Recombinant human interferon alpha-2b (rh IFN alpha-2b) therapy for steroid resistant idiopathic thrombocytopenic purpura (ITP)

How I treat refractory immune thrombocytopenia

This article summarizes our approach to the management of children and adults with primary immune thrombocytopenia (ITP) who do not respond to, cannot tolerate, or are unwilling to undergo splenectomy. We begin with a critical reassessment of the diagnosis and a deliberate attempt to exclude nonautoimmune causes of thrombocytopenia and secondary ITP. For patients in whom the diagnosis is affirmed, we consider observation without treatment. Observation is appropriate for most asymptomatic patients with a platelet count of 20 to 30 × 109/L or higher. We use a tiered approach to treat patients who require therapy to increase the platelet count. Tier 1 options (rituximab, thrombopoietin receptor agonists, low-dose corticosteroids) have a relatively favorable therapeutic index. We exhaust all Tier 1 options before proceeding to Tier 2, which comprises a host of immunosuppressive agents with relatively lower response rates and/or greater toxicity. We often prescribe Tier 2 drugs not alone but in combination with a Tier 1 or a second Tier 2 drug with a different mechanism of action. We reserve Tier 3 strategies, which are of uncertain benefit and/or high toxicity with little supporting evidence, for the rare patient with serious bleeding who does not respond to Tier 1 and Tier 2 therapies.

Chronic refractory ITP in children: beyond splenectomy

Idiopathic (or immune) thrombocytopenic purpura (ITP) is a relatively common hematologic condition, but one that the hematology community has failed to reach a consensus on with regard to treatment. In patients with chronic refractory ITP, there is even less agreement about treatment approaches, as this population represents a small, but challenging, fraction of the total cases of ITP. The aim of this article is to review the treatment options available for children with chronic refractory ITP, including a review of the benefits versus risks, rate of remission, and areas of ongoing and future research.

Successful treatment of idiopathic thrombocytopenic purpura-like syndrome in a cancer patient with low-dose interferon: case report and review of the literature

Idiopathic thrombocytopenic purpura (ITP)-like syndrome is a rare complication of carcinomas, and its treatment usually precedes cancer therapy in order to make further procedures safe. We describe the case of a 78-year-old man with a small-cell lung cancer of extended stage, associated with ITP-like syndrome, which proved resistant to treatment with corticosteroids and vincristine, short-responsive to IV immunoglobulin, but quickly and steadily responsive to low-dose interferon (ld IFN, 3 million IU, sc, twice weekly, for 8 weeks), until the patient's death, due to his primarily chemoresistant cancer. This case is, to our knowledge, the second reported ITP-like syndrome in a cancer patient who had been successfully treated with ld IFN. The excellent and cost-effective therapeutic index of ld IFN makes it an attractive alternative treatment in patients with this specific complication and calls for further investigation regarding its potential use as a first-line treatment.

Role of transforming growth factor-beta 1 gene polymorphisms in childhood idiopathic thrombocytopenic purpura

PURPOSE

To investigate whether transforming growth factor-beta 1 (TGF-beta 1) gene polymorphisms have a role in the development, clinical progress, and treatment response in children with idiopathic thrombocytopenic purpura (ITP).

PATIENTS AND METHODS

Thirty-five children with acute ITP, 40 children with chronic ITP, and 97 healthy children were enrolled. After genomic DNA was extracted, TGF-beta 1 gene 509 (C-->T), codon 25 (Arg-->Pro), and codon 10 (Leu-->Pro) polymorphisms were studied using a coupled polymerase chain reaction-restriction enzyme digestion method.

RESULTS

The genotype and allele frequencies of TGF-beta 1 polymorphisms between acute ITP, chronic ITP, and control group did not differ significantly. No significant association was found between TGF-beta 1 polymorphisms and therapy response.

CONCLUSIONS

These results demonstrate that the frequency of TGF-beta1 gene 509 (C-->T), codon 25 (Arg-->Pro), and codon 10 (Leu-->Pro) polymorphisms and alleles do not play a role as a genetic risk factor in the development and clinical progress of ITP. Different results may be obtained with further studies involving larger patient populations and other TGF-beta 1 gene polymorphisms.

Long-term follow-up of chronic autoimmune thrombocytopenic purpura refractory to splenectomy: a prospective analysis

Splenectomy remains the most effective treatment of chronic autoimmune idiopathic thrombocytopenia (ITP) (i.e. of > 6 months duration). Treatment of patients refractory to splenectomy (with absence of response or relapse after initial response) is difficult, and their long-term outcome is not well known. Over a 10-year period, 183 patients with chronic ITP were splenectomized including 158 adults and 25 children (</= 15 years). Forty-seven of them, who were refractory to this treatment, were prospectively followed up for 5-15 years (median 7.5 years). Twelve of them, with moderate thrombocytopenia, remained untreated, and 35 were treated by a median of two regimens (range 1--6), to which 27 responded. Thirty-six (77%) of the refractory cases reached platelet counts durably > 100 x 10(9)/l, nine of them without treatment and 27 of them with low-dose steroids or azathioprine; six (13%) remained moderately thrombocytopenic (35 x 10(9)/l to 100 x 10(9)/l platelets); the last five patients, without response to any treatment (up to six regimens), remained severely thrombocytopenic (platelets < 20 x 10(9)/l), and three of them died from bleeding. Twenty-seven (57%) of the 47 refractory cases required at least one hospitalization, in the majority of cases for intravenous immunoglobulin (IVIg) infusions. Seven of the refractory cases occurred in children. Six of them subsequently reached platelet counts > 100 x 10(9)/l, but one died from bleeding. Our findings confirm the overall favourable long-term prognosis of chronic ITP refractory to splenectomy.

Recombinant human interferon alpha-2a therapy in children with chronic immune thrombocytopenic purpura

BACKGROUND

In a prospective study, 11 children with chronic immune thrombocytopenic purpura between ages 3 and 18 years were treated with recombinant human interferon alpha 2a (rhIFN alpha-2a).

PATIENTS AND METHODS

A dose of 3 x 10(6) U/m2 three times weekly for 4 to 5 weeks (one cycle) was administered. Patients were treated with one to four cycles of rhIFN alpha-2a, and the outcomes were measured initially and 18 to 30 months after the last cycle.

RESULTS

Good therapeutic responses (defined as platelet count >100 x 10(9)/L) lasting for 18 to 30 months from the last interferon cycle were achieved in 6 of the 11 (55%) patients, including one with a probable spontaneous remission. Fair responses (platelet count 31-60 x 10(9)/L) for 18 months were achieved in 3 of the 11 (27%) patients. Only two patients, each treated only with one interferon cycle, exhibited no response. Side effects of treatment included fever and a flu-like syndrome, which were usually present during the first 14 days of therapy only.

CONCLUSIONS

Interferon-alpha appears to be an effective therapeutic approach to children with chronic immune thrombocytopenic purpura, with the potential of sustained long-term remission. A randomized, placebo-controlled study is needed to confirm its role in this population.

Involvement of Fc gamma receptor polymorphism in the therapeutic response of idiopathic thrombocytopenic purpura

Clearance of autoantibody-sensitized platelets through Fc gamma receptors on phagocytic cells is one of the main mechanisms of thrombocytopenia in idiopathic thrombocytopenic purpura (ITP). We examined the Fc gamma RIIA-131R/H and Fc gamma RIIIA-158V/F polymorphisms in 104 adult chronic ITP patients, and in 59 healthy control subjects using polymerase chain reaction-based allele-specific restriction analysis. The frequency of Fc gamma RIIA genotypes (131H/H, H/R, R/R) was not significantly different between patients and controls, and did not correlate with the responsiveness to treatment. In contrast, among Fc gamma RIIIA genotypes, frequency of 158F/F homotype was smaller in ITP (P < 0.05). Furthermore, in Fc gamma RIIIA-158V/V homotype, the complete remission (CR) rate with medication (treatment with corticosteroid or other immunosuppressive agents) was significantly higher (60%) than that in 158V/F (10%) or 158V/F plus 158F/F, (P < 0.01, P < 0.05). Conversely, the CR rate after splenectomy in 158F/F and 158V/F types (64.3% and 54.6%) was higher than in 158V/V (25%). Our results indicate that the polymorphism of Fc gamma RIIIA, but not Fc gamma RIIA, influences the response to treatment in ITP.

Differential regulation of human blood dendritic cell subsets by IFNs

Based on the relative expression of CD11c and CD1a, we previously identified subsets of dendritic cells (DCs) or DC precursors in human peripheral blood. A CD1a(+)/CD11c(+) population (CD11c(+) DCs), also called myeloid DCs, is an immediate precursor of Langerhans cells, whereas a CD1a(-)/CD11c(-) population (CD11c(-) DCs), sometimes called lymphoid DCs but better known as plasmacytoid DCs, is composed of type I IFN (IFN-alpha beta)-producing cells. Here, we investigate the effects of IFN-alpha beta and IFN-gamma as well as other cytokines on CD11c(+) and CD11c(-) DC subsets, directly isolated from the peripheral blood, instead of in vitro-generated DCs. IFN-gamma and IFN-alpha, rather than GM-CSF, were the most potent cytokines for enhancing the maturation of CD11c(+) DCs. Incubation of CD11c(+) DCs with IFN-gamma also resulted in increased IL-12 production, and this IL-12 allowed DCs to increase Th1 responses by alloreactive T cells. In contrast, IFN-alpha did not induce IL-12 but, rather, augmented IL-10 production. IFN-alpha-primed matured CD11c(+) DCs induced IL-10-producing regulatory T cells; however, this process was independent of the DC-derived IL-10. On the other hand, IFN-alpha by itself neither matured CD11c(-) DCs nor altered the polarization of responding T cells, although this cytokine was a potent survival factor for CD11c(-) DCs. Unlike IFN-alpha, IL-3 was a potent survival factor and induced the maturation of CD11c(-) DCs. The IL-3-primed CD11c(-) DCs activated T cells to produce IL-10, IFN-gamma, and IL-4. Thus, CD11c(+) and CD11c(-) DC subsets play distinct roles in the cytokine network, especially their responses to IFNs.

Management of patients with chronic, refractory idiopathic thrombocytopenic purpura

Chronic refractory idiopathic thrombocytopenic purpura (ITP) is defined as ITP with persistent thrombocytopenia despite conventional initial management with prednisone and splenectomy. Rare in children, It may occur in as many as one third of adults with ITP. The goal of treatment is not cure of the ITP, but only to achieve a safe platelet count, which is arbitrarily assumed to be greater than 30,000 to 50,000/microL. The risk for major bleeding seems great only when the platelet count is less than 10,000/microL. Treatment of patients with moderate thrombocytopenia and no clinically important bleeding symptoms should be avoided. There is no accepted algorithm for management of patients with chronic refractory ITP. Observation without specific treatment must be considered a cornerstone of management. Combination regimens of Immunosuppressive agents may be required for patients with severe and symptomatic thrombocytopenia. Additional supportive care measures are also important.

[Chronic idiopathic thrombocytopenic purpura. Current therapy concept and introduction to pathophysiologic, clinical and diagnostic aspects]

PATHOPHYSIOLOGY

Chronic idiopathic thrombocytopenic purpura (ITP) is an autoimmune disorder characterized by platelet destruction due to an antiplatelet autoantibody, usually of the IgG class, which coats autologue platelets and leads to their elimination by the reticuloendothelial system (RES). While in childhood ITP is more usually an acute and self-limiting problem which needs no drug treatment, adult ITP is a relatively common chronic hematological disease.

TREATMENT

Treatment aimes at inhibition of antibody-production and binding on thrombocytes and thrombocyte phagocytosis by the RES. Therapy should result in a platelet count of > 100,000/microliter or at least in stabilization of the platelet count without bleeding. Therapeutic approaches were divided into emergency and long-term treatment. In patients who require non-emergency treatment conventional-dose corticoids (1 to 2 mg/kg/d prednisone) are recommended as initial treatment, whereas pulsed high-dose dexamethason is recently reported to be effective in refractory ITP. After unsuccessful splenectomy or if treatment with gammaglobulins fails alternative and partly experimental therapies may have to be used.

CONCLUSION

Treatment of adult ITP includes established medical, immunological and surgical measurements. Their application depends on diseases progression as well as imminent or manifest complications. Remission is achieved in up to 75% of all patients. Alternative treatments remain for refractory cases.