Cryoglobulinemia

Engineering the variable region of therapeutic IgG antibodies

Since the first generation of humanized IgG1 antibodies reached the market in the late 1990s, IgG antibody molecules have been extensively engineered. The success of antibody therapeutics has introduced severe competition in developing novel therapeutic monoclonal antibodies, especially for promising or clinically validated targets. Such competition has led researchers to generate so-called second or third generation antibodies with clinical differentiation utilizing various engineering and optimization technologies. Parent IgG antibodies can be engineered to have improved antigen binding properties, effector functions, pharmacokinetics, pharmaceutical properties and safety issues. Although the primary role of the antibody variable region is to bind to the antigen, it is also the main source of antibody diversity and its sequence affects various properties important for developing antibody therapeutics. Here we review recent research activity in variable region engineering to generate superior antibody therapeutics.

[Type I cryoglobulinemia with a fatal outcome]

Type I cryoglobulinemia, a condition associated with lymphoproliferative disorders, is caused by monoclonal immunoglobulins that precipitate at low temperatures. It mostly involves the skin and pathology study shows no signs of vasculitis. Management is usually based on immunosuppressive drugs associated with plasmapheresis for severe disease. The use of rituximab has recently been described for resistant cases. We present an unusual case of long-standing type I cryoglobulinemia associated with a monoclonal gammopathy of unknown significance. The patient developed extremely severe skin lesions with histological signs of vasculitis. The patient died due to the onset of noncutaneous manifestations of the cryoglobulinemia and complications of the immunosuppressive treatment.

Clinical spectrum, treatment, and outcome of patients with type II mixed cryoglobulinemia without evidence of hepatitis C infection

OBJECTIVE

The clinical spectrum, etiologies, and best therapeutic approaches of type II mixed cryoglobulinemia (MC) not associated with hepatitis C virus (HCV) infection have been poorly described to date. We studied the clinical presentation and outcome of patients with type II MC with no evidence of HCV.

METHODS

This was a multicenter retrospective study on the clinical presentation and outcome of patients with type II MC without evidence of HCV infection. Only patients with symptomatic MC were included.

RESULTS

Thirty-three patients were included (median followup 67.2 mo). Extensive investigations for associated diseases were performed at presentation. MC was related to an autoimmune disease in 14 patients, to a lymphoid malignancy in 4 patients, and to an infectious disease in 2 patients, while MC was classified as essential (primary) in 13. Essential MC tended to be more severe than secondary disease with, in particular, more frequent renal and peripheral nerve involvement. Most patients were treated with steroid with or without immunosuppressive agents, mainly cyclophosphamide. These treatments were unable to induce sustained remission. One patient was successfully treated with lenalidomide. Seven patients with nonmalignant MC were treated with rituximab; 2 had a sustained complete remission, 3 improved greatly but relapsed within 5 months, and 2 experienced a disease flare.

CONCLUSION

An important proportion of non HCV-related type II MC remains essential. Efforts should be made to find other etiologies than HCV, because treatments with steroid and immunosuppressants are not satisfactory, especially in severe forms. In these situations anti-CD20 therapy may present the best option but should be used with caution. New agents such as lenalidomide remain to be evaluated.

Serglycin inhibits the classical and lectin pathways of complement via its glycosaminoglycan chains: implications for multiple myeloma

Serglycin (SG) is a proteoglycan expressed by hematopoietic cells and is constitutively secreted by multiple myeloma (MM) cells. SG participates in the regulation of various inflammatory events. We found that SG secreted by human MM cell lines inhibits both the classical and lectin pathways of complement, without influencing alternative pathway activity. The inhibitory effect of SG is due to direct interactions with C1q and mannose-binding lectin (MBL). C1q-binding is mediated through the glycosaminoglycan moieties of SG, whereas MBL binds additionally to SG protein core. Interactions between SG and C1q as well as MBL are diminished in the presence of chondroitin sulfate type E. In addition, we localized the SG-binding site to the collagen-like stalk of C1q. Interactions between SG and C1q as well as MBL are ionic in character and only the interaction with MBL was found to be partially dependent on the presence of calcium. We found the serum levels of SG to be elevated in patients with MM compared to healthy controls. Moreover, we found that SG expressed from myeloma plasma cells protects these cells from complement activation induced by treatment with anti-thymocyte immunoglobulins. This might protect myeloma cells during immunotherapy and promote survival of malignant cells.

Systemic vasculitis in patients with hepatitis C virus infection with and without detectable mixed cryoglobulinemia

OBJECTIVE

to describe hepatitis C virus (HCV)-related systemic vasculitis in patients without detectable mixed cryoglobulinemia (MC) and to compare them to typical cases of HCV-MC vasculitis.

METHODS

twelve HCV RNA+ patients with histologically proven vasculitis in the absence of detectable MC (cases) were retrospectively compared with 48 HCV RNA+ patients with MC vasculitis (controls). Each case was matched with 4 controls for age and sex.

RESULTS

the main epidemiological and virologic features were similar between cases and controls. No clinical difference was found, except for lower rates of arthralgias (33% vs 71%; p = 0.02) and purpura (50% vs 83%; p = 0.03) in cases. Cases showed higher mean serum C3 (1.17 ± 0.21 vs 0.93 ± 0.23 g/l; p = 0.01) and median C4 levels (0.25 vs 0.04 g/l; p < 0.001), lower median serum IgM levels (0.6 vs 1.9 g/l; p < 0.001), and lower rates of rheumatoid factor positivity (8% vs 82%; p < 0.001) than controls. The main histologic features were similar between cases and controls. Immunofluorescence analysis of skin biopsy from 1 case revealed perivascular deposits of C3 and IgA. After treatment, overall clinical response of vasculitis (75% vs 83%) and sustained virological response (40% vs 64%; p = 0.3) were similar between cases and controls, except for higher complete clinical response (42% vs 73%; p = 0.05) in controls.

CONCLUSION

HCV-related systemic vasculitis may occur in the absence of detectable MC. Our findings suggest that such vasculitis probably results from immune complex-mediated mechanisms, and that the therapeutic management of such vasculitis should be similar to that of HCV-MC vasculitis.

Cryoglobulinemia in elderly patients with HCV-related chronic hepatitis

Hepatitis C virus (HCV) infection affects about 3% of the world’s population and often leads to chronic liver disease. In some industrialized countries, HCV prevalence increases with age, but the optimal management of older patients has not been accurately defined. HCV infection can also lead to lymphoproliferative disorders, the most common being mixed cryoglobulinemia (MC), and also for this condition that frequently affects elderly patients, the optimal therapeutic strategy is still debated. We report the case of a 77-year-old Caucasian woman with HCV-related chronic hepatitis and cutaneous manifestations consisting of urticaria and pruritus related to MC resistant to antihistamines. The patient underwent a treatment with interferon and ribavirin. Such a treatment led to early biochemical and virological response associated with the resolution of cryoglobulinemia and cutaneous symptoms. After the end of treatment, HCV replication relapsed, but cryoglobulinemia and cutaneous symptoms did not recur. In the absence of definite treatment guidelines in this particular context, our experience suggests that the presence of symptoms related to HCV-infection that deeply affect patient quality of life warrants antiviral therapy even beyond the age limits that currently exclude patients from treatment.

Cryoglobulin evaluation: best practice?

Cryoglobulins are serum immunoglobulins that precipitate at temperatures below 37 degrees C and re-dissolve on warming. Cryoglobulinaemia leads to variable symptoms including characteristic purpura, ischaemia of extremities, renal failure, peripheral neuropathy, abdominal pain secondary to intestinal ischaemia and arthralgias. Cryoglobulin testing is underutilized in clinical practice. It has been neglected in clinical laboratories and by clinicians due to several factors, such as the length of time it takes for serum cryoglobulin analysis to be performed in the laboratory, the perceived difficulty in getting optimal sampling conditions and a failure to appreciate that even apparently low levels of cryoglobulin can be associated with severe symptoms in some patients. The most important variable confounding standardization of cryoglobulin testing is improper sample handling. A recent report critically appraising the current practice of cryoglobulin evaluation in 137 laboratories in Europe by United Kingdom National External Quality Assurance Scheme (UKNEQAS) illustrated the wide variability in practice. Although many clinical laboratories perform cryoglobulin evaluation, there are widespread differences in the methodology used and the care with which this is carried out and this leads to considerable intralaboratory and interlaboratory variability. The most common sources of error are false-negative results due to loss of cryoprecipitate during transport and storage. Better standardization is needed to avoid missed diagnoses and improve the comparability of results. Laboratories should ensure that sample temperature is maintained at 37 degrees C until the serum is separated. In this article, we briefly review the classification and clinical features of cryoglobulins and suggest best practice guidelines for laboratory detection and identification of cryoglobulins.

HLA DR-DQ combination associated with the increased risk of developing human HCV positive non-Hodgkin's lymphoma is related to the type II mixed cryoglobulinemia

This investigation was focused on the contribution of individual human leukocyte antigen (HLA)-DR and -DQ alleles to the human hepatitis C virus (HCV)(+) non-Hodgkin's lymphoma (NHL), with and without mixed cryoglobulinemia (MC), to study whether individual HLA class II alleles are expressed preferentially or equally in human HCV-specific NHL. For this purpose, peripheral blood mononuclear cells were obtained from two groups of patients with HCV(+) NHL and with or without MC (70 and 71 cases, respectively), and from 4575 blood donors. Eighty-three subjects with HCV infection only, and 118 patients with MC, only without lymphoma, were added as additional control groups. Individual HLA-DR and -DQ alleles were determined using high-resolution sequence-based typing and then data were collected by considering the HLA-DRB1 and DQB1 supertypes on the basis of common structural and functional features, proposed by in silico Bioinformatic studies. From the data, it is evidenced that the DR5-DQ3 HLA combination was strongly associated with the HCV (+) MC (+) NHL group of patients compared with bone marrow donor population (P<or= 0.001, RR = 2.498), while the contribution of DR1-DQ1 was higher in HCV (+) NHL without MC (P<or= 0.001, RR = 2.519). Thus, cryoglobulinemia clinical manifestation was found to be correlated with the preferential use of HLA DR-DQ combination in HCV-associated NHL. These data provide new insight into HCV-associated lymphoproliferative pathogenesis.

Skin manifestations of internal disease

Internal diseases can manifest in a myriad of skin dermatoses ranging from single disorders such as calciphylaxis, cryoglobulinemia, amyopathic dermatomyositis, and Raynaud phenomenon, to spectrum disorders such as the neutrophilic dermatoses and morphea. In this article the underlying causes, triggering events, constitutional symptoms, clinical features and presentations, appearance at various stages, and pathogenesis are described. The course of the diseases and probable healing outcomes are outlined. Finally, examination and diagnostic methods, and therapies and treatments are provided.

Clinical and morphologic spectrum of renal involvement in patients with mixed cryoglobulinemia without evidence of hepatitis C virus infection

Hepatitis C virus (HCV) infection represents, by far, the major cause of mixed cryoglobulinemia (MC). The renal disease associated with this pathological condition is now well described. By contrast, renal involvement in patients with MC not associated with HCV has been only poorly described, and few cases have been reported. We analyzed the demographic, clinical, and laboratory features and outcome in patients presenting with renal disease associated with MC not related to HCV infection. Records of 20 patients with MC and renal disease, with no evidence of HCV by serology and polymerase chain reaction analysis, were retrospectively analyzed. Renal biopsies and extensive searches for lymphoproliferative disorder were performed in all patients at presentation. MC was related to primary Sjögren Syndrome (pSS) in 9 patients, and to non-Hodgkin lymphoma in 1 patient, while MC was classified as essential in the remaining 10 cases. Renal involvement was characterized by microscopic hematuria in all patients, nephrotic range proteinuria in 75% of patients, hypertension in 80% of patients, and renal failure in 85% of patients (mean glomerular filtration rate, 46 mL/min per 1.73 m). Membranoproliferative glomerulonephritis with subendothelial deposits was observed in all kidney specimens. Skin vasculitis was the main extrarenal manifestation. In all patients, cryoglobulinemia was classified as type II MC, characterized by monoclonal IgMkappa and polyclonal IgG. Most patients (17/20) were treated with steroids or immunosuppressive agents, or both. Initial renal remission was observed in 94% of patients. However, renal relapse occurred in most patients, with 10% reaching end-stage renal disease. Three patients with essential MC developed B-cell lymphoma 36-48 months after the diagnosis of MC. Unexpectedly, B-cell lymphoma induced by Epstein-Barr virus infection occurred in only 1 of the 9 pSS patients. Forty percent of patients died as a result of extrarenal causes.Renal disease associated with MC unrelated to HCV is characterized by the high prevalence of pSS (45%), the finding of CD20+ B-lymphocyte nodular infiltrates in the kidney interstitium, and a high incidence of overt B-cell lymphoma during follow-up. These findings emphasize the need for repetitive clinical evaluation in those patients.

Efficacy and tolerability of rituximab with or without PEGylated interferon alfa-2b plus ribavirin in severe hepatitis C virus-related vasculitis: a long-term followup study of thirty-two patients

OBJECTIVE

To report on the long-term followup of a cohort of patients with hepatitis C virus (HCV)-related vasculitis treated with rituximab with or without PEGylated interferon alfa-2b (PEG-IFN alfa-2b) plus ribavirin.

METHODS

The study group comprised 32 HCV RNA-positive patients with HCV-related vasculitis: 20 patients were treated with rituximab and PEG-IFN alfa-2b (9 of whom had not previously received antiviral treatment and 11 of whom had experienced disease resistance to or relapse with antiviral treatment), and 12 antiviral-intolerant patients were treated with rituximab alone.

RESULTS

Treatment with rituximab and PEG-IFN alfa-2b plus ribavirin induced a complete clinical response and a partial clinical response in 80% and 15% of patients, respectively, a complete immunologic response and a partial immunologic response in 67% and 33% of patients, respectively, and a sustained virologic response in 55% of patients. Treatment with rituximab alone induced a complete clinical response and a partial clinical response in 58% and 9% of patients, respectively, and a complete immunologic response and a partial immunologic response in 46% and 36% of patients, respectively. B cell depletion was achieved in 96% of patients, and B cell recovery began after a median delay of 12 months. After a mean+/-SD followup period of 23+/-12 months, 22% of patients experienced a clinical relapse, and 34% of patients experienced an immunologic relapse. All relapses were associated with the absence of virologic control, and 78% of relapses were associated with B cell recovery. Six patients were re-treated with rituximab. All 6 of these patients had a complete clinical response, 50% had a complete immunologic response, and 50% had a partial immunologic response. Rituximab was well tolerated overall.

CONCLUSION

Rituximab is an effective treatment of severe and/or refractory HCV-related vasculitis. Relapses were consistently associated with the absence of virologic control. The clinical and immunologic efficacy of rituximab after repeated infusion appeared to be the same as that observed after induction therapy.

A case of bilateral renal arterial thrombosis associated with cryocrystalglobulinaemia

Cryocrystalglobulinaemia is an extremely rare complication of monoclonal gammopathy. Its presentation has features of both type I and II cryoglobulinaemia. Although peripheral and digital ischaemia is common, visceral ischaemia is rare. When it does occur, it is usually associated with multiple myeloma and has an extremely poor prognosis. We present a case of bilateral renal artery thrombosis associated with cryocrystalglobulinaemia in a patient without myeloma. More unusual, the cryocrystal protein in this case was associated with fibrinogen, which may have led to increased propensity towards thrombosis. Although the patient was unable to recover his kidney function, he remained alive on dialysis 2 years after the incident. The patient did not have any further ischaemic event despite no definitive therapy. This case represents an unusual presentation for this rare disease.

Prevalence of hepatitis C serum antibody in autoimmune diseases

OBJECTIVE

To evaluate the prevalence of serum antibodies against hepatitis C virus and other infectious agents in a large cohort of well-characterized patients with autoimmune diseases (AID).

METHODS

We utilized 1322 sera from patients with 18 different AID and 236 sera from healthy controls from the same countries and with similar age and sex distribution. All sera were tested for the presence of serum anti-hepatitis C virus (HCV) antibodies as well as antibodies directed at other infectious agents and autoantibodies.

RESULTS

Anti-HCV antibody was detected in 115/1322 (8.7%) of patients with AID and 0.4% of matched healthy controls (P < 0.0001). The prevalence of anti-HCV antibody was significantly higher in 7/18 different AID (i.e. cryoglobulinemia, mixed cryoglobulinemia pemphigus vulgaris, vasculitis, secondary anti-phospholipid syndrome, Hashimoto's thyroiditis, and inflammatory bowel disease) compared to controls. Patients with AID and serum anti-HCV positivity had an increased prevalence of antibodies against hepatitis B virus, Toxoplasma gondii and Cytomegalovirus as opposed to a lower frequency of serum autoantibodies.

CONCLUSIONS

The enhanced prevalence of anti-HCV serum antibodies in AID may suggest a role for HCV in tolerance to breakdown, similarly to its established role in mixed cryoglobulinemia. This immune mediated effect does not rule out the role of other infectious agents.

Persisting mixed cryoglobulinemia in Chikungunya infection

BACKGROUND

Chikungunya virus (CHIKV), an arbovirus, is responsible for a two-stage disabling disease, consisting of an acute febrile polyarthritis for the first 10 days, frequently followed by chronic rheumatisms, sometimes lasting for years. Up to now, the pathophysiology of the chronic stage has been elusive. Considering the existence of occasional peripheral vascular disorders and some unexpected seronegativity during the chronic stage of the disease, we hypothesized the role of cryoglobulins.

METHODS

From April 2005 to May 2007, all travelers with suspected CHIKV infection were prospectively recorded in our hospital department. Demographic, clinical and laboratory findings (anti-CHIKV IgM and IgG, cryoglobulin) were registered at the first consultation or hospitalization and during follow-up.

RESULTS

Among the 66 travelers with clinical suspicion of CHIKV infection, 51 presented anti-CHIKV IgM. There were 45 positive with the serological assay tested at room temperature, and six more, which first tested negative when sera were kept at 4 degrees C until analysis, became positive after a 2-hour incubation of the sera at 37 degrees C. Forty-eight of the 51 CHIKV-seropositive patients were screened for cryoglobulinemia; 94% were positive at least once during their follow-up. Over 90% of the CHIKV-infected patients had concomitant arthralgias and cryoglobulinemia. Cryoglobulin prevalence and level drop with time as patients recover, spontaneously or after short-term corticotherapy. In some patients cryoglobulins remained positive after 1 year.

CONCLUSION

Prevalence of mixed cryoglobulinemia was high in CHIKV-infected travelers with long-lasting symptoms. No significant association between cryoglobulinemia and clinical manifestations could be evidenced. The exact prognostic value of cryoglobulin levels has yet to be determined. Responsibility of cryoglobulinemia was suspected in unexpected false negativity of serological assays at room temperature, leading us to recommend performing serology on pre-warmed sera.

Nodular vasculitis in systemic lupus erythematosus

A 42-year-old man presented with fever, photosensitivity, headaches, myalgia, hyperhidrosis, muscle weakness, alopecia, nasal crustae, weight loss, painful nails, arthritis, oral ulcers, erythema, discoid cutaneous lesions, and painful subcutaneous nodes. We made a diagnosis of systemic lupus erythematosus (SLE), type II cryoglobulinemia, and nodular vasculitis. In the skin, different types of vasculitis may be observed. Typically, histology shows leukocytoclastic vasculitis of superficial vessels both in SLE and mixed cryoglobulinemia, which clinically results in palpable purpura. In our patient, however, histopathological examination of the subcutaneous nodes not only revealed leukocytoclastic vasculitis of the superficial vasculature but also showed even more extensive involvement of dermal and subdermal small and medium sized vessels, giving rise to a nodular vasculitis.

Multiple myeloma--an update on diagnosis and treatment

Multiple myeloma is a plasma cell (PC) malignancy characterized by the accumulation of monoclonal PCs in the bone marrow and the production of large amounts of a monoclonal immunoglobulin or paraprotein. In the past years, new approaches in the diagnosis and treatment were introduced aiming to identify high-risk patients who need proper anti-myeloma treatment. Intensive therapy including autologous hematopoietic stem cell transplantation and the new agents bortezomib, thalidomide, and lenalidomide have improved patients' responses. Further optimalization of the different treatment schedules in well-defined patient groups may prolong their survival. Patient stratification is currently based on patient characteristics, extent of myeloma disease, and associated cytogenetic and laboratory anomalies. More and more gene expression studies are introduced to stratify patients and to individualize therapy.

Cryoglobulinemia and renal disease

PURPOSE OF REVIEW

Cryoglobulinemia occurs in a variety of clinical settings including lymphoproliferative disorders, infection and autoimmune disease. The worldwide pandemic of hepatitis C virus infection has resulted in a significant increase in its extrahepatic complications including cryoglobulinemia and renal disease. Here we review the types of cryoglobulins, mechanisms of cryoglobulin formation, links between hepatitis C virus and renal disease, and current approaches to therapy.

RECENT FINDINGS

The prevalence of cryoglobulinemia in hepatitis C virus-infected individuals is surprisingly large and may be found in more than 50% of some infected subpopulations. Most of these patients will not have overt renal disease, but there is a population of unknown size of patients with subclinical glomerular disease that has the potential to become clinically significant. In cases of hepatitis C virus-associated cryoglobulinemia, treatment remains focused on eradication of viremia, but interventions directed at B lymphocytes are increasingly utilized. The mechanisms of cryoglobulin formation and renal injury remain largely obscure, but recent evidence implicates the innate immune system in the initiation of disease.

SUMMARY

The most common renal injury associated with hepatitis C virus infection, in patients both with and without evidence of cryoglobulinemia, is membranoproliferative glomerulonephritis. There has been increasing focus on defining the mechanisms that link these processes and the evolution of renal injury in all clinical settings of cryoglobulinemia.

Cryoglobulins as indicators of upregulated immune response in schizophrenia

OBJECTIVE

In the present work the concentration of abnormal immune complexes, cryoglobulins (Cgs), in the blood of schizophrenic patients was determined, and immunochemical composition of these complexes was studied.

PATIENTS AND METHODS

Eighty multiple-episode schizophrenia-affected subjects (55 medicated, 25 drug-free) and 40 healthy controls were involved in the study. Cgs were isolated by exposure of blood serum samples to precipitation at low temperature followed by extensive washings of Cg-enriched pellets. The immunochemical composition of Cgs was analyzed using different electrophoretic and immunoblotting systems.

RESULTS

Significantly increased blood serum levels of type III Cgs were detected in all schizophrenia-affected subjects, as compared to controls. We also revealed the presence of C1q and C3 complement proteins and their activation products in Cgs isolated from the blood of schizophrenic patients.

CONCLUSIONS

The results of the present study suggest that Cgs are involved in schizophrenia-associated upregulated immune response by binding the complement proteins, activating the complement cascade and triggering aberrant apoptosis.

B-cell lymphoproliferation in chronic inflammatory rheumatic diseases

Patients with chronic inflammatory rheumatic diseases, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and especially primary Sjögren's syndrome (SS), are at higher risk than the general population of developing B-cell non-Hodgkin lymphoma (NHL). Analyses of the association between various lymphoma subtypes and specific disease entities suggest that this association might be mediated by disease-specific mechanisms, as well as by mechanisms unique to lymphoma subtype. These specific associations can provide important information about abnormal B-cell stimulation in these conditions. Patients with primary SS, SLE and RA are at high risk of developing diffuse large B-cell lymphomas, a group of high-grade NHLs with remarkable heterogeneity. Patients with primary SS are at particularly high risk of developing marginal-zone B-cell lymphomas. The risk factors of lymphoma development in primary SS seem to be closely related to the underlying mechanisms of abnormal stimulation and/or impaired censoring mechanisms of B cells. In patients with RA and SLE, more intense disease activity and/or long-lasting disease might be indications of a higher risk of lymphoma development. This Review will focus on the risk of lymphoma, common and disease-specific mechanisms of B-cell lymphoma development, and on the clinical consequences of lymphoma in patients with inflammatory rheumatic diseases.