Abstract:Objective To improve the method of direct immunofluorescence staining of paraffin-embedded renal sections,and to increase the diagnostic accuracy of paraffin sections.Methods Conventional frozen sections were processed for direct immunofluorescence staining in 44patients(20 cases of IgA nephropathy,12 cases of lupus nephritis and 12 cases of membranous nephropa-thy) who underwent renal biopsy for diagnosis of glomerular disease in Shenzhen hospital of Peking university between June 2010and December 2010.In addition,paraffin-embedded renal sections were exposed to high temperature,high pressure and pepsin,and were examined by direct immunofluorescence staining for immunoglobulins(IgA,IgG and IgM),complement components(C3,C1q),fibrin(Fib),HBsAg and HBcAg.Results of immunofluorescence staining were compared between paraffin sections and frozen sections.Results In frozen sections,the number of glomeruli ranged from 1 to 12(average,5).In paraffin sections,the number of glomeruli ranged from 7 to 30(average,15).There were no significant differences in the fluorescence intensity of IgA,IgG,IgM,C3,C1q,Fib,HBcAg and HBsAg between paraffin sections and frozen sections(all P>0.05).Conclusion The further improved method of direct immunofluorescence staining of paraffin-embedded renal sections is an effective means of redress when frozen-section examination fails in patients with glomerular disease.Compared with frozen sections,paraffin sections canclearly show organizational structure and immune-complex deposition site can be easily judged.