Immunofluorescence on paraffin embedded renal biopsies: Experience of a tertiary care center with review of literature

Table 2 Renal pathologies diagnosed by immunofluorescence on paraffin embedded biopsies

Diagnosis	Total number of cases	Number of cases with non diagnostic IF-P (%)	Remarks
MPGN	32	21 (6.2%)	Classification into immune complex mediated MPGN ( 18 cases) and complement mediated MPGN ( 12 cases ) was possible 1In two cases C3 was not demonstrated and electron microscopy showed features of dense deposit disease
Membranous nephropathy	11	21 (22.2%)	In one case staining intensity of IgG was only 1+, however staining pattern was classical 1In 2 cases significant fine granular immunofluorescence was not noted
Lupus nephritis	25	11 (4%)	Classification into Class II ( 2 cases), Class III/IV ( 15 cases) and Class V (5 cases ) was possible Two cases of lupus podocytopathy were diagnosed 1In one case of lupus nephritis only IgM was demonstrated significantly, though electron dense deposits were noted on electron microscopy
Diffuse proliferative glomerulonephritis - post infectious glomerulonephritis	12	11 (8.3%)	1In one case only 1+ IgG and trace C3 deposition noted No tissue for electron microscopy was available
Pauciimmunecrescentic glomerulonephritis	7	-	-
IgAN	39	-	In 64 cases (minimal change morphology, mesangial proliferation or FSGS), IgAN was excluded by IF-P In one case of diabetic nephropathy IF-P was used to exclude secondary IgAN
C1q nephropathy	2	-	-
Light chain deposition disease	1	-	Tubular basement membrane and vascular deposits were also noted in addition to the glomerular deposits
Amyloidosis	4	-	2 cases of AL amyloid (demonstrating light chain restriction) and 2 cases of AA amyloid
CGN	8	3 (37.5%)	The immune complexes could not be demonstrated in 3 cases of chronic glomerulonephritis, one of these was a case of biopsy proven MPGN and the other was a case of IgAN. In one case of CGN no immune complexes were seen, however no previous renal biopsy record was available
Cast nephropathy	2	-	One case also demonstrated light chain restriction
Tubulointerstitial nephritis	9	-	Associated immune complex mediated glomerular disease was excluded

¹Non diagnostic cases and details of their immunofluorescence pattern. MPGN: Membranoproliferative glomerulonephritis; CGN: Chronic glomerulonephritis; IgAN: IgA nephropathy; FSGS: Focal segmental glomerulosclerosis.