[New advances in the subtyping of systemic amyloidosis]

Amyloidosis is a heterogeneous group of diseases caused by deposition of misfolded proteins, which usually leads to organ dysfunction. Accurate typing of amyloid deposits is of paramount importance because organ involvements and disease prognosis differ widely among different subtypes, and its treatments are type specific. Correct identification of amyloidogenic protein is crucial to proper treatment. Traditional antibody-based diagnostic methods such as immunohistochemistry and immunofluorescence are helpful in amyloid typing, but limitations of those approaches including antibody availability and serum protein contamination impair sensitivity and specificity of diagnosis. Sometimes misdiagnosis can lead to catastrophic therapeutic outcome. Genetic testing is important to confirm the diagnosis of hereditary amyloidosis. Nowadays proteomic analysis has been used as an advanced strategy for amyloid typing and the gold-standard today is laser microdissection followed by mass spectrometry (LMD/MS), which can identify causal protein without additional clinical information. Furthermore, LMD/MS is performed on formalin-fixed paraffin-embedded (FFPE) specimens, thus large scale retrospective studies based on archival material can be conducted. In recent studies, LMD/MS has been proven superior to traditional methods without the drawbacks mentioned above. This proteomic approach provides guarantee of appropriate clinical management and probability of new insights into the mechanism of amyloidosis.In this article the new advances of studies on subtyping of systemic amyloidosis are reviewed.