Renal immunofluorescence and the prediction of renal outcome in patients with proliferative lupus nephritis

The risk for endstage renal failure in patients with proliferative lupus ne phritis (PLN) depends largely on the severity and reversibility of the infl ammatory process as determined by light microscopy (LM). As the intrarenal formation of immune complexes is thought to initiate this inflammation. we studied whether renal immunofluorescence microscopy (IFM) provides clinical or prognostic information in addition to LM findings. Clinical data at the time of renal biopsy and during a mean follow-up of 46 months were extracted from the records of 69 SLE patients with proliferati ve LN (WHO class III/IV). Biopsy specimens were analyzed by LM for Al and C I, while IFM was performed on cryostat sections with the rise of antisera a gainst IgG. IgM, IgA, C3, Clq and fibrin. IFM findings were recorded in ter ms of the localization (glomerular. tubular or vascular) and intensity of f luorescence (score from zero to three). LFM findings were then related to c linical and LM findings and its prognostic value studied by survival analys is. Glomerular immune deposits were present in 99% of patients, tubular deposit s in 38% and vascular deposits In 17%. A 'full-house' pattern (all three Ig classes) was found in 67% of biopsies and C3 and Clq deposits rn 93% and 7 4% respectively. Median scores for Al and CI were 6(1-18) and 3 (0-10), asi de from a negative correlation between IgA deposits and CI, we found no oth er correlation between the amount or type of immune deposits and AI or CI. IgM deposits were associated with high serumlevels of anti-dsDNA, while IgG deposits correlated with high ESR and serumcreatinin levels. LFM scores we re nor related to steroiddose at the lime of biopsy and neither type of glo merular. tubular or overall renal immunedeposits had prognostic value for r enal survival. Renal immunofluorescence does not reflect light microscopy f indings in patients with PLN and does nor contribute prognostic information in patients with PLN.