Light chain immunofluorescence in various nephropathies.

Context: Light chain immunofluoresence (IF) in renal biopsy is routinely used in the diagnosis of light chain deposition disease (LCDD), amyloidosis and cast nephropathy. Light chain predominance has also been reported in certain glomerulopathies like IgA nephropathy. However, pathogenesis of this pattern of deposition in various glomerulopathies is uncertain. Aim: To discuss the pathogenesis and utility of light chain IF in nephropathies. Setting and Design: Retrospective study. Materials and Methods: The pattern of light chain IF and light microscopic diagnosis in 306 cases of various nephropathies was reviewed. Direct IF was done in all these cases with commercial fluorescence (Fluoresciene Isothiocynate ) conjugated polyclonal rabbit anti-human antisera against IgM, IgG, IgA, C3, C1q, kappa and lambda light chains. Results: Light chain deposits were seen in 240 (78.43%) cases. In IgA nephropathy, lupus nephritis and post-infectious glomerulonephritis (PIGN), lambda positivity was more as compared to kappa. Light chain deposits in LCDD and membranous nephropathy were more kappa type. The IF pattern in amyloidosis was not consistent. Conclusion: The pathogenesis of light chain predominance in glomerulopathies is not clear and it depends on isoelectric point and size of the immune complex. Light chain IF should be performed routinely in all the renal biopsies.

Morphologic evaluation of renal function using semi-quantitative method in primary nonproliferative glomerular diseases.

Context: Fibrosis is universally accepted as a poor prognostic finding in renal pathology. Semi-quantitative assessment is widely used for prognostication in pathology. Aims: We propose a semi-quantitative method to prognosticate primary nonproliferative glomerular diseases. Settings and Design: A semi-quantitative method based on Banff schema, 97 classification has been modified to suit the requirements. Glomerular, tubulointerstitial, and vascular compartments were scored independently, and the scores were totaled to obtain total scores. Materials and Methods: Seventy-six renal biopsies were assessed by semi-quantitative scores and the individual compartmental and total scores were correlated with serum creatinine levels. Follow-up was available in 24 cases. Statistical Analysis: Pearson correlation coefficient, two-tailed t test, to determine the P value. Results: P values were significant for the total scores as well as individual compartments. There is a linear correlation between the scores and serum creatinine levels. A total score of ≥5 was significant. Conclusions: The semi-quantitative scoring system based on modified Banff schema, 1997 is useful in prognosticating renal biopsies in primary nonproliferative glomerular diseases.