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Inflammation and inflammasomes have been proposed as important regulators of the host–microorganism interaction, playing a key role in morbidity and mortality due to the coronavirus disease 2019 (COVID-19) in subjects with chronic conditions and compromised immune system. The inflammasome consists of a multiprotein complex that finely regulates the activation of caspase-1 and the production and secretion of potent pro-inflammatory cytokines such as IL-1β and IL-18. The pyrin containing NOD (nucleotide-binding oligomerization domain) like receptor (NLRP) is a family of intracellular receptors, sensing patterns associated to pathogens or danger signals and NLRP3 inflammasome is the most deeply analyzed for its involvement in the innate and adaptive immune system as well as its contribution to several autoinflammatory and autoimmune diseases. It is highly expressed in leukocytes and up-regulated in sentinel cells upon inflammatory stimuli. NLRP3 expression has also been reported in B and T lymphocytes, in epithelial cells of oral and genital mucosa, in specific parenchymal cells as cardiomyocytes, and keratinocytes, and chondrocytes. It is well known that a dysregulated activation of the inflammasome is involved in the pathogenesis of different disorders that share the common red line of inflammation in their pathogenetic fingerprint. Here, we review the potential roles of the NLRP3 inflammasome in cardiovascular events, liver damage, pulmonary diseases, and in that wide range of systemic inflammatory syndromes named as a cytokine storm. [ABSTRACT FROM AUTHOR]

Cryoproteinaemia is characterised by the presence of detectable proteins in both serum and plasma that precipitate at 4°C and dissolve at 37°C. Cryoglobulins are constituted by immunoglobulins and are detectable in both serum and plasma, whereas cryofibrinogen is detectable only in plasma. The importance of studying cryoproteinemia was the main theme of the meeting held in Modena in March 2023, entitled: Cryoglobulinemia. Laboratory and clinic, a fruitful collaboration for the correct management of a rare pathology - 4th edition, organised by the Italian Society of Clinical Biochemistry and Molecular Biology (SIBioC) and the Italian Association for the fight against Cryoglobulinaemia (ALCRI). The aim of this conference is to promote a dialogue between clinicians and laboratory professionals, highlighting the information that the clinician expects from the laboratory and the critical points that the laboratory faces when performing a test that is still predominantly performed manually. During the meeting, data from three laboratories were presented and compared, and a group of clinicians who deal with cryoproteinemia in different medical fields -- rheumatologists, nephrologists, haematologists, and neurologists -- contributed their experience in treating patients with cryoproteinemia. The collaboration between laboratory and clinic and the respective scientific societies (SIBioC and ALCRI) have made possible to draw a common line to guide both entities in their daily activity. The road seems long and complex, but a common system is emerging from this interaction, the fruits from which patient will benefit. [ABSTRACT FROM AUTHOR]

Prolonged B cells stimulation due to the Hepatitis C virus (HCV) can result in autoimmunity, stigmatized by rising levels of cryoglobulins (CGs), the rheumatoid factor (RF), and free light chains (FLC) of immunoglobulins (Ig) associated with a range of symptoms, from their absence to severe cryoglobulinemic vasculitis and lymphoma. Here, we aimed to identify an immunological signature for the earliest stages of vasculitis when cryoprecipitate is still not detectable. We firstly analyzed the IgG subclasses, FLC, and RF in 120 HCV-RNA-positive patients divided into four groups according to the type of cryoprecipitate and symptoms: 30 asymptomatic without cryoprecipitate (No Cryo), 30 with vasculitis symptoms but without CGs that we supposed were circulating but still not detectable (Circulating), 30 type II and 30 type III mixed cryoglobulinemia (Cryo II and Cryo III, respectively). Our results revealed that patients with supposed circulating CGs displayed a pattern of serological parameters that closely resembled Cryo II and Cryo III, with a stronger similarity to Cryo II. Accordingly, we analyzed the groups of Circulating and Cryo II for their immunoglobulin heavy chain (IgH) and T-cell receptor (TCR) gene rearrangements, finding a similar mixed distribution of monoclonal, oligoclonal, and polyclonal responses compared to a control group of ten HCV-RNA-negative patients recovered from infection, who displayed a 100% polyclonal response. Our results strengthened the hypothesis that circulating CGs are the origin of symptoms in HCV-RNA-positive patients without cryoprecipitate and demonstrated that an analysis of clonal IGH and TCR rearrangements is the best option for the early diagnosis of extrahepatic complications. [ABSTRACT FROM AUTHOR]

Background: Inflammation plays a pivotal role in the pathophysiology of asthma. Free light chains (FLC) can cause inflammation by mast cell antigen-activation. Serum immunoglobulin (Ig) FLC κ, but not λ, were shown elevated in adult males with asthma. We sought to investigate if serum Ig FLC concentrations are affected by asthma severity and their relationships with inflammatory outcomes. Methods: By using immunoassays, we measured serum κ and λ Ig FLCs in 24 severe persistent asthma patients, 15 patients with moderate persistent asthma, 15 steroid-naïve mild persistent asthma patients and 20 healthy control subjects in a cross-sectional observational study. Total and specific serum IgE concentrations, fractional exhaled nitric oxide (FENO), lung function, peripheral blood eosinophils and neutrophils, and C reactive protein (CRP) were also measured. Results: Serum κ FLC concentrations were elevated in severe asthma patients compared mild asthma patients (p < 0.05) and healthy subjects (p < 0.05). Serum λ FLCs were higher in severe asthma patients than in healthy subjects (p < 0.05) and correlated with blood eosinophil counts (percentage, κ: r = 0.51, p = 2.9678-6; λ: r = 0.42, p = 1.7377-4; absolute values, κ: r = 0.45, p = 6.1284-5; λ: r = 0.38, p = 7.8261-4), but not with total or specific serum IgE. In severe asthma patients, serum Ig FLC correlated with serum CRP (κ: r = 0.33; p = 0.003; λ: r = 0.38, p = 8.8305-4) and blood neutrophil cell counts (percentage, κ: r = 0.31; p = 0.008; λ: r = 0.29, p = 0.01; absolute values, κ: r = 0.40; p = 3.9176-4; λ: r = 0.40, p = 4.5479-4), were elevated in subjects with blood eosinophilia (≥300 cells/μL) (n = 13) compared with non-eosinophilic subjects (n = 10) (κ: 19.2 ± 1.2 mg/L versus 12.1 ± 1.3 mg/L, p < 0.001; λ: 27.2 ± 2.6 mg/L versus 16.8 ± 2.5 mg/L, p < 0.01), but were similar in atopic (n = 15) versus nonatopic subjects (n = 9) (κ: p = 0.20; λ: p = 0.80). Serum FLC were negatively correlated with lung function tests, including forced expiratory volume in one second (FEV1) (κ: r = -0.33; p = 0.0034; λ: r = -0.33; p = 0.0035), and FEV1/forced vital capacity ratio (κ: r = -0.33; p = 0.0034; λ: r = -0.33; p = 0.0036). Conclusion: Serum Ig FLCs are elevated in severe asthma adults and might represent new surrogate markers of inflammation. The pathophysiological implications of these findings require further research. This study was approved by the ethics committee of the University Hospital Agostino Gemelli Foundation and Catholic University of the Sacred Heart (approval number P/1034/CE2012). [ABSTRACT FROM AUTHOR]

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease, ranging from pure steatosis to non-alcoholic steatohepatitis and ultimately to liver cirrhosis. In our study, adult NAFLD patients did not have different oxalate excretion values [ -0.26 (95% CI -1.59-1.08), I P i =.681] and only altered urinary ammonium and magnesium excretions were found as proposed risk factors for nephrolithiasis (Fig. Our findings indicate the need for further prospective studies to compare the characteristics of NAFLD patients with and without nephrolithiasis and its incidence at different degrees of NAFLD severity to expand on the observations reported here. [Extracted from the article]

The antibody-related immune response is mediated by immunoglobulins (Igs), soluble circulating glycoproteins produced by activated B cells that, upon the recognition of specific epitopes on pathogen surfaces, activate, proliferate, and differentiate into antibody-secreting plasma cells. Although the antibodies are effectors of the humoral immune adaptive response, their overproduction in response to a dysregulated proliferation of clonal plasma cell production in tumoral conditions (i.e., multiple myeloma), enriches the serum and urinary matrices, assuming the crucial role of biomarkers. Multiple myeloma (MM) is a plasma cell dyscrasia characterized by the expansion and accumulation of clonally activated plasma cells in bone marrow, determining the release of high amounts of monoclonal component (MC) that can be detected as intact immunoglobulin (Ig), immunoglobulin fragments, or free light chains (FLCs). The importance of detecting biomarkers for the diagnosis, monitoring, and prognosis of diseases is highlighted by the international guidelines that recommend specific assays for the analysis of intact Igs and FLC. Moreover, a developed assay called Hevylite® allows for the quantification of immunoglobulins that are both involved (iHLC) and not involved (uHLC) in the tumor process; this is a fundamental aspect of following up the patient's workup and evaluating the progression of disease, together with the treatments response. We here summarize the major points of the complex scenario involving monoclonal gammopathies and MM clinical management in view of advantages derived for the use of Hevylite®. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) represents a worldwide health matter with a major care burden, high prevalence, and poor prognosis. Its pathogenesis mainly varies depending on the underlying etiological factors, although it develops from liver cirrhosis in the majority of cases. This review summarizes the role of the most interesting soluble factors as biomarkers for early diagnosis and as recommended targets for treatment in accordance with the new challenges in precision medicine. In the premalignant environment, inflammatory cells release a wide range of cytokines, chemokines, growth factors, prostaglandins, and proangiogenic factors, making the liver environment more suitable for hepatocyte tumor progression that starts from acquired genetic mutations. A complex interaction of pro-inflammatory (IL-6, TNF-α) and anti-inflammatory cytokines (TGF-α and -β), pro-angiogenic molecules (including the Angiopoietins, HGF, PECAM-1, HIF-1α, VEGF), different transcription factors (NF-kB, STAT-3), and their signaling pathways are involved in the development of HCC. Since cytokines are expressed and released during the different stages of HCC progression, their measurement, by different available methods, can provide in-depth information on the identification and management of HCC. [ABSTRACT FROM AUTHOR]

COVID-19 continues to afflict the global population, causing several pathological diseases and exacerbating co-morbidities due to SARS-CoV-2's high mutation. Recent interest has been devoted to some neuronal manifestations and to increased levels of Nerve Growth Factor (NGF) and Brain-derived Neurotrophic Factor (BDNF) in the bloodstream during SARS-CoV-2 infection, neurotrophins that are well-known for their multifactorial actions on neuro-immune-endocrine and visual functions. Nineteen (19) patients were enrolled in this monocentric prospective study and subjected to anamnesis and biosamples collection (saliva and blood) at hospitalization (acute phase) and 6 months later (remission phase). NGF and BDNF were quantified by ELISA, and biochemical data were related to biostrumental measurements. Increased NGF and BDNF levels were quantified in saliva and serum during the acute phase of SARS-CoV-2 infection (hospitalized patients), and reduced levels were observed in the next 6 months (remission phase), never matching the baseline values. Salivary and circulating data would suggest the possibility of considering sera and saliva as useful matrices for quickly screening neurotrophins, in addition to SARS-CoV2 antigens and RNA. Overall, the findings described herein highlight the importance of NGF and BDNF as dynamic biomarkers for monitoring disease and reinforces the possibility of using saliva and sera for quick, non-invasive COVID-19 screening. [ABSTRACT FROM AUTHOR]

Oxidative and inflammatory damage underlie several conditions related to male infertility, including varicocele. Free light chains of immunoglobulins (FLCs) are considered markers of low-grade inflammation in numerous diseases. Coenzyme Q10 (CoQ10), a lipidic antioxidant and anti-inflammatory compound, is involved in spermatozoa energy metabolism and motility. We aimed to evaluate FLCs' seminal levels in patients with varicocele in comparison to control subjects and to correlate them with CoQ10 and Total Antioxidant Capacity (TAC) in human semen. Sixty-five patients were enrolled. Semen analysis was performed; patients were divided into three groups: controls, 12 normozoospermic patients, aged 34 (33–41) years; varicocele (VAR), 29 patients, aged 33 (26–37) years; and idiopathic, 24 oligo-, astheno- and oligoasthenozoospermic patients aged 37 (33.5–40.5) years. FLCs (κ and λ) were assayed by turbidimetric method; CoQ10 by HPLC; TAC by spectrophotometric method. λ FLCs showed a trend toward higher levels in VAR vs. controls and the idiopathic group. VAR showed a trend toward lower κ FLCs levels vs. the other two groups. When comparing κ/λ ratio, VAR showed significantly lower levels vs. controls and idiopathic. Moreover, CoQ10 seminal levels showed higher levels in VAR and idiopathic compared to controls. Data reported here confirm lower levels of κ/λ ratio in VAR and suggest a possible application in personalized medicine as clinical biomarkers for male infertility. [ABSTRACT FROM AUTHOR]

Immunoglobulins free light chains (FLCs) are assayable in several biological fluids. Currently, there are no reports on FLCs in seminal plasma. The aims of our study were to investigate the presence and detectability of FLCs in seminal plasma and to evaluate the usefulness of this assay in the diagnostic approach to infertile patients. We enrolled 61 patients aged 18-- 50 years. Semen analysis was performed. They were divided into four groups: controls-- normozoospermic, 10 patients, mean ± SEM age 35 ± 1.5 years; varicoceles (VAR), 18 patients aged 24.3 ± 0.96 years; inflammatory (INF) seminal fluids, 24 patients, aged 38.8 ± 2.2 years; and varicoceles and inflammatory (VAR/INF) seminal fluids, 9 patients, aged 29.5 ± 0.71 years. A trend towards higher λ FLCs levels was evidenced in the INF and VAR/INF groups. FLCs were higher in normozoospermic patients with lower levels in VAR, both isolated and associated with inflammatory parameters. This differential pattern of the two types of FLCs reached statistical significance when comparing /λ ratio, with significant lower levels in VAR vs controls. This is the first report of FLCs assay in seminal plasma. We can hypothesize that λ FLCs are increased in inflammatory processes, whether FLCs seem to be influenced by other molecular mechanisms related to varicocele. [ABSTRACT FROM AUTHOR]

Metabolic diseases are associated with a higher risk of a severer coronavirus disease 2019 (COVID‐19) course, since fatty liver is commonly associated with metabolic disorders, fatty liver itself is considered as a major contributor to low‐grade inflammation in obesity and diabetes. Recently a comprehensive term, metabolic (dysfunction) associated fatty liver disease (MAFLD), has been proposed. The hepatic inflammatory status observed in MAFLD patients is amplified in presence of severe acute respiratory syndrome coronavirus 2 infection. Intestinal dysbiosis is a powerful activator of inflammatory mediator production of liver macrophages. The intestinal microbiome plays a key role in MAFLD progression, which results in non‐alcoholic steatohepatitis and liver fibrosis. Therefore, patients with metabolic disorders and COVID‐19 can have a worse outcome of COVID‐19. This literature review attempts to disentangle the mechanistic link of MAFLD from COVID‐19 complexity and to improve knowledge on its pathophysiology. [ABSTRACT FROM AUTHOR]

Objectives The biomarkers of an immunological dysregulation due to a chronic HBV infection are indeed understudied. If untreated, this condition may evolve into liver impairment co-occurring with extrahepatic involvements. Here, we aim to identify a new panel of biomarkers [including immunoglobulin G (IgG) subclasses, RF, and Free Light Chains (FLCs)] that may be useful and reliable for clinical evaluation of HBV-related cryoglobulinemia. Methods We retrospectively analysed clinical data from 44 HBV-positive patients. The patients were stratified (according to the presence/absence of mixed cryoglobulinemia) into two groups: 22 with cryoglobulins (CGs) and 22 without CGs. Samples from 20 healthy blood donors (HDs) were used as negative controls. Serum samples were tested for IgG subclasses, RF (-IgM, -IgG, and -IgA type), and FLCs. Results We detected a strikingly different distribution of serum IgG subclasses between HDs and HBV-positive patients, together with different RF isotypes; in addition, FLCs were significantly increased in HBV-positive patients compared with HDs, while no significant difference was shown between HBV-positive patients with/without mixed cryoglobulinemia. Conclusion The immune-inflammatory response triggered by HBV may be monitored by a peculiar profile of biomarkers. Our results open a new perspective in the precision medicine era; in these challenging times, they could also be employed to monitor the clinical course of those COVID-19 patients who are at high risk of HBV reactivation due to liver impairment and/or immunosuppressive therapies. [ABSTRACT FROM AUTHOR]

Summary: Circulating free light chains (FLCs), considered biomarkers of B cell activity, are frequently elevated in patients affected by systemic inflammatory autoimmune diseases. As the systemic sclerosis (SSc) clinical course can be variable, this study is aimed at evaluating FLCs levels in affected individuals as biomarkers of disease activity. We assessed FLC levels in serum and urine of 72 SSc patients and 30 healthy controls (HC). Results were analyzed in comparison with overall clinical and laboratory findings, disease activity index (DAI) and disease severity scale (DSS). SSc patients displayed increased levels of κ and λ FLC in serum significantly higher than HC (p = 0.0001) alongside the mean values of free κ/λ ratio and κ + λ sum (p = 0.0001). SSc patients showed increased free κ in urine with a κ/λ higher than HC (p = 0.0001). SSc patients with increased κ + λ in serum showed that erythro‐sedimentation rate (p = 0.034), C‐reactive protein (p = 0.003), DAI (p = 0.024) and DSS (p = 0.015) were higher if compared to SSc patients with normal levels of FLC. A positive linear correlation was found between serum levels of free κ and DAI (r = 0.29, p = 0.014). In addition, SSc patients with increased free κ in urine had higher DAI (p = 0.048) than SSc patients with normal κ levels. Our results strengthen the role of serum FLC as useful biomarker in clinical practice to early diagnosis and monitor disease activity, showing for the first time that also urine FLC levels correlated with disease activity in SSc patients. [ABSTRACT FROM AUTHOR]

The loss of tolerance to self-antigens is the unequivocal "red line" of autoimmunity: both development of autoreactive T and B cells and production of polyclonal autoantibodies represent seminal keys to the pathogenesis of protean autoimmune diseases. Most of these autoantibodies are immunoglobulins G (IgG), functionally distinguished in four subclasses named IgG1, IgG2, IgG3, and IgG4, due to structural differences in the hinge and heavy chain constant regions. Different studies analyzed serum levels of IgG subclasses in the course of different disorders, showing that they might have a pathogenic role by regulating interactions among immunoglobulins, Fc-gamma receptors, and complement. To date, the mechanisms promoting different IgG subclasses distribution during the natural history of most autoimmune diseases remain somewhat unclear. Evidence from the medical literature shows that the serum IgG profile is peculiar for many autoimmune diseases, suggesting that different subclasses could be specific for the underlying driving autoantigens. A better knowledge of IgG subsets may probably help to elucidate their pathological task, but also to define their relevance for diagnostic purposes, patients' personalized management, and prognosis assessment. [ABSTRACT FROM AUTHOR]

Hepatitis C virus (HCV) represents the major risk factor for mixed cryoglobulinemia (MC), a small-vessel vasculitis that may evolve into an overt B-cell non-Hodgkin's lymphoma. Here, we aimed to identify a biomarker signature for the early diagnosis of minimal residual disease (MRD). We assessed free light chains (FLCs), IgM k,and IgM λ heavy/light chain (HLC) pairs, and vascular endothelial growth factor (VEGF) in sera from 34 patients with MC vasculitis (32 HCV- and 2 HBV-related), treated with low-dose rituximab (RTX). FLCs and IgM HLCs were measured by turbidimetric assay; VEGF by an enzyme-linked immunosorbent assay. After RTX, the positive (complete + partial) clinical and laboratory responses were of 85.29% and 50%, respectively; in contrast, the mean levels of FLCs, IgM HLCs, and VEGF were substantially unaffected in most patients and still above the normal range. In those achieving a reduction of FLCs and IgM k and λ chains values within the range of normality, we found that post-treatment free λ chains and IgM k values correlated with clinical and laboratory response. Our results suggest that high levels of FLCs, IgM HLCs, and VEGF could represent the signature of "dormant" B cell clones' activity that could be very useful to identify MRD indicative of possible relapse or worsening outcome. [ABSTRACT FROM AUTHOR]

In the natural history of SARS‐CoV‐2 infection, liver injury is frequent but quite mild and it is defined as any liver damage occurring during disease progression and treatment of infection in patients with or without pre‐existing liver diseases. The underlying mechanisms for hepatic injury in patients with COVID‐19 are still unclear but the liver damage in SARS‐CoV‐2 infection seems to be directly caused by virus‐induced cytopathic effects. In this review, we will summarize all data of updated literature, regarding the relationship between SARS‐CoV‐2 infection, acute response and liver involvement. An overview will be given on liver injury, liver transplant and the possible consequences of COVID‐19 in patients with pre‐existing liver diseases. [ABSTRACT FROM AUTHOR]

The use of rituximab (RTX), an anti-CD20 monoclonal antibody (Ab), in refractory myasthenia gravis (MG) is associated with a better response in patients with Abs to the muscle-specific tyrosine kinase (MuSK) than in other MG subgroups. Anti-MuSK Abs are mostly IgG4 with proven pathogenicity and positive correlation with clinical severity. The rapid and sustained response to RTX may be related to MuSK Ab production by short-lived Ab-secreting cells derived from specific CD20+ B cells. Here, we investigated the long-term effects of RTX in nine refractory MuSK-MG patients with a follow-up ranging from 17 months to 13 years. In patients' sera, we titrated MuSK-specific IgG (MuSK-IgG) and MuSK-IgG4, along with total IgG and IgG4 levels. Optimal response to RTX was defined as the achievement and maintenance of the status of minimal manifestations (MM)-or-better together with a ≥ 50% steroid reduction, withdrawal of immunosuppressants, and no need for plasma-exchange or intravenous immunoglobulin. After a course of RTX, eight patients improved, with optimal response in six, while only one patient did not respond. At baseline, MuSK-IgG and MuSK-IgG4 serum titers were positive in all patients, ranging from 2.15 to 49.5 nmol/L and from 0.33 to 46.2 nmol/L, respectively. MuSK Abs mostly consisted of IgG4 (range 63.80–98.86%). RTX administration was followed by a marked reduction of MuSK Abs at 2–7 months and at 12–30 months (p < 0.02 for MuSK-IgG and p < 0.01 for MuSK-IgG4). In patients with a longer follow-up, MuSK Ab titers remained suppressed, paralleling clinical response. In the patient who achieved long-term complete remission, MuSK-IgG4 was no longer detectable within 2 years, while MuSK-IgG remained positive at very low titers up to 10 years after RTX. In the patient who did not respond, MuSK-IgG and MuSK-IgG4 remained unchanged. In this patient series, total IgG and IgG4 transiently decreased (p < 0.05) at 2–7 months after RTX. The different trends of reduction between MuSK-IgG4 and total IgG4 after RTX support the view that short-lived Ab-secreting cells are the main producers of MuSK Abs. The ratio between short-lived Ab-secreting cells and long-lived plasma cells may influence the response to RTX, and B-cell severe depletion may reduce self-maintaining autoimmune reactivity. [ABSTRACT FROM AUTHOR]

We analyzed the prognostic impact of levels of free light chains (FLC) in 106 patients with DLBCL, selecting 61 patients with a monoclonal (M) protein in serum, and 45 patients without a M protein as an IPI-matched control group. Patients with a M protein had higher levels of FLC, but these were not of prognostic significance in this group. The presence of a M protein nullified associations of κ-FLC with several laboratory parameters indicating immune system activation observed in patients without a M protein. Patients without M protein and κ-FLC >50 mg/L had a significant inferior event-free survival (p =.004). The presence of M protein of an IgM type at diagnosis was a negative outcome predictor (p =.008), while a non-IgM M protein did not significantly impact on prognosis. In conclusion, the prognostic performance of the FLC assay is altered by the presence of a M protein. [ABSTRACT FROM AUTHOR]

Along years, the advent of biological therapy widely modified treatment of rheumatic diseases and other disorders. However, many agents may elicit in anti-drug antibodies (ADAbs) upon consecutive infusions, with a loss of response. For the right strategy of a personalized medicine, the therapeutic monitoring of TNF-α inhibitors and ADAbs represents an important effort in diagnostic–therapeutic pathway, to improve overall patient management and favoring an appropriate clinical approach. A raising number of diagnostic tests have been designed to elucidate the efficacy and/or safety of a specific drug or class of drugs for a targeted patient's group. Our paper reviewed the current understanding of the immunogenicity of biological drugs employed in the treatment of inflammatory diseases underlying the laboratory role. [ABSTRACT FROM AUTHOR]

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Clinical spectrum of hepatitis C virus (HCV)‐related cryoglobulinemia varies from an asymptomatic presentation to severe vasculitis and lymphoma. A recent study in HCV‐negative patients suggests that low cryoglobulins (CGs) levels are responsible for severe renal and neurological complications. The aim of this study was to identify a panel of serological biomarkers associated with low levels of CGs in HCV‐positive patients. We studied a population of 79 untreated patients with chronic HCV infection: 13 naïve patients without CGs; 28 patients with asymptomatic mixed cryoglobulinemia (MC) and low levels of CGs (16/28 with polyclonal type III and 12/28 with microheterogeneous type III CGs); 38 patients with symptomatic MC and high levels of type II CGs. Serum samples were collected and examined for rheumatoid factor (RF) IgG and IgM, free light chains (FLCs) and C3 and C4 complement components. We found that RF‐IgG and IgM, free k chains and k+λ were increased while C4 component was reduced, both in symptomatic and asymptomatic patients. Our results suggest that, even in absence of MC symptoms, the low levels of CGs may represent a trigger of activation for immune system in course of HCV infection. The identification of a correlated biomarkers panel could improve the clinical management of these patients and pave the way for target treatment strategies. © 2018 BioFactors, 45(3):318–325, 2019 [ABSTRACT FROM AUTHOR]

The study of free light chains (FLCs) has grown as area of enormous interest for many clinicians with the aim of disclosing the exact biological role and potential use of FLCs in the clinical routine. Moreover, the attention given to immunological functions of FLCs has sparked a new light into their pathogenic contribution in different chronic autoimmune-based inflammatory diseases. The release of intracellular antigens following cell death or ineffective clearance of apoptotic debris, modification of self-antigens, and molecular mimicry may trigger the production of immunoglobulins after activation and polyclonal expansion of B cells, by which FLCs are released. The discovery of polyclonal FLCs as potential biomarkers started with the observation of their increased concentrations in a variety of biological fluids related to patients with autoimmune diseases. This review deals with the use of polyclonal FLCs for identifying severity and monitoring outcome after treatment in some autoimmune diseases, namely systemic lupus erythematosus, myasthenia gravis, systemic sclerosis, rheumatoid arthritis and Sjögren's syndrome, as supported by the fact that levels of FLCs correlate with both B cell activation markers and other specific markers of disease activity. In a near future, following the evidence shown, FLCs might probably work as early prognostic markers of severity and also as indicators of response to treatment or early assessment of relapse in selected autoimmune diseases. [ABSTRACT FROM AUTHOR]

Biological functions of immunoglobulin‐free light chains (FLCs), other than in chronic inflammatory diseases, are still poorly defined; the field of insulin resistance (IR) has not been investigated, despite the strict relationships with oxidative stress (OS) and inflammation. Therefore, we evaluated FLCs levels and their relationships with metabolic parameters in adult growth hormone deficiency (GHD) and metabolic syndrome (MetS), both characterized by IR. One hundred subjects were enrolled: group A, patients with GHD [n =31, 24–69 years, mean ± SEM body mass index (BMI) 26.8 ± 1.5 kg/m2]; group B, patients with MetS (n = 29, 21–70 years, BMI 31.9 ± 1.3); group C, controls (N = 40, 21–62 years, BMI 21.6 ± 1.1). Groups were matched by age range and, for patients, by BMI. Morning blood sample was collected for metabolic parameters and FLCs, assessed by turbidimetric assay. GHD patients show levels of FLCs significantly higher than MetS and controls (mean ± SEM κ 37.21 ± 6.97, 15.27 ± 0.86, 12.34 ± 0.85 mg/l; λ 19.44 ± 2.61, 11.78 ± 0.72 and 11.67 ± 0.77 mg/l; κ/λ ratio 1.77 ± 0.13, 1.38 ± 0.09; and 1.10 ± 0.06, respectively); only κ were higher in MetS versus controls. Therefore, the ratio showed progressive declining values in GHD versus MetS versus controls. Our data show increased FLCs levels in GHD and MetS, with the highest values in the former. Both conditions show OS, but with different molecular patterns. FLCs may contribute to chronic inflammation, leading to OS, and cardiovascular complications of GHD. Prognostic and therapeutic implications require further investigation. © 2018 BioFactors, 44(5):480–484, 2018 [ABSTRACT FROM AUTHOR]

Background: Serological levels of free immunoglobulin light chains (FLCs), produced in excess of heavy chains during synthesis of immunoglobulins by plasma cells, can be considered a direct marker of B cell activity in different systemic inflammatory-autoimmune conditions and may represent a useful predictor of rituximab (RTX) therapeutic efficacy, as reported for rheumatoid arthritis and systemic lupus erythematosus. Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction with antibodies (abs) targeting the acetylcholine receptor (AChR) or the muscle-specific tyrosine kinase (MuSK), inducing muscle weakness and excessive fatigability. As MG course may be remarkably variable, we evaluated the possible use of FLCs as biomarkers of disease activity.Subjects and Methods: We assessed FLC levels in 34 sera from 17 AChR-MG and from 13 MuSK-MG patients, in comparison with 20 sera from patients with systemic autoimmune rheumatic diseases and 18 from healthy blood donors, along with titers of specific auto-abs and IgG subclass distribution.Results: We found a statistically significant increase in free κ chains in both AChR- and MuSK-MG patients, while free λ chain levels were increased only in AChR-MG. We also observed a significant reduction of both free κ and λ chains in 1/4 MuSK-MG patients along with specific abs titer, two months after RTX treatment.Conclusions: From our data, FLCs appear to be a sensitive marker of B cell activation in MG. Further investigations are necessary to exploit their potential as reliable biomarkers of disease activity. [ABSTRACT FROM AUTHOR]

Cryoglobulins are immunoglobulins that precipitate in serum at temperatures below 37°C and resolubilize upon warming. The clinical syndrome of cryoglobulinemia usually includes purpura, weakness, and arthralgia, but the underlying disease may also contribute other symptoms. Blood samples for cryoglobulin are collected, transported, clotted and spun at 37°C, before the precipitate is allowed to form when serum is stored at 4°C in a Wintrobe tube for at least seven days. The most critical and confounding factor affecting the cryoglobulin test is when the preanalytical phase is not fully completed at 37°C. The easiest way to quantify cryoglobulins is the cryocrit estimate. However, this approach has low accuracy and sensitivity. Furthermore, the precipitate should be resolubilized by warming to confirm that it is truly formed of cryoglobulins. The characterization of cryoglobulins requires the precipitate is several times washed, before performing immunofixation, a technique by which cryoglobulins can be classified depending on the characteristics of the detected immunoglobulins. These features imply a pathogenic role of these molecules which are consequently associated with a wide range of symptoms and manifestations. According to the Brouet classification, Cryoglobulins are grouped into three types by the immunochemical properties of immunoglobulins in the cryoprecipitate. The aim of this paper is to review the major aspects of cryoglobulinemia and the laboratory techniques used to detect and characterize cryoglobulins, taking into consideration the presence and consequences of cryoglobulinemia in Hepatitis C Virus (HCV) infection. [ABSTRACT FROM AUTHOR]

The article discusses a study which evaluates the use of the pentavalent immunofixation electrophoresis test as a screening test prior to urine Bence Jonce protein-immunofixation (BJP-IFE) investigation. BJP-IFE was used to stratify patients according to the type of disorder. The results are consistent with the evidence omn the diagnostic accuracy of tests for plasma cell disorders.

Introduction: The involvement of complement system in the phenotypic expression of systemic sclerosis (SSc) is a debated topic. We aimed to assay complement fractions in SSc patients and to correlate their levels with the clinical course of disease. Key points: 1. CH50 is increased in SSc patients compared to HC; 2. Serum C2 levels are increased in SSc patients compared to HC; 3. CH50 may represent a biomarker of skin and lung fibrosis severity in SSc patients. Method: Complement hemolysis 50% (CH50), C2, C3 and C4 levels have been assessed in 85 SSc patients and 47 healthy controls (HC). Results: SSc patients displayed a statistically significant higher value of CH50 [76.3 U/mL (IQR 65.8–89.4 U/mL) vs. 29.6 U/mL (IQR 24.7–34 U/mL); p < 0.0001] and of C2 [26.1 mg/L (IQR 24.1–32.1 mg/L) vs. 22.7 mg/L (IQR 20.6–24.4 mg/L); p < 0.0001] if compared to HC. Patients with diffuse cutaneous SSc (dcSSc) had higher levels of CH50 than patients with limited cutaneous SSc (lcSSc) [83.6 U/mL (IQR 72.3–102.7 U/mL) vs. 71.3 U/mL (IQR 63.7–83.6 U/mL); p = 0.003]. SSc patients with interstitial lung disease (ILD) had higher CH50 levels if compared to SSc patients without ILD [79.6 U/mL (IQR 68.3–97.4 U/mL) vs. 69.7 U/mL (54.6–85.7 U/mL); p = 0.042]. A positive linear correlation existed between CH50 and the modified Rodnan Skin Score (mRSS) (r = 0.285, p = 0.008) and disease severity scale (DSS) (r = 0.285, p = 0.005); a negative linear correlation was demonstrated between CH50 and the diffusing capacity of carbon monoxide (DLco) (r = −0.252, p = 0.012). In multiple linear regression analysis, only DSS was significant (p = 0.01, beta coefficient 2.446). Conclusions: Our results show an increment of CH50 and serum C2 levels in SSc patients in comparison to HC; we retain that CH50 may represent a biomarker of disease severity and of skin and lung fibrosis in these patients. [ABSTRACT FROM AUTHOR]

Simple Summary: The progression of liver disease is accompanied by pathological angiogenesis, a prerequisite for the development of HCC. In this paper, we analyzed the clinical significance of serum angiogenic markers VEGF, Ang-1, Ang-2, angiopoietin receptor Tie1/2, HGF, and PECAM-1 in 62 patients with liver disease, out of which 33 were diagnosed with HCC and 29 with liver cirrhosis without signs of neoplasia. Biomarkers levels were investigated as a function of "Model for End-Stage Liver Disease" (MELD) score and Fibrosis Index (FI). HCC patients showed higher HGF levels than ones with cirrhosis, while high Ang-1 levels appeared to have a protective role in HCC as well as prognostic significance; we also found a strong correlation between HGF levels, Ang-2, and VEGF levels, further supporting their role in tumor angiogenesis. Due to the complexity of angiogenesis and the small size of the study group, further investigations are widely desired especially in the era of immunotherapy and HCC-targeted anti-angiogenic drugs. Background: Hepatocellular carcinoma (HCC) is a global health problem associated with chronic liver disease. Its pathogenesis varies according to the underlying etiological factors, although in most cases it develops from liver cirrhosis. The disease progression is accompanied by pathological angiogenesis, which is a prerequisite that favors the development of HCC. Aims: This study aims at contributing to our understanding of the role of angiogenic factors in the progression of liver disease. For this purpose, we evaluate the clinical significance of serum angiogenic markers (VEGF, Ang-1, Ang-2, the angiopoietin receptor Tie1/2, HGF, and PECAM-1) first in cirrhotic and HCC patients separately, and then comparing cirrhotic patients with and without HCC. Materials and Methods: We enrolled 62 patients, out of whom 33 were diagnosed with HCC and 29 with liver cirrhosis without signs of neoplasia. Patients underwent venous blood sampling before and after receiving treatments for the diagnosed disease. Serum markers were evaluated using ELISA assays for Tie1 and the Bio-Plex Multiplex system for the remaining ones. Biomarker levels were investigated as a function of clinical scores for disease staging (MELD and Fibrosis Index, FI). Results: In cirrhotic patients, Ang-1 and Ang-2 correlate with MELD (ρAng-1 = −0.73, p = 2E−5) and FI (ρAng-1 = −0.52, p = 7E−3, ρAng-2 = 0.53, p = 3E−3). A reduction of Ang-2 levels (p = 0.047) and of the Ang-2/Ang-1 ratio (p = 0.031) is observed in cirrhotic patients diagnosed with viral hepatitis after antiviral treatments. In HCC patients, Ang-1 negatively correlates with FI (ρ = −0.63, p = 1E−4), and PECAM-1 positively correlates with MELD (ρ = 0.44, p = 0.01). A significant Ang-1 reduction was observed in deceased patients during the study compared to ones who survived (p = 0.01). In HCC patients, VEGF levels were increased after tumor treatment (p = 0.037). Notably, HGF levels in cirrhotic patients with HCC are significantly raised (p = 0.017) compared to that in those without HCC. Conclusions: Our results suggest that serum angiogenic markers, with emphasis on Ang-1/2, can contribute to the development of quantitative tools for liver disease staging and therapy monitoring. The comparison between cirrhotic patients with and without HCC suggests that HGF levels are potentially useful for monitoring the insurgence of HCC after a cirrhosis diagnosis. High Ang-1 levels in HCC patients appear to have a protective role as well as prognostic significance. [ABSTRACT FROM AUTHOR]

Myasthenia gravis with antibodies (Abs) against the muscle-specific tyrosine kinase (MuSK) is a rare autoimmune disorder (AD) of the neuromuscular junction (NMJ) and represents a prototype of AD with proven IgG4-mediated pathogenicity. Thanks to the mechanism of Fab-arm exchange (FAE) occurring in vivo, resulting MuSK IgG4 k/λ Abs increase their interference on NMJ and pathogenicity. The characterization of hybrid MuSK IgG4 as a biomarker for MG management is poorly investigated. Here, we evaluated total IgG4, hybrid IgG4 k/λ, and the hybrid/total ratio in 14 MuSK-MG sera in comparison with 24 from MG with Abs against acetylcholine receptor (AChR) that represents the not IgG4-mediated MG form. In both subtypes of MG, we found that the hybrid/total ratio reflects distribution reported in normal individuals; instead, when we correlated the hybrid/total ratio with specific immune-reactivity we found a positive correlation only with anti-MuSK titer, with a progressive increase of hybrid/total mean values with increasing disease severity, indirectly confirming that most part of hybrid IgG4 molecules are engaged in the anti-MuSK pathogenetic immune-reactivity. Further analysis is necessary to strengthen the significance of this less unknown biomarker, but we retain it is full of a diagnostic-prognostic powerful potential for the management of MuSK-MG. [ABSTRACT FROM AUTHOR]

The ongoing outbreak of coronavirus disease 2019 (COVID-19), which impairs the functionality of several organs, represents a major threat to human health. One of the hardest challenges in the fight against COVID-19 is the development of wide-scale, effective, and rapid laboratory tests to control disease severity, progression, and possible sudden worsening. Monitoring patients in real-time is highly demanded in this pandemic era when physicians need reliable and quantitative tools to prioritize patients' access to intensive care departments. In this regard, salivary biomarkers are extremely promising, as they allow for the fast and non-invasive collection of specimens and can be repeated multiple times. Methods: We compare salivary levels of immunoglobulin A subclasses (IgA1 and IgA2) and free light chains (kFLC and λFLC) in a cohort of 29 SARS-CoV-2 patients and 21 healthy subjects. Results: We found that each biomarker differs significantly between the two groups, with p-values ranging from 10−8 to 10−4. A Receiving Operator Curve analysis shows that λFLC level is the best-suited candidate to discriminate the two groups (AUC = 0.96), with an accuracy of 0.94 (0.87–1.00 95% CI), a precision of 0.91 (0.81–1.00 95% CI), a sensitivity of 1.00 (0.96–1.00 95% CI), and a specificity of 0.86 (0.70–1.00 95% CI). Conclusion: These results suggest λFLC as an ideal indicator of patient conditions. This hypothesis is strengthened by the consideration that the λFLC half-life (approximately 6 h) is significantly shorter than the IgA one (21 days), thus confirming the potential of λFLC for effectively monitoring patients' fluctuation in real-time. [ABSTRACT FROM AUTHOR]

The production of antibodies is accompanied by a slight excess of synthesis of κ and λ immunoglobulin light chains; small amounts of them are released in the peripheral blood and can also be found in various body fluids, such as synovial fluid, cerebrospinal fluid, urine and saliva. They are rapidly filtered by the glomerulus and > 99% are reabsorbed from the cells of the proximal convoluted tubule, making them present in the urine in only trace amounts. The production of an excess of protein without a reason or a specific function in a biological system is rare. Free light chains, considered for years a waste product of Ig synthesis, are currently known to be very active molecules, able to bind antigens as well as whole immunoglobulin and helping to develop specific antibody affinity. The ability of free light chains to activate mast cells and then become an active part of the pathogenic mechanisms of chronic inflammatory diseases has increased interest in their clinical use, both as an attractive therapeutic target or as a biochemical marker of disease evolution or remission. This is an overview of relevant scientific interest that immunoglobulin light chains κ and λ have attracted over the years, a report on the progress in knowledge about their structure and function, with a special focus on their biological meaning and potential clinical utility in different diseases. [ABSTRACT FROM AUTHOR]

Background and Aims: Adaptive immunity is gaining a significant role in progression of metabolic dysfunction-associated steatotic liver disease (MASLD). B-cell activity can be assessed by serum-free light chains (sFLCs) k and λ levels. The objective of the present investigation is to examine the utility of sFLCs as non-invasive biomarkers for the stratification of MASLD., Methods: We enrolled a consecutive cohort from an outpatient liver unit. Diagnosis of metabolic dysfunction-associated steatohepatitis (MASH) was made with liver biopsy according to current guidelines. Compensated advanced chronic liver disease (cACLD) and clinically significant portal hypertension (CSPH) were defined according to Baveno VII criteria. sFLCs were measured by turbidimetry using an immunoassay., Results: We evaluated 254 patients, 162/254 (63.8%) were male. Median age was 54 years old, and the median body mass index was 28.4 kg/m 2 . A total of 157/254 (61.8%) subjects underwent liver biopsy: 88 had histological diagnosis of MASH, 89 were considered as simple metabolic dysfunction-associated steatotic liver (MASL) and 77/254 (30.3%) patients with compensated metabolic dysfunction-associated cirrhosis. By using Baveno VII criteria, 101/254 (39.7%) patients had cACLD; among them, 45/101 (44.5%) had CSPH. Patients with cACLD showed higher sFLC levels compared with patients without cACLD (p < .01), and patients with CSPH showed higher sFLC levels than patients without CSPH (p < .01). At multivariable analysis, sFLCs were associated with cACLD (p < .05) independently from γ-globulins and other known dysmetabolic risk factors. κFLC was associated with CSPH (p < .05) independently from γ-globulins and other known dysmetabolic risk factors., Conclusion: sFLCs could be a simple biomarker for stratification of cACLD in MASLD patients., (© 2024 The Author(s). Liver International published by John Wiley & Sons Ltd.)

Hepatocellular carcinoma (HCC) represents a worldwide health matter with a major care burden, high prevalence, and poor prognosis. Its pathogenesis mainly varies depending on the underlying etiological factors, although it develops from liver cirrhosis in the majority of cases. This review summarizes the role of the most interesting soluble factors as biomarkers for early diagnosis and as recommended targets for treatment in accordance with the new challenges in precision medicine. In the premalignant environment, inflammatory cells release a wide range of cytokines, chemokines, growth factors, prostaglandins, and proangiogenic factors, making the liver environment more suitable for hepatocyte tumor progression that starts from acquired genetic mutations. A complex interaction of pro-inflammatory (IL-6, TNF-α) and anti-inflammatory cytokines (TGF-α and -β), pro-angiogenic molecules (including the Angiopoietins, HGF, PECAM-1, HIF-1α, VEGF), different transcription factors (NF-kB, STAT-3), and their signaling pathways are involved in the development of HCC. Since cytokines are expressed and released during the different stages of HCC progression, their measurement, by different available methods, can provide in-depth information on the identification and management of HCC.

Free light chain (FLC) kappa (k) and lambda (λ) consist of low molecular weight proteins produced in excess during immunoglobulin synthesis and secreted into the circulation. In patients with normal renal function, over 99% of FLCs are filtered and reabsorbed. Thus, the presence of FLCs in the serum is directly related to plasma cell activity and the balance between production and renal clearance. FLCs are bioactive molecules that may exist as monoclonal (m) and polyclonal (p) FLCs. These have been detected in several body fluids and may be key indicators of ongoing damage and/or illness. International guidelines now recommend mFLC for screening, diagnosis and monitoring multiple myeloma and other plasma cell dyscrasias. In current clinical practice, FLCs in urine indicate cast nephropathy and other renal injury, whereas their presence in cerebrospinal fluid is important for identifying central nervous system inflammatory diseases such as multiple sclerosis. Increased pFLCs have also been detected in various conditions characterized by B cell activation, i.e., chronic inflammation, autoimmune disease and HCV infection. Monitoring the coronavirus (COVID-19) pandemic by analysis of salivary FLCs presents a significant opportunity in clinical immunology worthy of scientific pursuit., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Hepatocellular carcinoma (HCC) is a global health problem associated with chronic liver disease. Its pathogenesis varies according to the underlying etiological factors, although in most cases it develops from liver cirrhosis. The disease progression is accompanied by pathological angiogenesis, which is a prerequisite that favors the development of HCC., Aims: This study aims at contributing to our understanding of the role of angiogenic factors in the progression of liver disease. For this purpose, we evaluate the clinical significance of serum angiogenic markers (VEGF, Ang-1, Ang-2, the angiopoietin receptor Tie1/2, HGF, and PECAM-1) first in cirrhotic and HCC patients separately, and then comparing cirrhotic patients with and without HCC., Materials and Methods: We enrolled 62 patients, out of whom 33 were diagnosed with HCC and 29 with liver cirrhosis without signs of neoplasia. Patients underwent venous blood sampling before and after receiving treatments for the diagnosed disease. Serum markers were evaluated using ELISA assays for Tie1 and the Bio-Plex Multiplex system for the remaining ones. Biomarker levels were investigated as a function of clinical scores for disease staging (MELD and Fibrosis Index, FI)., Results: In cirrhotic patients, Ang-1 and Ang-2 correlate with MELD (ρ Ang-1 = -0.73, p = 2E-5) and FI (ρ Ang-1 = -0.52, p = 7E-3, ρ Ang-2 = 0.53, p = 3E-3). A reduction of Ang-2 levels ( p = 0.047) and of the Ang-2/Ang-1 ratio ( p = 0.031) is observed in cirrhotic patients diagnosed with viral hepatitis after antiviral treatments. In HCC patients, Ang-1 negatively correlates with FI (ρ = -0.63, p = 1E-4), and PECAM-1 positively correlates with MELD (ρ = 0.44, p = 0.01). A significant Ang-1 reduction was observed in deceased patients during the study compared to ones who survived ( p = 0.01). In HCC patients, VEGF levels were increased after tumor treatment ( p = 0.037). Notably, HGF levels in cirrhotic patients with HCC are significantly raised ( p = 0.017) compared to that in those without HCC., Conclusions: Our results suggest that serum angiogenic markers, with emphasis on Ang-1/2, can contribute to the development of quantitative tools for liver disease staging and therapy monitoring. The comparison between cirrhotic patients with and without HCC suggests that HGF levels are potentially useful for monitoring the insurgence of HCC after a cirrhosis diagnosis. High Ang-1 levels in HCC patients appear to have a protective role as well as prognostic significance.

Cryoglobulinaemia consists of circulating monoclonal and/or polyclonal immunoglobulins with rheumatoid factor (RF) activity that precipitate at temperatures <37°C. Cryoglobulinaemic syndrome, characterised by clinical signs of systemic vasculitis, is associated with chronic infection of hepatitis C virus (HCV) and might evolve in B-cell malignancies. In about one third of all HCV infection cases, serum autoantibodies are commonly found. This is probably due directly to the transformation of infected B cells but, also, indirectly, to the viral chronic stimulation of a pool of autoreactive B cells. The pattern of IgG subclasses seems to contribute to the worsening progression of HCV infection into lymphoproliferative and/or autoimmune diseases. Many evidences showed that B cells circulating in patients with HCV-associated mixed cryoglobulinaemia (MC) are profoundly abnormal; moreover, in most of cases, normal B cells are replaced by expanded clonal B cells characterized by the low expression of CD21. After viral eradication, these cells persist in circulation and their occurrence does not correlate with serum cryoglobulins nor with vasculitis response or relapse. It is probably due to the persistence of monoclonal B cells producing RF, that in course of MC can be reactivated by circulating immune complexes, highly produced during infections or tumours. Here, we aimed to review current literature focusing the pathogenesis of MC referring to specificity and immunochemical characteristics of the immunoglobulins involved in cryoprecipitation.

Cryoglobulins consist of serum immunoglobulins that precipitate below 37°C and resolubilize upon warming. The clinical triad of cryoglobulinemia usually includes purpura, weakness, and arthralgia. Cryoglobulinemic syndrome, clinically defined as a systemic vasculitis, is associated with chronic infection with hepatitis C virus (HCV) and autoimmune disorders and can evolve into B-cell malignancies. While the current literature about HCV-associated cryoglobulinemia is not very limited, little is known about the immunologic and serologic profiles of affected patients. Therefore, comprehension of the pathogenetic mechanisms underlying cryoprecipitation could be very helpful. Due to the persistence of viral antigenic stimulation, biomarkers to use after the worsening progression of HCV infection to lymphoproliferative and/or autoimmune diseases are widely needed. Laboratory methods used to detect and characterize low concentrations of cryoprecipitates and immunotyping patterns could improve patient management. The most critical factor affecting cryoglobulin testing is that the pre-analytical phase is not fully completed at 37°C., Competing Interests: Competing interests The authors have no conflicts of interest to disclose., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Infections, autoimmunity and cancer play a role as determinants of etiology in Hepatitis C virus (HCV) related mixed cryoglobulinemia (MC). Several factors of risk have been suggested as markers of pathogenesis and progression of HCV-related MC into B cell Non-Hodgkin's Lymphoma (B-NHL). Here, we evaluated IgG subclass distribution, free light chains (FLCs) and vascular endothelial growth factor (VEGF) as a new combination of biomarkers., Methods: We measured IgG1-4 subclasses, FLCs and VEGF levels in sera 53 from HCV-related MC, in comparison with 40 sera from HCV negative patients with rheumatoid arthritis (RA) and 30 from healthy blood donors (HBD)., Results: IgG3 levels were significantly higher in HCV-MC patients with a decrement of IgG2 and IgG4; FLC levels significantly increased in both MC and RA patients' groups; serological VEGF was higher in HCV-MC patients than in HBD in correlation with k and λ levels., Conclusion: Our results suggest that a specific IgG subclasses pattern together with raised levels of FLCs and VEGF could represent the biomarker "signature" of an inflammation multistage of acquired immune system., (Copyright © 2019 Elsevier B.V. All rights reserved.)