A recent study conducted in Iran and published recently in the International Journal of Hematology Oncology and Stem Cell Research found that large-scale studies carried out across a range of ethnic groups could assist in predicting the severity of thrombocytopenia, including fetal and neonatal alloimmune thrombocytopenia (FNAIT).
How do HPAs work?
Platelets, which are also called thrombocytes, are a type of blood cell that contain a variety of hormones and growth factors known to stimulate several cellular functions. Although numerous antigenic markers can be found on the platelet membrane, some of them, including human platelet antigens (HPAs), are recognized as being specific to platelets.
HPAs play a key clinical role in the development of alloimmunization and immune-mediated disorders, including FNAIT, immune thrombocytopenia (ITP) and post-transfusion purpura (PTP). A thorough understanding of the genetic profiles of HPAs is thus vital to the prevention and treatment of these conditions.
HPA1a, which is recognized as being the first and most critical alloantigen, is found on glycoprotein IIIa. In fact, HPA1a is known to be responsible for approximately 85% of all cases of FNAIT. HPA4 antigens, which are located on glycoprotein IIIa as well, are involved in PTP, FNAIT and multi-platelet refractoriness. Some studies have found anti-HPA15 antibodies in the maternal serum obtained from patients with FNAIT.
Read more about FNAIT testing and diagnosis
The link between HPA antigens and FNAIT
Realizing the limitations involved in the use of serologic techniques for establishing HPA genotypes, the researchers sought to evaluate the relationship between the genotypes of HPA1, HPA2, HPA3, HPA4 and HPA15 antigens and the development of autoimmune thrombocytopenia among individuals residing in Lorestan Province, Iran. In their analysis, the investigators utilized the polymerase chain reaction sequence-specific primer (PCR-SSP) method.
The current study included a total of 80 patients who had been diagnosed with ITP (patient group) and 120 healthy individuals (control group). All samples were obtained from the Oncology Department of Shahid Madani Hospital, located in Khorramabad, Iran. Persons in both of the study arms were matched by gender and Lor ethnicity, with age another factor to be considered in additional analyses.
Results of the study showed that those individuals who carried the HPA2b allele had a 5.31-fold statistically significantly increased risk for the development of ITP. Likewise, presence of the HPA15b allele was linked to a 6.54-fold significantly elevated risk for ITP. There were no significant associations observed between the other genes and ITP.
“Future studies are recommended to be conducted on a larger scale and across different ethnic groups,” the authors explained. “This could help refine diagnostic methods, predict the severity of thrombocytopenia, improve treatment approaches, and assist in the removal of antibodies implicated in the disease from the bloodstream.”
