Importance of immune response genes in hemophilia A

Hemophilia A is a disease caused by a deficiency of coagulation factor VIII resulting from genetic inheritance linked to chromosome X. One treatment option is the administration of plasma or recombinant FVIII. However, some patients develop inhibitors or antibodies against this factor. Inhibitors are alloantibodies that bind to the epitope of factor VIII causing it to be recognized by the immune system as a foreign peptide. This is the most serious complication in hemophilia patients in respect to replacement therapy. Some studies have suggested that genetic factors influence the development of factor VIII inhibitors such as ethnicity, family history, mutations in the factor VIII gene and in genes of the immune system. The aim of this study was to conduct a literature review to assess the influence of genetic factors of immune response genes, especially genes of the major histocompatibility complex and cytokines, which may be related to the development of factor VIII inhibitors in hemophilia A patients. Understanding these risk factors will help to determine future differential treatment in the control and prevention of the development of inhibitors.

Efeitos quantitativos da estocagem de sangue periférico nas determinações do hemograma automatizado / Storage effects on peripheral blood samples as identified from automated hemograms

O presente trabalho avaliou as possíveis alterações em vários parâmetros do hemograma (contagem de eritrócitos totais, hematócrito, concentração de hemoglobina, volume corpuscular médio (VCM), hemoglobina corpuscular média (HCM), concentração da hemoglobina corpuscular média (CHCM), contagem total de leucócitos e contagem de plaquetas), frente a diferentes tempos de armazenamento da amostra em ambiente refrigerado a 4ºC e temperatura ambiente. As determinações foram realizadas através do contador automatizado Sysmex® XT2000i. As amostras sanguíneas foram obtidas de indivíduos sem alterações hematológicas diagnosticadas, sem clínica de doença, sendo considerados indivíduos com valores de referências hematológicos normais. Os resultados foram avaliados através de análise estatística descritiva e comparação de médias através da análise de variância (ANOVA). Os resultados dos parâmetros CHCM e contagem de plaquetas mostraram diferenças estatisticamente significativas para ambas as temperaturas de estocagem. Na temperatura ambiente, os parâmetros que também apresentaram diferença estatística significante foram para o hematócrito, VCM e índice de variação do tamanho dos eritrócitos ( RDW). Conclui-se, portanto, que os resultados dos hemogramas liberados pelo aparelho analisado podem ser satisfatórios quando realizados entre 12 a 24 horas após a coleta da amostra para a maioria dos parâmetros avaliados.

This study evaluated possible alterations in different hematologic parameters [total erythrocyte count, hematocrit, hemoglobin concentration, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MHCM), total leukocyte count and platelet count], of blood samples submitted to varied storage times at both 4ºC and at room temperature. The analyses were performed using a Sysmex XT2000i automated hematology analyzer. Written consent was obtained from donors with no hematological disorders or clinical abnormalities and thus from individuals with apparently normal laboratory reference values for healthy adults. The results were analysed by descriptive statistics with comparisons of the means being achieved by analysis of variance (ANOVA). The means of the MCHC parameters and platelet count showed significant statistical differences for both storage temperatures. At room temperature the hematocrit, MCV and red cell distribution width (RDW) readings also presented statistically significant differences. Therefore, it can be concluded that hemogram results performed by automated blood analyzers are satisfactory when carried out within 24 hours after drawing the blood sample for most of the parameters evaluated.