ABSTRACT
Cardiac amyloidosis is a rare cause of cardiomyopathy, however, it is part of an underdiagnosed underlying systemic disease. For transthyretin (ATTR) amyloidosis, which is caused by the deposition of incorrectly folded transthyretin, either as the wild-type (wtATTR) or mutated (mATTR) form, novel evidence-based treatment options were recently shown to reduce disease progression as well as hospitalisation rates for heart failure. Thus, it is important to establish early and reliable diagnosis of cardiac involvement with ATTR amyloidosis.Modern non-invasive imaging (cardio magnetic resonance (CMR) and scintigraphic methods) together with immune fixation with determination of free light chains allow fast and reliable clinical screening for cardiac amyloidosis, whereas endomyocardial biopsy and genetics are used for confirmation of the underlying diagnosis. Interdisciplinary teams including hemato-oncology, neurology, nephrology in addition to cardiology are essential to enable personalized targeted treatment strategies.
Subject(s)
Amyloidosis/diagnosis , Cardiomyopathies/diagnosis , Amyloid Neuropathies, Familial/diagnosis , Amyloid Neuropathies, Familial/genetics , Amyloid Neuropathies, Familial/pathology , Amyloid Neuropathies, Familial/therapy , Amyloidosis/genetics , Amyloidosis/pathology , Amyloidosis/therapy , Biopsy , Cardiomyopathies/genetics , Cardiomyopathies/pathology , Cardiomyopathies/therapy , Diagnosis, Differential , Diagnostic Imaging , Early Diagnosis , Evidence-Based Medicine , Humans , Interdisciplinary Communication , Intersectoral Collaboration , Mass Screening , Myocardium/pathologyABSTRACT
BACKGROUND: Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a bleeding disorder caused by transplacental passage of maternal antibodies to fetuses whose platelets (PLTs) express the corresponding human PLT antigen (HPA). STUDY DESIGNS AND METHODS: We observed a fetus with FNAIT who died from a severe intracranial hemorrhage. Analysis of maternal serum in antigen capture assay with paternal PLTs showed reactivity with PLT glycoprotein (GP)IIb/IIIa (α(IIb) ß(3) ) and GPIa/IIa (α(2) ß(1) integrin), indicating the presence of anti-HPA-1a and an additional alloantibody against GPIa (termed anti-Swi(a) ). RESULTS: By immunochemical studies, the localization of the Swi(a) antigen on GPIa/IIa could be confirmed. Analysis of paternal GPIa full-length cDNA showed a single-nucleotide substitution C(3347) T in Exon 28 resulting in a Thr(1087) Met amino acid substitution. Testing of family members by polymerase chain reaction-restriction fragment length polymorphism using MslI endonuclease showed perfect correlation with phenotyping. Extended family and population studies showed that 4 of 10 members of the paternal family but none of 500 unrelated blood donors were Swi(a) carriers. Expression studies on allele-specific transfected Chinese hamster ovary (CHO) cells confirmed that the single-amino-acid substitution Thr(1087) Met was responsible for the formation of the Swi(a) epitope. Adhesion of CHO cells expressing the Swi(a) alloantigen to immobilized collagens was not impaired compared to the wild-type control and was not inhibited by anti-Swi(a) alloantibodies. CONCLUSION: In this study we defined a new PLT alloantigen Swi(a) that was involved in a case of additional immunization against HPA-1a. Our observations demonstrate that combinations of PLT-specific alloantibodies may comprise low-frequency alloantigens.
