RESUMO
The association between myelodysplastic syndromes (MDS) and autoimmune manifestations is not uncommon. As a rule, autoimmune abnormalities follow the diagnosis of MDS. We describe here a patient with MDS who developed a striking spectrum of diverse autoimmune disorders, including dermatitis, polyarthritis, and vasculitis, which preceded the clinical appearance of MDS.
Assuntos
Doenças Autoimunes/diagnóstico , Doenças Autoimunes/terapia , Síndromes Mielodisplásicas/diagnóstico , Síndromes Mielodisplásicas/terapia , Idoso , Idoso de 80 Anos ou mais , Artrite/complicações , Artrite/diagnóstico , Doenças Autoimunes/complicações , Transfusão de Sangue/métodos , Terapia Combinada , Dermatite/complicações , Dermatite/diagnóstico , Quimioterapia Combinada , Epoetina alfa , Eritropoetina/uso terapêutico , Filgrastim , Seguimentos , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Humanos , Masculino , Metilprednisolona/uso terapêutico , Síndromes Mielodisplásicas/complicações , Proteínas Recombinantes , Medição de Risco , Índice de Gravidade de Doença , Resultado do Tratamento , Vasculite/complicações , Vasculite/diagnósticoRESUMO
Infectious complications constitute the second most common cause of mortality and a main cause of morbidity in beta-thalassemia. Besides the high risk of blood-borne infections associated with multiple transfusions, the increased susceptibility of these patients to infectious diseases has been attributed to a coexistent immune deficiency. Immune abnormalities have also been held responsible for the frequent occurrence of malignancies in beta-thalassemia, especially leukemia and lymphomas. Recent studies on immune competence in beta-thalassemia have revealed numerous quantitative and functional defects, involving T and B lymphocytes, immunoglobulin production, neutrophils and macrophages, chemotaxis, and phagocytosis, as well as the complement system. Regarding pathogenesis, iron overload, a primary complication of both thalassemia itself and transfusion therapy, is thought to be the main precipitating mechanism, due to the important immunoregulatory properties of iron and its binding proteins; iron excess may derange the immune balance in favor of the growth of infectious organisms. Other factors include multiple transfusions, associated with constant allo-antigenic stimulation, as well as with transmission of immunosuppressive viruses; splenectomy, resulting in increased susceptibility to infections by encapsulated bacteria and to immune system modifications; low levels of zinc, another immune regulator; iron chelation therapy, which predisposes to serious infections by yersinia species; and the circulation of abnormal native thalassemic erythrocytes, forming another permanent immune stimulus. Thus surveillance for infections in patients with beta-thalassemia is crucial, while further studies are warranted on immune function abnormalities and the implicated mechanisms.