Diagnostic Immunostaining of Renal Biopsies: An Overview of Markers for Glomerular Diseases.

BACKGROUND: The analysis of a renal biopsy is made complex by multifactorial etiologies involving different renal compartments. Recent proteomic data, pattern-based classification, and a better understanding of various glomerular renal diseases have underscored the importance of immunohistology as an integral part of the diagnostic evaluation of renal biopsies. These include immunofluorescence on formalin-fixed paraffin-embedded renal tissue (IF-P), IgG subclass staining, typing of amyloid, and other organized deposits, classification of membranous nephropathy, etc. SUMMARY: We describe the recent immunohistological markers on immunofluorescence (IF) and immunohistochemistry (IHC) on fresh and formalin-fixed paraffin-embedded renal native biopsies for proper evaluation and classification of glomerular diseases. The article also provides information on the diagnostic utility, interpretation, and established antibody clones described in the literature for various glomerular diseases. The indications of IF-P in renal biopsies are also outlined. KEY MESSAGES: Immunohistology has become integral to diagnosing and classifying various glomerular renal diseases. A specific protein or antigen-based classification has prognostic and therapeutic implications. Additionally, it provides clue for screening the patient for an underlying etiology.