Immunological and clinical follow up of hepatitis C virus associated cryoglobulinaemic vasculitis

Measuring Vasculitis with Numbers: Outcome Scores

Primary Systemic Vasculitides (PSV) are a heterogeneous group of diseases. Outcome scores are important to evaluate vasculitis patients in a more structured and standard way and these help physicians to predict patients with poor prognosis or high risk of relapse. Furthermore, we need reliable outcome measures for clinical trials. There are a number of vasculitis outcome scores available in the clinical practice with different strengths and limitations. These are mainly measures of disease activity, disease damage, response to treatment and quality of life. Birmingham Vasculitis Activity Score (BVAS) and its pediatric version aim to evaluate a wide scope of PSV. On the other hand, some outcome studies have focused on a single vasculitis type since the whole group includes different diseases with heterogeneous clinical features. The aim of this review is to provide an overview on outcome measures currently being used in the evaluation of patients with PSV. We mainly focus on immunoglobulin A vasculitis/Henochschönlein purpura, Kawasaki disease, anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, polyarteritis nodosa, Takayasu arteritis and Behçet's disease.

Disease assessment in systemic vasculitis

The anti-neutrophil cytoplasm antibody-associated vasculitides are complex multi-system disorders with many overlapping clinical features. Their outcome has been transformed by effective immunosuppression, preventing death in over 70% of cases. The quality of survival is affected by the disease course, which is characterized by a significant likelihood of relapse in 38%, chronic effects from the disease and its treatment, as well as emerging or worsening comorbidity, all of which contribute to the patient's clinical condition and outcome. Whilst imaging and laboratory testing including histology are important aspects of diagnosis, they are of limited value in assessing response to therapy or subsequent disease course. We have developed standardized validated clinical methods to quantify disease activity and damage; we are developing effective measures of patient experience to complement these procedures. This approach provides a rational basis for clinical management as well as being essential in the conduct of clinical trials and studies in vasculitis, by providing reproducible definitions of relapse, remission and response to therapy for patients with systemic vasculitis. Clinical assessment remains the current gold standard for evaluating disease progress, but requires regular training to ensure standardization. The development of biomarkers in future may produce a more accurate description of disease and identify potential targets for therapy as well as predictors of response to drugs.

Tubulointerstitial Nephritis Caused by Peritubular Capillaritis Accompanied by Cryoglobulinemia

A 73-year-old man with fever, renal insufficiency, and purpura was referred to our hospital to be evaluated for renal insufficiency. Renal biopsy revealed acute and chronic tubulointerstitial nephritis with no laboratory findings of sarcoidosis or connective tissue disease. Low C4 levels and elevation of rheumatoid factors suggested cryoglobulinemia, which was confirmed with quantitative analysis. CD34 staining of kidney tissue revealed peritubular capillaritis. Antineutrophil cytoplasmic antibodies were negative. The etiology of peritubular capillaritis was not clear in our patient; however, it might be associated with cryoglobulinemia because we cannot find any other diseases that could have induced the peritubular capillaritis.

TLR3-dependent immune regulatory functions of human mesangial cells

In glomerulonephritis, the migration of inflammatory cells into the glomerulus is an important step in disease initiation and progression. The viral receptor Toll-like receptor 3 (TLR3) is known to play a role in virus-associated glomerulonephritis. Based on this knowledge, this study aimed to define the effects of the TLR3 ligand polyriboinosinic:polyribocytidylic acid (poly(I:C)) on the expression of adhesion molecules and macrophage colony-stimulating factor (M-CSF) on resident glomerular cells. Experiments in MCs demonstrated that the activation of viral receptors by poly(I:C) leads to a time- and dose-dependent induction of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1) and M-CSF at both the mRNA and protein levels; these results were confirmed by incubating MCs with HCV RNA. As shown in knockdown experiments, this effect is specifically mediated by TLR3. The prestimulation of MCs with proinflammatory cytokines increases the effects of poly(I:C), except for its induction of VCAM-1. Tumor-necrosis factor (TNF)-α, likewise, induces ICAM-1, VCAM-1 and M-CSF, and amplifies the mesangial response to poly(I:C). These results were confirmed by incubating MCs with HCV RNA. We thus provide evidence that human MCs represent a potential target of the leukocytes and monocytes that infiltrate the glomerulus in viral disease-associated GN, highlighting the possibility that MCs may act as resident antigen-presenting cells.

Time to focus on outcome assessment tools for childhood vasculitis

Childhood systemic vasculitides are a group of rare diseases with multi-organ involvement and potentially devastating consequences. After establishment of new classification criteria (Ankara consensus conference in 2008), it is now time to establish measures for proper definition of activity and damage in childhood primary vasculitis. By comparison to adult vasculitis, there is no consensus for indices of activity and damage assessment in childhood vasculitis. Assessment of disease activity is likely to become a major area of interest in pediatric rheumatology in the near future. After defining the classification criteria for primary systemic childhood vasculitis, the next step was to perform a validation study using the original Birmingham vasculitis activity score as well as the disease extent index to measure disease activity in childhood vasculitis. Presently, there are efforts in place to develop a pediatric vasculitis activity score. This paper reviews the current understanding about the assessment tools (i.e., clinical features, laboratory tests, radiologic assessments, etc.) widely used for evaluation of the disease activity and damage status of the children with vasculitis.

Hepatitis C virus (genotype 4)-associated mixed cryoglobulinemia vasculitis: effects of antiviral treatment

OBJECTIVE

Type II mixed cryoglobulinemia (MC) is a systemic vasculitis usually associated with hepatitis C virus (HCV). The present trial was performed to investigate the efficacy of therapy with pegylated interferon alfa-2a (PEG-IFN alfa-2a) plus ribavirin in patients with HCV-related MC vasculitis and evaluate the factors associated with clinical remission of MC.

METHODS

A total of 46 consecutive patients with HCV-related Type II MC received PEG-IFN alfa-2a (standard dose 180 mg/week) subcutaneously plus oral ribavirin (800-1,200 mg/day) for 48 weeks. The response to treatment was analyzed by comparing clinical, immunologic, and virologic parameters at the initial evaluation with those observed at the end of follow-up. Logistic regression was used to assess the factors associated with clinical remission.

RESULTS

A total of 22 patients (48%) had a sustained virologic response and were complete clinical responders. Serum cryoglobulin disappeared in 26 of 46 patients (56%), and complement levels normalized in 70% of the patients. In univariate analysis, factors associated with complete clinical response were early virologic response at 4 weeks [OR 1.4 (95% CI 0.1-17.1)], proteinuria [OR 1.4 (95% CI 0.2-8.2)] and the fibrosis score [OR 1.09 (95% CI 0.6-1.9)], peripheral neuropathy [OR 0.9 (95% CI 0.1-6.5)], arthralgia [OR 0.7 (95% CI 0.1-3.9)], sicca syndrome [OR 0.6 (95% CI 0.1-3.2)], cryoglobulin [OR 0.2 (95% CI 0.07-1.09)], and purpura [OR 0.1 (95% CI 0.01-1.3)]. In multivariate analysis, only cryoglobulinemia was independently associated with complete clinical response. No patient had side effects for which discontinuation of therapy was required.

CONCLUSION

The results indicated that treatment with PEG-IFN alfa-2a plus ribavirin can achieve a complete clinical response in patients with HCV-related MC. Complete clinical response correlates with the eradication of HCV.

A retrospective analysis of treatment outcomes in patients with hepatitis C related systemic vasculitis receiving intravenous methylprednisolone and cyclophosphamide

The aim of this work is to describe the outcome of a series of patients with hepatitis C virus (HCV)-related vasculitis who were treated with corticosteroids and I.V. cyclophosphamide without receiving any antiviral therapy. The data of 16 patients with HCV infection and vasculitis were retrospectively analyzed for the treatment outcome in the present study. Eleven patients were females (68.8%) with a mean age of 49.6 ± 10.0 years. Nine patients (56.2%) had medium-sized vessel vasculitis (group A) and seven patients (43.8%) had small vessel vasculitis (group B). Disease activity was assessed using the Birmingham Vasculitis Activity Score (BVAS 2003) and organ damage was assessed by the Vasculitis Damage Index (VDI). HCV infection was confirmed in all patients by the detection of antibodies to HCV in serum by ELISA and HCV RNA using qualitative PCR. Quantitative PCR was done using the branched DNA technique. None of our study patients had received antiviral therapy, but they all received I.V.-pulsed cyclophosphamide monthly for 6 months, then every 3 months for six times if needed, preceded by I.V. methylprednisolone. Twelve patients (75%) had undetectable viral load by the quantitative technique. The drop in mean BVAS recorded at different intervals was highly significant. Although there was a drop in the VDI mean between the first and second reading, it was not statistically significant. All patients responded to treatment. Seven patients (43.8%) had relapse. Two patients died (12.5%). One patient died from renal failure (group B) and another died from sepsis (group A). The treatment outcomes were not statistically significant between the two vasculitis groups. A subset of patients with HCV-related vasculitis and with low levels of viremia can be safely treated with corticosteroids and cyclophosphamide alone. Despite successful treatment, a significant proportion of patients relapse and some develop severe complications and death.

Successful combination of Rituximab and plasma exchange in the treatment of cryoglobulinemic vasculitis with skin ulcers: a case report

Introduction

Type II mixed cryoglobulin syndrome is a systematic vasculitis mainly linked to immune complex deposition in several organs and to hepatitis C virus infection. Therapeutic strategies can target either the viral trigger hepatitis C virus if present, or pathogenic events downstream the triggering infection, e.g, the proliferation B-cells directly. Antiviral therapy should be considered as a first-line treatment in many HCV-positive patients. However, it may prove ineffective, contraindicated, or poorly tolerated. The other available treatment [such as cytotoxic agents, steroids] may lead to life-threatening complications and may be difficult to manage in the long term.

Case presentation

We report on a 75-year-old patient with long-lasting hepatitis C virus infection [18 years], a long-lasting cryoglobulinemia [7 years] resistant to common antiviral therapy, diabetes mellitus and deep skin ulcers, successfully treated with the combination therapy of Rituximab and plasma exchange.

Conclusion

Plasma exchange in combination with Rituximab may be useful to heal skin in those patients who are non responsive to Rituximab alone, by avoiding a leg amputation.

Efficacy of low-dose rituximab for mixed cryoglobulinemia

Rituximab at 375 mg/m(2) x 4 is effective for refractory HCV-related mixed cryoglobulinemia. We conducted a pilot study to assess the efficacy of a lower dosage, 250 mg/m(2) x 2. Six consecutive patients with mixed cryoglobulinemia were treated. All patients had severe or life-threatening disease manifestations, including necrotizing skin ulcers, renal disease, hyperviscosity or intestinal vasculitis. Four of five evaluable patients (excluding one early death) had >80% decrease of cryocrit and remission of vasculitis at the end of a 22- to 55-week (median 40) follow-up. The non-responder failed to respond to additional rituximab treatment, suggesting intrinsic resistance rather than insufficient dosage as the cause of treatment failure. No sustained increase of HCV viremia after rituximab was observed. Rituximab at 250 mg/m(2) x 2 may be as effective as at 375 mg/m(2) x 4 for treating mixed cryoglobulinemia. Larger studies are required to assess the efficacy of low-dose rituximab.

Dermatologic disorders associated with chronic hepatitis C: effect of interferon therapy

Chronic hepatitis C virus infection (HCV) is associated with extrahepatic manifestations, including such dermatologic conditions as mixed cryoglobulinemia, porphyria cutanea tarda, and lichen planus. Patients with chronic HCV and extrahepatic manifestations are often excluded from clinical trials evaluating interferon (IFN) therapy due to concerns about poor response, adverse events, and toxicity. Thus, data regarding the efficacy of IFN not only on the underlying chronic HCV, but also on extrahepatic manifestations, are limited in these patients. Case reports suggest that the response of dermatologic extrahepatic manifestations to IFN in patients with chronic HCV is highly variable. This review summarizes available data on dermatologic conditions associated with chronic HCV and their response to IFN therapy.

Antiviral therapy for hepatitis C virus--associated mixed cryoglobulinemia vasculitis: a long-term followup study

OBJECTIVE

To evaluate the long-term efficacy of anti-hepatitis C virus (HCV) therapy in patients with HCV-associated mixed cryoglobulinemia (HCV-MC) vasculitis and to assess the factors associated with clinical remission of MC.

METHODS

This was a single-center study of 72 consecutive patients who received treatment with IFN alfa-2b (3 million IU 3 times a week; n = 32 patients) or PEGylated IFN alfa-2b (PEG-IFN alfa-2b) (1.5 mug/kg/week; n = 40 patients), both in combination with oral ribavirin (600-1,200 mg/day), for at least 6 months. Logistic regression was used to assess factors associated with clinical remission of MC.

RESULTS

The mean +/- SD duration of followup after discontinuation of antiviral therapy was 39.7 +/- 24.4 months. Eight deaths (11.1% of patients) occurred during the study, primarily as a result of cardiovascular disease, liver disease, or infection. A complete clinical response of the MC occurred in 45 patients (62.5%), a sustained virologic response occurred in 58.3%, and cryoglobulins cleared in 45.8%. Compared with patients treated with IFN alfa-2b plus ribavirin, those receiving PEG-IFN alfa-2b plus ribavirin had a higher sustained clinical (67.5% versus 56.3%), virologic (62.5% versus 53.1%), and immunologic (57.5% versus 31.3%) response, regardless of HCV genotype and viral load. In multivariate analyses, an early virologic response (odds ratio 3.53 [95% confidence interval 1.18-10.59]) was independently associated with a complete clinical response of MC. A glomerular filtration rate <or=70 ml/minute (odds ratio 0.18 [95% confidence interval 0.05-0.67]) was negatively associated with a complete clinical response of MC.

CONCLUSION

PEG-IFN alfa-2b plus ribavirin should be considered as induction therapy for HCV-MC vasculitis. An early virologic response and the absence of renal insufficiency are the key factors in the clinical response.

Infection-related vasculitis

Infection-related vasculitis constitutes the most common cause of secondary vasculitis. A great variety of microorganisms can induce directly or indirectly inflammatory vascular damage resulting in vascular occlusion, tissue ischemia, and necrosis. In the developed world hepatitis B and C-related vasculitis remain the most common clinical syndromes, while HIV-associated vasculitis remains a concern in developing countries.

Treatment with peg-interferon alfa-2b and ribavirin of hepatitis C virus-associated mixed cryoglobulinemia: a pilot study

BACKGROUND/AIMS

The aim of this study is to verify the efficacy and safety of peg-interferon alfa-2b in combination with ribavirin for initial treatment of HCV-associated mixed cryoglobulinemia.

METHODS

Eighteen patients (7 women and 11 men) affected by mixed cryoglobulinemia were included in the study and treated with peg-interferon alfa-2b 1.0 microg/kg once a week plus ribavirin (1000 mg daily) for 48 weeks, regardless of the HCV genotype.

RESULTS

At the end of the treatment HCV-RNA became undetectable in 15 patients (83%) and most patients improved clinically. One subject suspended treatment at 13th week due to depression. A large fraction of the patients (8 cases: 44%) relapsed both virologically and clinically a few weeks after the end of therapy. At the end of follow-up, only eight patients (44%) obtained a sustained virological response.

CONCLUSIONS

Peg-interferon alfa-2b in combination with ribavirin seems safe and useful for patients affected by mixed cryoglobulinemia, but not as effective as in patients with HCV-positive chronic hepatitis without cryoglobulinemia.

Long-term effects of anti-CD20 monoclonal antibody treatment of cryoglobulinaemic glomerulonephritis

BACKGROUND

Type II mixed cryoglobulinaemia (MC) is a systemic vasculitis, associated in most cases with hepatitis C virus (HCV) infection, and sustained by proliferation of oligoclonal cells. Systemic B-cell depletion and clinical remission can be achieved in non-Hodgkin lymphoma by a human/mouse chimeric monoclonal antibody that specifically reacts with the CD20 antigen (Rituximab). Similar effects could be expected in type II MC.

METHODS

Six patients, mean age 64.2 years (range: 37-76 years), with HCV infection genotype 2a2c (three cases) or 1b (three cases) and symptomatic type-II MC with systemic manifestations, including renal involvement (five cases) and bone marrow clonal restriction (three cases), were considered eligible for Rituximab therapy. Rituximab was administered intravenously at a dose of 375 mg/m(2) on days 1, 8, 15 and 22. Two more doses were administered 1 and 2 months later. No other immunosuppressive drugs were added. Response was evaluated by assessing the changes in clinical signs, symptoms and laboratory parameters for < or = 18 months.

RESULTS

Levels of proteinuria, erythrocyte sedimentation rate and cryocrit significantly decreased at 2, 6 and 12 months. Rheumatoid factor and IgM significantly decreased at 6 months whereas C4 values significantly increased at 2 and 6 months. HCV viral load and immunoglobulin G remained stable. Bone marrow abnormalities were found to reverse to normal in all three positive cases. Constitutional symptoms (skin ulcers, purpura, arthralgia, weakness, paraesthesia and fever) disappeared or improved. No acute or delayed side effects were observed.

CONCLUSIONS

Rituximab appears to be a safe and effective therapeutic option in symptomatic patients with HCV-associated MC glomerulonephritis and signs of systemic vasculitis.

Donor hepatitis-C seropositivity is an independent risk factor for the development of accelerated coronary vasculopathy and predicts outcome after cardiac transplantation

BACKGROUND

It is possible, but unproven, that hepatitis C (HCV) infection accelerates atherosclerosis. We evaluated the hypothesis that donor HCV seropositivity predicts mortality and the development of coronary vasculopathy in cardiac transplant recipients.

METHODS

Thirty-four cardiac transplant recipients who were seronegative for HCV at the time of transplantation received hearts from HCV-seropositive donors. We compared the mortality and the incidence of vasculopathy in this group of patients (study group) with a group of 183 successive heart transplant recipients (control group) with no evidence of HCV in the donor or in the recipient.

RESULTS

After transplantation, 75% of the HCV-seronegative patients who received hearts from HCV-seropositive donors had detectable and persistent viremia (presence of HCV-RNA by reverse-transcription polymerase chain reaction). After a mean follow-up of 4.2 +/- 1.9 years, mortality was 2.8-fold greater in the study group than in controls (95% confidence interval [CI], 1.3-5.7; p = 0.006). The risk of having any vasculopathy after a mean follow-up of 3.4 +/- 1.6 years and after adjustment for other significant risk factors was 3-fold greater (hazards ratio, 3.08; 95% CI 1.52-6.20; p = 0.001) in the HCV group compared with controls. The risk of developing advanced vasculopathy was much greater in the study group compared with controls (hazard ratio, 9.4; 97% CI, 3.3-26.6; p = < 0.0001). The risk of mortality (p = 0.005) and vasculopathy (p = < 0.0001) was greatest in patients with combined donor HCV seropositivity and the presence of antibodies against donor B cells by flow cytometry.

CONCLUSION

We conclude that donor hepatitis-C virus seropositivity is an independent risk factor for increased mortality and for the development of accelerated allograft vasculopathy after cardiac transplantation. These observations may have implications for the use of HCV-positive donors in heart transplant recipients.

Reference distributions for complement proteins C3 and C4: a practical, simple and clinically relevant approach in a large cohort

The two serum proteins of the complement cascade in the highest concentrations, C3 and C4, respond to various conditions in much the same manner as do other positive acute-phase proteins. A major difference is that they are relatively sluggish in response to cytokine drive, requiring several days rather than hours to be detectably elevated by serial measurements. As with other acute-phase proteins, there are many processes that up- or down-regulate synthesis, including infection or inflammation, hepatic failure, and immune-complex formation. Clinicians may find it difficult to distinguish among these processes, because they often occur simultaneously. The situation is further complicated by genetic polymorphism, with rare instances of markedly reduced synthesis and circulating levels, and consequent vulnerability to infection. C3 and C4 are measured for clinical purposes to help define certain rheumatic and immunologically mediated renal diseases. Interpreting the measured blood levels of these two components requires one to consider the intensity of the inflammatory drive, the timing of the suspected clinical process, the production of complement-consuming immune complexes, and the possible existence of benign circumstances. In this fifth article in a series, reference ranges for serum levels of two complement proteins (C3 and C4) are examined. The study is based on a cohort of over 55,000 Caucasian individuals from northern New England, who were tested in our laboratory in 1994-1999. Measurements were standardized against certified reference material (CRM) 470/reference preparation for proteins in human serum (RPPHS), and analyzed using a previously described statistical approach. Individuals with unequivocal laboratory evidence of inflammation (C-reactive protein of 10 mg/L or higher) were excluded. Our results show that the levels of C3 and C4 change little during life and between the sexes, except that they increase slightly and then fall after age 20 in males and at about age 45 in females. When values were expressed as multiples of the age- and gender-specific median levels, the resulting distributions fitted a log-Gaussian distribution well over a broad range. When patient data are normalized in this manner, the distribution parameters can be used to assign a centile corresponding to an individual's measurement, thus simplifying interpretation.

C3/Ig and Ig/C3 two-component-determined circulating immune complexes (TCIC) in patients with HCV infection

In the present study, we measured the levels of immunoglobulin (Ig)- and complement 3 (C3)-determined circulating immune complexes (two-component-determined CIC, or TCIC) in hepatitis C virus (HCV)-infected patients. TCIC was dissected into C3/Ig-TCIC and Ig/C3-TCIC by a reciprocal use of coating and detecting antibodies. The current study was carried out in 117 infected HCV patients and 252 healthy controls. We found that C3/Ig-TCIC elevation was a common feature in patients with HCV infection. Positive rates and levels of C3/IgG-TCIC and C3/IgM-TCIC were significantly higher in the patients with abnormal alanine aminotransferase (ALT) than patients with normal ALT (70.6% vs. 17.0%, 0.56 OD vs. 0.47 OD and 0.71 OD vs. 0.65 OD, respectively, P<0.001). However, the levels of IgM/C3-TCIC and IgA/C3-TCIC were significantly higher in individuals with HCV infection than in healthy controls, whereas the level of IgG/C3-TCIC was significantly lower in the former group than in the latter group. In summary, our results suggest that IgG and C3 TCIC may play an important role in liver cell injury during the course of HCV infection and may be a hallmark for hepatitis C pathogenesis. Elevated C3/Ig-TCIC, accompanied by decreased Ig/C3-TCIC, forms a peculiar trait in HCV infection. Our findings thus provide new insights into HCV pathogenesis.

No effect of transfusion transmitted virus viremia on the distribution and activation of peripheral lymphocytes in hemodialyzed patients

AIM

We aimed to examine the distribution and activation of peripheral T cells in TTV positive (n = 32) and negative (n = 17) hemodialyzed patients. The control group (n = 20) consisted of healthy blood donors.

METHOD

TTV-DNA was detected by seminested PCR. CD3, CD4, CD8, CD19, CD56, CD3/HLA-DR, CD3/CD69 and the Th1/Th2 ratio of T cells were analyzed by flow cytometry. Circulating IFN-gamma, IL-2, IL-4, IL-6, IL-10, IL-13, TNF-alpha, TGF-beta levels were measured by ELISA in the sera.

RESULTS

There was no difference between the CD3, CD4, CD8 and CD19 values of HD subjects. In addition, the expression of both activation markers, HLA-DR and CD69, was significantly elevated in the TTV-positive and -negative HD groups compared to the controls, but not showing any difference from each other. The measurements of intracellular cytokines showed the enhanced occurrence of INF-gamma + CD4 T cells, and decreased appearance of IL-4 + CD4 lymphocytes in the HD groups without any significant difference between the TTV virus positive and negative patients. In addition, HD also elevated the expression of IL-10 in CD4 and CD8 (Th2) cells. There were only two significant changes in the levels of circulating cytokines: (a) IL-2 increased; (b) IL-13 decreased in both groups of HD patients compared to the controls, independently of TTV positivity or negativity.

CONCLUSIONS

We assume that transfusion-transmitted virus does not cause any specific change in the distribution and activation of lymphocytes in the peripheral blood of hemodialyzed patients. Hemodialysis itself, however, results in a significant activation of peripheral T cells with the domination of increased production of Th1 type cytokines, IFN-gamma, IL-2, in contrast to the decreased synthesis of Th2 type cytokines, IL-4 and IL-13. Furthermore, the increased expression of IL-10 in the CD4 and CD8 cells of HD patients can be the sign of a contraregulatory Th2 activation as an answer on the Th1 effect.

Rheumatoid factors: host resistance or autoimmunity?

Rheumatoid factors (RFs), autoantibodies that bind to the Fc portion of IgG, are important in the immune response. RF-committed B-cells exist in the circulating lymphocyte pool in a high frequency (approximately 1-2 %) in normal individuals and in patients with pathological conditions associated with the sustained levels of circulating RF, such as rheumatoid arthritis (RA), Sjogren's syndrome (SS), and mixed cryoglobulinemia, associated with hepatitis C virus infection. RFs are induced by many infectious entities (viruses, bacteria, parasites) as a consequence of a secondary immune response to the pathogen, but usually the response is transient. It is likely that RFs play an important role in the host's defense against infection, both at the cellular level, where the RF B-cell can be an antigen presenting cell which can promote the antipathogen response, and at the humoral level, where RFs can contribute to the mopping up of the IgG antipathogen antibodies by contributing to immune complex formation and clearance. There has been much research on RFs in chronic pathological conditions, and the literature pertaining to their origin, structure, binding specificities, and possible roles in disease are discussed. The importance of the host defense, sometimes at the expense of an autoimmune response, is a balance that needs to be considered in light of a possible outcome of health or disease.

Treatment of chronic hepatitis C infection with cryoglobulinemia

Mixed cryoglobulinemia is characterized by a wide spectrum of manifestations that may vary from mild symptoms (such as purpura, arthralgias, and Raynaud phenomenon) to life-threatening conditions (such as acute abdomen, hyperviscosity syndrome, and renal involvement). Hepatitis C virus infection is considered the principal trigger of the disease. Therefore, the treatment not only should be tailored to the prevailing symptom but also take into account the presence of a chronic, often smoldering infection. Symptomatic therapies are to be used in cases of minor clinical manifestations and aggressive modalities in cases of life-threatening conditions. The use of aggressive cytotoxic regimens should actually be stopped and every potentially immunosuppressive drug should be used with caution. Antiviral medications are used with growing frequency. To date, a few small trials with interferon-alpha alone or in combination with ribavirin in mixed cryoglobulinemia have been conducted. This overview deals with the current approach to the management of mixed cryoglobulinemia, focusing in particular on antiviral treatment in hepatitis C virus infection with or without mixed cryoglobulinemia.

Apheresis in cryoglobulinemia complicating hepatitis C and in other renal diseases

Removal of cryoglobulins by plasma exchange is now an accepted therapy. Cryoglobulins are circulating complexes that can deposit on small vessels and cause limited or extensive tissue injury. There are 3 major classes of cryoglobulins. Type I cryoglobulins are monoclonal and are detected in a variety of lymphoproliferative disorders. Type II cryoglobulins are mixed containing monoclonal and polyclonal IgG or IgM molecules. Type III cryoglobulins are also mixed and contain polyclonal IgG. Type II cryoglobulins are largely caused by hepatitis C virus infection; hence, they are the most common of the 3 types. In hepatitis C, cryoglobulins are linked to glomerular immune complex injury, often times accompanied by vasculitis of the skin, nerves, and other vital organs. Immediate removal of cryoglobulins by plasma exchange is an effective short-term treatment that can complement more-specific therapies. Plasma exchange has also been used to remove other circulating nephrotoxic agents such as antiglomerular basement antibodies that cause Goodpasture's syndrome, protease inhibitor autoantibodies that cause thrombotic thrombocytopenic purpura, and antiglomerular factors that cause some types of focal glomerulosclerosis.