Purpose of review: Laser microdissection (LMD) and mass spectrometry (MS) is a new technique that consists of dissection of glomeruli, tryptic digestion of dissected material, analysis by MS and generation of a protein profile using different algorithms. The review focuses on the use of this methodology as an ancillary technique in a clinical laboratory for the diagnosis of kidney diseases.
Recent findings: LMD/MS is used in the diagnosis and typing of kidney diseases with organized deposits such as amyloidosis. Uncommon and familial forms of renal amyloidosis are diagnosed and typed on the basis of the presence of specific amyloidogenic proteins. LMD/MS is used to confirm and identify immunoglobulins and complement factors in immune complex mediated and complement-mediated proliferative glomerulonephritis, respectively. In particular, LMD/MS can detect monoclonal immunoglobulins in cases of equivocal immunofluorescence studies in monoclonal immunoglobulins-associated glomerulonephritis. LMD/MS can detect specific complement factors of the alternative pathway and terminal pathway in complement-mediated glomerulonephritis.
Summary: LMD/MS is currently used for diagnosis and typing of amyloidosis. In addition, LMD/MS is useful in determining the type of immunoglobulins and complement factors in immune complex and complement-mediated glomerulonephritis, respectively.