Human Platelet Antigens (HPAs) are polymorphic glycoproteins expressed on the platelet surface. In Neonatal Alloimmune Thrombocytopenia (NAIT), the mother lacks a specific HPA that the fetus inherits from the father. During pregnancy, the mother becomes sensitized to this paternal HPA and produces IgG antibodies against it. These antibodies cross the placenta and bind to the fetal platelets, marking them for destruction by macrophages in the fetal spleen. This leads to severe thrombocytopenia (low platelet count) in the fetus and newborn, which carries a high risk of intracranial hemorrhage (bleeding in the brain). The most common cause in Caucasians is HPA-1a incompatibility, where the mother is HPA-1b/1b (lacks HPA-1a) and the fetus is HPA-1a positive. Diagnosis involves platelet antigen genotyping of parents and detection of maternal anti-HPA antibodies.

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Zambia

• Joseph Soko – 101 pts

• Visual Pathway Lesions
• Positive and Negative Symptoms
• Hallucinations and Delusions
• Antipsychotic Medications
• Emergency: Environmental Emergencies