Mass Spectrometry-Based Proteomics Reveals Distinct Immunoglobulin Light Chain Variable Region Usage In Systemic Versus Localized AL Amyloidosis

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3142-3142
Author(s):  
Oana M Mereuta ◽  
Surendra Dasari ◽  
Jason D Theis ◽  
Julie A Vrana ◽  
Karen L Grogg ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gene Family ◽  
Light Chain ◽  
Gene Families ◽  
Al Amyloidosis ◽  
Gi Tract ◽  
Immunoglobulin Light Chain ◽  
Protein Mass ◽  
V Region ◽  
Region Usage

Abstract Background Immunoglobulin light chain-associated amyloidosis (AL) is caused by deposition of immunoglobulin light chain molecules with unique, clonotypic variable (V) regions. Detection and identification of the V region, however, has been challenging due heterogeneity inherent in V regions. We developed a new method for detecting IGKV and IGLV region fragments in AL deposits using protein mass spectrometry and novel bioinformatics approach. We report distinct IGKV and IGLV usage in localized versus systemic AL. Methods Shotgun protein mass spectrometry on amyloid plaques was performed as previously described (Blood. 2009; 114: 4957-9). Peptide tandem mass spectra (MS/MS) were searched against a composite sequence database containing SwissProt's human complete proteome augmented with 1764 IG V region sequences obtained from ImMunoGeneTics database and a Mayo Clinic internal database. Reversed sequences were appended to the database for estimating identification false discovery rates (FDRs). Peptide identifications were processed with Scaffold software. Confident protein identifications (probability > 0.9) with at least one unique peptide identifications and five MS/MS matches were considered. Detected variable gene family (if any) with most number of peptide and spectral matches is considered to be present in the deposit. The method was first validated in 8 cases of AL amyloidosis with known IGKV and IGLV region sequences and then applied on 1238 systemic and 393 localized AL cases. Differences between groups were measured by generating hypergeometric p-values. Results In all 8 AL cases with known IGKV and IGLV region usage, gene family identified in the AL deposit via proteomics matched the gene family inferred from bone marrow plasma cells by Sanger sequencing of IGLC genes. Armed with this method, we analyzed the amyloid proteomics data from 1238 patients with systemic AL amyloidosis and 393 patients with localized AL amyloidosis. The anatomical site distribution in systemic cohort was 296 GI tract, 364 heart, 225 kidney, 81 liver and 272 fat aspirate; Localized cohort has 78 bladder, 158 lung and 157 skin cases. Figure 1 shows the normalized frequency of the variable gene families detected between the systemic and localized AL amyloidosis. For AL-kappa, KV1 was more prevalent in systemic cases when compared to localized cases (p=7.2E-12) suggesting KV1 clones as a hallmark for systemic AL-kappa amyloidosis. KV3 was more frequently seen in localized AL-kappa cases when compared to systemic AL-kappa cases (p =2.8E-11). For AL-lambda, LV1 and LV2 gene families were more prevalent in localized cases when compared to systemic cases (p= 0.039 and 2.7E-05). LV6 was more prevalent in systemic AL-lambda cases (p=1.4E-07). We also detected a higher incidence of mixed AL/AH type in localized AL (18%) when compared to systemic AL (5%; Odds Ratio=4.2673, p<0.0001). We next turned to the organ specific IGKV and IGLV gene family usage patterns in patients with localized amyloidosis. For 147 localized AL-kappa cases, KV3 was most dominant in lung (64%) and KV1 was dominant in skin (38%). For 246 localized AL-lambda cases, LV2 was most prevalent in lung (34%) and LV3 was most prevalent in skin (36%). For bladder, both LV1 and LV2 had comparable prevalence (42% and 32%). For 361 systemic AL-kappa cases, KV1 consistently ranked at the top of gene families used in GI tract (55%), heart (71%), kidney (59%), liver (75%) and fat aspirate (50%). For 877 systemic AL-lambda cases, LV2 was predominant in GI tract (30%), LV3 in heart (35%) and LV6 in kidney (33%). The prevalence of LV1, LV2 and LV3 in liver is comparable (36%, 22% and 31%). LV6 and LV3 had comparable prevalence (22% and 24%) in AL-lambda fat aspirates. Conclusion The novel proteomics method detects IGLC V family usage in large cohorts of AL patients. It identifies unique profiles in systemic and localized cases, and in different organ sites. This information will be helpful in determining systemic versus localized nature of AL amyloidosis at diagnosis and to assess risk of specific end organ involvement. We found also a strong association between IGKV and IGLV gene usage and organ involvement. Disclosures: No relevant conflicts of interest to declare.

Immunoglobulin Light Chain Gene Constant Region Is An Invariable Part of Amyloid Deposits in AL Amyloidosis

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3128-3128
Author(s):  
Jason D. Theis ◽  
Julie A. Vrana ◽  
Jeffrey D. Gamez ◽  
Angela Dispenzieri ◽  
Stephen R. Zeldenrust ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Light Chain ◽  
Proteomic Analysis ◽  
Laser Microdissection ◽  
Variable Region ◽  
Al Amyloidosis ◽  
Constant Region ◽  
Immunoglobulin Light Chain ◽  
Amyloid Deposits ◽  
Region I

Abstract Background: Amyloidosis caused by immunoglobulin light chain (IGLC) deposition, so-called AL-type or primary amyloidosis, is the most common type of amyloidosis. It has been long believed that IGLC variable regions form the core of the AL-type amyloid deposits and peptides derived from IGLC constant region peptides are only occasionally integrated into this core. For this reason, the scientific effort to identify thge risk factors for development of AL amyloidosis and the biochemical characteristics amyloid deposits has focused on IGLC variable region derived proteins. To understand the peptide constituents of AL amyloidosis better, we undertook a comprehensive study of AL amyloidosis using a novel mass spectrometry based proteomic analysis approach. Methods: Paraffin embedded tissue from 100 cases of AL amyloidosis was studied. In each case amyloid type was previously established by clinical and pathological examination. Congo red stained paraffin sections were prepared and amyloid deposits were microdissected by laser microdissection microscopy. The microdissected tissue fragments were processed and trypsin digested into peptides. The peptides were analyzed by nano-flow liquid chromatography electrospray tandem mass spectrometry (LC-MS/MS). The resulting LC-MS/MS data were correlated to theoretical fragmentation patterns of tryptic peptide sequences from the Swissprot database using Scaffold (Mascot, Sequest, and X!Tandem search algorithms). Peptide identifications were accepted if they could be established at greater than 90.0% probability and protein identifications were accepted if they could be established at greater than 90.0% probability and contain at least 2 identified spectra. The identified proteins were subsequently examined for the presence or absence of amyloid related peptides. Results and Discussion: LC-MS/MS gave peptide profiles consistent with AL amyloidosis in each case. The analysis showed IGLC-lambda deposition in 66 cases and IGLC-kappa deposition in 34 of cases. In each case, LC MS/MS confirmed the previous clinicopathological diagnosis. Interestingly peptides representing IGLC constant region were present in each case. Using this LC-MS/MS methodology, theoretically it is possible to cover 78% of the IGLC-lambda and 87% IGLC-kappa constant regions. In our samples, the average coverage of the IGLC-lambda and IGLC-kappa constant regions were 40% (range 14–78%)and 55% (range 16–87%) respectively. Additionally, the distribution of the peptides suggested that in the majority of the cases whole of the IGLC constant region was deposited. LC MS/MS also identified IGLC-lambda variable region peptides in 37 of 66 cases and IGLC-kappa variable region peptides in 29 of 34 cases studied. The variable region coverage was more restricted and the peptides identified were frequently within the framework segments. It is likely that the peptides derived from CDR segments were present but not detected by the methodology as somatic hypermutation randomly alters the amino acid sequence in the CDR segments and such new sequences are not available in public databases used by algorithms for peptide identification. In the cases with the IGLC variable region hits, it was also possible to assign variable region family usage. IGLC-lambda cases frequently used IGLC-lambda variable region I, II and III families whereas, in IGLC-kappa cases, IGLC-kappa variable region I and III families dominated. Conclusions: AL amyloidosis can be accurately diagnosed using laser microdissection and LC-MS/MS based proteomic analysis in routine clinical specimens. AL amyloidosis invariably contains IGLC constant region peptides and, frequently, the whole of the constant region is deposited. This finding suggests that studies on molecular pathogenesis of amyloidosis should not only consider the IGLC-variable region but also the constant region. It is possible to identify IGLC variable region family usage in AL amyloidosis using LC MS/MS based proteomic analysis. In the clinical setting, this information may be helpful in predicting organ distribution and clinical outcome.

Frequency of Amyloid Subtyping Among Patients with Immunoglobulin Light-Chain Amyloidosis Referred for High-Dose Chemotherapy and Autologous Stem Cell Transplant

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5601-5601
Author(s):  
Andrew J. Cowan ◽  
David G. Coffey ◽  
Teresa S. Hyun ◽  
Pamela S. Becker ◽  
Damian J. Green ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Plasma Cell ◽  
Light Chain ◽  
Congo Red ◽  
Plasma Cell Dyscrasia ◽  
High Dose ◽  
Al Amyloidosis ◽  
Cell Transplant ◽  
Immunoglobulin Light Chain ◽  
Organ Systems

Abstract Background: The amyloidoses comprise a heterogeneous group of diseases characterized by misfolding of amyloidogenic proteins and subsequent deposition as amyloid fibrils. To date, over 30 proteins are known to be amyloidogenic (Sipe Amyloid 2014). Immunoglobulin light chain (AL) amyloidosis, a plasma cell dyscrasia, is the most common subtype. The standard diagnostic algorithm in AL amyloidosis is to obtain a biopsy of a clinically involve organ, and once Congo red positivity is confirmed, perform subtyping analyses with immunohistochemistry or mass spectrometry. Accurate subtyping of amyloidosis is essential to appropriate treatment, as misdiagnosis occurs in up to 10% of patients and may lead to inappropriate administration of chemotherapy (Comenzo Blood 2006; Lachmann NEJM 2002). We sought to determine the patterns of amyloid subtyping among patients with a diagnosis of AL amyloidosis referred to a tertiary referral center for HDM/SCT. Methods: Sequential patients with confirmed amyloidosis, age ≥ 18 years who underwent HDM/SCT between 2001 and 2014 at the Fred Hutchinson Cancer Research Center and University of Washington Medical Center were eligible. Presence of a Congo red-positive biopsy for each patient referred for transplant was confirmed and the pathology reports and medical records were reviewed to determine if subtyping was performed, and which modality was used. Results: Fifty-one patients with AL amyloidosis were referred for transplant; of these, 45 proceeded with HDM/SCT. The organ systems most commonly involved were renal in 34/51, and gastrointestinal in 5/51. Of the biopsies, subtyping was performed in 35 (68.6%), and no subtyping was performed in 16 patients (31.3%). Immunofluorescence was the most common modality used for subtyping in 33 biopsies (94.2%) and laser capture/mass spectrometry (LC/MS) was used in 2 patients (5.7%). All patients had evidence of a clonal plasma cell dyscrasia by bone marrow biopsy and peripheral blood testing. Of the patients without subtyping, 8 (50%) were diagnosed before 2008. Discussion: Misdiagnosis of amyloidosis due to a lack of appropriate subtyping is a well-described and ongoing problem for patients with amyloidosis. These data suggest that definitive subtyping is still not routinely performed in the evaluation of amyloidosis. At our center, efforts to standardize the evaluation of Congo-red positive biopsies using definitive typing are underway. Disclosures Gopal: Seattle Genetics: Research Funding.

Deposition of Lambda Chain Constant Region within AL-Amyloid Lesion

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3348-3348
Author(s):  
Hiroyuki Hata ◽  
Masayoshi Tasaki ◽  
Konen Obayashi ◽  
Taro Yamashita ◽  
Yukio Ando ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Light Chain ◽  
Mass Spectrometry Analysis ◽  
Light Chains ◽  
High Dose ◽  
Al Amyloidosis ◽  
Constant Region ◽  
Rt Pcr ◽  
Immunoglobulin Light Chain ◽  
Lambda Light Chain

Abstract [Introduction] Diagnosis of AL amyloidosis is dependent on the proof of light chains in amyloid lesions. However, immunostaining does not always successfully prove the presence of light chains in lesions in AL amylidosis patients. Here we report that the constant region of immunoglobulin lambda light chain (IGLC2) is seen in amyloid lesions where no positive signals are found with regular immunostaining. [Materials and Methods] Amyloid samples were stained with anti-human lambda light chain antibody (DAKO PO-0130) and analyzed with mass-spectrometry combining laser micro-dissection. Bone marrow samples were obtained from patients with amyloidosis, who gave written informed consent, and were subjected to plasma cell purification using CD138-immunomagnetic beads. Expression of immunoglobulin light chain mRNA was examined with RT-PCR. Anti-human IGLL5 antibody, capable of detecting immunoglobulin light chain constant region 2 (IGLC2) in paraffin embedded samples, was utilized. [Results and Discussion] We performed immunostaining for immunoglobulin light chains with 18 samples and found that six and eight cases were positive for kappa and lambda light chains, respectively, whereas light chains were not detected in remaining four cases (immunostaining-negative amyloidosis; INA). However, interestingly, mass spectrometry analysis revealed the presence of IGLC2 in all of the INA cases. RT-PCR analysis revealed the presence of IGLC2 mRNA in plasma cells from such INA cases. Surprisingly, amyloid lesions in all of the INA cases were positively stained with anti-IGLL5 antibody, whereas no staining was found in other samples positively stained with DAKO PO-0130. These observations suggest that the deposition of IGLC2 may cause AL amyloidosis, which otherwise could not be diagnosed with regular immunostaining. Although high dose chemotherapy produced hematological remission, half of such cases died within one year, suggesting irreversible and life-threatening amyloid fibril depositions in critical organs in IGLC2-related cases. We further examined additional twelve cases with AL amyloidosis to determine the incidence of IGLC2-related amyloidosis by immunostaining. With regular immunostaining, kappa and lambda chain were found in three and five cases, respectively. Interestingly, the remaining four cases were negative with regular immunostaining but positive with anti-IGLL5 antibody. Taken these observations together, eight IGLC2-related amyloidosis cases and thirteen lambda type amyloidosis were identified. Thus, the incidence of IGLC2-related amyloidosis should be approximately 38% (8/21) among lambda type AL amyloidosis. We conclude that diagnosis of IGLC2-related AL amyloidosis was possible only with the use of anti-IGLL5 antibody, but not with regular immunostaining. Given the relatively high incidence and often poor prognosis of IGLC2-related amyloidosis, it is important that this clinical entity is recognized to potentially improve outcomes of treatments. Analysis of mechanisms regulating amyloid formation with IGLC2 peptides is currently underway. Disclosures No relevant conflicts of interest to declare.

Two distinct mechanisms of neuropathy in immunoglobulin light chain (AL) amyloidosis

2021 ◽  
pp. 117305
Author(s):  
Haruki Koike ◽  
Naohiro Mouri ◽  
Yuki Fukami ◽  
Masahiro Iijima ◽  
Koji Matsuo ◽  
...  
Keyword(s):  
Light Chain ◽  
Al Amyloidosis ◽  
Immunoglobulin Light Chain

scholarly journals Quantitative Immunoprecipitation Free Light Chain Mass Spectrometry (QIP-FLC-MS) Simplifies Monoclonal Protein Assessment and Provides Added Clinical Value in Systemic AL Amyloidosis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4375-4375 ◽  
Author(s):  
Faye Amelia Sharpley ◽  
Hannah Victoria Giles ◽  
Richa Manwani ◽  
Shameem Mahmood ◽  
Sajitha Sachchithanantham ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Light Chain ◽  
Residual Disease ◽  
Renal Involvement ◽  
Light Chains ◽  
Al Amyloidosis ◽  
Free Light Chains ◽  
Accurate Identification ◽  
Monoclonal Protein ◽  
Serum And Urine

Introduction Early diagnosis, effective therapy and precise monitoring are central for improving clinical outcomes in systemic light chain (AL) amyloidosis. Diagnosis and disease response assessment is primarily based on the presence of monoclonal immunoglobulins and free light chains (FLC). The ideal goal of therapy associated with best outcomes is a complete responses (CR), defined by the absence of serological clonal markers. In both instances, detection of the monoclonal component (M-component) is based on serum FLC assessment together with traditional serum and urine electrophoretic approaches, which present inherent limitations and lack sensitivity particularly in AL where the levels are typically low. Novel mass spectrometry methods provide sensitive, accurate identification of the M-component and may prove instrumental in the timely management of patients with low-level amyloidogenic light chain production. Here we assess the performance of quantitative immunoprecipitation FLC mass spectrometry (QIP-FLC-MS) at diagnosis and during monitoring of AL amyloidosis patients treated with bortezomib-based regimens. Methods We included 46 serial patients with systemic AL amyloidosis diagnosed and treated at the UK National Amyloidosis Centre (UK-NAC). All patients had detailed baseline assessments of organ function and serum FLC measurements. Baseline, +6- and +12-month serum samples were retrospectively analysed by QIP-FLC-MS. Briefly, magnetic microparticles were covalently coated with modified polyclonal sheep antibodies monospecific for free kappa light chains (anti-free κ) and free lambda light chains (anti-free λ). The microparticles were incubated with patient sera, washed and treated with acetic acid (5% v/v) containing TCEP (20 mM) in order to elute FLC in monomeric form. Mass spectra were acquired on a MALDI-TOF-MS system (Bruker, GmbH). Results were compared to serum FLC measurements (Freelite®, The Binding Site Group Ltd), as well as electrophoretic assessment of serum and urine proteins (SPE, sIFE, UPE and uIFE). Results Cardiac (37(80%) patients) and renal (31(67%) patients) involvement were most common; 25(54%) patients presented with both. Other organs involved included liver (n=12), soft tissue (n=4), gastrointestinal tract (n=3) and peripheral nervous system (n=2). Baseline Freelite, SPE, sIFE and uIFE measurements identified a monoclonal protein in 42(91%), 22(48%), 34(74%) and 21(46%) patients, respectively. A panel consisting of Freelite + sIFE identified the M-component in 100% of the samples. QIP-FLC-MS alone also identified an M-component in 100% of the samples and was 100% concordant with Freelite for typing the monoclonal FLC (8 kappa, 34 lambda). In 4 patients, QIP-FLC-MS identified an additional M-protein that was not detected by the other techniques. In addition, 4/8(50%) kappa and 4/38(11%) lambda patients showed a glycosylation pattern of monoclonal FLCs at baseline by mass spectrometry. Interestingly, the frequency of renal involvement was significantly lower for patients with non-glycosylated forms (25% vs 76%, p=0.01), while no similar relationship was found for any other organs. During the 1-year follow-up period, 17 patients achieved a CR; QIP-FLC-MS identified serum residual disease in 13(76%) of these patients. Conclusion In our series, QIP-FLC-MS was concordant with current serum methods for identifying the amyloidogenic light chain type and provided, against all other individual tests, improved sensitivity for the detection of the monoclonal protein at diagnosis and during monitoring. The ability to measure the unique molecular mass of each monoclonal protein offers clone-specific tracking over time. Glycosylation of free light chains is over-represented in AL patients which may allow earlier diagnosis and better risk-assessment of organ involvement. Persistence of QIP-FLC-MS positive M component in patients otherwise in CR may allow targeted therapy. Overall, QIP-FLC-MS demonstrates potential to be exploited as a single serum test for precise serial assessment of monoclonal proteins in patients with AL amyloidosis. Disclosures Wechalekar: GSK: Honoraria; Janssen-Cilag: Honoraria; Amgen: Research Funding; Takeda: Honoraria; Celgene: Honoraria.

scholarly journals Hereditary systemic immunoglobulin light-chain amyloidosis

Blood ◽  
2015 ◽  
Vol 125 (21) ◽  
pp. 3281-3286 ◽  
Author(s):  
Merrill D. Benson ◽  
Juris J. Liepnieks ◽  
Barbara Kluve-Beckerman
Keyword(s):  
Light Chain ◽  
Plasma Cell Dyscrasia ◽  
Al Amyloidosis ◽  
Constant Region ◽  
Immunoglobulin Light Chain ◽  
Region Gene ◽  
Dna Analyses ◽  
Key Points ◽  
Constant Region Gene ◽  
Immunoglobulin Light Chain Amyloidosis

Key Points Protein and DNA analyses reveal that mutation in the immunoglobulin κ light-chain constant region gene may cause hereditary amyloidosis. Sequencing of immunoglobulin light-chain constant region genes is indicated for patients with AL amyloidosis and no evidence of a plasma cell dyscrasia.

Autologous Stem Cell Transplantation In Immunoglobulin Light Chain Amyloidosis With Factor X Deficien

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2151-2151
Author(s):  
Stefan F Cordes ◽  
Morie A Gertz ◽  
Francis K Buadi ◽  
Yi Lin ◽  
Martha Q Lacy ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Stem Cell ◽  
Light Chain ◽  
Research Funding ◽  
Splenic Rupture ◽  
Al Amyloidosis ◽  
Factor X ◽  
Immunoglobulin Light Chain ◽  
Hemorrhagic Complications ◽  
Transient Improvement

Abstract Background Acquired factor X (FX) deficiency is associated with immunoglobulin light chain (AL) amyloidosis and may be accompanied by hemorrhage. There are limited data on the effects of autologous stem cell transplant (ASCT) on FX deficiency. We reviewed hemorrhagic complications and the effect of high dose melphalan (HDM) and ASCT on FX levels in AL amyloidosis patients with FX deficiency. Methods We conducted a retrospective chart review of patients with AL amyloid with FX levels below 60%, not on chronic anti-coagulation who underwent HDM/ASCT at the Mayo Clinic, Rochester, MN between 1995 and 2011. Results Forty-one of 358 patients (11%) met our study criteria. Median pre-ASCT FX was 45% (range: 2%, 59%). The most common bleeding complication was central line associated n=15 (37%) followed by gastrointestinal n=10 (24%) and genitourinary n=9 (22%). The most frequent and severe bleeding complications occurred in patients with FX levels less than 10%. Four patients required emergent splenectomy owing to splenic rupture; one of these patients died from hemorrhagic shock. Periprocedural prophylaxis included activated recombinant Factor VII (rFVIIa) infusions, fresh frozen plasma (FFP) infusions and platelet transfusions. rFVIIa was efficacious in controlling bleeding during splenectomy (n=5) and, in conjunction with arterial embolization, for retroperitoneal bleed (n=1). Elective splenectomy for FX deficiency (n=1) resulted in only transient improvement in FX level. No relationship between the degree of pre-ASCT FX deficiency and other laboratory values (alkaline phosphatase, AST, total bilirubin, serum albumin, total serum protein, serum creatinine, total urine protein, beta2 microglobulin, troponin T) was found. Post-ASCT FX levels were determined in seventeen patients. In four of these patients, post-ASCT FX levels were determined in the acute/subacute phase of ASCT before steady state FX levels could be achieved; the median change in FX for these patients was -6.5% (range: -19%, 3%). In the remaining thirteen patients, who were between 99 and 1920 days from ASCT, FX improved by median 26% (range: -15%, 92%). Overall post-ASCT FX increased in twelve of thirteen (92%) patients. The improvement in FX correlated with improvement in the degree of proteinuria (p = 0.04) and showed a trend towards significant correlation with improvement in serum alkaline phosphatase (p = 0.06). Conclusions Hemorrhagic complications are most frequent and severe for FX levels below 10%. rFVIIa infusions, FFP and platelets were effective prophylactic agents. In the single patient who underwent elective splenectomy, a transient improvement in FX level was seen. Splenectomy was otherwise reserved for patients with splenic rupture/hematoma. Post-ASCT FX levels increased in twelve (92.3%) of the remaining thirteen patients; five of the patients (38.5%) were no longer FX deficient after ASCT. The degree of improvement in FX levels was correlated with improvement in markers of renal or hepatic involvement by amyloid. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Onyx: Consultancy, Research Funding.

scholarly journals A comparison of immunohistochemistry and mass spectrometry for determining light chain amyloid fibril protein from formalin-fixed renal biopsy tissue in a single Chinese center

2019 ◽  
Author(s):  
Ying Sun ◽  
Jian Sun ◽  
Wei Sun ◽  
Junyi Pang ◽  
Yubing Wen ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Renal Biopsy ◽  
Light Chain ◽  
Protein Identification ◽  
Amyloid Fibrils ◽  
Al Amyloidosis ◽  
Precise Diagnosis ◽  
Ffpe Tissues ◽  
Amyloid Light Chain ◽  
Formalin Fixed

Abstract Background Amyloidosis, a disease caused by abnormal protein deposition in tissues, is classified according to the protein precursor that form amyloid fibrils. Diagnosis of amyloidosis is type-specific as the identification of amyloid protein determines the following treatment. However, around a quarter of amyloidosis cases cannot be accurately subtyped by most commonly used immunohistochemistry (IHC). In order to obtain precise diagnosis, our study is focusing on another protein identification methods, laser microdissection and mass spectrometry (LDMS). Methods 20 cases of Amyloid Light-chain (AL) amyloidosis without further subtype were included. IHC and LDMS were used to detect light chains on formalin-fixed paraffin-embedded (FFPE) tissues from renal biopsy. Results 100% consistence between positive IHC and LDMS results were observed, however, chances of subtyping using LDMS is increased to 94% compared to IHC which is only 76%. Conclusion LDMS is a valuable tool in regard to subtyping amyloidosis.

Sign in / Sign up

Export Citation Format

Share Document