ملخص مقدمة : نقص الصفائح الدموية مناعيا عند الأجنة والأطفال حديثي الولادة ( ( TFNAI يمكن أن يكون له عواقب وخيمة في حالة نزيف داخل الجمجمة . في حالات الحمل اللاحقة هذا الضرر يكون حادا و نسبة تكراره عالية جدا. التشخيص المنتظم هو خيار في الصحة العمومية يقلل من معدلات الاعتلال والوفيات. الطريقة: الدراسة شملت حوالي 1000 من النساء الحوامل. التقنيات المستعملة هي ELISA, MAIPA, PCR-SSP النتائج والمناقشة : تم تحديد 28 حالة في خطر نقص الصفائح الدموية المناعي ما في ذلك 03 من 13 (23.07٪) حاملين HLA-DRB3*0101 في مثل هذه الحالات وجود هذا الأليل يزيد من شدة خطر TFNAI وقد لوحظت نتيجة إيجابية في ~ 93٪ من الحالات. ا لاستنتاج : بفضل دراسات التشخيص المنتظم وبرنامج التدخل نتمكن من منع ما يقرب من 80٪ من حالات الوفاة والإعاقة المتعلقة ب TFNAI Resume Introduction. les thrombopenies fœtales et neonatales allo-immunes (TFNAI) peuvent avoir des consequences deleteres en cas d’hemorragie intracrânienne (HIC). La recurrence de l’atteinte fœtale est tres elevee et sa severite est amplifiee lors des grossesses ulterieures. Le depistage systematique des TFNAI est une option de sante publique et permet de reduire la morbidite et la mortalite. Materiel et methodes. Pres de 1000 femmes enceintes sont incluses. Le diagnostic des TFNAI est realise par MAIPA. Le phenotypage HPA-1 par ELISA et les genotypages HPA-1 et HLA-DRB3*0101 par PCR-SSP. Resultats et Discussion . 28 cas homozygotes HPA-1bb (2.94%) ont ete identifie a risque potentiel d’allo-immunisation plaquettaire dont 03/13 (23.07%) sont HLA-DRB3*0101. La presence de cet allele augmente le risque de severite de la TFNAI. Chez ces cas la thrombopenie neonatale etait severe sans detection serologique d’anticorps anti-HPA-1a par MAIPA. L’issue favorable a ete observee dans ~93% des cas. Conclusion . Les observations tirees de ces etudes beneficiant de programme de screening et d’intervention montrent qu’on peut prevenir approximativement 80% de deces et de sequelles lies aux TFNAI. Mots cles : Allo-immunisation plaquettaire, Thrombopenie, Hemorragie intracrânienne, Depistage, HPA, MAIPA, PCR-SSP Abstract Introduction : fetal and neonatal alloimmune thrombocytopenia (FNAIT) can have deleterious consequences in case of intracranial hemorrhage (ICH). The recurrence of fetal damage is very high and its severity is amplified in subsequent pregnancies. FNAIT screening is a public health option and may reduce morbidity and mortality. Material and Methods . Nearly 1,000 pregnant women are included. Diagnosis of FNAIT is performed by MAIPA. HPA-1 phenotyping is made by ELISA and HPA-1/HLA-DRB3*0101 genotyping by PCR-SSP. Results and Discussion . 28 homozygous women HPA-1bb (2.94%) were identified at high-risk of platelet alloimmunization. In which, 3/13 were HLA-DRB3*0101 (23.07%). The presence of this HLA allele increases the risk of severity of FNAIT. In these cases the thrombocytopenia was severe without serological detection of anti-HPA-1a antibodies (Ab). Favorable outcomes were observed in ~93% of cases. Conclusion : The findings from these studies benefiting from screening and intervention programs show that we can prevent approximately 80% of death and disability related to FNAIT. Keywords : Platelet alloimmunization, Thrombocytopenia, Intracranial hemorrhage, screening, HPA, MAIPA, PCR-SSP
The typing of human platelet antigens (HPA) can be useful in many clinical situations such as neonatal alloimmune thrombocytopenia, post‐transfusion purpura, and platelet transfusion refractoriness. The fluorescent‐based single‐strand conformation polymorphism (F‐SSCP) technique is a fast and convenient way to perform HPA genotyping. Universal sequences from phage M13 were introduced at both ends of specific PCR‐products by using 5′‐tailed primers. A short second round of PCR with universal primers coupled to Cy‐5 enabled the PCR‐products to be fluorescently labelled. F‐SSCP was performed by gel electrophoresis on an automated fluorescent DNA analyser. Genotyping of the three major HPA systems carried by the GP IIb–IIIa complex showed the F‐SSCP technique to be accurate and reliable. A single gel procedure has been sufficient to detect HPA genetic polymorphisms tested to date. Neither restriction enzyme, radioactive material, nor any other hazardous chemicals such as ethidium bromide were required. This technique enabled us to genotype HPA‐1, ‐3 and ‐4 alleles easily and to diagnose materno‐fetal incompatibility in a rare alloantigenic system. F‐SSCP is a promising technique for the detection of new mutations and/or DNA polymorphisms on a large scale.
Le purpura post-transfusionnel est une complication rare mais severe de la therapeutique transfusionnelle. C’est habituellement devant la survenue brutale d’une thrombopenie profonde chez une femme d’âge moyen ayant eu des grossesses, une semaine apres une transfusion, que ce diagnostic doit etre evoque. Ce syndrome doit etre distingue principalement des thrombopenies associees a l’heparine et des thrombopenies post-transfusionnelles passives liees a la presence d’alloanticorps chez le donneur. Le mecanisme de destruction des plaquettes du receveur n’est pas completement elucide et est probablement complexe. Le diagnostic biologique repose sur la mise en evidence chez la patiente d’un alloanticorps serique dirige contre un antigene specifiquement plaquettaire qu’elle-meme ne possede pas. Le traitement, a base de perfusion d’immunoglobulines polyvalentes a fortes doses, doit etre mis en place sans retard, afin d’eviter les complications hemorragiques parfois letales.
Maternal plasma and/or serum levels of anti-HPA-1a at delivery were compared to neonatal platelet (PLT) counts.Samples from HPA-1bb women who gave birth to children with thrombocytopenia or had anamnestic information about a previous child with neonatal alloimmune thrombocytopenia (NAIT) were collected at delivery. A modified monoclonal antibody immobilization of PLT antigen method was used for quantification of anti-HPA-1a.The anti-HPA-1a level in women with severely thrombocytopenic children was higher than the corresponding level in mothers of children born with moderate thrombocytopenia or normal PLT counts.Our data show a significant correlation between maternal anti-HPA-1a level and the neonatal PLT count and indicate strongly that this may be a reliable predictive measure for NAIT. Suitable test systems for quantitative measurements of anti-HPA-1a must be developed and evaluated for this particular purpose.
