Effect of intravenous immunoglobulin on a spontaneous inhibitor to factor VIII

Intravenous immunoglobulin therapy for acquired coagulation inhibitors: a critical review

Intravenous immunoglobulin (IVIG) therapy has been used for autoimmune diseases and disorders involving autoantibodies, including coagulation inhibitors. In this review, we have evaluated the efficacy and safety of IVIG therapy for acquired coagulation inhibitors, including factor VIII inhibitor, and for acquired von Willebrand syndrome on the basis of 44 reports published between 1965 and 2005. Among 35 patients with factor VIII inhibitor, we estimated the efficacy of IVIG therapy alone (which includes complete remissions and partial responses with a clinical benefit) to be 30% (11 cases), whereas the response to combination therapy with IVIG plus immunosuppressive agents (eg, corticosteroid, cyclophosphamide) seemed to be better (approximately 70%, 33/45 cases) than with IVIG therapy alone. In acquired von Willebrand syndrome, the efficacy of IVIG therapy was estimated to be 30%. The response to IVIG therapy appears to occur rapidly, and coagulation inhibitors seem to be neutralized immediately. Moreover, severe complications or side effects rarely occur during IVIG treatment. IVIG therapy thus may be considered one choice for treating acquired coagulation inhibitors, although its efficacy improves when used in combination with immunosuppressive agents.

CD4 and CD8 subpopulation changes during high dose intravenous immunoglobulin treatment

High doses of immunoglobulin, when given intravenously (IVIgG), influence lymphocyte subset numbers and function. T-lymphocytes may be subdivided into two functionally different groups, helper/inducer (CD4+) and suppressor/cytotoxic (CD8+). Considerable functional as well as phenotypic heterogeneity exists within the two major subsets. CD4+ cells have been further subdivided into helper/inducer and suppressor/inducer sets by the differential binding of two monoclonal antibodies 4B4 (CDw29) and 2H4 (CD45R). Similarly, the CD8+ subset may be subdivided into suppressor and cytotoxic populations by the differential binding of monoclonal antibodies which identify the C3bi receptor (CD11). During IVIgG treatment of patients with autoimmune thrombocytopenic purpura (ATP) the change in CD4/CD8, due to an absolute increase in CD8+ cells, has been shown to correlate with the response to treatment as determined by platelet increase. However, the total CD4+ and CD8- numbers may not reflect changes in their constituent subpopulations. To examine this possibility the CD4 and CD8 subpopulations were analysed in 15 ATP patients, during IVIgG treatment, using a double fluorescence technique. In 10 of these patients the in vitro response to pokeweed mitogen (PWM) and Staphylococcus aureus Cowan I (STA Cowan I) was determined. There was no correlation between the change in CD8+ subpopulations and response to treatment but there was a correlation between the CD4+ change and platelet increment. In addition there was a correlation between the 4B4/2H4 change and the in vitro response to PWM but no correlation with the response to STA Cowan I. These findings suggest that during IVIgG treatment the CD4+ 4B4+ helper/inducer population is influenced resulting in reduced T-dependent B-cell activation.

The concept of anti-idiotypic regulation of selected autoimmune diseases by intravenous immunoglobulin

Evidence that physiological control of human humoral autoimmune reactions depends, at least in part, on the formation of anti-idiotypic antibodies is accumulating. Upon binding to the corresponding idiotypes, anti-idiotypes will prevent autoantibodies from reacting with the primary antigen and/or eventually expedite removal of autoantibodies from the circulation and down-regulate their formation. In patients with autoantibodies against clotting factor VIII:C or fibrinogen, clinical improvement was associated with formation of anti-idiotypes against the autoantibodies. In addition, iv immunoglobulin (IVIg) preparations derived from plasma pools of thousands of healthy donors expressed anti-idiotypes against such autoantibodies as anti-clotting factor VIII:C, antithyroglobulin, and anti-intrinsic factor, but the specificity of the anti-idiotypes appears to be restricted for particular idiotypes. This explains why not all patients are responders to therapeutic intervention with IVIg. On one hand, definite in vitro neutralization of autoantibody activity by IVIg added in multiple proportions is not followed infallibly by in vivo response, and on the other hand, a good therapeutic effect often lasts long beyond normal half-lives of infused IVIg. The present overview compares the authors' own work with that described in recently published literature on exploring anti-idiotypy in therapy.

Clinical use of intravenous immunoglobulin in blood disorders

The protective effect of passively administered immunoglobulin has been known for many years. Although its accepted use over the last 40 years has been in the prevention and treatment of infection its widest and, arguably, most important application has been in the prevention of Rhesus haemolytic disease of the newborn. However, the development over the last decade of a number of safe and effective immunoglobulin preparations for intravenous use has allowed its more widespread utilisation in clinically appropriate settings. It is now widely accepted that intravenous immunoglobulin (IVIgG) is indicated, on a repeat basis, as treatment of choice as replacement therapy for patients with primary antibody deficiency. It may also be effective, in the non-immune deficient patient, in the management of certain bacterial as well as viral infections. This is particularly the case in the pre-term neonate but may have an application in the infected intensive care patient. The benefit in these patient groups has led to a re-evaluation of the use of immunoglobulin replacement therapy in the severe secondary antibody deficiency states associated with such haematological conditions as multiple myeloma and chronic lymphocytic leukaemia. These are currently the subject of randomised, controlled studies. The observation that the use of IV IgG may be associated with effects other than passive transfer of antibody were first made by Imbach in Switzerland. While treating children with immunodeficiency he noticed that two with a coincident immune thrombocytopenia had a rapid platelet increment in close association with the immunoglobulin infusion. He subsequently confirmed that this was a rapid and predictable form of therapy in childhood idiopathic thrombocytopenic purpura (ITP) and that in some children it appeared to affect the natural history of the disease. Since these initial observations the response has been confirmed in both children and adults and extended to other immune-based haematological disorders.