Clinical effects of interferon in patients with idiopathic mixed cryoglobulinemia

Serum interferon (IFN)-neutralizing antibodies and bioactivities of IFNs in patients with severe type II essential mixed cryoglobulinemia

The efficacy of alpha interferon (IFN-alpha) in the treatment of severe type II essential mixed cryoglobulinemia (EMC) has been reported previously. In some patients, the development of neutralizing antibodies to recombinant IFN-alpha (rIFN-alpha) can affect the clinical response achieved with rIFN-alpha; a second treatment with natural IFN-alpha preparations may reinduce the clinical response. In the present study the ability of leukocyte IFN (LeIFN) to restore the response was investigated from a pharmacodynamic viewpoint. Specifically, the pharmacodynamic profiles of different IFN-alpha preparations were studied by measuring the serum neopterin levels and the levels of expression of protein MxA mRNA in in vivo peripheral blood mononuclear cells in two patients with EMC whose resistance to rIFN-alpha2a treatment increased concomitantly with the development of neutralizing antibodies. These markers were measured before injection and at 24 and 48 h after a single injection of rIFN-alpha2a, consensus IFN [(C)IFN], or LeIFN. No increase or only a slight increase in MxA mRNA levels was detectable after administration of rIFN-alpha2a or (C)IFN, whereas a significant increase (>/=10-fold) in MxA mRNA expression was recorded following administration of LeIFN. The neutralizing antibodies to rIFN-alpha2a cross-react with (C)IFN. Sera from these patients neutralized most but not all of the subtypes present in the natural IFN-alpha (LeIFN) mixture, and no significant increase in neopterin levels was observed after these patients were switched to LeIFN treatment. In summary, the data demonstrate that the problem of neutralizing antibodies still exists and that LeIFN may induce an increase in the level of MxA mRNA expression but not an increase in neopterin levels in patients who are resistant to treatment with rIFN-alpha2a or (C)IFN.

Cryoglobulinemia vasculitis

Cryoglobulins are immunogloblulins that persist in the serum, precipitate with cold temperature, and resolubilize when rewarmed. Mixed cryoglobulins, composed of different immunoglobulins, with a monoclonal component in type II and only polyclonal immunoglobulins in type III, are associated with connective tissue, malignant hematologic, or obvious infectious diseases. The syndrome of mixed cryoglobulinemia represents the consequence of an immune complex-type vasculitis. It is characterized by the clinical triad of purpura, arthralgia, and asthenia, and may involve numerous organs, particularly the peripheral nervous system and the kidneys. Mixed cryoglobulinemia frequently is associated with clinical and biologic evidence of liver disease. It seems fairly clear that mixed cryoglobulinemia is often a manifestation of underlying chronic active or persistent hepatitis. In the last 10 years, many studies have demonstrated that infection with hepatitis C virus is involved in the pathogenesis of most mixed cryoglobulinemia vasculitis. This review analyzes the main published data of hepatitis C virus-mixed cryoglobulinemia, the role of liver alterations, the predictive factors associated with mixed cryoglobulin production in hepatitis C virus patients and whether its character is symptomatic, and the different types of vasculitis associated with hepatitis C virus chronic infection and their treatments.

Long-term results regarding the use of recombinant interferon alpha-2b in the treatment of II type mixed essential cryoglobulinemia

Thirty-three patients with II type mixed essential cryoglobulinemia (MEC) were randomized into two groups: one to receive combined therapy including prednisone plus interferon, the other to receive prednisone therapy. Interferon was administered as induction treatment (3 Mu/day) and then as maintenance therapy (3 Mu three times a week). 83% of the combined therapy patients responded as opposed to 27% of the prednisone treated patients. Among the patients that responded to combined therapy, nine of them had a complete response, four a partial response, and two a minor response. None of the patients treated with prednisone therapy responded completely but only two had a partial and two a minor response. Four patients (three of combined therapy and one of prednisone therapy) showed proteinuria before the treatment which improved at the end of the induction therapy. Ten patients showed anti-HCV positivity which remained unchanged after the treatment. Three patients showed liver involvement secondary to cryoglobulinemia and an improvement of histological pattern after the induction with combined therapy. One patient showed an improvement of peripheral neuropathy after induction with the combined therapy. These data suggest the effectiveness of interferon given as induction and as maintenance treatment in the therapy of II type mixed essential cryoglobulinemia.

[Treatment of systemic vasculitis]

Progress in the treatment of systemic vasculitis have permitted a decrease of mortality but with an increase in iatrogenic morbidity. Steroids remain the cornerstone of the treatment but precise modalities and other concomitant treatments are depending upon the type of vasculitis. In most cases, systemic vasculitis are primary and the treatment, although important, is symptomatic. However, in some cases such as hepatitis B virus-induced polyarteritis nodosa or hepatitis C virus-induced cryoglobulinemia, the treatment can be etiologic and is directed against the antigen responsible for the systemic vasculitis. In the future, a better understanding of pathological mechanisms, particularly of etiologic factors, and new treatment such as monoclonal antibodies should increase the prognosis of systemic vasculitis.