Immune thrombocytopenia after alpha-interferon therapy in patients with cancer

Unexpected hematologic effects of biotherapeutics in nonclinical species and in humans

Biotherapeutics are expanding the arsenal of therapeutics available for treating and preventing disease. Although initially thought to have limited side effects due to the specificity of their binding, these drugs have now been shown to have potential for adverse drug reactions including effects on peripheral blood cell counts or function. Hematotoxicity caused by a biotherapeutic can be directly related to the activity of the biotherapeutic or can be indirect and due to autoimmunity, biological cascades, antidrug antibodies, or other immune system responses. Biotherapeutics can cause hematotoxicity primarily as a result of cellular activation, cytotoxicity, drug-dependent and independent immune responses, and sequelae from initiating cytokine and complement cascades.  The underlying pathogenesis of biotherapeutic-induced hematotoxicity often is poorly understood. Nonclinical studies have generally predicted clinical hematotoxicity for recombinant cytokines and growth factors.  However, most hematologic liabilities of biotherapeutics are not based on drug class but are species specific, immune-mediated, and of low incidence. Despite the potential for unexpected hematologic toxicity, the risk-benefit profile of most biotherapeutics is favorable; hematologic effects are readily monitorable and managed by dose modification, drug withdrawal, and/or therapeutic intervention.  This article reviews examples of biotherapeutics that have unexpected hematotoxicity in nonclinical or clinical studies. 

Gene expression profile of idiopathic thrombocytopenic purpura (ITP)

To search for novel mechanisms that contribute to the pathophysiology of idiopathic thrombocytopenic purpura (ITP), we determined the whole blood gene expression profile in five ITP patients and five control samples. Using DNA microarrays that contained 24,473 unique putative genes, we found 176 cDNAs that were strongly correlated with ITP. These included a cluster of interferon-regulated genes and TLR7, as well many less-well characterized genes which are candidates for further study. We believe this approach is likely to yield new insights into our understanding of the molecular pathophysiology of ITP.

Systemic sarcoidosis presenting as a granulomatous tattoo reaction secondary to interferon-alpha treatment for chronic hepatitis C and review of the literature

Sarcoidosis is a multisystem granulomatous disease of unknown etiology. Immune alterations involving heightened T-helper-1 responses have been proposed to play a major role in the pathogenesis of sarcoidosis. Interferon-alpha therapy and hepatitis C infection have been implicated in the development of a variety of autoimmune diseases. However, despite the wide use of IFN-alpha therapy for hepatitis C, only a few cases of sarcoidosis have been reported in this context. We report the case of a 42-year-old white female with hepatitis C, who developed systemic sarcoidosis shortly after therapy with IFN-alpha2b. The disease was heralded by the appearance of a cutaneous sarcoid/ foreign body granulomatous reaction at the site of an old tattoo. The sarcoidosis responded to a short course of oral prednisone therapy. We also reviewed the other reported cases and discussed the possible immunological mechanisms involved.

Expression and biological activity of two recombinant polypeptides related to subunit 1 of the interferon-alpha receptor

Abnormal production of interferon alpha (IFN-alpha) has been found in certain autoimmune diseases and can be also observed after prolonged therapy with IFN-alpha. IFN-alpha can contribute to the pathogenesis of allograft rejection in bone marrow transplants. Therefore, the development of IFN-alpha inhibitors as a soluble receptor protein may be valuable for the therapeutic control of these diseases. We have expressed two polypeptides encoding amino acids 93-260 (P1) and 261-410 (P2) of the extracellular domain of subunit 1 of the interferon-alpha receptor (IFNAR 1-EC) in E. coli. The activities of the recombinant polypeptides and of their respective antibodies were evaluated using antiproliferative and antiviral assays. Expression of P1 and P2 polypeptides was achieved by transformation of cloned plasmid pRSET A into E. coli BL21(DE3)pLysS and by IPTG induction. P1 and P2 were purified by serial sonication steps and by gel filtration chromatography with 8 M urea and refolded by dialysis. Under reducing SDS-PAGE conditions, the molecular weight of P1 and P2 was 22 and 17 kDa, respectively. Polyclonal anti-P1 and anti-P2 antibodies were produced in mice. P1 and P2 and their respective polyclonal antibodies were able to block the antiproliferative activity of 6.25 nM IFN-alphaB on Daudi cells, but did not block IFN-alphaB activity at higher concentrations (>6. 25 nM). On the other hand, the polypeptides and their respective antibodies did not inhibit the antiviral activity of IFN-alphaB on Hep 2/c cells challenged with encephalomyocarditis virus.

Local cutaneous necrotizing lesions associated with interferon injections

Long-term i.m. or s.c. injections of interferon-alpha, beta, and gamma(IFN) in patients with chronic myelogenous leukemia (CML) can cause severe, long-lasting cutaneous complications consistent with necrotizing vasculitis. The purpose of this study was to describe the cutaneous lesions and the course of illness in 7 well-documented patients with Philadelphia chromosome-positive (Ph+) CML treated with IFN. We reviewed 7 patients diagnosed with Ph+ CML at M.D. Anderson Cancer Center between 1983 and 1994 who experienced cutaneous lesions at the injection site after treatment with i.m. or s.c. IFN (3 patients treated with IFN-alpha, 3 with combined IFN-alpha and IFN-gamma, and 1 with IFN-beta). According to pathology reports available for 3 patients, the cutaneous lesions seem to be consistent with necrotizing vasculitis. The skin reactions occurred independent of the IFN type, administration modality (i.m. or s.c.), duration of previously received IFN therapy (3-108 months), stage of disease, and cytogenetic response to IFN treatment. Of 7 patients, 4 developed low-grade fever during the occurrence of skin reactions, but all cultures taken from the abscesslike lesions were negative for bacterial or fungal infection. These lesions either did not resolve and required surgical debridement (5 patients) or resolved slowly with conservative management that included discontinuation of IFN at the specific, involved site. Independent of the IFN type or i.m. or s.c. injections, IFN can cause painful and long-lasting cutaneous lesions that frequently require surgical intervention. Whether this is a result of the high concentration of IFN at the injection site, the diluent, or an immunologic reaction remains unclear.

No evidence for increased frequency of autoantibodies during interferon-beta1b treatment of multiple sclerosis

Interferon-beta1b (IFN-beta1b) is a widespread therapy of multiple sclerosis (MS), reducing the numbers and severity of exacerbations and the total lesion load measured by magnetic resonance imaging of the brain. Since IFN-beta1b has potent immunomodulatory properties, a potential side-effect of IFN-beta1b treatment could be the development of autoimmune responses. The frequencies of antinuclear and smooth muscle antibodies, antibodies against microsomal antigen of thyroid epithelial cells as well as a group of heterophilic antibodies were determined in 26 MS patients treated with IFN-beta1b for 3-20 months. No elevation of antibody titres was found for any of the antibodies studied when compared with paired samples obtained from most of the patients before the initiation of treatment. Although examined on a rather small group of patients, the results show no evidence of increased frequency of autoantibodies during interferon-beta1b treatment of multiple sclerosis.

The role of alpha-interferon in essential thrombocythaemia, polycythaemia vera and myelofibrosis with myeloid metaplasia (MMM): a concise update

Treatment of essential thrombocythaemia (ET), polycythaemia vera (PV), and myelofibrosis with myeloid metaplasia (MMM) patients is frequently a difficult issue. To date, there is no generally accepted treatment for these diseases which can reduce the risk of thromboembolism and/or haemorrhagic events, avoid any increase in the frequency of secondary myelofibrosis and terminal blast transformation and decrease the reticulin content in the bone marrow of MMM patients. The most frequently used myelosuppressive agent is hydroxyurea (HU), but widespread application has failed to demonstrate that is not leukaemogenic. In patients with MMM, conflicting results have been obtained following alpha-IFN treatment. Haematological responses have been seen in 50% of the patients. Usually the patients showing good responses had a hyperproliferative type of disease. In only one case was a reduction of reticulin content of the bone marrow observed. Thus, these findings do not indicate alpha-IFN as a first-line therapy. On the other hand, the results of several reports in ET and PV patients have shown a reduction in the abnormal proliferation of megakaryocytes and erythroid elements, following alpha-IFN treatment. A reduction in spleen size has also frequently been seen. Together with the improvement of haematological parameters, clinical symptoms have also responded positively. Long term control of these diseases can be obtained with a well-tolerated low dose of alpha-IFN. However, PV and ET are not usually characterized by cytogenetic abnormalities, making it very difficult to demonstrate the disappearance of clonal haemopoiesis following alpha-IFN therapy, even if this does occasionally occur, as evident from the two cytogenetic convertions described in the literature. As compared to myelosuppressive drugs or phlebotomy, alpha-IFN thus represents an attractive new treatment, able to exert a fundamental influence on these diseases, presumably without any untoward leukaemogenic or gonadotoxic activity.

Clinical and immunohistochemical studies of skin eruptions: relationship to administration of interferon-alpha

We observed transient, erythematous skin eruptions in 6 patients during the intravenous administration of interferon (INF)-alpha for chronic active hepatitis C. The eruptions appeared 5 to 14 days (mean: 6.8 days) after initiating its administration. They were localized or disseminated and consisted of edematous, erythematous, and/or papular changes. Vesicles and petechiae also appeared in some cases. The eruptions disappeared in 10 to 14 days, despite the continuance of INF-alpha and without specific treatment. Histological examination obtained from skin eruptions revealed perivascular infiltration of lymphoid cells, the majority which were CD4-positive, of the upper dermis. Edematous changes were present in the papillary dermis. Vascular endothelial cells in the upper dermis expressed both intercellular adhesion molecule-1 (ICAM-1) and endothelial leukocyte adhesion molecule-1 (ELAM-1), while the epidermal keratinocytes produced neither. These findings suggested a nonallergic mechanism for such eruptions.

Hypothyroidism and arthritis during interferon therapy

The development of autoantibodies during interferon therapy is frequent, but clinical symptoms of autoimmune disease are uncommon. We report on a female patient who developed arthritis with strongly positive antinuclear factor (ANA) and autoimmune thyroiditis while being treated with alpha 2b interferon (IFN) for chronic myelocytic leukaemia (CML). The arthritis subsided promptly after discontinuation of IFN and initiation of nonsteroidal anti-inflammatory drugs.

Exacerbation of symptoms of autoimmune disease in patients receiving alpha-interferon therapy

The occurrence of autoimmune disease in patients receiving alpha-interferon (alpha-IFN) therapy has been reported in several studies; these include autoimmune thyroiditis, thrombocytopenia, anemia, exacerbation of psoriasis, and the occurrence of sarcoidosis. The primary mechanism presumably is the emergence of autoantibodies to various structural proteins or receptors. Two studies have recently shown that a significant percentage of patients treated with recombinant alpha-interferon (r alpha-IFN) do form autoantibodies. The authors report six additional cases of development or exacerbation of autoimmune phenomena in patients receiving alpha-IFN therapy. Five of these patients developed symmetric polyarthropathies and the sixth had thyroiditis. The presence of a history of underlying autoimmune disease or baseline serologic abnormalities in five of these patients, including the patient who developed thyroiditis, suggests that alpha-IFN treatment can lead to the exacerbation of an underlying subclinical autoimmune process.