Different biochemical patterns in type II and type III mixed cryoglobulinemia in HCV positive patients.

BACKGROUND: Reversible cryoprecipitability of proteins is observed as a concomitant feature of immune complex formation. Mixed cryoglobulinemia (MC) is systemic vasculitis, associated with mixed IgM and IgG cryoglobulins (CGs) showing rheumatoid factor (RF) activity. It is frequently associated with hepatitis C virus (HCV). This study investigates the presence of IgG RF and anti-nuclear antibodies (ANA) in cryoprecipitates of patients with type III and type II MC, to understand the biochemical patterns associated with different types of MC to a greater degree. METHODS: Sera from 70 HCV untreated patients with type III or type II MC were tested by immunofixation for IgG3 and through ELISA for IgG RF. Cryoprecipitates were analysed for ANA by indirect immunofluorescence to identify specific patterns. RESULTS: After stratification according to MC type, the ANA patterns between type II and type III MC were statistically different. IgG3 levels and IgG-RF positivity were significantly higher in type III cryoprecipitate. We observed a higher positivity of IgG3 and a significant difference between the liver fibrosis stage, ANA and IgG-RF in the cryoprecipitate. CONCLUSION: Results show a combination of biochemical markers and autoantibodies associated to mixed cryoglobulinemia; these findings could be further investigated in order to ascertain their usefulness in assessing the risk for the development of mixed cryoglobulinemia.

Crioglobulinas: características y metodología de estudio. Recomendación (2014) / Cryoglobulins: features and methodology of study. Recommendation (2014)

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Autoimmunity and lymphoproliferation markers in naïve HCV-RNA positive patients without clinical evidences of autoimmune/lymphoproliferative disorders.

BACKGROUND: HCV can lead to both chronic liver disease and B-cell lymphoproliferative disorders. A strong association exists between HCV and mixed cryoglobulinaemia (MC). METHODS: Anti-nuclear antibodies (ANA), rheumatoid factor Ig-G (RF-IgG), free light chain κ and λ (FLC-κ, FLC-λ) levels and κ/λ ratio were evaluated in 50/420 subjects unexpectedly resulted anti-HCV positive after routine screenings for non-hepathological procedures. RESULTS: Three/fifty patients had HCV-RNA undetectable in the serum and were excluded from the analysis. Thirty-nine/fifty patients had laboratory evidence of circulating cryoglobulins without liver disease and MC-related symptoms. Among them, 17 resulted ANA-positive. The mean cryocrit was higher in ANA-positive patients, while no other demographic/clinical differences were observed between the groups. Significantly higher levels of RF-IgG were observed in ANA-positive vs ANA-negative patients. κ and λ FLC were higher in ANA-positive patients. A ROC analysis, based on ANA-positivity vs ANA-negativity, confirmed a high sensitivity and specificity of RF-IgG test. CONCLUSIONS: Published data concerning MC come mostly from symptomatic vasculitis. We analyzed HCV-patients without MC symptoms, founding cryoglobulins in the majority of them. The increased levels of FR-IgG and FLC in CGs-ANA-positive patients, suggest these test could be used to identify a state of silent autoimmune and/or lymphoproliferative condition before the transition to a frank disease in naïve HCV-patients without symptoms of extrahepatic manifestations.

Cryoglobulinemia.

Cryoglobulinemia refers to the presence in serum of immunoglobulins that precipitate at a cold temperature. Type I cryoglobulins are single monoclonal immunoglobulins usually associated with haematological disorders. Types II and III are mixed cryoglobulins, composed of monoclonal or polyclonal IgM respectively, having rheumatoid factor activity that bind to polyclonal immunoglobulins. Mixed cryoglobulinemia (MC) syndrome is a consequence of immune-complex mediated vasculitis and is characterized by a typical clinical triad: purpura, weakness, arthralgias; many organs particularly kidney and peripheral nervous system may be involved. MC may be associated with infectious and systemic disorders and since 1990 studies have demonstrated that hepatitis C virus (HCV) may be considered the principal trigger of the disease. The relation between MC and HCV infection shows new insights in the interpretation of the link between viral infection, autoimmune phenomena and lymphoproliferative disorders evolution. In fact, the virus chronically stimulates B-cell polyclonal proliferation from which a monoclonal population may emerge. In symptomatic patients with HCV related MC therapeutic strategy should include an attempt at viral eradication. Antiviral therapy may also be effective in determining the regression of B-cell lymphoproliferative disorder. Rituximab could represent a safe and effective alternative to standard immunosuppression and exerts selective B-cell control.

Can cryoglobulins interfere with the measurement of IgM antiphosphatidylethanolamine antibodies by ELISA?

Clinical manifestations of the antiphospholipid antibody syndrome (APS) have been recently related to the presence of phosphatidylethanolamine antibodies (aPE). However, it is well known that some molecules such as cryoglobulins, immunoglobulins that undergo a reversible precipitation at low temperatures, may interfere with biological assays. With this in view, we report the case of a patient with APS who was positive for both IgM aPE and type III cryoglobulinemia. Moreover, we show for this patient a potential implication of aPE in the cryoprecipitate formation. To further analyze the potential association between cryoglobulins and aPE, and also the possible consequences for aPE assay, we selected 55 patients according to positivity for both IgM aPE and cryoglobulinemia. Determination of IgM aPE levels was made before and after removal of cryoprecipitate from the serum. Of the 55 selected patients, 52 (95%) presented no significant difference for IgM aPE levels before and after cryoprecipitation. These results were ascertained whatever the aPE levels and clinical status of the patient. Taken together, our results indicate that cryoprecipitation does not interfere in most cases (95%) with the dosage of IgM aPE. Thus, IgM aPE do not appear to be involved in the formation of the cryoprecipitate.

Crioglobulinemias / Cryoglobulinemia

Cryoglobulinemia is a systemic vasculitis that principally affects small and medium caliber vessels. It is thought that the inmunocomplex deposit made up of cryoglobulins that precipitate at temperatures under 38°C activate vessel wall complement, which in turn causes damage to the same. The cryoglobulins have been found in a wide spectrum of pathologies, though generally transitory and with no clinical importance. Monoclonal cryoglobulinemia is associated with hematologic diseases, while mixed cryoglobulinemias are found in infectious and systemic diseases. The association between the hepatitis C (VHC) virus and mixed cryoglobulinemias (MC) is more and more evident, and estimates show that 90 percent of cases include this infection. Clinical manifestations are varied and are due to the tissular ischemia caused by vessel occlusion, affecting the skin and visceral organs. Chronic VHC infection induces a persistent stimulation of the immune system, generating a constellation of autoimmune and neoplastic diseases.

Cryoglobulins: an important but neglected clinical test.

Cryoglobulin (CR) denotes a serum immunoglobulin that precipitates at temperatures below 37 degrees C and dissolves on re-warming. CRs are heterogeneous in chemical composition and behave differently in vivo and in vitro. The majority are mixed antigen-antibody complexes that occur with high incidence in autoimmune and infectious disorders. Their measurement is important in the management of patients with vasculitis. CRs elicit variable symptoms in patients, mostly purpura, weakness, and arthralgias, and they require various methods of treatment. Sometimes CRs are not associated with any symptoms; but they can be associated with very severe conditions such as nephropathy and neuropathy. Treatment depends on the symptoms and causes, and on the phenotyping of the CR. Considering the high incidence of CR in diseases such as hepatitis C virus (HCV) infection, together with the high worldwide prevalence of this disease, it is clear that testing for CR is underutilized in clinical practice. CR testing has been neglected in routine clinical laboratories and by clinicians due to several factors, such as the lengthy time for serum CR analysis and failure to appreciate that low levels of CR can be associated with severe symptoms. In a series of 194 serum samples that gave positive tests for CR at our institution, the majority contained low CR concentrations (65% of the samples were type II with a mean of 372 mg/L and 39% of type III with a mean of 216 mg/L; reference range 0-60 mg/L). Case studies are presented to illustrate the importance of such low levels of CR. There is a need for more rapid and more reliable methods for quantification and phenotyping of low concentrations of serum CR. Based on our experience in the routine analysis, quantification, and phenotyping of serum CR, some practical solutions to these problems are presented.

[Cryoglobulins: detection, type determination and quantitation. A study of healthy subjects and patients with chronic hepatitis C]. / Cryoglobuline: recherche, typage et quantification. Etude chez le sujet sain et chez des patients atteints d'une hépatite C chronique.

Cryoglobulins are immunoglobulins or immune complexes which precipitate at a temperature lower than 37 degrees C and re-dissolve when rewarmed. So their collection and processing are critical. We describe the methodology used in the biochemical laboratory of Military hospital Laveran (Marseille) for detection determination of type and quantitation of cryoglobulins. In this study, we have found cryoglobulins in 53% of healthy subjects and in 77% of patients with chronic hepatitis C.

[Cryoglobulinemia in chronic hepatitis C virus infection. About 76 cases]. / FRequence de la cryoglobulinemie au cours de l'infection virale chronique C. A propos d'une série de 76 malades.

UNLABELLED: Cryolobulines are immunoglobulins that persist in the serum, precipitate with cold temperature and resolubilize when rewarmed. There are 3 types of cryoglobulinemia. Type II and III define mixed cryoglobulinemia. 40% approximately of patients with chronic hepatitis C virus (HCV) infection had cryoglobulinemia. OBJECTIVE: To evaluate the frequency of cryoglobulinemia in a chronic hepatitis virus (CHV) infection group and determine the characteristics of positive cryoglobulinemia patients. RESULTS: 76 patients were included. There were 53 women an 23 men. The mean age was 59.45 years. Mixed cryoglobulinemia was detected in 65 patients (85.5 %). Cirrhosis, old age and the long duration of CHV infection were the 3 factors associated with cryoglobulinemia positivity. CONCLUSION: Mixed cryoglobulinemia is a frequent manifestation during chronic hepatitis C infection virsus especially in patients with cirrhosis.

Systemic vasculitis in patients with hepatitis C.

OBJECTIVE: To analyze the main characteristics of patients infected with hepatitis C virus (HCV) presenting with different types of vasculitis syndrome. METHODS: We retrospectively compared 2 groups of patients with HCV presenting with systemic vasculitis: 10 with biopsy proven polyarteritis nodosa-type systemic vasculitis (PAN, Group 1) and 7 with mixed cryoglobulinemia syndrome (MC, Group 2). RESULTS: Patients of Group 1 presented with different features than Group 2: life threatening systemic vasculitis (10 vs 0; p < 0.01), severe multifocal sensorimotor mononeuropathies versus distal moderate sensory polyneuropathies, malignant hypertension (5 vs 0; p = 0.04), cerebral angiitis (2 vs 0), ischemic abdominal pain (2 vs 0), kidney and liver microaneurisms (2 vs 0), increased erythrocyte sedimentation rate and C-reactive protein (7 vs 0; p < 0.01), renal insufficiency (5 vs 0; p = 0.04), HCV genotype 1b (3 vs 6; p = 0.06), and lower activity of chronic hepatitis (p = 0.02). Neuromuscular biopsies showed lesions of vasculitis in all patients, but the type of vasculitis was different in Group 1 compared to Group 2: medium size artery involvement (7 vs 0; p < 0.01), necrotizing vasculitis (10 vs 0; p < 0.01), and mononuclear cell infiltrate in perivascular areas (0 vs 7; p < 0.01). Using prednisone, plasma exchanges, and interferon-alpha, complete recovery was obtained in all PAN-type patients except one. In Group 2 patients, interferon-alpha did not have any effect on the peripheral neuropathy. CONCLUSION: HCV infection may be associated with different types of systemic vasculitis, i.e., polyarteritis nodosa or mixed cryoglobulinemia. Because of differences in clinical and pathological features and therapeutic strategy, PAN-type vasculitis should be distinguished from MC-type vasculitis in HCV patients.

Mixed cryoglobulinemia in hepatitis C patients. GERMIVIC.

Cryoglobulins are immunoglobulins that persist in the serum, precipitate with cold temperature and resolubilize when rewarmed. Types II and III are mixed cryoglobulins (MC), composed of different immunoglobulins, with a monoclonal component in type II and only polyclonal immunoglobulins in type III. Mixed cryoglobulins are associated with connective-tissue disease, malignant hematological disorder (type B lymphoproliferation) or obvious infectious process. Mixed cryoglobulinemia syndrome is characterized by the clinical triad of purpura, arthralgia and asthenia associated with type II or type III MC. The disorder is the consequence of an immune-complex-type vasculitis as supported by clinical features, analysis of the cryoglobulins, the usually depressed level of complement during the active phase of the disease, and the deposition of immunoglobulins and complement in the lesions. Such cryoglobulinemia vasculitis may involve numerous organs, particularly the peripheral nervous system and the kidneys. MC is frequently associated with clinical and biological evidence of liver disease. There has been some controversy about which comes first, MC or chronic liver disease, but it seems fairly clear that MC is often a manifestation of underlying chronic active or persistent hepatitis. In MC patients, the hepatotropic antigen(s) capable of triggering production of antibodies which can later form immune complexes has been sought for many years. In the last ten years, numerous studies have demonstrated that infection with hepatitis C virus is involved in the pathogenesis of most mixed cryoglobulinemia. This review analyzes the main published data on hepatitis C virus-mixed cryoglobulinemia, the role of liver alterations, the predictive factors associated with MC production in HCV patients and its symptomatic nature or not, and the different types of vasculitis associated with HCV chronic infection.

Renal manifestations associated with hepatitis C virus.

Among the several types of chronic glomerulonephritis (GN) described in association with hepatitis C virus (HCV) infection, cryoglobulinemic glomerulonephritis is by far the most frequent. It is usually associated with type II cryoglobulinemia with IgM k rheumatoid factor. It is a membranoproliferative GN, which shows some distinctive histologic features (intraglomerular monocyte infiltration, intraluminal thrombi due to massive precipitation of cryoglobulins, renal vasculitis), has a chronic course with acute recurrent episodes that can be controlled by corticosteroids more than by antiviral therapy (interferon alpha). More controversial is the association with type I non-cryoglobulinemic membranoproliferative GN, which has been found in some series from the USA and Japan but not in others. The demonstration of HCV antibodies and/or HCV-RNA in other types of chronic glomerulonephritis is usually reported in a small minority of cases suggesting the possibility of a coincidental finding more than an etiologic factor.

The rheumatoid factor response in the etiology of mixed cryoglobulins associated with hepatitis C virus infection.

Studies of mixed cryoglobulins (MC) from patients infected with hepatitis C virus (HCV) show that the principal constituents in cryoprecipitate are IgM rheumatoid factors (RF), polyclonal IgG anti-HCV antibodies, and HCV RNA. The HCV-induced RF response is biased to produce IgM RF encoded by a restricted set of Ig V genes, predominantly the VH/VL gene pair 51p1/kv325. The propensity of such IgM RF to cryoprecipitate is likely a coincidental property of their V region sequences, but the clinical effect of this bias is increased by the persistence of circulating HCV-IgG immune complexes. These complexes might induce production of cryoprecipitable IgM RF and furnish multi-molecular structures that favor binding by cryoprecipitable IgM RF. The V gene sequences of HCV-induced IgM RF have features seen in other RF responses, suggesting a common immunological mechanism that is independent of HCV. B cell proliferation is probably enhanced by HCV-specific properties, however, including the ability of HCV proteins to bind to CD81 on the B cell surface, and to influence intracellular regulatory functions following viral entry into B cells. The V gene bias in HCV-induced RF is most apparent among the B cells in monoclonal expansions responsible for type II cryoglobulins, but it might originate early the polyclonal RF response, before MC are detectable. Monoclonal B cell expansions and lymphomatoid bone marrow infiltrates in HCV+ patients predominantly involve CD5-negative IgM RF B cells. Non-RF B cells can also be expanded, including producers of IgG1 and IgG3 that are likely anti-HCV antibodies. The initial site of B cell clonal expansion may be in the liver, where lymphoid aggregates are abundant and RF are produced. Sorting out how MC formation is influenced by properties that are inherent to the RF response, or specific to HCV infection, will be a challenge to future HCV research.

Two-dimensional electrophoretic analysis of cryoproteins: a report of 335 samples.

Cryoproteins are defined as proteins precipitating at low temperature. Most frequently, the precipitate contains immunoglobulins (Igs), and are therefore called cryoglobulins. Three types of cryoglobulins have been described: type I contains a single monoclonal Ig, whereas type II is a mixture of a monoclonal Ig with polyclonal Igs, and type III is a mixture of polyclonal Igs of different isotypes, most frequently IgG and IgM. Type II and type III are also called mixed cryoglobulins. A new type of cryoglobulins, containing polyclonal IgG associated with a mixture of polyclonal and monoclonal IgM has recently been described after two-dimensional polyacrylamide gel electrophoresis (2-DE). This type of cryoglobulin has been called type II-III cryoglobulin. In this study, we report on 2-DE analysis of 335 cryoproteins from patients with heterogeneous clinical conditions. In 69 out of 335 samples (20.7%), 2-DE revealed patterns that were inadequate to characterize the cryoproteins. Out of 335 (79.3%) cryoproteins, 266 were identified according to their two-dimensional patterns: 265 samples contained Igs and were diagnosed as cryoglobulins, and one sample consisted of fibrinogen, and was identified as cryofibrinogen. Among the 265 cryoglobulins, types I, II, and III were observed in 9 (3.4%), 69 (26%), and 116 (43.8%) cases, respectively, whereas type II-III was detected in 71 (26.8%) cases. Eleven of the latter consisted of oligoclonal Igs (IgM in 10 cases, IgA in 1 case) mixed with traces of polyclonal IgG. These cryoproteins were tentatively named type II-IIIvariant cryoglobulins. Taken together, our result clearly show that 2-DE is a suitable technique to analyze cryoproteins.

Clinical implications of the types of cryoglobulins determined by two-dimensional polyacrylamide gel electrophoresis.

BACKGROUND AND OBJECTIVE: Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) is a new method which can be used to study cryoprecipitates from the sera of cryoglobulinemic patients. It led to the identification of a new type of cryoprecipitate, tentatively named II-III, characterized by polyclonal IgG associated with a mixture of polyclonal and monoclonal IgM. Some discrepancies with the conventional classification of cryoglobulins were revealed. The association of particular clinical features with the classification of cryoglobulins by 2-D PAGE is examined. DESIGN AND METHODS: Sixty consecutive patients affected by cryoglobulinemic syndrome with mixed cryoglobulins were included in the study. All patients were evaluated for cutaneous, articular, hepatic, renal and nervous involvement. The washed cryoprecipitates were typed using both techniques: immunofixation electrophoresis (IFE) and 2-D PAGE. RESULTS: Sixteen (6 cases of type II and 10 of type III by IFE) of 60 cryoprecipitates (26.6%) appeared as type II-III by 2-D PAGE analysis. Nine cases were classified differently by IFE and 2-D PAGE. Mixed cryoglobulins of type II-III were not associated with a particular clinical pattern. Examining the clinical findings in the mono group (those with monoclonal IgM alone) and the poly group (those with polyclonal IgM alone or polyclonal and monoclonal IgM) we found clearly significant differences: more severe liver involvement in the poly group, and higher cryocrit and creatinine values, lower C4 level and more severe purpura in the mono group. INTERPRETATION AND CONCLUSIONS: Our results confirm the reliability of 2-D PAGE in characterizing cryoprecipitates. This sensitive method can demonstrate a higher number of monoclonal components, undetectable by IFE. Type II-III cryoglobulins are not associated with a particular clinical pattern. The presence or absence of polyclonal IgM in mixed cryoglobulins seems to be correlated with some clinical findings.

Hepatitis C virus infection and cryoglobulinaemia.

Mixed cryoglobulins (CG) are serum proteins that precipitate at low temperature and are commonly classified into two types according to the presence (type II) or not (type III) of monoclonal immunoglobulins. Mixed CG are observed in a wide variety of diseases. Some mixed cryoglobulinaemia occurs without evidence of an underlying disease and is considered as essential mixed cryoglobulinaemia (EMC). Many studies have underlined the possible involvement of liver diseases in the pathogenesis of cryoglobulinaemia and particularly viral hepatitis. Recently, it has been shown that 50 to 80% of patients with EMC are in fact infected with HCV. It has also been shown that CG may be found in about 50% of patients infected with HCV. HCV-RNA genomic sequences are specifically concentrated in CG as well as IgG reactive with HCV-related proteins, and monoclonal IgM with rheumatoid factor (RF) activity. The monoclonal IgM RF detected in HCV infected patients is highly restricted to the same cross-idiotype OWAO. In addition to hepatocytes, HCV-RNA has been found in both peripheral blood and BM mononuclear cells. These cells could represent a reservoir of virus and may play a major role in viral persistence; they also could act as effectors of tissue injury in various organs. HCV shows high genomic variability. It is not clear whether these genetic variations have a significant clinical impact (i.e. severity of the disease) but there is evidence that they may influence both the efficacy of the host immune response and the interferon treatment response. The role of viral factors has been studied but a clear relationship between the presence of cryoglobulinaemia, the viral load or the HCV genotype have not been demonstrated. The frequency of clinical symptoms related to mixed cryoglobulinaemia reported in the literature is extremely variable according to the series. The striking association between HCV infection and mixed type II CG (usually considered as a benign lymphoproliferative disorder) and the occurrence of HCV infection in patients with NHL suggest that HCV could be involved in the pathogenesis of some malignant lymphoproliferative disease. The progression to malignancy probably involves the accumulation of multiple mutations facilitated by chronic antigenic stimulation. The efficacy of anti-viral treatment on both CG levels and related symptoms argue strongly that HCV is involved in the production of CG.