Immune globulin products from human plasma were first used in 1952 to treat immune deficiency. Intravenous immunoglobulin (IVIG) contains the pooled immunoglobulin G (IgG) immunoglobulins from the plasma of approximately a thousand or more blood donors. Initially, immune globulin products were administered by intramuscular injection.
One of biggest advances with IVIG in recent years has been the use of sorbitol-based formulations as opposed to sucrose-based formulations.
IVIG was initially shown to be effective in autoimmune idiopathic thrombocytopenic purpura (ITP) in 1981.IVIGs are sterile, purified IgG products manufactured from pooled human plasma and typically contain more than 95% unmodified IgG, which has intact Fc-dependent effector functions and only trace amounts of immunoglobulin A (IgA) or immunoglobulin M (IgM).
The image below is a schematic representation of an immunoglobulin G molecule.
IVIG is an immunomodulating agent that has multiple activities. These include modulation of complement activation; suppression of idiotypic antibodies; saturation of Fc receptors on macrophages; and suppression of various inflammatory mediators, including cytokines, chemokines, and metalloproteinases.The Fc region of IgG facilitates interaction with and signaling through Fc receptors on phagocytes, B cells, and other cells and with Fc-binding plasma proteins (eg, components of the complement system).
Blockade of macrophage Fc receptors is considered the primary mechanism of action of immune globulin in persons with ITP and other autoantibody-mediated cytopenias. In persons with Kawasaki disease and dermatomyositis, IVIG is thought to inhibit the generation of membrane attack complexes (C5b-C9) and subsequent complement-mediated tissue damage by binding the activated components C3b and C4b, thus preventing their deposition on target surfaces. In persons with dermatomyositis, IVIG induces a decrease in plasma levels of membrane attack complex and a substantial decrease in the amounts of C3b and membrane attack complex deposited in endomysial capillaries. The high content of anti-idiotypes against autoantibodies in IVIG facilitates its ability to neutralize autoantibodies, as is shown in patients with acquired hemophilia due to autoantibodies against factor VIII.
Specific effects of IVIG have been described. The results of in vitro C3 uptake studies and the effect of IVIG on the clearance of preopsonized cells suggest that IVIG produces a kinetic depression of C3 uptake and modifies the process of complement fragment deposition on erythrocytes.
Normal serum contains IgG, IgM, and IgA antibodies, which are referred to as natural antibodies because they are induced without deliberate immunization and are independent of antigenic exposure. They are considered key to the immunoregulatory effects of immune globulin in immune-mediated disorders.  Natural autoantibodies appear to be more polyreactive than immune antibodies; natural antibodies can frequently bind to different antigens. [Natural autoantibodies can (1) bind to pathogens; (2) help remove senescent or altered molecules, cells, and tumors; (3) induce remyelination; and (4) inhibit the growth of autoreactive B-cell clones. In the multifocal motor neuropathy disease state, IVIG intercedes to stop complement deposition that is triggered by anti-GM1 antibodies.
IVIG contains cytokines, antibodies of unclear clinical significance, perhaps neutralizing; interestingly, antibodies against granulocyte macrophage colony-stimulating factor, interferon, interleukin 1, and interleukin 6 in immune globulin have biologic activity in vivo.  IVIG contains natural antibodies, accounting for some of its effects.
The broad range of applications of IVIG shows the importance of immunoglobulins in the immune homeostasis in healthy people.
A liquid, pasteurized, 10% concentrated intravenous gammaglobulin preparation is as effective as a 5% concentrated preparation.
IVIG replacement prevents severe and lower respiratory tract infections, but not upper respiratory tract and non-respiratory infections in persons with common variable immune deficiency.
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The largest challenge faced in 2014 is indemnifying those persons with specific diseases who will respond to IVIG and what biomarkers might inform apposite therapy.
IVIG is used to treat various autoimmune, infectious, and idiopathic diseases. IVIG is an approved treatment for graft versus host disease and ITP. It is accepted for use in persons with Kawasaki disease, Guillain-Barré syndrome, and polymyositis/dermatomyositis. The beneficial effects of an intramuscular injection of immune globulin for the prophylactic treatment of patients with primary immunodeficiency syndromes are well established.
It does not work for all diseases; for example, a Korean study of 63 patients (ie, folliculitis decalvans hidradenitis suppurativa, folliculitis, furunculosis) with recalcitrant suppurative skin diseases reported that it helped 59% of patients, but with only a 20% success rate in treating hidradenitis. 
Diseases that are purely of hematological or clotting factor defects such as Degos disease or paroxysmal nocturnal hemoglobinuria do not respond to IVIG. 
The US Food and Drug Administration has approved the use of IVIG for the following conditions [13, 14, 15] :
Its reported uses have been outlined by the National Guideline Clearinghouse, including the following (off-label) applications:
The IVIG that is available contains complete IgG molecules. The IgG subclasses match those in normal human serum. Most preparations contain trace amounts of IgA, which can sensitize IgA-deficient persons during long-term treatment. Immune globulin also contains trace amounts of cytokines, soluble CD4, CD8, and HLA molecules.
Immune globulin is prepared from pooled plasma from 3000-10,000 healthy blood donors. In some instances, blood from as many as 100,000 donors is used. The entire array of variable (antigen-binding) regions of antibodies in normal serum is contained in IVIG. The large number of donors in the pool increases the number of individual antibody activities in the preparation but risks diluting any useful rare activity. Thus, IVIG has the full array of immune antibodies directed compared with nonhost antigens. The large number of donors makes contamination by viruses more possible, but this is rare.
All preparations of IgG have traces of IgA. IgA-deficient patients with severe recurrent viral or bacterial respiratory tract infections or with isolated IgA deficiency (and additional IgG2 and IgG4 deficiency) who may develop severe anaphylactic reactions after an IVIG infusion should receive the first infusion in the hospital under medical supervision.
The significance of IgA content in these preparations for patients with IgA deficiency is unclear. The pharmacokinetic properties of IVIG in healthy persons are well defined and last approximately 22 days; however, in persons with certain illnesses, they can last as few as 6 days.
IVIG therapy should be monitored, and obtaining a history and performing a physical examination, with an emphasis on obtaining information regarding hepatic or kidney disease or a history of reactions to blood products or transfusion reactions, is prudent.
Laboratory tests may include the following:
Finally, store a small amount of serum used before each infusion for analysis in the event of infectious disease transmission.
Because most skin disease has an immunological effect, the fact that IVIG is helpful for treating these conditions is not surprising. It has been reported useful in the treatment of autoimmune blistering diseases, lupus erythematosus, dermatomyositis, scleroderma, toxic epidermal necrolysis, atopic dermatitis, pyoderma gangrenosum, epidermolysis bullosa acquisita, herpes gestationis, erythema multiforme, and chronic autoimmune urticaria. Other uses include treatment for pemphigus foliaceus, mucous membrane pemphigoid, and mixed connective-tissue disease.
IVIG has both agonistic and blocking antibodies against Fas (CD95), the receptor for the Fas ligand, which triggers apoptotic signals into cells. This is likely what underlies its efficacy for treating toxic epidermal necrolysis.
In persons with dermatomyositis, IVIG decreases plasma levels of membrane attack complex and substantially decreases the amounts of C3b and membrane attack complex deposited in endomysial capillaries.
A prime use of IVIG is in the treatment of hematological diseases. The first description of the treatment of individuals with ITP with IVIG was by Imbach et al in 1981.  They noted that dose administration of IVIG promoted a rapid recovery for children with ITP.
Platelet destruction occurs in the spleen. The spleen contains large numbers of Fc receptor (Fc-gamma-R)–bearing phagocytic cells, such as monocytes and macrophages. These cells can bind and destroy opsonized platelets. Although platelets are destroyed in many different organs, splenectomy is a successful treatment for many cases of ITP. In 1982, Fehr et al demonstrated that in cases of ITP without splenectomy, the infusion of IVIG prolonged the clearance of radiolabeled, antibody-sensitized RBCs in vivo. 
In 1983, Salama et al suggested that the success of IVIG in the treatment of ITP was due to competitive inhibition of Fc receptors on phagocytic cells within the reticuloendothelial system by sensitized erythrocytes.  Possible mechanisms that underlie this are (1) IVIG dimers and multimers, which are present in low but significant levels in preparations of IVIG, bind to Fc receptors and block platelet clearance and (2) IVIG contains IgG molecules that have a multitude of host antigenic reactivities. These IgG molecules likely bind to host antigens, form immune complexes, and compete with antibody-sensitized platelets for Fc receptors in the reticuloendothelial system, resulting in prolonged platelet survival. 
Other suggested mechanisms for IVIG include the regulatory properties of an antibody type referred to as antiidiotypic antibodies, ie, antibodies that interact with the antigen-combining region of other antibodies. Others have suggested that competitive inhibition by IVIG-induced immune complexes and opsonized platelets for occupancy of activating Fc-gamma-R in the reticuloendothelial system affects the course of ITP. IVIG also has its own immunological effects on the cellular immune response. These involve expression of interleukins and cytokines and growth arrest of lymphocytes.
The standard dose of IVIG is 400 mg/kg daily for 5 days. [33, 34] A new dosing level is 1 g/kg/d for 2 days, which appears to be more effective.
In the United States, the recommended treatment for Kawasaki disease(see the Kawasaki Disease Diagnostic Criteria calculator) in the acute phase is a single, high dose of intravenous gammaglobulin (2 g/kg) and a high dose of aspirin (80-100 mg/kg/d).
The therapeutic mechanism of IVIG in Kawasaki disease may be partially due to the reversal of the inhibited lymphocyte apoptosis.  Intravenous gammaglobulin has inhibitory effects on platelet adhesion and thrombus formation. Some competitive inhibition between intact IgG and adhesive protein (eg, von Willebrand factor) is suggested, and Fc receptors of the platelet membrane and Fab and Fc receptors of the subendothelium of the vessel wall may have some role in the interaction. IVIG therapy induces neutrophil apoptosis in persons with Kawasaki disease.
High-dose IVIG down-regulates the activated levels of inflammatory indices (except erythrocyte sedimentation rate) in the acute stage of Kawasaki disease.
IVIG has been shown to decrease the severity of acute graft versus host disease in recipients of allogeneic bone marrow transplants. The dosage is 250 or 500 mg/kg/wk. Prevention against acute graft versus host disease with IVIG might be mediated by the induction of apoptosis of activated alloreactive CD4+ CD134+ donor T cells. 
See the list below:
Undesirable effects from IVIG occur in less than 5% of patients. The most common adverse effects occur soon after infusions and can include headache, flushing, chills, myalgia, wheezing, tachycardia, lower back pain, nausea, and hypotension. If this happens during an infusion, the infusion should be slowed or stopped. If symptoms are anticipated, a patient can be premedicated with antihistamines and intravenous hydrocortisone.