Correction to: Determination of serum free light chains as a marker of systemic lupus flare

Clinical Rheumatology -     

Determination of serum free light chains as a marker of systemic lupus flare

Clinical Rheumatology - The aim of this study was to explore the usefulness of the determination of free light chains (FLC) in serum as a biomarker of flare in patients with systemic lupus...     

Kinetics of organ response and survival following normalization of the serum free light chain ratio in AL amyloidosis

Despite successful treatment of the clonal plasma cell implicated in its pathogenesis, patients with AL amyloidosis (AL) experience significant morbidity related to underlying amyloid mediated organ dysfunction. While normalization of the serum free light chain measurements [normal ratio of involved and uninvolved free light chains (nFLCr)] is the goal of therapy and centerpiece of hematologic response criteria, achieving (or not achieving) meaningful organ response (OR) is clinically significant for its implications on long‐term symptomatology as well as overall survival (OS), and remains the ultimate goal of treatment. Expectations for organ recovery following successful therapy leading to nFLCr in AL remain poorly described. We evaluated the timeframe and predictive factors for OR, and long‐term outcome, in 313 AL patients who achieved nFLCr following therapy initiation. OR was seen in 80% of surviving AL patients within 1‐year of nFLCr. Patients achieving early OR within 1 year of nFLCr had superior OS compared with those who despite obtaining nFLCr did not achieve early OR. We further evaluated factors predicting OR and OS among patients achieving nFLCr. Higher values of dFLC (involved–uninvolved) at diagnosis predict OR, and early OR predicts improved OS following successful hematologic therapy in AL. Am. J. Hematol. 90:181–186, 2015. © 2014 Wiley Periodicals, Inc.     

Elevated serum free light chains are associated with inferior event free and overall survival in Hodgkin lymphoma

The serum free light chain (FLC) assay quantitates free immunoglobulin kappa and lambda light chains, which has prognostic value in plasma cell dyscrasias. However, there is limited data on serum FLC in lymphoid malignancies. We analyzed the association of pretreatment FLC with event-free survival (EFS) and overall survival (OS) in 100 patients with Hodgkin lymphoma (HL). Elevated polyclonal FLC were present in 30% of patients; these patients had an inferior EFS (HR = 4.84; 95% CI: 1.84-12.7) and OS (HR = 8.87; 95% CI: 2.35-33.52) compared to patients with normal FLC. Further studies of FLC in HL are warranted.     

Prognostic value of serum free light chain ratio at diagnosis in multiple myeloma

The prognostic value of baseline serum free light chain ratio (sFLCR) was investigated in 94 multiple myeloma (MM) patients. sFLCR was calculated as kappa/lambda or lambda/kappa, depending on the patients' dominating monoclonal light chain. Median baseline sFLCR was 3.57 in kappa-MM patients, 45.09 in lambda-MM. 'High' sFLCR (> or = the observed median value for kappa- and lambda-MM respectively) correlated with elevated serum creatinine and lactate dehydrogenase, extensive marrow infiltration and light chain type MM. The 5-year disease-specific survival was 82% and 30% in patients with sFLCR lower than and equal or greater than the median, respectively (P = 0.0001). sFLCR was an independent prognostic factor.     

Quantitative serum free light chain assay in the diagnostic evaluation of AL amyloidosis

We compared a new serum immunoassay for quantitation of serum free light chains (FLC) with the conventional tests for clonal immunoglobulin production: bone marrow immunohistochemistry, serum immunofixation electrophoresis, and urine immunofixation electrophoresis. Serum samples from 169 patients with AL amyloidosis and 20 controls were examined. Elevated levels of κ-FLC and λ-FLC were found in 94% and 93% of patients with the respective clonal disease. However, false positive elevations of κ-FLC and λ-FLC were found in 30% and 44% of patients with clonal disease of the other light chain subtype. We found that the FLC level was a reliable test for the diagnosis of clonal disease when the FLC κ:λ ratio was abnormal and was comparable to the conventional tests in patients with AL amyloidosis. After a histologic tissue diagnosis of amyloidosis, determining the type as AL amyloidosis relies on a panel of hematologic tests to determine light chain clonality and the exclusion other forms of amyloidosis.     

Free light chains in plasma of patients with light chain amyloidosis and non-amyloid light chain deposition disease. High proportion and heterogeneity of disulfide-linked monoclonal free light chains as pathogenic features of amyloid disease

Immunoglobulin light chain amyloidosis (AL) and non-amyloid light chain deposition disease (NALCDD) are different forms of protein aggregation disorders accompanied by a monoclonal gammopathy. Monoclonal free light chains (FLCs) are precursors of the pathological light chain tissue deposits that are fibrillar in AL and granular in NALCDD. However, direct biochemical examination of plasma FLC precursors, which would allow comparison and better understanding of these two diseases, is still lacking. In this study, we examined FLCs in plasma of patients with AL and NALCDD by employing separation on Sep-PaK C18 cartridges, micro-preparative electrophoresis, Western blotting and mass spectrometry. Comparative analysis of AL versus NALCDD and control plasma samples showed new evidence of increased level and heterogeneity of circulating disulfide-bound FLC species in AL. In addition to full length monomers comprising the disulfide-linked FLCs, the monoclonal disulfide-bound FLC fragments were typically revealed in AL plasma. We hypothesized that enhanced disulfide binding of FLCs in AL interferes with their normal clearance and metabolism, which in turn might play a role in amyloid formation. The applied methods might be useful to diagnose or predict the pathological form of the disease and shed light on the mechanisms involved in light chain aggregation in tissues.     

Potential pitfalls of serum free light chain analysis to assess treatment response for multiple myeloma

Response to treatment in patients with a plasma cell disorder is typically measured by evaluating the bone marrow and myeloma markers, including monoclonal protein spike and immunofixation (IFE) in blood and urine, and serum free light chains (sFLCs). Stringent complete response criteria for Multiple Myeloma (MM) patients require a normal FLC ratio and absence of clonal cells in bone marrow by immunohistochemistry or immunofluorescence. We performed a retrospective chart review to further evaluate these criteria. A total of 142 patient charts were analysed. Of these, 17 patients were found to have an abnormal sFLC ratio, but no other evidence of disease, including normal flow cytometry and normal fluorescence in situ hybridization (FISH) analysis on highly selected plasma cells. In all patients, the abnormal sFLC ratio was caused by abnormalities in the serum kappa light chains. These results suggest that current definitions may need to be revised to take aberrancies related to abnormal immune recovery into account.     

Abnormal serum free light chain ratio predicts poor overall survival in mantle cell lymphoma

Serum free light Chain (sFLC) ratios have been correlated with survival outcomes in Hodgkin and non‐Hodgkin lymphoma subtypes. This study was undertaken to investigate the prognostic impact of abnormal sFLC ratios in mantle cell lymphoma (MCL). two patient cohorts were analysed for sFLC parameters: a preliminary retrospective cohort and a uniformly treated cohort of 20 relapsed/refractory MCL patients, enrolled in a phase II clinical trial of single agent lenalidomide treatment. 52% of patients had an abnormality of one or more sFLC parameter (71% of the first cohort and 40% of the second cohort). In cohort two, a high baseline SFLC ratio correlated with poorer overall survival (OS) compared to a low/normal ratio (median OS: 1·4 months vs. 19 months respectively; P = 0·001). For patients presenting with an elevated sFLC ratio at trial entry a rise of >35% in the sFLC ratio correlated with disease progression and a sFLC ratio of >2× normal at trial entry correlated with aggressive disease. These data are the first to show a clear clinical correlation between sFLC ratios and survival outcomes in a uniformly treated cohort of MCL patients. We suggest that these markers may be useful in managing patients with MCL in the future.     

Quantitative serum free light chain assay in the diagnostic evaluation of AL amyloidosis.

We compared a new serum immunoassay for quantitation of serum free light chains (FLC) with the conventional tests for clonal immunoglobulin production: bone marrow immunohistochemistry, serum immunofixation electrophoresis, and urine immunofixation electrophoresis. Serum samples from 169 patients with AL amyloidosis and 20 controls were examined. Elevated levels of kappa-FLC and lambda-FLC were found in 94% and 93% of patients with the respective clonal disease. However, false positive elevations of kappa-FLC and lambda-FLC were found in 30% and 44% of patients with clonal disease of the other light chain subtype. We found that the FLC level was a reliable test for the diagnosis of clonal disease when the FLC kappa:lambda ratio was abnormal and was comparable to the conventional tests in patients with AL amyloidosis. After a histologic tissue diagnosis of amyloidosis, determining the type as AL amyloidosis relies on a panel of hematologic tests to determine light chain clonality and the exclusion other forms of amyloidosis.     

Histological regression of amyloid in AL amyloidosis is exclusively seen after normalization of serum free light chain

Background

Histological regression of amyloid has not been studied systematically but is assessed by clinical parameters. We analyzed the change of amyloid deposition in fat tissue in patients with AL amyloidosis following chemotherapy and studied the relation with type of hematologic response.

Design and Methods

Between January 1994 and July 2007 all consecutive patients with AL amyloidosis were evaluated in whom fat tissue aspirate was obtained before and following chemotherapy. Patients were divided into three groups depending on response of serum free light chain: complete, partial or non-responders. Fat tissue was assessed using a validated semi-quantitative test (grading 0–4). A change of 2 grades of amyloid deposition in fat tissue was considered significant and used as event to construct Kaplan-Meier curves of the patients who were able to reflect such a change.

Results

One hundred and twenty consecutive patients were studied. Fifty-one patients fulfilled inclusion criteria. Thirty patients had a complete response of the amyloidogenic free light chain a median 0.5 year (range 0.3–2.9 years) following chemotherapy. Reduction of 2 grades of amyloid deposition in fat tissue was seen in 50% of these patients after 2.4 years and in 80% after 3.2 years. In contrast to complete responders, none of the patients with partial (n=9) and non-response (n=12) showed reduction of 2 grades (p=0.02) with median follow-up of fat tissue analysis of 1.3 and 0.8 years, respectively.

Conclusions

This study in a selected group of patients with AL amyloidosis shows significant histological regression of amyloid deposition in fat tissue exclusively after normalization of serum free light chain.     

Immunoglobulin heavy light chain test quantifies clonal disease in patients with AL amyloidosis and normal serum free light chain ratio

Abstract

Background: Serum and urine immunofixation electrophoreses (SIFE/UIFE) are used for clonal detection in plasma cell dyscrasias, while serum free light chain (sFLC) testing provides quantitation of clonal disease. Up to 20% of patients with light chain (AL) amyloidosis may present with normal FLC ratio (FLCr).

Methods: We assessed the diagnostic, quantitative and prognostic potential of serum heavy light chain ratio (HLCr) in 199 untreated patients at initial evaluation.

Results: An abnormal HLCr was found in 37.2%, abnormal FLCr in 81.9% and positivity by SIFE/UIFE in 94% of patients. HLCr together with SIFE/UIFE identified clonality in 94% patients; the combination with FLCr yielded 100% sensitivity. An HLCr abnormality was significantly over-represented in normal compared to abnormal FLCr group (63.9% versus 31.3%). HLCr did not predict overall survival (OS) (log rank, p?=?0.09), while an abnormal FLCr was associated with decreased OS (log rank, p?=?0.03). The combined use of both ratios trended toward increased OS in the abnormal HLCr/normal FLCr group (log rank, p?=?0.11; Wilcoxon, p?=?0.04). On multivariate analysis, HLCr was not predictive of OS, whereas an abnormal FLCr was associated with shorter OS (HR?=?1.7, p?=?0.04).

Conclusions: The HLC assay has potential as a supplemental test to quantify monoclonal protein in patients with normal FLCr results.     

Heavy/light chain ratio for the assessment of minimal residual disease in myeloma patients achieving complete response

To prevent relapse, high risk paediatric acute lymphoblastic leukaemia (ALL) is treated very intensively. However, most patients who eventually relapse have standard or medium risk ALL with low minimal residual disease (MRD) levels. We analysed recurrent microdeletions and other clinical prognostic factors in a cohort of 475 uniformly treated non‐high risk precursor B‐cell ALL patients with the aim of better predicting relapse and refining risk stratification. Lower relapse‐free survival at 7 years (RFS) was associated with IKZF1 intragenic deletions (P < 0·0001); P2RY8‐CRLF2 gene fusion (P < 0·0004); Day 33 MRD>5 × 10⁻⁵ (P < 0·0001) and High National Cancer Institute (NCI) risk (P < 0·0001). We created a predictive model based on a risk score (RS) for deletions, MRD and NCI risk, extending from an RS of 0 (RS0) for patients with no unfavourable factors to RS2 +  for patients with 2 or 3 high risk factors. RS0, RS1, and RS2 +  groups had RFS of 93%, 78% and 49%, respectively, and overall survival (OS) of 99%, 91% and 71%. The RS provided greater discrimination than MRD‐based risk stratification into standard (89% RFS, 96% OS) and medium risk groups (79% RFS, 91% OS). We conclude that this RS may enable better early therapeutic stratification and thus improve cure rates for childhood ALL.     

The acute-phase response and serum amyloid A inhibit the inflammatory response to Acinetobacter baumannii Pneumonia

BACKGROUND: Acinetobacter baumannii is an emerging pathogen in nosocomial pneumonia. Trauma and postsurgical patients display a profound acute-phase protein response and are susceptible to pneumonia. METHODS: To study the way in which the acute-phase response induced by sterile tissue injury influences pulmonary host defense, mice were injected subcutaneously with turpentine or saline in both hind limbs either 2 or 5 days before intranasal inoculation with A. baumannii. RESULTS: Turpentine-injected mice demonstrated strong increases in levels of the acute-phase proteins serum amyloid A (SAA) and serum amyloid P. The inflammatory response to A. baumannii was significantly impaired in turpentine-injected mice, as shown by decreased local cytokine and chemokine levels, reduced neutrophil influx and lung myeloperoxidase activity, less pulmonary inflammation on histological examination, and lower total protein levels in their bronchoalveolar lavage fluid, which was associated with reduced bacterial clearance of A. baumannii. The late acute-phase protein response still caused lower pulmonary cytokine levels and neutrophil recruitment. Furthermore, previous injection of SAA, a major acute-phase protein, also reduced inflammatory responses to A. baumannii pneumonia. CONCLUSIONS: These data suggest that the acute-phase response and SAA inhibit the local inflammatory response to A. baumannii pneumonia, which may facilitate bacterial outgrowth.     

Presence of monoclonal free light chains in the serum predicts risk of progression in monoclonal gammopathy of undetermined significance

We hypothesized that the presence of monoclonal free light chains (FLC) in the serum of patients with monoclonal gammopathy of undetermined significance (MGUS) is a marker of clonal evolution and a risk factor for progression. Forty-seven patients with MGUS and documented progression to myeloma or related malignancy were compared with 50 age- and gender-matched patients with MGUS and no evidence of progression after 5 or more years of follow-up. The presence of an abnormal kappa/lambda FLC ratio in the serum was associated with a higher risk of MGUS progression (relative risk 2.5; 95% confidence interval: 1.6-4.0; P < 0.001).