The Experts below are selected from a list of 250110 Experts worldwide ranked by ideXlab platform
Samih H Nasr - One of the best experts on this subject based on the ideXlab platform.
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Immunofluorescence staining for immunoglobulin heavy chain light chain on kidney biopsies is a valuable ancillary technique for the diagnosis of monoclonal gammopathy associated kidney diseases
Kidney International, 2021Co-Authors: Samih H Nasr, Mary E Fidler, Samar M Said, Justin W Koepplin, Jamie M Altamiranoalonso, Nelson LeungAbstract:Heavy chain/light chain (HLC) antibodies target conformational epitopes at the junctions of the heavy chain and light chain constant regions (CH1 and CL) of serum IgGκ, IgGλ, IgAκ, IgAλ, IgMκ, and IgMλ to provide quantitation of intact HLC pairs. Here, we developed an HLC tissue Immunofluorescence protocol to test if it can complement conventional Immunofluorescence in the diagnosis of monoclonal gammopathy-associated kidney diseases. HLC Immunofluorescence was performed on archived frozen tissue of 104 kidney biopsies. The sensitivity and specificity of HLC Immunofluorescence was confirmed by testing cases of lupus nephritis, other polyclonal immunoglobulin nephropathies, and light chain nephropathies (light chain amyloidosis and deposition disease). Testing of ten cases of the IgG variant of proliferative glomerulonephritis with monoclonal immunoglobulin deposits excluded monoclonal deposits in two by revealing positivity for IgGκ and IgGλ. Testing of 12 cases of monotypic IgA nephropathy excluded monoclonal deposits in six by revealing staining for IgAκ and IgAλ. Testing of six cases of monotypic fibrillary glomerulonephritis excluded monoclonal deposits in three by revealing positivity for IgGκ and IgGλ. None of 14 cases of glomerulonephritis in which HLC Immunofluorescence unmasked polytypic deposits were associated with a serum or urine monoclonal immunoglobulins matching the conventional Immunofluorescence results. HLC Immunofluorescence outperformed paraffin Immunofluorescence and IgG subclass staining in 10/13 (77%) of cases. Testing of 18 cases of cryoglobulinemic glomerulonephritis showed better correlation with serum cryoprecipitate immunofixation than conventional Immunofluorescence with regards to the type of cryoglobulin in 47% of cases. Thus, HLC Immunofluorescence is a valuable ancillary technique in kidney pathology for the diagnosis of monoclonal gammopathy-associated nephropathies, and could be utilized to confirm or exclude the monoclonal nature of deposits.
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the sensitivity and specificity of the routine kidney biopsy Immunofluorescence panel are inferior to diagnosing renal immunoglobulin derived amyloidosis by mass spectrometry
Kidney International, 2019Co-Authors: Samih H Nasr, Lynn D Cornell, Paul J Kurtin, Maria Gonzalez L Suarez, Pingchuan Zhang, Insara Jaffer Sathick, Wonngarm Kittanamongkolchai, Mariam P Alexander, Mary E FidlerAbstract:Immunoglobulin light chain amyloidosis is the most frequent type of renal amyloidosis in the United States, accounting for 81% of cases. Accurate typing is crucial for early diagnosis and treatment of immunoglobulin-derived amyloidosis and to avoid treating other amyloidoses with potentially toxic chemotherapy. Immunofluorescence is the first step to type renal immunoglobulin-derived amyloidosis but the performance characteristics of this method are largely unknown. Here, we establish the sensitivity and specificity of Immunofluorescence for diagnosing immunoglobulin-derived amyloidosis in patients whose amyloid typing was performed by the current gold standard of laser microdissection/mass spectrometry. Renal biopsy pathology reports originating from several institutions with a diagnosis of amyloidosis and which had amyloid typing by laser microdissection/mass spectrometry performed at our center were reviewed. Reported Immunofluorescence staining for kappa or lambda of 2+ or more, with weak or no staining for the other light chain was considered positive for light chain amyloidosis by Immunofluorescence. Based on microdissection/mass spectrometry results, of the 170 cases reviewed, 104 cases were typed as immunoglobulin-derived amyloidosis and 66 were typed as non-immunoglobulin-derived amyloidosis. Immunofluorescence sensitivity for diagnosing immunoglobulin-derived amyloidosis was 84.6%. The remaining 16 cases could not be diagnosed by Immunofluorescence due to reported weak staining for all antigens or reported lack of preferential staining for one antigen. Immunofluorescence specificity was 92.4%. Five cases, all amyloid A amyloidosis, were misdiagnosed as immunoglobulin-derived amyloidosis by Immunofluorescence. Immunofluorescence failed to accurately differentiate immunoglobulin-derived from non-immunoglobulin-derived amyloidosis in 12.3% of cases of renal amyloidosis. Relying on Immunofluorescence alone for determining immunoglobulin-derived vs. non-immunoglobulin-derived amyloidosis may lead to misdiagnosis. Thus, Immunofluorescence has inferior sensitivity and specificity compared with laser microdissection/mass spectrometry in the typing of immunoglobulin-derived amyloidosis.
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paraffin Immunofluorescence a valuable ancillary technique in renal pathology
Kidney International Reports, 2018Co-Authors: Samih H Nasr, Mary E Fidler, Samar M SaidAbstract:Immunofluorescence on frozen tissue is the gold standard immunohistochemical technique for evaluation of immune deposits in the kidney. When frozen tissue is not available or lacks glomeruli, Immunofluorescence can be performed on paraffin tissue after antigen retrieval (paraffin Immunofluorescence). Excellent results can be obtained by paraffin Immunofluorescence in most immune complex–mediated glomerulonephritides and dysproteinemia-associated kidney lesions, and thus this technique has become a valuable salvage technique in renal pathology. Furthermore, new data have emerged suggesting that paraffin Immunofluorescence can be used as an unmasking technique, as it is more sensitive than frozen tissue Immunofluorescence in some kidney lesions, such as crystalline light chain proximal tubulopathy and is needed to establish the diagnosis of certain unique lesions, such as membranous-like glomerulopathy with masked IgG kappa deposits and membranoproliferative glomerulonephritis with masked monotypic Ig deposits. However, it is important to recognize and be aware of the limitations and pitfalls associated with paraffin Immunofluorescence. These include poor sensitivity for detection of C3 deposits and for the diagnosis of primary membranous nephropathy. Here, we summarize the available techniques of paraffin Immunofluorescence, review its role and performance as a salvage and unmasking technique in renal pathology, address its limitations and pitfalls, and highlight unusual forms of glomerulopathy that require paraffin Immunofluorescence for diagnosis.
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membranoproliferative glomerulonephritis with masked monotypic immunoglobulin deposits
Kidney International, 2015Co-Authors: Christopher P Larsen, Lynn D Cornell, Mary E Fidler, Mariam P Alexander, Nidia C Messias, Patrick D Walker, Loren Herrera P Hernandez, Sanjeev Sethi, Samih H NasrAbstract:The diagnosis of membranoproliferative glomerulonephritis (MPGN) has recently undergone change from an electron microscopy-based classification scheme to one based largely on Immunofluorescence findings. This change is due to the recognition that many of these cases are driven by abnormalities of the alternative complement cascade, resulting in the concept of C3 glomerulopathy. Here we reviewed our case files to identify those with an MPGN pattern that show false negative staining for monoclonal immunoglobulins by routine Immunofluorescence. Monoclonal immunoglobulin deposits were unmasked by performing Immunofluorescence on formalin-fixed paraffin embedded tissue after protease digestion. Clinico-pathological details of 16 such cases with a mean serum creatinine of 2.7 mg/dl and mean 24 h proteinuria of 7.1 g were then determined. Hypocomplementemia was present in two-thirds of patients. Fourteen patients had a paraprotein on serum immunofixation, all of which matched the biopsy Immunofluorescence staining pattern. Bone marrow biopsy showed plasma cell dyscrasia or B-cell lymphoproliferative disorder in 13 patients. Ten of these patients had findings on biopsy most consistent with C3 glomerulonephritis prior to performing paraffin Immunofluorescence. Thus a high index of suspicion is necessary to avoid misdiagnosis in these cases, as many would have been mistakenly diagnosed as C3 glomerulopathy or unclassified MPGN if paraffin Immunofluorescence was not performed.
Xavier Bossuyt - One of the best experts on this subject based on the ideXlab platform.
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detection of antinuclear antibodies by automated indirect Immunofluorescence analysis
Clinica Chimica Acta, 2013Co-Authors: Xavier Bossuyt, Patrick Verschueren, Rene Westhovens, Daniel Engelbert Blockmans, Sarah Cooreman, Heidi De Baere, Godelieve MarienAbstract:Abstract Background Testing for antinuclear antibodies is useful for the diagnosis of systemic rheumatic diseases. Automated systems for image acquisition and interpretation of indirect Immunofluorescence-based tests are increasingly used. The diagnostic performance of such automated approach in untreated patients has not been reported. Methods Antinuclear antibodies were measured by automated indirect Immunofluorescence using Zenit G. Sight on HEp2 and HEp2000 substrate in 268 consecutive samples submitted to the laboratory for antinuclear antibody testing, and in 231 patients with a systemic rheumatic disease at the time of diagnosis, 143 blood donors, 134 patients with chronic fatigue syndrome, and 133 diseased controls. Results Image acquisition by G-Sight was of high quality. The accuracy of pattern assignment was limited. There was a significant correlation between automated estimation of fluorescence intensity (probability index of positivity) and end-point titer. Probability index interval specific likelihood ratios for systemic rheumatic disease increased with increasing level of positivity probability. With the HEp-2 substrate, the likelihood ratio for systemic lupus erythematosus was 0.06, 0.4, 6.8, 12.1, and 43.9 for a probability measure of positivity of ≤ 10, 11–≤ 30, 31–≤ 50, 51–≤ 85, and > 85, respectively. Conclusion Quantitative data generated by automated image acquisition facilitates standardized interpretation.
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detection of antinuclear antibodies by indirect Immunofluorescence and by solid phase assay
Autoimmunity Reviews, 2011Co-Authors: Katrijn Op De Beeck, Pieter Vermeersch, Patrick Verschueren, Rene Westhovens, Godelieve Marien, Daniel Engelbert Blockmans, Xavier BossuytAbstract:Testing for antinuclear antibodies is useful for the diagnosis of systemic rheumatic diseases. Solid phase assays are increasingly replacing indirect Immunofluorescence for detection of antinuclear antibodies. In the most recent generation of solid phase assays, manufacturers attempt to improve the performance of the assays by adding extra antigens. Solid phase assay (EliA CTD Screen, Phadia, in which antibodies to 17 antigens are detected) was compared to indirect Immunofluorescence for the detection of antinuclear antibodies in diagnostic samples of 236 patients with autoimmune connective tissue diseases, in 149 healthy blood donors, 139 patients with chronic fatigue syndrome, and 134 diseased controls. The sensitivity of EliA CTD Screen for systemic lupus erythematosus, systemic sclerosis, primary Sjogren's syndrome, mixed connective tissue disease, and inflammatory myopathy was 74%, 72%, 89%, 100%, and 39%, respectively. The reactivity in blood donors, in patients with chronic fatigue syndrome, and in diseased controls was <4%. Likelihood ratios increased with increasing antibody concentrations. Generally, a positive test result by EliA CTD Screen had a higher likelihood ratio for systemic rheumatic disease than a positive test result by indirect Immunofluorescence. A negative test result by indirect Immunofluorescence, however, had a lower likelihood ratio than a negative test result by EliA CTD Screen, indicating that the negative predictive value was higher for indirect Immunofluorescence than for EliA CTD screen.
Mary E Fidler - One of the best experts on this subject based on the ideXlab platform.
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Immunofluorescence staining for immunoglobulin heavy chain light chain on kidney biopsies is a valuable ancillary technique for the diagnosis of monoclonal gammopathy associated kidney diseases
Kidney International, 2021Co-Authors: Samih H Nasr, Mary E Fidler, Samar M Said, Justin W Koepplin, Jamie M Altamiranoalonso, Nelson LeungAbstract:Heavy chain/light chain (HLC) antibodies target conformational epitopes at the junctions of the heavy chain and light chain constant regions (CH1 and CL) of serum IgGκ, IgGλ, IgAκ, IgAλ, IgMκ, and IgMλ to provide quantitation of intact HLC pairs. Here, we developed an HLC tissue Immunofluorescence protocol to test if it can complement conventional Immunofluorescence in the diagnosis of monoclonal gammopathy-associated kidney diseases. HLC Immunofluorescence was performed on archived frozen tissue of 104 kidney biopsies. The sensitivity and specificity of HLC Immunofluorescence was confirmed by testing cases of lupus nephritis, other polyclonal immunoglobulin nephropathies, and light chain nephropathies (light chain amyloidosis and deposition disease). Testing of ten cases of the IgG variant of proliferative glomerulonephritis with monoclonal immunoglobulin deposits excluded monoclonal deposits in two by revealing positivity for IgGκ and IgGλ. Testing of 12 cases of monotypic IgA nephropathy excluded monoclonal deposits in six by revealing staining for IgAκ and IgAλ. Testing of six cases of monotypic fibrillary glomerulonephritis excluded monoclonal deposits in three by revealing positivity for IgGκ and IgGλ. None of 14 cases of glomerulonephritis in which HLC Immunofluorescence unmasked polytypic deposits were associated with a serum or urine monoclonal immunoglobulins matching the conventional Immunofluorescence results. HLC Immunofluorescence outperformed paraffin Immunofluorescence and IgG subclass staining in 10/13 (77%) of cases. Testing of 18 cases of cryoglobulinemic glomerulonephritis showed better correlation with serum cryoprecipitate immunofixation than conventional Immunofluorescence with regards to the type of cryoglobulin in 47% of cases. Thus, HLC Immunofluorescence is a valuable ancillary technique in kidney pathology for the diagnosis of monoclonal gammopathy-associated nephropathies, and could be utilized to confirm or exclude the monoclonal nature of deposits.
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the sensitivity and specificity of the routine kidney biopsy Immunofluorescence panel are inferior to diagnosing renal immunoglobulin derived amyloidosis by mass spectrometry
Kidney International, 2019Co-Authors: Samih H Nasr, Lynn D Cornell, Paul J Kurtin, Maria Gonzalez L Suarez, Pingchuan Zhang, Insara Jaffer Sathick, Wonngarm Kittanamongkolchai, Mariam P Alexander, Mary E FidlerAbstract:Immunoglobulin light chain amyloidosis is the most frequent type of renal amyloidosis in the United States, accounting for 81% of cases. Accurate typing is crucial for early diagnosis and treatment of immunoglobulin-derived amyloidosis and to avoid treating other amyloidoses with potentially toxic chemotherapy. Immunofluorescence is the first step to type renal immunoglobulin-derived amyloidosis but the performance characteristics of this method are largely unknown. Here, we establish the sensitivity and specificity of Immunofluorescence for diagnosing immunoglobulin-derived amyloidosis in patients whose amyloid typing was performed by the current gold standard of laser microdissection/mass spectrometry. Renal biopsy pathology reports originating from several institutions with a diagnosis of amyloidosis and which had amyloid typing by laser microdissection/mass spectrometry performed at our center were reviewed. Reported Immunofluorescence staining for kappa or lambda of 2+ or more, with weak or no staining for the other light chain was considered positive for light chain amyloidosis by Immunofluorescence. Based on microdissection/mass spectrometry results, of the 170 cases reviewed, 104 cases were typed as immunoglobulin-derived amyloidosis and 66 were typed as non-immunoglobulin-derived amyloidosis. Immunofluorescence sensitivity for diagnosing immunoglobulin-derived amyloidosis was 84.6%. The remaining 16 cases could not be diagnosed by Immunofluorescence due to reported weak staining for all antigens or reported lack of preferential staining for one antigen. Immunofluorescence specificity was 92.4%. Five cases, all amyloid A amyloidosis, were misdiagnosed as immunoglobulin-derived amyloidosis by Immunofluorescence. Immunofluorescence failed to accurately differentiate immunoglobulin-derived from non-immunoglobulin-derived amyloidosis in 12.3% of cases of renal amyloidosis. Relying on Immunofluorescence alone for determining immunoglobulin-derived vs. non-immunoglobulin-derived amyloidosis may lead to misdiagnosis. Thus, Immunofluorescence has inferior sensitivity and specificity compared with laser microdissection/mass spectrometry in the typing of immunoglobulin-derived amyloidosis.
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paraffin Immunofluorescence a valuable ancillary technique in renal pathology
Kidney International Reports, 2018Co-Authors: Samih H Nasr, Mary E Fidler, Samar M SaidAbstract:Immunofluorescence on frozen tissue is the gold standard immunohistochemical technique for evaluation of immune deposits in the kidney. When frozen tissue is not available or lacks glomeruli, Immunofluorescence can be performed on paraffin tissue after antigen retrieval (paraffin Immunofluorescence). Excellent results can be obtained by paraffin Immunofluorescence in most immune complex–mediated glomerulonephritides and dysproteinemia-associated kidney lesions, and thus this technique has become a valuable salvage technique in renal pathology. Furthermore, new data have emerged suggesting that paraffin Immunofluorescence can be used as an unmasking technique, as it is more sensitive than frozen tissue Immunofluorescence in some kidney lesions, such as crystalline light chain proximal tubulopathy and is needed to establish the diagnosis of certain unique lesions, such as membranous-like glomerulopathy with masked IgG kappa deposits and membranoproliferative glomerulonephritis with masked monotypic Ig deposits. However, it is important to recognize and be aware of the limitations and pitfalls associated with paraffin Immunofluorescence. These include poor sensitivity for detection of C3 deposits and for the diagnosis of primary membranous nephropathy. Here, we summarize the available techniques of paraffin Immunofluorescence, review its role and performance as a salvage and unmasking technique in renal pathology, address its limitations and pitfalls, and highlight unusual forms of glomerulopathy that require paraffin Immunofluorescence for diagnosis.
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membranoproliferative glomerulonephritis with masked monotypic immunoglobulin deposits
Kidney International, 2015Co-Authors: Christopher P Larsen, Lynn D Cornell, Mary E Fidler, Mariam P Alexander, Nidia C Messias, Patrick D Walker, Loren Herrera P Hernandez, Sanjeev Sethi, Samih H NasrAbstract:The diagnosis of membranoproliferative glomerulonephritis (MPGN) has recently undergone change from an electron microscopy-based classification scheme to one based largely on Immunofluorescence findings. This change is due to the recognition that many of these cases are driven by abnormalities of the alternative complement cascade, resulting in the concept of C3 glomerulopathy. Here we reviewed our case files to identify those with an MPGN pattern that show false negative staining for monoclonal immunoglobulins by routine Immunofluorescence. Monoclonal immunoglobulin deposits were unmasked by performing Immunofluorescence on formalin-fixed paraffin embedded tissue after protease digestion. Clinico-pathological details of 16 such cases with a mean serum creatinine of 2.7 mg/dl and mean 24 h proteinuria of 7.1 g were then determined. Hypocomplementemia was present in two-thirds of patients. Fourteen patients had a paraprotein on serum immunofixation, all of which matched the biopsy Immunofluorescence staining pattern. Bone marrow biopsy showed plasma cell dyscrasia or B-cell lymphoproliferative disorder in 13 patients. Ten of these patients had findings on biopsy most consistent with C3 glomerulonephritis prior to performing paraffin Immunofluorescence. Thus a high index of suspicion is necessary to avoid misdiagnosis in these cases, as many would have been mistakenly diagnosed as C3 glomerulopathy or unclassified MPGN if paraffin Immunofluorescence was not performed.
Godelieve Marien - One of the best experts on this subject based on the ideXlab platform.
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detection of antinuclear antibodies by automated indirect Immunofluorescence analysis
Clinica Chimica Acta, 2013Co-Authors: Xavier Bossuyt, Patrick Verschueren, Rene Westhovens, Daniel Engelbert Blockmans, Sarah Cooreman, Heidi De Baere, Godelieve MarienAbstract:Abstract Background Testing for antinuclear antibodies is useful for the diagnosis of systemic rheumatic diseases. Automated systems for image acquisition and interpretation of indirect Immunofluorescence-based tests are increasingly used. The diagnostic performance of such automated approach in untreated patients has not been reported. Methods Antinuclear antibodies were measured by automated indirect Immunofluorescence using Zenit G. Sight on HEp2 and HEp2000 substrate in 268 consecutive samples submitted to the laboratory for antinuclear antibody testing, and in 231 patients with a systemic rheumatic disease at the time of diagnosis, 143 blood donors, 134 patients with chronic fatigue syndrome, and 133 diseased controls. Results Image acquisition by G-Sight was of high quality. The accuracy of pattern assignment was limited. There was a significant correlation between automated estimation of fluorescence intensity (probability index of positivity) and end-point titer. Probability index interval specific likelihood ratios for systemic rheumatic disease increased with increasing level of positivity probability. With the HEp-2 substrate, the likelihood ratio for systemic lupus erythematosus was 0.06, 0.4, 6.8, 12.1, and 43.9 for a probability measure of positivity of ≤ 10, 11–≤ 30, 31–≤ 50, 51–≤ 85, and > 85, respectively. Conclusion Quantitative data generated by automated image acquisition facilitates standardized interpretation.
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detection of antinuclear antibodies by indirect Immunofluorescence and by solid phase assay
Autoimmunity Reviews, 2011Co-Authors: Katrijn Op De Beeck, Pieter Vermeersch, Patrick Verschueren, Rene Westhovens, Godelieve Marien, Daniel Engelbert Blockmans, Xavier BossuytAbstract:Testing for antinuclear antibodies is useful for the diagnosis of systemic rheumatic diseases. Solid phase assays are increasingly replacing indirect Immunofluorescence for detection of antinuclear antibodies. In the most recent generation of solid phase assays, manufacturers attempt to improve the performance of the assays by adding extra antigens. Solid phase assay (EliA CTD Screen, Phadia, in which antibodies to 17 antigens are detected) was compared to indirect Immunofluorescence for the detection of antinuclear antibodies in diagnostic samples of 236 patients with autoimmune connective tissue diseases, in 149 healthy blood donors, 139 patients with chronic fatigue syndrome, and 134 diseased controls. The sensitivity of EliA CTD Screen for systemic lupus erythematosus, systemic sclerosis, primary Sjogren's syndrome, mixed connective tissue disease, and inflammatory myopathy was 74%, 72%, 89%, 100%, and 39%, respectively. The reactivity in blood donors, in patients with chronic fatigue syndrome, and in diseased controls was <4%. Likelihood ratios increased with increasing antibody concentrations. Generally, a positive test result by EliA CTD Screen had a higher likelihood ratio for systemic rheumatic disease than a positive test result by indirect Immunofluorescence. A negative test result by indirect Immunofluorescence, however, had a lower likelihood ratio than a negative test result by EliA CTD Screen, indicating that the negative predictive value was higher for indirect Immunofluorescence than for EliA CTD screen.
Samar M Said - One of the best experts on this subject based on the ideXlab platform.
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Immunofluorescence staining for immunoglobulin heavy chain light chain on kidney biopsies is a valuable ancillary technique for the diagnosis of monoclonal gammopathy associated kidney diseases
Kidney International, 2021Co-Authors: Samih H Nasr, Mary E Fidler, Samar M Said, Justin W Koepplin, Jamie M Altamiranoalonso, Nelson LeungAbstract:Heavy chain/light chain (HLC) antibodies target conformational epitopes at the junctions of the heavy chain and light chain constant regions (CH1 and CL) of serum IgGκ, IgGλ, IgAκ, IgAλ, IgMκ, and IgMλ to provide quantitation of intact HLC pairs. Here, we developed an HLC tissue Immunofluorescence protocol to test if it can complement conventional Immunofluorescence in the diagnosis of monoclonal gammopathy-associated kidney diseases. HLC Immunofluorescence was performed on archived frozen tissue of 104 kidney biopsies. The sensitivity and specificity of HLC Immunofluorescence was confirmed by testing cases of lupus nephritis, other polyclonal immunoglobulin nephropathies, and light chain nephropathies (light chain amyloidosis and deposition disease). Testing of ten cases of the IgG variant of proliferative glomerulonephritis with monoclonal immunoglobulin deposits excluded monoclonal deposits in two by revealing positivity for IgGκ and IgGλ. Testing of 12 cases of monotypic IgA nephropathy excluded monoclonal deposits in six by revealing staining for IgAκ and IgAλ. Testing of six cases of monotypic fibrillary glomerulonephritis excluded monoclonal deposits in three by revealing positivity for IgGκ and IgGλ. None of 14 cases of glomerulonephritis in which HLC Immunofluorescence unmasked polytypic deposits were associated with a serum or urine monoclonal immunoglobulins matching the conventional Immunofluorescence results. HLC Immunofluorescence outperformed paraffin Immunofluorescence and IgG subclass staining in 10/13 (77%) of cases. Testing of 18 cases of cryoglobulinemic glomerulonephritis showed better correlation with serum cryoprecipitate immunofixation than conventional Immunofluorescence with regards to the type of cryoglobulin in 47% of cases. Thus, HLC Immunofluorescence is a valuable ancillary technique in kidney pathology for the diagnosis of monoclonal gammopathy-associated nephropathies, and could be utilized to confirm or exclude the monoclonal nature of deposits.
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paraffin Immunofluorescence a valuable ancillary technique in renal pathology
Kidney International Reports, 2018Co-Authors: Samih H Nasr, Mary E Fidler, Samar M SaidAbstract:Immunofluorescence on frozen tissue is the gold standard immunohistochemical technique for evaluation of immune deposits in the kidney. When frozen tissue is not available or lacks glomeruli, Immunofluorescence can be performed on paraffin tissue after antigen retrieval (paraffin Immunofluorescence). Excellent results can be obtained by paraffin Immunofluorescence in most immune complex–mediated glomerulonephritides and dysproteinemia-associated kidney lesions, and thus this technique has become a valuable salvage technique in renal pathology. Furthermore, new data have emerged suggesting that paraffin Immunofluorescence can be used as an unmasking technique, as it is more sensitive than frozen tissue Immunofluorescence in some kidney lesions, such as crystalline light chain proximal tubulopathy and is needed to establish the diagnosis of certain unique lesions, such as membranous-like glomerulopathy with masked IgG kappa deposits and membranoproliferative glomerulonephritis with masked monotypic Ig deposits. However, it is important to recognize and be aware of the limitations and pitfalls associated with paraffin Immunofluorescence. These include poor sensitivity for detection of C3 deposits and for the diagnosis of primary membranous nephropathy. Here, we summarize the available techniques of paraffin Immunofluorescence, review its role and performance as a salvage and unmasking technique in renal pathology, address its limitations and pitfalls, and highlight unusual forms of glomerulopathy that require paraffin Immunofluorescence for diagnosis.