Trombastenia de Glanzmann: conceptos clave de la enfermedad / Glanzmann thrombasthenia: key concepts of the disease

La trombastenia de Glanzmann (TG), es un trastorno autosómico recesivo en el cual hay una reducción grave o ausencia de la agregación plaquetaria. Se debe a las alteraciones cualitativas o cuantitativas de la integrina α IIb o de integrina β 3, codificados por los genes ITGA2B e ITGB3 y relacionadas con la glicoproteína IIb/IIIa, que intervienen en la activación plaquetaria. La mayor incidencia de TG ha sido reportada en la población judía-iraquí, pero también se ha presentado en Israel, Jordania, Arabia saudita, Italia y, en menor número, en familias gitanas y pakistaníes. A pesar de ser poco frecuente, este trastorno se debe sospechar en casos de trastornos hemorrágicos graves espontáneos o inducidos por traumatismos, que varían desde hemorragias gastrointestinales y mucocutáneas, como epistaxis y hemorragias gingivales recurrentes de difícil manejo, las cuales son potencialmente mortales y en más del 75 por ciento de los casos requieren transfusión sanguínea o plaquetaria. Para realizar la confirmación del diagnóstico, los hallazgos de laboratorio se caracterizan por tiempos de sangrado prolongados, retracción del coágulo disminuida y respuestas anormales de agregación plaquetaria a estímulos fisiológicos. Aunque, actualmente no existe una cura para la enfermedad, el tratamiento adecuado con transfusiones plaquetarias y en caso de refractariedad, el uso del factor VIIa, permiten un buen pronóstico para los pacientes. Aún queda mucho por estudiar en estos casos debido a esto se están realizando nuevos estudios para la posibilidad de otros tratamientos, entre ellos la terapia génica plaquetaria(AU)

Glanzmann's thrombasthenia (GT) is an autosomal recessive disorder in which there is a severe reduction or absence of platelet aggregation. It is due to the qualitative or quantitative alterations of integrin #945; IIb or integrin #946; 3, encoded by the ITGA2B and ITGB3 genes and related to glycoprotein IIb / IIIa, which intervene in platelet activation. The highest incidence of GT has been reported in the Jewish-Iraqi population, but it has also been reported in Israel, Jordan, Saudi Arabia, Italy, and in smaller numbers in Gypsy and Pakistani families. Despite being uncommon, this disorder should be suspected in cases of severe spontaneous or trauma-induced bleeding disorders, ranging from gastrointestinal and mucocutaneous hemorrhages such as epistaxis and recurrent, difficult to manage gingival hemorrhages, which are potentially fatal and more than 75 percent of cases require blood or platelet transfusion. To confirm the diagnosis, the laboratory findings are characterized by prolonged bleeding times, decreased clot retraction and abnormal platelet aggregation responses to physiological stimuli. Although there is currently no cure for the disease, adequate treatments with platelet transfusions and in case of refractoriness, the use of factor VIIa, allow a good prognosis for patients. There is still much to study in these cases, because of this, new studies are being conducted for the possibility of other treatments, including platelet gene therapy(AU)

Antiplatelet antibodies in cases of Glanzmann's thrombasthenia with and without a history of multiple platelet transfusion.

Antiplatelet antibodies are known to be present in a wide spectrum of patients, which include chronic Idiopathic Thrombocytopenic Purpura (ITP), infections, etc., including Glanzmann's thrombasthenia (GT) patients who receive multiple platelet transfusions. The presence of natural antibodies to platelet receptors is not studied in cases of GT. We studied the antiplatelet antibodies in 23 patients with GT, 15 of which had received multiple transfusions and eight that had not received transfusions, along with 50 cases of chronic ITP. The prevalence and specificity of platelet-bound antibodies were detected by inhibition assays using O-group platelets on flow cytometry. The mean antiplatelet antibodies in 15 patients of GT who had not received transfusions and eight patients with multiple transfusions was 8427 + 2131.88 and 9038 + 2856 antibodies/platelet, respectively, while in case of the 50 ITP patients studied, it was 22166 + 5616 antibodies/platelet (Normal Range 1500–3200 antibodies/platelet). We conclude that GT patients who have not received transfusions may develop antiplatelet antibodies to the missing/abnormal receptor. Whether this is due to a molecular mimicry or due to some other mechanism needs to be explored.