år.…”

“…Dette innebaerer at i Norge blir 30-60 nyfødte rammet hvert år. I de fleste tilfeller er ikke tilstanden forbundet med alvorlige blødningskomplika-sjoner, men intrakranial blødning opptrer i 7-26 % av tilfellene, med neonatal død som følge hos omtrent en tredel av disse (8 …”