Interferon-alpha is effective in the treatment of HIV-1-related, severe, zidovudine-resistant thrombocytopenia. A prospective, placebo-controlled, double-blind trial

Successful Use of Eltrombopag in a Pediatric Patient With Human Immunodeficiency Virus (HIV)–Associated Thrombocytopenia

Thrombocytopenia and other hematologic manifestations related to HIV are not uncommon. Treatment of HIV-related thrombocytopenia is challenging: treatment options are not effective in all patients, or less well studied, particularly in the pediatric population. We aim to present and discuss the case of a 13-year-old with HIV and persistent thrombocytopenia who, after failing monthly IVIG infusions, showed normalization of platelet count on the novel thrombopoietin receptor agonist, eltrombopag. A retrospective chart review of the case patient's medical record was conducted. Additionally, a thorough literature review was performed on this topic, including the pathophysiology of underlying HIV-related thrombocytopenia and its treatment modalities. The patient was treated initially with monthly IVIG infusions for about 1 year but did not show a sustained response, particularly in between infusions. After initiation with eltrombopag 50 mg daily, the patient showed a sustained increase in his platelet count. During a brief lapse in eltrombopag treatment, his platelet count dropped, which then increased upon his reinitiation of therapy. He has continued to show a sustained platelet response and has not been symptomatic or required IVIG for more than 1 year. To our knowledge, this is the first report of a pediatric patient with HIV-related thrombocytopenia who has benefited from the use of eltrombopag.

Effect of aspirin treatment on abacavir-associated platelet hyperreactivity in HIV-infected patients

BACKGROUND

Ischemic cardiovascular events are a relevant cause of morbidity and mortality in HIV-infected patients. Use of abacavir (ABC), a nucleoside analog reverse transcriptase inhibitor, has been associated with increased risk of myocardial infarction (MI) and with platelet hyperreactivity. We explored whether low-dose aspirin reduces in vivo platelet activation and platelet hyperreactivity induced by ABC in HIV-infected subjects.

METHODS AND RESULTS

In a randomized, placebo-controlled, cross-over study forty HIV-infected patients with ABC-associated platelet hyperreactivity, defined by a score based on laboratory variables reflecting in vivo platelet activation and ex vivo platelet hyperresponsiveness, were randomized to aspirin 100 mg daily for 15 days with subsequent cross-over to placebo for additional 15 days or placebo for 15 days with subsequent cross-over to aspirin for further 15 days. In vivo and ex vivo platelet activation markers were measured at day 15 and 30. One group of healthy subjects, one of untreated HIV infected-patients and one treated without ABC, were studied concomitantly. Serum TxB₂ and urinary 11-dehydro-TxB₂ were decreased by aspirin in ABC-treated patients, but not as much as in healthy controls. Aspirin therapy reduced significantly platelet hyperreactivity (score: from 9.3, 95% CIs 8.7 to 10.0, to 7.5, 6.9 to 8.0), however without bringing it back to the levels of healthy controls (score: 4.6, 95% CIs 3.6 to 5.6).

CONCLUSION

Aspirin reduces ABC-induced in vivo platelet activation and platelet hyperreactivity in HIV-infected patients, however without normalizing them. Whether the observed reduction of platelet activation is sufficient to prevent cardiovascular events requires a prospective trial.

In vivo platelet activation and platelet hyperreactivity in abacavir-treated HIV-infected patients

Abacavir (ABC) has been associated with ischaemic cardiovascular events in HIV-infected patients, but the pathogenic mechanisms are unknown. Aim of our study was to assess whether ABC induces in vivo platelet activation and ex vivo platelet hyper-reactivity. In a retrospective, case-control study, in vivo platelet activation markers were measured in 69 HIV-infected patients, before starting therapy and after 6-12 months of either ABC (n=35) or tenofovir (TDF) (n=34), and compared with those from 20 untreated HIV-infected patients. A subgroup of patients was restudied after 28-34 months for ex vivo platelet reactivity. In vivo platelet activation markers were assessed by ELISA or flow cytometry, ex vivo platelet reactivity by light transmission aggregometry (LTA) and PFA-100®. Thein vitro effects of the ABC metabolite, carbovir triphosphate, on aggregation and intra-platelet cGMP were also studied. sPLA2, sPsel and sGPV increased significantly 6-12 months after the beginning of ABC, but not of TDF or of no treatment. Ex vivo platelet function studies showed enhanced LTA, shorter PFA-100® C/ADP closure time and enhanced platelet expression of P-sel and CD40L in the ABC group. The intake of ABC blunted the increase of intraplatelet cGMP induced by nitric oxide (NO) and acutely enhanced collagen-induced aggregation. Preincubation of control platelets with carbovir triphosphate in vitro enhanced platelet aggregation and blunted NO-induced cGMP elevation. In conclusion, treatment with ABC enhances in vivo platelet activation and induces platelet hyperreactivity by blunting the inhibitory effects of NO on platelets. These effects may lead to an increase of ischaemic cardiovascular events.

Immunological HCV-associated thrombocytopenia: short review

Infection with Hepatitis C virus (HCV) is affecting about 3% of the world's population, leading to liver damage, end-stage liver disease, and development of hepatocellular carcinoma, being thus the first indication for liver transplantation in the USA. Apart from the cirrhotic-liver-derived clinical signs and symptoms several conditions with immunological origin can also arise, such as, glomerulonephritis, pulmonary fibrosis, and thrombocytopenia. HCV-related autoimmune thrombocytopenia shows specific pathogenetic characteristics as well as symptoms and signs that differ in severity and frequency from symptoms in patients that are not HCV infected. Aim of this short paper is to estimate the epidemiological characteristics of the disease, to investigate the pathogenesis and clinical manifestation, and to propose treatment strategies according to the pertinent literature.

Infectious causes of chronic immune thrombocytopenia

Persistent thrombocytopenia may be the consequence of chronic infections with hepatitis C virus (HCV), human immunodeficiency virus (HIV), and Helicobacter pylori, and should be considered in the differential diagnosis of primary immune thrombocytopenia (ITP). Studies have shown that on diagnosis of infections, treatment of the primary disease often results in substantial improvement or complete recovery of the thrombocytopenia. In patients with thrombocytopenia due to HCV-related chronic liver disease, the use of eltrombopag, a thrombopoietin receptor agonist, normalizes platelet levels, thereby permitting the initiation of antiviral therapy. Antiviral therapy with highly active antiretroviral therapy for HIV has aided in platelet recovery, with a corresponding decrease in circulating viral load. Thrombocytopenia in the absence of other disease symptoms requires screening for H. pylori, especially in countries such as Japan, where there is a high prevalence of the disease and the chances of a platelet response to eradication therapy are high.

Therapeutic strategies for hepatitis- and other infection-related immune thrombocytopenias

Secondary thrombocytopenia may result from autoimmune diseases, lymphoproliferative disorders, infections, myelodysplastic syndromes, common variable immunodeficiency, agammaglobulinemia, hypogammaglobulinemia, immunoglobulin A deficiency, and drugs. The presence of thrombocytopenia may result from chronic infections with hepatitis C virus (HCV), human immunodeficiency virus (HIV), and Helicobacter pylori and should be considered in the differential diagnosis of immune thrombocytopenic purpura (ITP). Studies have shown that upon diagnosis of infections, treatment of the primary disease allows for stabilization of platelet counts. Antiviral therapy with highly active antiretroviral therapy (HAART) for HIV has aided in platelet recovery with a corresponding decrease in circulating viral load. In some cases, the use of a thrombopoietin (TPO) agonist, eltrombopag, normalizes platelet levels in patients with these infections. Thrombocytopenia in the absence of other disease symptoms requires screening for H pylori, especially in regions where there is a high prevalence of the disease, such as in Japan, and in cases where platelets have normalized following eradication therapy. In other regions where these infections are not prevalent, such testing is controversial.

Viral-Associated Immune Thrombocytopenic Purpura

Chronic immune thrombocytopenic purpura (CITP) is a diagnosis of exclusion that occurs either de novo or secondary to other underlying disorders. Chronic infection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) are now well-characterized causes of CITP. Between 6% and 15% of patients infected with HIV may develop thrombocytopenia. Patients with CITP with risk factors for HIV infection should be screened for the virus. Treatment of HIV-related CITP should be directed toward antiviral therapy with highly active antiretroviral therapy (HAART) regimens. Hepatitis C viral infection can also be associated with chronic thrombocytopenia, even in the absence of overt liver disease. While HCV-related thrombocytopenia is typically less severe than primary CITP, affected patients are at greater risk of major bleeding. Sustained suppression of HCV virus with interferon-ribavirin therapy can improve platelet counts. Screening for HCV infection should be considered in patients with ITP with risk factors for infection, from regions with high rates of infection or in patients with unexplained mild elevations of liver enzymes.

Acute, short-term hyperglycemia enhances shear stress-induced platelet activation in patients with type II diabetes mellitus

OBJECTIVES

The aim of our study was to assess whether acute, short-term hyperglycemia affects platelet reactivity in patients with Type II diabetes mellitus (T2DM).

BACKGROUND

Hyperglycemic spikes are thought to precipitate ischemic events in T2DM. Previous studies have shown in vivo platelet activation in diabetes; however, no studies have assessed whether acute in vivo hyperglycemia induces further activation of platelets.

METHODS

In a cross-over, randomized, double-blind study, 12 patients with T2DM underwent 4 h of either acute hyperglycemia (13.9 mmol/l, 250 mg/dl) or euglycemia (5.5 mmol/l, 100 mg/dl). Shear stress-induced platelet activation, P-selectin and lysosomal integral membrane protein (LIMP) expression on platelets in the bleeding-time blood, urinary 11-dehydro-thromboxane B(2) (TxB(2)) excretion, von Willebrand factor:antigen (vWF:Ag), and von Willebrand factor:activity (vWF:activity) were measured before and after hyperglycemia or euglycemia.

RESULTS

Shear stress-induced platelet activation, P-selectin and LIMP expression on platelets in the bleeding-time blood, and urinary 11-dehydro-TxB(2) excretion increased significantly after hyperglycemic clamping, whereas no changes were observed after euglycemic clamping. Plasma vWF:Ag and vWF:activity increased strikingly in parallel fashion after hyperglycemic clamping, whereas no changes were observed after euglycemic clamping.

CONCLUSIONS

Our data demonstrate that acute, short-term hyperglycemia induces an increased activation of platelets exposed to high shear stress conditions in vitro (filtration method) or in vivo (bleeding time). In vivo platelet activation is reflected by an increased urinary excretion of 11-dehydro-TxB(2). The increased levels of vWF in the circulation correlate with the increase in platelet activation markers and may indicate some degree of causation. Acute, short-term hyperglycemia in T2DM may precipitate vascular occlusions by facilitating platelet activation.

Detrimental effects of high-dose dexamethasone in severe, refractory, HIV-related thrombocytopenia

OBJECTIVE

To report a case of HIV-related thrombocytopenia in which high-dose dexamethasone was ineffective and immunologically detrimental.

CASE SUMMARY

A 39-year-old white man with persistent, severe, HIV-1-related thrombocytopenia was admitted for epistaxis, bleeding gums, petechiae, and bruising. Previous unsuccessful attempts to reverse the thrombocytopenia included zidovudine, prednisone, vincristine, interferon alfa, and intravenous immune globulins. Based on previous anecdotal reports of the effectiveness of high-dose dexamethasone in refractory, HIV-related thrombocytopenia, we instituted treatment with intravenous dexamethasone 40 mg/d for four sequential days every 28 days. After three cycles of therapy, the platelet count remained < 15 x 10(9)/L; however, the CD4+ lymphocyte count decreased progressively from 1447 x 10(6)/L at baseline to 560 x 10(6)/L three months after the third cycle. Due to persistent, severe thrombocytopenia and bleeding, the patient underwent splenectomy, resulting in normalization of the platelet count.

DISCUSSION

High-dose dexamethasone has been proposed as treatment for patients with immune thrombocytopenia as an alternative to chronic oral corticosteroids and claimed to be associated with better effectiveness and fewer adverse effects. The results of this treatment in our patient show that this regimen may not only be ineffective, but may also be immunologically detrimental in HIV-infected patients. Although the deterioration of the immunologic status of our patient cannot be fully attributed to high-dose dexamethasone based on the Naranjo scale, the previous long-lasting stability of CD4+ cells and the temporal relationship of a decrease in the CD4+ cell count coinciding with administration of high-dose dexamethasone suggest a causative role of the treatment.

CONCLUSIONS

A possible cause-effect relationship between the treatment and the decrease in the CD4+ cell count suggests that the use of high-dose dexamethasone may not be justified in patients with severe, HIV-related thrombocytopenia.

It is hazardous to treat HIV patients with interferon-alpha

Interferon-alpha is shown to play a key role in the progressing immunodysfunction that characterizes HIV infection. In particular, interferon-alpha is responsible for the development of an autoimmune state that is prone to serious complications. Therefore, treatment of HIV patients with IFN-alpha is hazardous. There are results suggesting that anti-interferon-alpha immunization might be a method for prophylaxis and treatment of the autoimmune state in HIV patients. This treatment may prevent complications of HIV infection and the transition to AIDS.

Management of chronic autoimmune thrombocytopenic purpura (ITP) in adults

The management of thrombocytopenia in adults is a therapeutic challenge requiring not only the science but the art of medicine. The disease is usually chronic and a third of those affected will have significant thrombocytopenia despite attempts at presently accepted forms of management. Adults tolerate moderate degrees of thrombocytopenia and treatment of asymptomatic patients with platelet counts greater than 30 x 10(9)/L is usually not required. Steroids, splenectomy, and the use of steroid-sparing immunosuppressive drugs remain the mainstay of treatment, although short-term responses to intravenous immunoglobulin (IVIg) and anti-D may be beneficial. The multitude of therapies with anecdotal reports of responses attests to the frustration felt by hematologists in the management of this disease when conventional treatments fail.

Low-dose splenic irradiation in the treatment of immune thrombocytopenia in HIV-infected patients

PURPOSE

To determine the effect of low-dose splenic irradiation on severe Zidovudine-resistant, HIV-1-associated thrombocytopenia (HAT).

METHODS AND MATERIALS

Between September 1994 and October 1996, 17 patients were included in a prospective study. The patients met the following criteria for inclusion: hemorrhagic symptoms or a platelet count below or equal to 50 x 10(9)/l and normal numbers of megakaryocytes on bone aspiration. The mean baseline platelet count was 20.3 (+/- 14.4) x 10(9)/l; four patients had a platelet count inferior to 10 x 10(9)/l. Splenic volume was defined by ultrasonography. A total dose of 9 Gy was given using an isocentric parallel pair field technique.

RESULTS

One month after the end of treatment six patients had a significant rise in their platelet count. Clinically, hemorrhagic symptoms stopped for all patients that were symptomatic. Unfortunately, duration of response was short because for one patient only the platelet count remains stable with a follow-up of 6 months. All patients are alive and in recent evaluation, with four out of eight patients receiving a combination of antiretroviral therapy had a platelet count above 50 x 10(9)/l.

CONCLUSION

Our results are disappointing concerning the duration of response, especially comparatively to those reported in autoimmune thrombocytopenia. Mechanisms of HAT are more complex, and megakaryocytes' infection may play an important role. Splenic irradiation should be considered as palliative treatment for the minority of patients with severe bleeding that does not respond to standard medical treatment.

Hematologic complications of human immunodeficiency virus infection and the acquired immunodeficiency syndrome

The hematologic manifestations of HIV infection and AIDS are common and may cause symptoms that are life-threatening and impair the quality of life of these patients. The most important of these manifestations are cytopenias. Anemia and neutropenia are generally caused by inadequate production because of suppression of the bone marrow by the HIV infection through abnormal cytokine expression and alteration of the bone marrow microenvironment. Thrombocytopenia is caused by immune-mediated destruction of the platelets, in addition to inadequate platelet production. The incidence and severity of cytopenia are generally correlated to the stage of the HIV infection. Other causes of cytopenia in these patients include adverse effects of drug therapy, the secondary effects of opportunistic infections or malignancies, or other preexisting or coexisting medical problems that may be prevalent in the HIV-infected population. Diagnosis of the mechanism and cause of the cytopenia may allow for specific management. Optimal management of the underlying HIV infection is essential, and mild cytopenia in asymptomatic patients may need no specific management. Supportive care for anemia includes the use of erythropoietin in addition to the judicious use of red blood cell transfusions. Therapy for neutropenia includes the use of the myeloid growth factors G-CSF and GM-CSF. Immune-mediated thrombocytopenia may be treated with a combination of zidovudine, corticosteroids, IVGG, and splenectomy. Platelet transfusions are sometimes needed for the treatment of thrombocytopenia caused by decreased production. Other hematologic manifestations such as hypergammaglobulinemia and lupus anticoagulants are commonly asymptomatic and usually require no specific therapy, but they can rarely cause morbidity and require specific interventions.

[Hemostasis anomalies and human immunodeficiency virus infection]

Because hemostasis disorder in HIV infected patients are frequent and have clinical effects, they have aroused the interest of internal medicine. Such anomalies are not yet clearly defined and include various parameters. Thrombocytopenia which is the most widespread and the best documented manifestation, whether of peripheral origin by immunological platelet destruction or of central origin by a shortage in platelet production, responds well to medical treatment, especially to zidovudine. The circulating anti-coagulants frequently observed in HIV infected patients, whether anti-phospholipid antibodies or anti-cardiolipines are mostly asymptomatic. Other coagulation disorders (affection of the inhibitory system or fibrinolysis) are rarely observed and generally have no clinical incidence. Apart from thrombocytopenias and thrombotic thrombocytopenic purpura the incidence of clinical signs (thrombotic or hemorrhagic accidents) in HIV infected patients is not higher than in an HIV-free population and respond to the same treatment.