Cryoglobulinemia--a study of twenty-nine patients. I. IgG and IgM cryoglobulins and factors affecting cryoprecipitability

Insights into the immunological description of cryoglobulins with regard to detection and characterization in Slovenian rheumatological patients

The detection of cryoglobulins (CG) used to diagnose cryoglobulinemic vasculitis requires strict adherence to protocol, with emphasis on the preanalytical part. Our main objectives were to introduce a more sensitive and specific protocol for the detection of CG and to characterize CG in Slovenian patients diagnosed with cryoglobulinemic vasculitis, other vasculitides, connective tissue diseases or non-rheumatic diseases examined at the Department of Rheumatology (University Medical Centre Ljubljana). Samples were routinely analyzed for the presence of CG with the protocol using the Folin-Ciocalteu reagent. In the newly introduced protocol, the type of CG was determined by immunofixation on visually observed positive samples and the concentration of CG in the cryoprecipitate and rheumatoid factor (RF) activity were measured by nephelometry. RF, C3c and C4 were measured in patients` serum and a decision tree analysis was performed using all results. The agreement between negative and positive results between the two protocols was 86%. Of the 258 patient samples tested, we found 56 patients (21.7%) with positive CG (37.5% - type II, 62.5% - type III). The RF activity was observed in 21.4% of CG positive subjects. The median concentration of type II CG was significantly higher than that of type III CG (67.4 mg/L vs. 45.0 mg/L, p = 0.037). Patients with type II had lower C4 concentrations and higher RF compared to patients with type III CG. In the decision tree, C4 was the strongest predictor of cryoglobulinemia in patients. With the newly implemented protocol, we were able to improve the detection and quantification of CG in the samples of our rheumatology patients and report the results to adequately support clinicians.

Ocular manifestations of cryoglobulinemia: a reappraisal

BACKGROUND/OBJECTIVES

To describe frequency and type of ocular manifestations in patients with cryoglobulinemic vasculitis (CV), as well as management approaches and outcomes.

SUBJECTS/METHODS

This was a retrospective, observational, cohort study of patients who were diagnosed with CV at a single center and regularly underwent a comprehensive ocular assessment.

RESULTS

Ophthalmologic manifestations were recorded in 16 patients (28%). The diagnoses included dry eye disease and primary Sjögren syndrome in 5 and 2 patients, respectively; peripheral ulcerative keratitis and anterior scleritis in 1 patient each; hyperviscosity syndrome and hypertensive retinopathy in 2 patients each; and Purtscher- like retinopathy in 3 patients. Twelve patients (75%) were anti-HCV/HCV RNA-positive, 11 of whom achieved a sustained virologic response (SVR) following treatment with interferon-α2b plus ribavirin or direct-acting antivirals. All patients were treated with ocular lubricants. Systemic therapeutic measures, including glucocorticoids, immunosuppressive and biologic agents, induced the disappearance or ≥50% reduction of cryoglobulins and major signs of vasculitis in 11 patients (68.7%). In the remaining 5 patients (31.3%), cryoglobulins and CV manifestations remained unchanged or decreased by <50%. The corresponding ophthalmologic assessment showed a variable degree of improvement in the ocular symptoms in all but 2 patients (87.5%). The best corrected visual acuity following treatment improved in 26 eyes, was unchanged in 3 eyes, and worsened in 3 eyes.

CONCLUSIONS

Eye involvement is not a rare event in CV patients. A timely diagnosis and the correct employment of the available therapeutic measures may result in a favorable outcome of the ocular and extra-ocular manifestations.

Cholestatic HCV Cryoglobulinemia: A New Clinical and Pathological Entity before and after Direct-Acting Antiviral Therapies-A Case-Control Study

Twenty-nine patients with HCV infection (HCV+) and mixed cryoglobulinemia (MC+) were retrospectively selected and matched for age and sex with 31 HCV+ MC- patients. Biomarkers of cholestasis (direct bilirubin, alkaline phosphatase, and gamma-glutamyl transferase), HCV-RNA and genotype, and plasma cryoprecipitates were measured before and after virus eradication; liver histology and plasma cells (aggregation and distribution), observed blinded by two pathologists, were analyzed. Sixty participants (mean age: 56.5; range: 35-77, males: 50%) with HCV infection were enrolled. Cholestasis (≥2 pathologically increased cholestasis biomarkers) was significantly higher in the MC group (p = 0.02) and correlated with cryoglobulinemia (OR 6.52; p = 0.02). At liver histological assessment, plasma cells were significantly increased in the MC+ group (p = 0.004) and tended to form aggregates more than the control group (p = 0.05). At multivariate analysis with MC, age, HCV-RNA, HBV diabetes, and cirrhosis, cholestasis was only significantly correlated to MC (OR 8.30; p < 0.05). In 25% patients, MC persisted after virus eradication with new antiviral treatment. Our study identified for the first time an association between MC, cholestasis, and an increased number of intrahepatic plasma cells in chronic hepatitis C (CHC) patients before virus eradication. Future studies are required to understand how MC contributes to liver damage and how its persistence affects the patients' follow-up after antiviral therapies.

Extrahepatic Manifestations of Chronic HBV Infection and the Role of Antiviral Therapy

The hepatitis B virus (HBV) infection leads to chronic hepatitis, cirrhosis, and hepatocarcinoma. However, about 20% of patients experience extrahepatic manifestations such as polyarteritis nodosa, non-rheumatoid arthritis, non-Hodgkin lymphoma, cryoglobulinemic vasculitis, and glomerulonephritis. These influence the patient's morbidity, quality of life and mortality. The treatment of an HBV infection is based on nucleotide analogues (NAs) which are safe and effective for the suppression of HBV-DNA in almost 100% of cases. A few studies have shown that NAs induce a viral response and an improvement of extrahepatic diseases. There is a lack of a thorough analysis of the available treatments for extrahepatic HBV manifestations. In 90% to 100% of cases, the NAs stop the HBV replication, and they produce a clinical response in the majority of patients with mild to moderate extrahepatic signs/symptoms. Arthritis can definitely disappear after the HBV elimination and, in some cases, the HBV eradication following NAs therapy appears to improve the renal function in HBV-related nephropathies. Plasma exchange can be used in subjects who are suffering from the most aggressive forms of cryoglobulinemic vasculitis and glomerulonephritis, progressive peripheral neuropathy, and life-threatening cases, and this can be combined with glucocorticosteroids and antiviral agents. In selected refractory patients, the use of rituximab in conjunction with NAs therapy can be considered. The review provides an update on extrahepatic conditions that are linked to HBV and the impact of treating HBV with NAs.

The wide spectrum of cryoglobulinemic vasculitis and an overview of therapeutic advancements

Immunoglobulins that reversibly precipitate at temperatures below 37 °C are called cryoglobulins (CGs). Cryoglobulinemia often manifests as cryoglobulinemic vasculitis (CV), whose symptoms range in severity from purpuric eruptions to life-threatening features. The majority of CV patients are infected with hepatitis C virus (HCV), whereas lymphoproliferative disorders or connective tissue diseases (CTD) are commonly diagnosed among patients with CV of non-infectious origin. In the absence of detectable associated disease, cryoglobulinemia is classified as “essential” (EMC). All HCV-positive CV patients should be given direct-acting antiviral agents (DAAs) that are consistently able to induce a sustained virologic response (SVR). Glucocorticoids (GCs) can mitigate CV-associated vasculitis, but they have no role as maintenance therapy. Cyclophosphamide restrains the hyperactive phase(s) of the disease and the post-apheresis rebound of newly synthesized CGs. Its use has been largely replaced by rituximab (RTX) in patients unresponsive to DAAs, patients progressing to B-cell non-Hodgkin lymphoma (B-NHL) and patients in whom CV persists or reappears after clearance of HCV. Therapeutic apheresis is an emergency treatment for CV patients with hyperviscosity syndrome. HCV-positive CV patients are at an increased risk of developing NHL, but the achievement of SVR can effectively prevent HCV-related NHL or induce the remission of an already established lymphoma, even without chemotherapy. The treatment of patients with IgM or IgG monoclonal cryoglobulins and an underlying immunoproliferative disorder is based on the regimens adopted for patients with the same B-cell malignancies but without circulating CGs. For patients with CTD, GCs plus alkylating agents or RTX are similarly effective as first-line therapy and in the relapse/refractory setting. In patients with EMC, treatment should consist of GCs plus RTX, with the dose of GCs tapered as soon as possible to reduce the risk of infectious complications.

Cryoglobulins: Identification, classification, and novel biomarkers of mysterious proteins

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.

Hepatitis B Virus-Related Cryoglobulinemic Vasculitis: Review of the Literature and Long-Term Follow-Up Analysis of 18 Patients Treated with Nucleos(t)ide Analogues from the Italian Study Group of Cryoglobulinemia (GISC)

Hepatitis B virus (HBV) chronic infection causes progressive liver damage, although about 20% of patients develop extrahepatic manifestations such as cryoglobulinemic vasculitis (CV). Clinical manifestations range from mild to moderate (purpura, asthenia, arthralgia) to severe (leg ulcers, peripheral neuropathy, glomerulonephritis, non-Hodgkin lymphoma). A comprehensive review of therapeutic options for HBV-related CV is lacking. Nucleos(t)ide analogues (NA) suppress HBV replication in 90–100% of cases and induce clinical response in most patients with mild-to-moderate CV. Plasma exchange can be performed in patients with severe CV and should be considered in severe or life-threatening cases combined with high doses of corticosteroids and antiviral treatment. A cautious use of rituximab can be considered only in association with NA treatment in refractory cases. A review of the literature and an analysis of data collected by six centers of the Italian Group for the Study of Cryoglobulinemia on 18 HBV-CV nucleotide/nucleoside analogues (NAs)-treated patients were carried out.

The Clone Wars: Diagnosing and Treating Dysproteinemic Kidney Disease in the Modern Era

Dysproteinemic kidney diseases are disorders that occur as the result of lymphoproliferative (B cell or plasma cell) disorders that cause kidney damage via production of nephrotoxic monoclonal immunoglobulins or their components. These monoclonal immunoglobulins have individual physiochemical characteristics that confer specific nephrotoxic properties. There has been increased recognition and revised characterization of these disorders in the last decade, and in some cases, there have been substantial advances in disease understanding and treatments, which has translated to improved patient outcomes. These disorders still present challenges to nephrologists and patients, since they are rare, and the field of hematology is rapidly changing with the introduction of novel testing and treatment strategies. In this review, we will discuss the clinical presentation, kidney biopsy features, hematologic characteristics and treatment of dysproteinemic kidney diseases.

Human hepatitis viruses-associated cutaneous and systemic vasculitis

Human hepatitis viruses (HHVs) include hepatitis A virus, hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis delta virus, and hepatitis E virus and can cause liver inflammation in their common human host. Usually, HHV is rapidly cleared by the immune system, following acute HHV invasion. The morbidities associated with hepatitis A virus and hepatitis E virus infection occur shortly after their intrusion, in the acute stage. Nevertheless, the viral infectious process can persist for a long period of time, especially in HBV and HCV infection, leading to chronic hepatitis and further progressing to hepatic cirrhosis and liver cancer. HHV infection brings about complications in other organs, and both acute and chronic hepatitis have been associated with clinical presentations outside the liver. Vascular involvement with cutaneous and systemic vasculitis is a well-known extrahepatic presentation; moreover, there is growing evidence for a possible causal relationship between viral pathogens and vasculitis. Except for hepatitis delta virus, other HHVs have participated in the etiopathogenesis of cutaneous and systemic vasculitis via different mechanisms, including direct viral invasion of vascular endothelial cells, immune complex-mediated vessel wall damage, and autoimmune responses with stimulation of autoreactive B-cells and impaired regulatory T-cells. Cryoglobulinemic vasculitis and polyarteritis nodosa are recognized for their association with chronic HHV infection. Although therapeutic guidelines for HHV-associated vasculitis have not yet been established, antiviral therapy should be initiated in HBV and HCV-related systemic vasculitis in addition to the use of corticosteroids. Plasma exchange and/or combined cyclophosphamide and corticosteroid therapy can be considered in patients with severe life-threatening vasculitis manifestations.

Cryoglobulinemic vasculitis: pathophysiological mechanisms and diagnosis

PURPOSE OF REVIEW

Cryoglobulins (CG) are immunoglobulins that precipitate in the cold, and dissolve at 37°C. In vivo, in cold exposed tissues and organs, they can induce vasculitis and occlusive vasculopathy after deposition on vascular endothelium under low temperature and high concentration conditions. Clinical manifestations are cutaneous (purpura, ulcers, vasomotor symptoms, and livedo reticularis), rheumatological (arthralgia and arthritis), and peripheral neuropathy (paresthesia and pain in the lower limbs). In profound organs such as the kidneys, CG deposition is less temperature-dependent, favored by local protein and anion concentrations, and can lead to glomerulonephritis. This review will focus on cryoglobulinemic vasculitis and vascular lesion, and their diagnosis.

RECENT FINDINGS

The mechanisms of vascular lesions of pathogenic CG in function of CG type and their characteristics are better defined. Optimal conditions for CG detection are critical. The importance of looking for underlying diseases, especially hepatitis C virus status in mixed CG, is reminded.

SUMMARY

A decision diagram for CG vasculitis diagnosis based on clinical and biological parameters is proposed.

Prevalence of cryoglobulinemia and cryoglobulinemic vasculitis in chronically HCV-infected Brazilian patients

INTRODUCTION AND OBJECTIVES

Cryoglobulinemia is one of the most frequent extrahepatic manifestations of chronic hepatitis C virus (HCV) infection and it may evolve to cryoglobulinemic vasculitis (CryoVas) which is a systemic vasculitis that affects small-sized vessels. The objective of this study was to evaluate the prevalence of cryoglobulinemia and CryoVas in HCV patients in São Paulo, Brazil.

MATERIALS AND METHODS

A cross-sectional study was conducted and included sixty-eight viremic HCV patients, without HIV or hepatitis B coinfection. A thorough clinical and laboratory evaluation was performed including the detection of serum cryoglobulins and measurement of serum complement components. The classification criteria for CryoVas were applied.

RESULTS

The study population comprised mainly women (61.8%) with long term HCV infection (median 11.0 years). Advanced hepatic fibrosis was detected in 20.6% (14/68) of cases. Cryoglobulins were detected in 48.5% (33/68) of HCV-patients with type III cryoglobulinemia being the most frequent. CryoVas was present in 10.3% (7/68) and the main manifestations were peripheral neuropathy (85.7%), palpable purpura (42.8%), arthralgias (42.8%) and renal involvement (42.8%). Life-threatening manifestations were rare. Low hemolytic C2, C4 and total hemolytic complement (CH100) levels were common findings in the cryoglobulinemia group. Low C4 levels were independently associated with the development of CryoVas.

CONCLUSION

A high prevalence of cryoglobulinemia and CryoVas was found in Brazilian HCV-patients. CryoVas patients mostly presented non-life-threatening manifestations, especially peripheral neuropathy. Complement abnormalities were common in patients with cryoglobulinemia and low serum C4 levels were associated with CryoVas.

Recent news in the treatment of hepatitis B virus-related cryogobulinemic vasculitis

Hepatitis B virus (HBV) is a hepatotropic virus that causes hepatitis, cirrhosis and hepatocellular carcinoma. Twenty percent of HBV patients may develop extra-hepatic manifestations, such as polyarthritis nodosa, glomerulonephritis, dermatitis, poly-arthralgia and arthritis, and aplastic anemia. The association of HBV and cryoglobulinemic vasculitis (CV) has been highlighted by several epidemiological investigations. CV can develop in 0.5-4% of HBV infected patients. It has been demonstrated that suppression of HBV replication by nucleot(s)ide analogues (NAs) effectively induces clinical response in most patients with mild to moderate CV, but low responses are seen in severe CV. Based on this evidence, NAs therapy represents the first line therapeutic option in subjects with mild or moderate HBV related CV. Peg-interferon-Alfa can be an alternative treatment for HBV related CV, but the few studies published so far have shown no encouraging results. In patients with severe vasculitis and/or skin ulcers, peripheral neuropathy and glomerulonephritis treatment with rituximab (RTX) and NAs should be considered as a first line treatment. The long-term administration of low-medium glucocorticoid doses has been widely used in few studies to control clinical symptoms, but it should be used as a second option, when RTX is ineffective or not tolerated and in association with NAs. This review focuses on novel treatments for HBV related CV.

Cryoglobulinemic vasculitis with interruption of ibrutinib therapy for chronic lymphocytic leukemia (CLL)

Chronic lymphocytic leukemia (CLL) can trigger autoimmune phenomena, with immune thrombocytopenia (ITP) the most common presentation. Upon cessation of CLL therapy, including ibrutinib, autoimmune flares can occur. In a 68-year-old man with CLL, ibrutinib was held for 2 weeks prior to elective shoulder surgery. Eleven days after stopping therapy, he presented with a purpuric rash on his right hip, buttock, and lower extremities. He experienced two episodes of seizure activity while hospitalized. MRI brain demonstrated patchy areas of altered signal involving deep white matter and sub-cortical white matter structures concerning for cerebral vasculitis. Although there was no evidence of hemolysis, serum cold agglutinin titer was elevated at > 1:512 and cryoglobulin levels were positive at 36%. He was diagnosed with type I cryoglobulinemia and treated with rituximab, plasmapheresis, methylprednisolone, and ibrutinib was restarted. This regimen resolved his symptoms. A rare complication of CLL is the production of cryoglobulins, which can present at initial diagnosis or in relapsed disease. Our case demonstrates that the cessation of ibrutinib therapy, even for a short time, can precipitate complications. To our knowledge, we report the first case of a patient with well-controlled CLL who rapidly developed cryoglobulinemic vasculitis after stopping ibrutinib therapy.

New insights in cryoglobulinemic vasculitis

Cryoglobulins are antibodies that precipitate at low temperatures and dissolve after rewarming. Cryoglobulinemia refers to the presence of circulating cryoglobulins and generally leads to a systemic inflammatory syndrome characterized by fatigue, arthralgia, purpura, ulcers, neuropathy and/or glomerulonephritis. The disease mainly involves small to medium-sized blood vessels and causes vasculitis due to cryoglobulin-containing immune complexes. Cryoglobulinemia is classified into three types (I, II and III) on the basis of immunoglobulin composition. Predisposing conditions include lymphoproliferative, autoimmune diseases and hepatitis C virus infection. The diagnosis of cryoglobulinemic syndrome is predominantly based on the presence of clinical features and laboratorial demonstration of serum cryoglobulins. The treatment strategy depends on the cause of cryoglobulinemia. For patients with chronic HCV infection, antiviral therapy is indicated. Immunosuppressive or immunomodulatory therapy, including steroids, plasmapheresis and cytotoxic agents, is reserved for organ-threatening manifestations. In this review, we discuss the main clinical presentations, diagnostic approach and treatment options.

Cryoglobulinemic vasculitis and glomerulonephritis: concerns in clinical practice

OBJECTIVE

Cryoglobulinemia often causes systemic vasculitis, thereby damaging to skin and internal organs including kidneys, even life-threatening. This review aimed to introduce the advances in understanding, detection, and treatment of this disease in recent years, with a particular concern to clinical practice.

DATA SOURCES

All the data in this review were from the English or Chinese literature in the PubMed and China National Knowledge Infrastructure databases as of March 2019.

STUDY SELECTION

This review selected important original articles, meaningful reviews, and some reports on cryoglobulinemia published in recent years and in history, as well as the guidelines for treatment of underlying diseases which lead to cryoglobulinemia.

RESULTS

Diagnosis of cryoglobulinemia relies on serum cryoglobulin test, in which to ensure that the blood sample temperature is not less than 37°C in the entire pre-analysis phase is the key to avoid false negative results. Cryoglobulinemic vasculitis (Cryo Vas), including cryoglobulinemic glomerulonephritis (Cryo GN), usually occurs in types II and III mixed cryoglobulinemia, and can also be seen in type I cryoglobulinemia caused by monoclonal IgG3 or IgG1. Skin purpura, positive serum rheumatoid factor, and decreased serum levels of C4 and C3 are important clues for prompting types II and III Cryo Vas. Renal biopsy is an important means for diagnosis of Cryo GN, while membranous proliferative GN is the most common pathological type of Cryo GN. In recent years, great advances have been made in the treatment of Cryo Vas and its underlying diseases, and this review has briefly introduced these advances.

CONCLUSIONS

Laboratory examinations of serum cryoglobulins urgently need standardization. The recent advances in the diagnosis and treatment of Cryo Vas and GN need to be popularized among the clinicians in related disciplines.

Recommendations for managing the manifestations of severe and life-threatening mixed cryoglobulinemia syndrome

OBJECTIVE

Some of the manifestations of mixed cryoglobulinemia syndrome (MCS) can be severe or life-threatening, and should be rapidly contained but, as the therapeutic approaches to such conditions are largely based on anecdotal data, a consensus conference was organised by the Italian Group for the Study of Cryoglobulinemia (GISC) with the aim of providing a set of recommendations based on an in-depth survey of the available data and expert opinion.

METHODS

The consensus panel, which included specialists working in different medical fields involved in the management of MCS patients, was first asked to divide the manifestations of MCS into severe or life-threatening conditions on the basis of their own experience, after which a complete literature review was carried out in accordance with the Cochrane guidelines for systematic reviews.

RESULTS

Therapeutic plasma exchange (TPE) was considered the elective first-line treatment in the case of life-threatening manifestations of MCS (LT-MCS) and patients with severe clinical symptoms (S-MCS) who fail to respond to (or who are ineligible for) other treatments. The data supporting the combined use of cyclophosphamide and TPE were considered limited and inconclusive. High-dose pulsed glucocorticoid (GCS) therapy can be considered the first-line treatment of severe MCS, generally in association with TPE. Rituximab (RTX)-based treatments should be considered in patients with skin ulcers, peripheral neuropathy or glomerulonephritis, and in patients with persistent LT-MCS after TPE. In patients with hepatitis C virus-related MCS with S-MCS, viral eradication should be attempted as soon as a patient's condition allows the use of direct-acting antivirals.

Clinical practice: hepatitis C virus infection, cryoglobulinemia and cryoglobulinemic vasculitis

Cryoglobulins are circulating immunoglobulins that reversibly precipitate at temperatures below 37 °C. Type-II cryoglobulins consist of monoclonal IgM/polyclonal IgG immune complexes (ICs), whereas in type-III cryoglobulins both IgM and IgG are polyclonal. The clinical condition resulting from the presence of cryoglobulins in the blood is called mixed cryoglobulinemia (MC), which can be asymptomatic or manifest as cryoglobulinemic vasculitis (CV). Type-I cryoglobulins, consisting of a single monoclonal isotype, are detected in patients with lymphoproliferative disorders. It is now established that > 90% of MCs are associated with HCV infection. Clinically, the spectrum of symptoms may range in severity from occasional purpuric eruptions to life-threatening features. In addition to the development of liver cirrhosis and hepatocellular carcinoma, the possible progression of HCV-positive CV patients to B-cell non-Hodgkin lymphoma (B-NHL) has been reported. The pathogenetic role played by HCV infection in the onset of B-NHL is suggested by regression of the latter following the achievement of a sustained virologic response (SVR). For several years, interferon-α alone or combined with ribavirin has been the standard of care. However, the rates of clinical, biochemical, and virologic responses have been low, and the occurrence of relapse frequent. The addition of rituximab has resulted in a higher rate of responses. With the advent of direct-acting antiviral agents, SVR has been achieved in ~ 95% of CV patients. However, in a minority of patients, despite SVR, CV may persist or reappear over variable lengths of time from the completion of therapy. The eventual appearance of B-NHL is also possible.

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.

Apheresis treatment of cryoglobulinemic vasculitis: A multicentre cohort study of 159 patients

OBJECTIVE

To assess the effectiveness of apheresis therapy (AT) in treating the clinical manifestations of patients with complicated cryoglobulinemic vasculitis (CV).

METHODS

A retrospective cohort study of 159 CV patients attending 22 Italian Centers who underwent at least one AT session between 2005 and 2015. The response to AT was evaluated on the basis of a defined grading system.

RESULTS

Peripheral neuropathy was the most frequent clinical condition leading to AT. Therapeutic plasma exchange was used in 70.4% of cases. The outcome of AT was rated very good in 19 cases, good in 64, partial/transient in 40, and absent/not assessable in 36. Life-threatening CV-related emergencies and renal impairment independently correlated with failure to respond to AT. The independent variables associated with an increased risk of death were age at the time of the first AT session, multi-organ life-threatening CV, the presence of renal impairment and failure to respond to AT. The time-dependent probability of surviving until CV-related death in the second year was 84%, with an AHR in patients with absent/not assessable response to AT of 11.25.

CONCLUSION

In this study AT is confirmed to be a safe procedure in patients with CV. Early AT should be considered in patients with severe CV, especially in cases with impending renal involvement, in order to prevent irreversible kidney damage. Although its efficacy in patients with multi-organ failure is limited, AT is the only treatment that can rapidly remove circulating cryoglobulins, and should be considered an emergency treatment.

Cryoglobulins: An update on detection, mechanisms and clinical contribution

Cryoglobulins are immunoglobulins precipitating in cold condition. They are classified in 3 types according to the Brouet classification and may lead to vasculitis of small and medium size vessels. Vasculitis is related to vessel obstruction by monoclonal cryoglobulin aggregates in type I cryoglobulins and immune complex deposition in type II and III mixed cryoglobulins. This phenomenon is favored by low temperature, especially in skin, joints, and peripheral nerves, or increased cryoglobulin concentration in kidneys. For their detection, collection and clotting at 37°C are critical pre-analytical conditions. Cryoglobulin characterization and quantification are important to identify the underlying disease. Since detection and identification of cryoglobulins lack standardization, a protocol for such detection, characterization and quantification is proposed.

It's not what it looks like: atypical rash in cryoglobulinaemic vasculitis

A 48-year-old man with a history of intravenous drug use and chronic, untreated hepatitis C presented to the emergency room with acute bilateral lower extremity swelling, erythema and maculopapular rash. Serum C4 levels were low, but dermatology felt the rash was due to venous stasis dermatitis. The patient was discharged with compression stockings, but returned to the hospital 5 days later with no improvement in his symptoms. A more extensive laboratory workup revealed hepatitis C viral load of 4 million, elevated serum cryoglobulins, and skin biopsy showing leucocytoclastic vasculitis. He was treated with oral prednisone, with complete resolution of his symptoms after 2 weeks. He was scheduled for follow-up in gastroenterology clinic for treatment of his hepatitis C for definitive cure of his mixed cryoglobulinaemia, but failed to get insurance authorisation to begin treatment with Harvoni. He presented to the hospital 4 months later with diffuse alveolar haemorrhage.

Recurrent Mixed Cryoglobulinemia Despite Sustained Virologic Response to Treatment: A Case Report

Cryoglobulinemia is a manifestation of hepatitis C virus (HCV) infection. Treatment of HCV is the mainstay of therapy for mixed cryoglobulinemia syndrome, and newer HCV therapies with direct-acting antiviral agents have achieved great success in treating HCV infection compared with pegylated interferon alfa and ribavirin. Recurrence of mixed cryoglobulinemia syndrome following successful treatment with direct-acting antiviral agents is uncommon, and when it occurs, it is most often due to relapse of HCV viremia. We report a case of recurrent mixed cryoglobulinemia syndrome following HCV treatment with a new direct-acting antiviral agent (sofosbuvir) and ribavirin, in which HCV RNA was undetectable in serum, but detectable in the cryoprecipitate.

Cryoglobulin Test and Cryoglobulinemia Hepatitis C-Virus Related

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.

Immunotactoid Glomerulopathy and Cryoglobulinemic Nephropathy: Two Entities with Many Similarities. A Unified Conceptual Approach

Immunotactoid glomerulopathy is a rare disorder that has been characterized at the ultrastructural level. Due to its rarity, there are few comprehensive studies relating to this disorder. Electron microscopy essentially characterizes this disease. The glomerular electron dense deposits which are typical of this condition consist of aggregates of highly organized microtubular structures of various diameters, but generally measuring 30-50 nm in width with a propensity to dispose themselves in parallel bundles intersecting in different planes. This study compares a large series of patients with cryoglobulinemic nephropathy with a series of patients with immunotactoid glomerulopathy to address whether there may be similarities that warrant considering these two entities part of a spectrum. This study reviews the clinicopathologic features of both entities and emphasizes ultrastructural findings that characterize them. Significant immunomorphologic overlap was found when these two disorders were compared in this study. There were also striking similarities in clinical presentation/behavior, laboratory findings and prognosis. Proteomic analysis has also demonstrated similar spectra for both entities. We postulate that immunotactoid glomerulopathy and cryoglobulinemic nephropathy are part of the spectrum of renal manifestations in patients with circulating cryoglobulins and renal disease.

Diagnostics and treatment of cryoglobulinaemia: it takes two to tango

Cryoglobulins are immunoglobulins that reversibly precipitate in the cold. They come in different flavours and, as such, are differentially associated with lymphoproliferative diseases (type I), or systemic autoimmune diseases, and/or infectious diseases (type II/III). The clinical manifestations of cryoglobulinaemia result from either hyper-viscosity or small vessel vasculitis. Hepatitis C virus (HCV) is a well-known factor in the aetiology of cryoglobulinaemia, but substantial geographical differences exist in the association between cryoglobulins and HCV. In the absence of any underlying disease, cryoglobulinaemia is referred to as 'idiopathic' or 'essential'. Detection of cryoglobulins in the laboratory is hampered by several pitfalls, in particular in the pre-analytical stage as well as in the quantification. In addition, our personal experience reveals that the detection of rheumatoid factor, most often present in high concentrations in patients with mixed cryoglobulinaemia, relies on the choice of the test system. Hence, interpretation of the laboratory results in relation to the clinical manifestations requires a partnership between the clinician and the laboratory specialist in order to make a correct diagnosis. Treatment options are primarily directed by identification of underlying diseases, i.e. infections or systemic autoimmune diseases. Idiopathic cryoglobulinaemia is treated with corticosteroids and immunosuppression, or B cell depleting anti-CD20 biologicals. In this overview, the recent literature on current laboratory and clinical practice of cryoglobulinaemia is discussed from a personal perspective.

[Treatment of cryoglobulinemic vasculitis associated with hepatitis C virus infection]

Cryoglobulinemia is a heterogeneous systemic autoimmune disease with a wide variety of causes, symptoms and outcomes, and different etiopathogenic pathways involved in the vasculitic organ damage. The discovery of the hepatitis C virus (HCV) in 1989 changed radically the focus of research of the so-called "essential" cryoglobulinemia. Cryoglobulins can be detected in 25-30% of patients with HCV, overwhelmingly representing mixed cryoglobulins. However, only 10-15% of patients present with cryoglobulinemic vasculitis, with a broad spectrum of symptoms including mild or life-threatening manifestations. Consequently, not all patients can be uniformly treated. The key therapeutic points in HCV+ patients with cryoglobulinemic vasculitis cover different aspects. The first is to treat the underlying cause of cryoglobulinemia whenever possible, hence the use of antiviral therapies must always be considered in these patients. An individualized diagnostic approach to assess the number of organs involved and the severity of organ involvement is also essential in the therapeutic planning. This complex clinical scenario leads to an equally complex therapeutic scenario. There are three main treatment strategies for HCV-associated cryoglobulinemic vasculitis: conventional immunosuppression, antiviral treatment and biological therapies. The most recent studies are suggesting a change from the classical therapeutic approach (monotherapeutic regimens) to combination/sequential regimens, including treatments targeting the virus and those directed against the induced autoimmune disease, with the aim of blocking the various etiopathogenic pathways involved.

Anti-nuclear antibody detection in cryoprecipitates: distinctive patterns in hepatitis C virus-infected patients

BACKGROUND

Anti-nuclear antibodies are immunoglobulins directed against nuclear antigens. They are associated with many autoimmune disorders, but are frequently found in patients infected with hepatitis C virus, possibly indicating an underlying common origin. Likewise, mixed cryoglobulinemia often accompanies autoimmune diseases and hepatitis C infection.

AIM

To compare anti-nuclear antibodies and immunoglobulin content of cryoprecipitates from hepatitis C virus-positive patients in order to assess their predictive value in the onset of hepatitis C virus-driven extrahepatic disorders.

METHODS

Serum from 40 hepatitis C virus-positive patients and 50 controls with rheumatoid arthritis was processed for cryoglobulin detection: all subjects presented with Type III mixed cryoglobulinemia. Immunoglobulin content and immunoglobulin subclasses of cryoprecipitates were assessed by immunofixation and tested by ELISA for rheumatoid factor. Cryoprecipitates were also analysed for anti-nuclear antibodies by indirect immuno-fluorescence to identify specific patterns typical of each condition.

RESULTS

Anti-nuclear antibody patterns differed significantly; 26 infected subjects (65%) were IgG3 positive: of these, 25 were also anti-nuclear antibody-positive (96.1%).

CONCLUSIONS

IgG3 are autoreactive clones unrelated to viral recognition and possibly involved in autoimmune disorders. Altogether, these results may represent useful diagnostic device for early detection of hepatitis C virus-induced autoimmune diseases.

Finger necrosis due to cryoglobulinemic vasculitis in association with membranous nephropathy

Cryoglobulinemic vasculitis is a small vessel vasculitis that has been associated with chronic infections and autoimmune, lymphoproliferative, and neoplastic disorders. When no significant etiological factors are identified, it is called essential mixed cryoglobulinemia. A detailed and thorough laboratory investigation is required to exclude all possible causes of cryoglobulin formation. Although cryoglobulin testing is simple, careful temperature regulation is needed to avoid false-negative results. Consensus diagnosis should be developed and implemented for appropriate cryoglobulin detection and accurate clinical diagnosis for cryoglobulinemic vasculitis. Here we present an interesting, first-ever case report of a 54-year-old Hispanic-American woman with essential mixed cryoglobulinemia presenting with significant digital necrosis in association with membranous nephropathy.

The many faces of cryoglobulinemic nephropathy: a clinico-pathologic study of 47 cases with emphasis on the value of electron microscopy

The clinical and pathologic manifestations of cryoglobulinemic nephropathy (CN) are heterogeneous. The role that electron microscopy plays in the diagnosis of CN has not been properly evaluated. The main objective of this study was to define the value of ultrastructural evaluation in the diagnosis of CN. Although most of the CN cases in this series exhibited glomerular pathology with a membranoproliferative pattern, a significant number of the cases showed less well-defined morphologic patterns on light microscopic examination (i.e. mesangial proliferation, hyaline thrombi in glomerular capillaries without significant cellular proliferation, exudative glomerulonephritis, etc). Immunofluorescence microscopy also revealed variable immunoglobulin and complement component patterns, some with "full-house" expression of immunoreactants. A subset of these CN cases was associated with light chain restriction. Thus, differential diagnosis can be a challenge as many other glomerulonephritis overlap in immunomorphologic characteristics. Because the immunomorphologic manifestations of CN are so varied, confirmation of a suspected diagnosis of CN or making a diagnosis in a less than a typical immunomorphologic setting required careful ultrastructural evaluation to find unequivocal diagnostic findings or at least supportive evidence in the form of detection of substructure in the electron dense glomerular deposits consistent with cryoglobulins. Even in cases where the light and immunofluorescence findings in suspicious clinical situations were quite consistent with CN, electron microscopy provided the final proof to substantiate the diagnosis in the great majority of the cases.

Prevalence of mixed cryoglobulinaemia syndrome and circulating cryoglobulins in a population-based survey: the Origgio study

Mixed cryoglobulinaemia syndrome (MCS) is associated with a number of infectious, autoimmune and lymphoproliferative disorders, particularly chronic hepatitis C infection. Although circulating mixed cryoglobulins (cMCGs) are a frequent finding in HCV-infected patients, only a minority of them develop a frank MCS. The only available data concerning the prevalence of MCS, which is generally considered a rare disease, come from hospital records. The aim of this investigation was to estimate the prevalence of cMCGs and MCS in a population-based study. All of the adult residents in Origgio, a town of about seven thousand inhabitants in northern Italy, were mailed a validated questionnaire, and a randomly selected sample of respondents was invited to undergo a clinical examination and laboratory tests including the determination of cMCGs. The 1594 respondents to the questionnaire (54.3% women, 64.5% aged >49years) accounted for 26.4% of the total adult population. Forty-nine (3.1%) positively responded to at least two questions, including a disproportionately high number of people aged >70years (p=0.001). Of the 266 randomly selected subjects invited to undergo a clinical examination and laboratory tests, 147 accepted, 30 (20.4%) of whom had asymptomatic type III cMCGs and four MCS. The risk of cMCG positivity was independently associated with C4 levels of <16mg/dL (adjusted odds ratio [AOR] 4.40, 95% confidence interval [CI] 1.07-18.08; p=0.040) and HCV positivity (AOR 6.87, 95% CI 1.16-40.79; p=0.034). No co-morbidities known to be related to cMCG production could be detected in more than 50% of the positive cases. After including the other positive respondents who agreed to undergo a clinical examination, the number of diagnosed MCS increased to seven: five HCV-related, one HBV-related, and one essential MCS. In conclusion, MCS seems to be more frequent than expected for a 'rare' disease, and the unexpectedly high prevalence of cMCGs raises questions about the frequency with which they are triggered, the spectrum of diseases involved in triggering them, and their real role as disease indicators.

Mixed cryoglobulinemia: an unusual presentation of hepatitis C

A 50-year-old man with a history of hepatitis C presented with recurrent episodes of abdominal pain, arthralgia, and weakness. Although these symptoms seemed rather non-specific, a purpuric rash of the lower extremities was the final clue to diagnosis. The diagnosis was then confirmed by histopathologic and serologic testing.

Life-Threatening Cryoglobulinemic Patients With Hepatitis C: Clinical Description and Outcome of 279 Patients

Cryoglobulinemia is characterized by a wide range of causes, symptoms, and outcomes. Hepatitis C virus (HCV) infection is detected in 30%-100% of patients with cryoglobulins. Although more than half the patients with cryoglobulinemic vasculitis present a relatively benign clinical course, some may present with potentially life-threatening situations. We conducted the current study to analyze the clinical characteristics and outcomes of HCV patients presenting with life-threatening cryoglobulinemic vasculitis. We evaluated 181 admissions from 89 HCV patients diagnosed with cryoglobulinemic vasculitis consecutively admitted to our department between 1995 and 2010. In addition, we performed a systematic analysis of cases reported to date through a MEDLINE search.The following organ involvements were considered to be potentially life-threatening in HCV patients with cryoglobulinemic vasculitis: cryoglobulinemic, biopsy-proven glomerulonephritis presenting with renal failure; gastrointestinal vasculitis; pulmonary hemorrhage; central nervous system (CNS) involvement; and myocardial involvement. A total of 279 patients (30 from our department and 249 from the literature search) fulfilled the inclusion criteria: 205 presented with renal failure, 45 with gastrointestinal vasculitis, 38 with CNS involvement, 18 with pulmonary hemorrhage, and 3 with myocardial involvement; 30 patients presented with more than 1 life-threatening cryoglobulinemic manifestation. There were 146 (52%) women and 133 (48%) men, with a mean age at diagnosis of cryoglobulinemia of 54 years (range, 25-87 yr) and a mean age at life-threatening involvement of 55 years (range, 25-87 yr). In 232 (83%) patients, life-threatening involvement was the first clinical manifestation of cryoglobulinemia. Severe involvement appeared a mean of 1.2 years (range, 1-11 yr) after the diagnosis of cryoglobulinemic vasculitis. Patients were followed for a mean of 14 months (range, 3-120 mo) after the diagnosis of life-threatening cryoglobulinemia. Sixty-three patients (22%) died. The main cause of death was sepsis (42%) in patients with glomerulonephritis, and cryoglobulinemic vasculitis itself in patients with gastrointestinal, pulmonary, and CNS involvement (60%, 57%, and 62%, respectively). In conclusion, HCV-related cryoglobulinemia may result in progressive (renal involvement) or acute (pulmonary hemorrhage, gastrointestinal ischemia, CNS involvement) life-threatening organ damage. The mortality rate of these manifestations ranges between 20% and 80%. Unfortunately, this may be the first cryoglobulinemic involvement in almost two-thirds of cases, highlighting the complex management and very elevated mortality of these cases.

Impact of Cryoglobulinemic Syndrome on the Outcome of Chronic Hepatitis C Virus Infection: A 15-Year Prospective Study

We evaluated the influence of cryoglobulinemic syndrome (CS) on the outcome of chronic hepatitis C virus (HCV) infection in a 15-year prospective study. We assessed a cohort of 950 chronically HCV-infected patients, collected from the beginning of 1990 to the end of 2010. All patients had received a liver histologic diagnosis. Mixed cryoglobulinemia (MC) was determined in 246 patients (25.8%), of whom 184 also had CS. They were assessed every 3 months for 15 years, at least; 141 patients with CS and 601 without MC completed the study.No spontaneous clearance of cryoglobulins was noted. Type II to type III spontaneous switching was ascertained in 1.6% (0.08%/yr) patients. The estimated progression rate of liver fibrosis was lower in CS(+) than in MC(-) patients (p < 0.05). The 15-year cumulative probability of developing cirrhosis and/or hepatocellular carcinoma was higher in MC(-) than in CS(+) patients (24.9% vs. 14.2%, p < 0.005 and 20.3% vs. 7.5%, p = 0.003, respectively). Renal insufficiency, neurologic impairment, or B-cell non-Hodgkin lymphoma were significantly more frequent in CS(+) than in MC(-) patients (32.6% vs. 3%, p < 0.0001; 31.2% vs. 4.8%, p < 0.0001; and 15% vs. 7.1%, p = 0.003, respectively). However, in spite of different morbidity features and causes of death, the 15-year survival rate was similar in the 2 groups (70.2% vs. 71.7%). Antiviral therapy had an undisputable impact on patient outcome.This 15-year prospective cohort study shows that, although CS has no influence on the overall survival of HCV-infected patients, it significantly modifies the natural history of chronically HCV-infected patients.

Hepatotropic viral infection associated systemic vasculitides-hepatitis B virus associated polyarteritis nodosa and hepatitis C virus associated cryoglobulinemic vasculitis

Two hepatotropic viruses have been shown to have causal relationship with systemic vasculitis-hepatitis B with classical polyarteritis nodosa and hepatitis C with cryoglobulinemic vasculitis. The present paper provides an updated overview on the clinical presentations and management of these vasculitides. HBV associated PAN patients have higher weight loss, peripheral neuropathy, mononeuritis multiplex, abdominal pain, gastrointestinal manifestations requiring surgery, cardiomyopathy, orchitis, hypertension, and/or elevated transaminase levels. Microaneurysms are also more common in mesenteric artery. Skin manifestations, however are less common. These patients also have a severe disease as suggested by higher five factor score and higher BVAS. Though relapses are less common, mortality is higher in patients with HBV PAN as compared to non HBV PAN. Plasmapheresis has a role in treatment in clearing off immune complexes. The common clinical manifestations of HCV associated cryoglobulinemic vasculitis are skin lesions, peripheral neuropathy, glomerulonephritis, arthritis, and sicca symptoms. Though combination therapy comprising of pegylated interferon α and ribavirin is the first line of management, immunotherapy is needed for severe or life threatening manifestations. Recent randomized trials have shown the efficacy of rituximab in such situations.

Autoimmunity and infection in Sjögren's syndrome

PURPOSE OF REVIEW

To summarize the recent developments concerning the potential viral pathomechanisms and involvement of viruses in Sjögren's syndrome, and to highlight the areas for future research and therapies.

RECENT FINDINGS

Activated IFN-1 pathway plays an important part in the autoimmune disease process of Sjögren's syndrome; therefore, several therapies aiming to reduce or inhibit the IFN-1 production and its effects may be a target for future treatment plans. Activated aryl hydrocarbon receptor may interact with latent Epstein-Barr virus (EBV) infection, which in turn may predispose to the development of Sjögren's syndrome. It is estimated that the population is 95% positive for EBV serology. Microbial factors may incite autoimmune disease. Although this hypothesis is proven in a few illnesses such as rheumatic fever, there is no definitive evidence of an infectious environmental trigger in Sjögren's syndrome. However, there are circumstantial data with regard to viruses and several potential mechanisms of disease. These include antigen mimicry, polyclonal lymphocyte activation, and infection-mediated innate end-organ inflammation. In addition, hepatitis C virus infection clearly causes a Sjögren's-syndrome-like illness.

SUMMARY

Data continue to implicate viral infection in the cause of Sjögren's syndrome, but there are no definitive studies incriminating a particular virus.

Aggregates, crystals, gels, and amyloids: intracellular and extracellular phenotypes at the crossroads of immunoglobulin physicochemical property and cell physiology

Recombinant immunoglobulins comprise an important class of human therapeutics. Although specific immunoglobulins can be purposefully raised against desired antigen targets by various methods, identifying an immunoglobulin clone that simultaneously possesses potent therapeutic activities and desirable manufacturing-related attributes often turns out to be challenging. The variable domains of individual immunoglobulins primarily define the unique antigen specificities and binding affinities inherent to each clone. The primary sequence of the variable domains also specifies the unique physicochemical properties that modulate various aspects of individual immunoglobulin life cycle, starting from the biosynthetic steps in the endoplasmic reticulum, secretory pathway trafficking, secretion, and the fate in the extracellular space and in the endosome-lysosome system. Because of the diverse repertoire of immunoglobulin physicochemical properties, some immunoglobulin clones' intrinsic properties may manifest as intriguing cellular phenotypes, unusual solution behaviors, and serious pathologic outcomes that are of scientific and clinical importance. To gain renewed insights into identifying manufacturable therapeutic antibodies, this paper catalogs important intracellular and extracellular phenotypes induced by various subsets of immunoglobulin clones occupying different niches of diverse physicochemical repertoire space. Both intrinsic and extrinsic factors that make certain immunoglobulin clones desirable or undesirable for large-scale manufacturing and therapeutic use are summarized.

Hepatitis C virus infection and autoimmune diseases

Hepatitis C virus (HCV) infection is associated with a number of extrahepatic disorders. The most studied conditions associated with HCV are type II mixed cryoglobulinemia and B cell lymphoma. However, many reports suggest that HCV might also be associated with a number of autoimmune disorders, both organ-specific and not organ-specific. Although concomitant treatment of HCV infection is a confounding factor when ascertaining the actual role of HCV in inducing autoimmune disease, a considerable amount of experimental data indicates that HCV is able to subvert the immune system and consequently induce autoimmunity. In the present review, we report a series of observations which associate chronic HCV infection with the onset of autoimmune disorders.

A randomized controlled trial of rituximab for the treatment of severe cryoglobulinemic vasculitis

OBJECTIVE

To conduct a long-term, prospective, randomized controlled trial evaluating rituximab (RTX) therapy for severe mixed cryoglobulinemia or cryoglobulinemic vasculitis (CV).

METHODS

Fifty-nine patients with CV and related skin ulcers, active glomerulonephritis, or refractory peripheral neuropathy were enrolled. In CV patients who also had hepatitis C virus (HCV) infection, treatment of the HCV infection with antiviral agents had previously failed or was not indicated. Patients were randomized to the non-RTX group (to receive conventional treatment, consisting of 1 of the following 3: glucocorticoids; azathioprine or cyclophosphamide; or plasmapheresis) or the RTX group (to receive 2 infusions of 1 gm each, with a lowering of the glucocorticoid dosage when possible, and with a second course of RTX at relapse). Patients in the non-RTX group who did not respond to treatment could be switched to the RTX group. Study duration was 24 months.

RESULTS

Survival of treatment at 12 months (i.e., the proportion of patients who continued taking their initial therapy), the primary end point, was statistically higher in the RTX group (64.3% versus 3.5% [P < 0.0001]), as well as at 3 months (92.9% versus 13.8% [P < 0.0001]), 6 months (71.4% versus 3.5% [P < 0.0001]), and 24 months (60.7% versus 3.5% [P < 0.0001]). The Birmingham Vasculitis Activity Score decreased only after treatment with RTX (from a mean ± SD of 11.9 ± 5.4 at baseline to 7.1 ± 5.7 at month 2; P < 0.001) up to month 24 (4.4 ± 4.6; P < 0.0001). RTX appeared to be superior therapy for all 3 target organ manifestations, and it was as effective as conventional therapy. The median duration of response to RTX was 18 months. Overall, RTX treatment was well tolerated.

CONCLUSION

RTX monotherapy represents a very good option for severe CV and can be maintained over the long term in most patients.

Hepatitis C virus infection and mixed cryoglobulinemia

Hepatitis C virus (HCV) chronic infection is recognized as the major cause of mixed cryoglobulinemia (MC). Its persistence represents a continuous stimulus for host immune system with production of circulating immune complexes (ICs), one-third of them with cryoprecipitate property. Several factors contribute to the biological activities of ICs, many of which are not completely known. Among them, complement factors play a crucial role in the cold-insoluble ICs-mediated vasculitis, involving primarily small blood vessels in different tissues including skin, kidney, peripheral, and central nervous system. Liver represents the major target of HCV infection with inflammatory infiltrates, resembling secondary lymphoid follicles. Cytokine like CXCL13 contribute to B-cell homing in intraportal lymphoid aggregates, in which B-cell clonal selection may arise. B-cell clonal expansion starts as an antigen-driven event and expands towards indolent and malignant B-cell proliferation. Occurrence of intrahepatic B-cell clonalities correlates with extrahepatic clinical manifestations of HCV infection. In this context, cryoglobulinemic patients should be considered a peculiar HCV-infected population that needs a clinical multidisciplinary approach and more articulated therapeutic measures.