Superior effect of intravenous anti-D compared with IV gammaglobulin in the treatment of HIV-thrombocytopenia: results of a small, randomized prospective comparison

Clinical Features, Treatment, and Outcome of HIV-Associated Immune Thrombocytopenia in the HAART Era

The characteristics of HIV-associated ITP were documented prior to the HAART era, and the optimal treatment beyond HAART is unknown. We performed a review of patients with HIV-associated ITP and at least one platelet count <20 × 10⁹/L since January 1996. Of 5290 patients in the BC Centre for Excellence in HIV/AIDS database, 31 (0.6%) had an ITP diagnosis and platelet count <20 × 10⁹/L. Initial ITP treatment included IVIG, n = 12; steroids, n = 10; anti-RhD, n = 8; HAART, n = 3. Sixteen patients achieved response and nine patients achieved complete response according to the International Working Group criteria. Median time to response was 14 days. Platelet response was not significantly associated with treatment received, but complete response was lower in patients with a history of injection drug use. Complications of ITP treatment occurred in two patients and there were four unrelated deaths. At a median followup of 48 months, 22 patients (71%) required secondary ITP treatment. This is to our knowledge the largest series of severe HIV-associated ITP reported in the HAART era. Although most patients achieved a safe platelet count with primary ITP treatment, nearly all required retreatment for ITP recurrence. New approaches to the treatment of severe ITP in this population are needed.

Intravenous immunoglobulin and anti-RhD therapy in the management of immune thrombocytopenia

Intravenous immunoglobulin and intravenous anti-D are common therapies in the management of patients with immune thrombocytopenia (ITP). Both are pooled plasma products and both result in an increase in the platelet count in approximately 60% to 70% of patients with ITP. Despite immediate increases in the platelet count, the duration of response is limited, with platelet increments lasting between 2 and 4 weeks. Infusion reactions are common but adverse events rare. Although responses are similar, human and murine data suggest that the mechanisms of action of these treatments are complex and likely different.

Therapeutic approaches to secondary immune thrombocytopenic purpura

Secondary thrombocytopenia is similar to primary or idiopathic thrombocytopenia (ITP) in that it is characterized by reduced platelet production or increased platelet destruction resulting in platelet levels<60,000/microL. Thrombocytopenia can occur from secondary causes associated with chronic disorders or with disturbed immune function due to chronic infections, lymphoproliferative and myeloproliferative disorders, pregnancy, or autoimmune disorders. Diagnosis of secondary ITP in some cases is complex, and the thrombocytopenia can often be resolved by treating the underlying disorder to the extent this is possible. In most cases, treatment is focused on reducing platelet destruction, but, in some cases, treatment may also be directed at stimulating platelet production. The most problematic cases of thrombocytopenia may be seen in pregnant women. This review will address various agents and their utility in treating ITP from secondary causes; in addition, thrombocytopenia in pregnancy, ITP in immunodeficiency conditions, and drug-induced thrombocytopenia will be discussed. Unlike primary ITP, treatment often must be tailored to the specific circumstance underlying the secondary ITP, even if the condition itself is incurable.

Investigation of whether the acute hemolysis associated with Rh(o)(D) immune globulin intravenous (human) administration for treatment of immune thrombocytopenic purpura is consistent with the acute hemolytic transfusion reaction model

BACKGROUND

Immune thrombocytopenic purpura and secondary thrombocytopenia patients treated with Rh(o)(D) immune globulin intravenous (human; anti-D IGIV) have experienced acute hemolysis, which is inconsistent with the typical presentation of extravascular hemolysis -- the presumed mechanism of action of anti-D IGIV. Although the mechanism of anti-D-IGIV-associated acute hemolysis has not been established, the onset, signs/symptoms, and complications appear consistent with the intravascular hemolysis of acute hemolytic transfusion reactions (AHTRs). In transfusion medicine, the red blood cell (RBC) antigen-antibody incompatibility(-ies) that precipitate AHTRs can be detected in vitro with compatibility testing. Under the premise that anti-D-IGIV-associated acute hemolysis results from RBC antigen-antibody-mediated complement activation, this study evaluated whether the incompatibility(-ies) could be detected in vitro with a hemolysin assay, which would support the AHTR model as the hemolytic mechanism.

STUDY DESIGN AND METHODS

Seven anti-D IGIV lots were tested to determine the RBC antibody identities in those lots, including four lots that had been implicated in acute hemolytic episodes. Hemolysin assays were performed that tested each of 73 RBC specimens against each lot, including the RBCs of one patient who had experienced acute hemolysis after anti-D IGIV administration.

RESULTS

Only two anti-D IGIV lots contained RBC antibodies beyond those expected. No hemolysis endpoint was observed in any of the hemolysin assays.

CONCLUSION

Although the findings did not support the AHTR model, the results are reported to contribute knowledge about the mechanism of anti-D-IGIV-associated acute hemolysis and to prompt continued investigation into cause(s), prediction, and prevention of this potentially serious adverse event.

Intravenous gammaglobulin treatment in HIV-1 infection

The two main indications for the use of intravenous gammaglobulin--antibody replacement therapy and immunomodulation--are pertinent only for a few scenarios in HIV-1 infection. The role of gammaglobulin in the treatment of HIV-1 infection has changed significantly with the introduction of highly active antiretroviral therapy. Antiretroviral drugs have not only controlled the progression of disease but also had far-reaching effects on HIV-1-induced immunologic aberrations. Complete or partial immunologic reconstitution and prevention of immunologic damage have been the hallmarks of success for highly active antiretroviral therapy. This article addresses the use of gammaglobulin before and after the era of effective antiretroviral therapies.