Insight into the Protein Composition of Immunoglobulin Light Chain Deposits of Eyelid, Orbital and XXXX .

@entity1 @entity20915 @entity527 @entity2783 @entity2204 @entity557 @entity262 @entity74 @entity1675
UNASSIGNED: @entity2783 is a disease characterized by the formation of extracellular @entity527 . Immunoglobulin light-chain @entity2783 can appear as a @entity74 presenting with mild symptoms or as a life threatening @entity262 . The systemic form of immunoglobulin light-chain @entity2783 is the most common type of @entity2783 in western countries although it is a rare disease. Identification of the proteins forming amyloid fibrils is essential for the diagnosis of the disease and knowledge about the overall protein composition of the deposits may lead to a larger understanding of the deposition events thereby facilitating a more detailed picture of the molecular pathology. In this pilot study, we investigated the protein composition of @entity527 isolated from @entity1 specimens of the eyelid, conjunctiva, and orbit. Deposits and internal control tissue ( @entity1 tissue without apparent deposits) were procured by laser capture microdissection. Proteins in the captured amyloid and control samples were quantified by liquid chromatography tandem mass spectrometry using the label-free exponential modified Protein Abundance Index (emPAI) method. Immunoglobulin light chain kappa or lambda was found to be the most predominant protein in the @entity527 from the eyelid, conjunctiva, and orbit. Five proteins, @entity1675 , @entity557 ( @entity557 ), complement component C9, @entity20915 and plasminogen were found solely across all amyloid but not in the control tissue. In addition, the protein profiles identified @entity2204 and serum amyloid P component to be associated with the immunoglobulin light chain deposits across all three tissues analyzed. The method used in this study provided high sensitivity and specificity for the type of amyloid and may provide additional information on the pathology of the @entity527 in the ocular tissues studied.
