**1. Introduction**

There is a large number of immunodeficient patients requiring lifelong IgG replacement. This review is focused on currently available Intravenous Immunoglobulin (IVIG) preparations, manufacturing procedures, dose arrangements, mechanisms of actions, benefits of antibody replacement treatment and careful administration of IVIG considering, numerous side effects. Subcutaneous IgG (SCIG) treatment has gained ground in recent years as an alternative to IVIG. Data show that the efficacy of SCIG in preventing infections is proportional to the steady-state levels achieved and similar to that of IVIG.

Intravenous immunoglobulin (IVIG) is mainly indicated as replacement therapy for patients with primary and selected secondary immunodeficiency diseases characterized by absent or deficient antibody production. Antibody deficiencies are a heterogeneous group of diseases mainly consisting of primary immunodeficiency diseases (PID) [1-4]. Primary antibody deficiencies (PAD) can be divided into four main subgroups: X-linked agammaglobulinaemia, class-switch recombination defects (hyper-IgM syndromes (HIGM), hypogammaglobulinaemia (particularly common variable immunodeficiency (CIVD) and selective immunoglobulin deficiencies (selective IgA deficiency). Over the past 20 years, 18 genetic defects have been defined as leading causes of PAD, but no gene defects were identified in patients with hypogammaglobulinaemia and selective immunoglobulin deficiencies, because of the variability of the affected stages of B cell differentiation and maturation, and the onset time of clinical symptoms like childhood or adulthood with increased susceptibility to mainly bacterial infections [5,6].

Substitution of immunoglobulin G (IgG) is the efficient and standard treatment for many years [7-11]. Immunoglobulins pooled from thousands of healthy donors contain a wide range of antibody specificities. These immunoglobulin preparations also have antiinflammatory and immunomodulatory effects in addition to their use as replacement

© 2012 Camcıoğlu, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2012 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

therapy [12,13]. The benefits in diseases such as childhood thrombocytopenia and Kawasaki disease refractory to or intolerant of conventional treatment have been well established [14,15]. It has been 30 years since therapeutic contribution of intravenous immunoglobulin (IVIG) administration has been proven by scientists, an increasing number of immunemediated diseases have been treated with intravenous immunoglobulin rather than corticosteroids and cytoxic drugs. IVIG has become the therapy of choice in autoimmune diseases, severe asthma, neurological diseases, transplantation, sepsis, septic shock, toxic shock syndromes and dermatologic disorders [15,16]. The recommendation of IVIG treatment in other diseases than those approved by FDA is based on limited data or some of these diseases do not have any alternative treatment regimen to compare with [16]. However, IVIG administration in the treatment of many diseases is raising the possibility of product shortages and increasing costs. Thus, concerning the shortages of products, cost and adverse reactions, definite indications for IVIG treatment are essential [12,13,16,17]. The aim of immunoglobulin therapy should be to protect the patients from frequent and severe infections finally resulting in organ damage. Advances in human immunology, has led to identify responsible genes for PID, thereby particular groups of defects are associated with susceptibility to specific types of infection [18]. Improved diagnostic precision is likely to increase more specialized management strategies of patients with PID, some of which are only supported by expert consultation. However, there are no sufficient number of studies in PID, to optimize the quality and uniformity of management of PID**.** 

Immunoglobulin Treatment of Immunodeficient Patients 91

Intravenous immunoglobulin (IVIG) preparations contain 16% human serum immunoglobulin and more than 95% IgG, scanty amount of IgA, IgM and other serum proteins. IgA and IgM do not have any therapeutic effects due to their short half-life and small amount [22,23]. Prognosis of patients with deficient IgG production has thoroughly improved after replacement therapy with IVIG [24]. Since 1980, it has been the most striking therapeutic agent due to its unproposed anti-inflammatory and immunomodulatory effects and used to treat a wide variety of pathologies including vasculitis, HIV infection, autoimmune diseases and immune-mediated neurological diseases [12,14,15, 25-28]. Currently, subcutaneous immunoglobulin infusions administered by a special pump has become an alternative to IVIG treatment. It has been demonstrated that this product is safe and has some clinical advantages over intravenous preparations. It has been recommended

IVIG preparations are derived from plasma of a huge number of human blood donors or paid plasmapheresis donors. Since IVIG preparations are blood-derived products having the risk of transmission of infectious transfusional diseases, viral safety needs to be considered [13,21,23]. The safety of IVIG products depends on donors, validated manufacturing

To produce a single product lot, sufficient number of donor recruitment and screening of viral markers (HBs-Ag, HIV-p24 antigen, antibodies to syphilis, HIV-1,HIV-2, HCV, HAV)

FDA (Center for Biologics Evaluations and Research) and Plasma Protein Therapeutics Association recommended the number of donors to be minimum 15.000, but not more than 60.000. Manifacturing processes implemended in commercial IVIG preparations are the classical Cohn fractionations treated with solvent detergent, caprylate, acid or pepsin to

Immunoglobulin, produced by cold ethanol fractionation method may contain trace amounts of contaminants such as prekallikrein activator, prekallikrein, activated coagulation factors, complement proteins, IgM, IgA, plasmin and plasminogen. Currently many manufacturers began to use purification with anion exchange (DEAE) chromatography adjusted to cold ethanol fractionations in order to obtain safe products.

Treatment at pH4 with trace amounts of pepsin is also validated by some manifacturers. Both, alcohol fractionation and acid treatment procedures eliminate other proteins and

especially for selected patients with primary immunodeficiencies [29,30].

processes and various virus clearance steps as listed below:

are necessary to prevent the transmission of viruses [21].

inactivate dangerous live viruses such as HIV, Hepatitis B, HCV.

c. use of validated manufacturing processes d. effective viral inactivation/removal procedures

**3. IVIG production** 

a. recruitment of the donor b. donation screening

inactivate pathogens [31-33].

#### **2. History and recent development (IVIG)**

Cohn et al produced the first human immunoglobulin IgG product in1946 and it was referred as immune serum globulin (ISG)[19]. This first commercial human ISG solution tended to form aggregates during storage, therefore it was delivered via the intramuscular or subcutaneous route. After diagnosing his first patient with agammaglobulinemia in 1952, Bruton began to treat his patients by subcutaneous replacement therapy with ISG [20]. After a short time, intramuscular ISG treatment became available for all patients, but the amount of Ig used for treatment was limited and not effective enough to reduce recurrent infections and the adverse effects were also high due to IgG aggregates [21]. These disadvantages were abolished by Cohn fraction II that had been developed in 1960's by Barandum and his colleagues in collaboration with Swiss Red Cross [9,21]. The first IVIG was produced by pepsin digestion (enzymatic method: pepsin or trypsin) to reduce anticomplement activity, but this process cleaved the immunoglobulin molecule into two parts, resulting in fragments of the fc portion and Fab. Several manifacturers produced chemically modified IVIGs containing minimal anti-complement activity and no IgG fragments. Reduced bacterial opsonic activities and shortened circulating half-lives were demonstated in some antibodies of enzyme-digested or chemically modified IVIG preparations. Non-denaturating processes such as precipitation with polyethylene glycol (PEG), ion exchange chromatography, diafiltration and stabilisation of IgG at low pH, do not modify the IgG molecule and the half-life of IgG is generally 22-25 days [21].

Intravenous immunoglobulin (IVIG) preparations contain 16% human serum immunoglobulin and more than 95% IgG, scanty amount of IgA, IgM and other serum proteins. IgA and IgM do not have any therapeutic effects due to their short half-life and small amount [22,23]. Prognosis of patients with deficient IgG production has thoroughly improved after replacement therapy with IVIG [24]. Since 1980, it has been the most striking therapeutic agent due to its unproposed anti-inflammatory and immunomodulatory effects and used to treat a wide variety of pathologies including vasculitis, HIV infection, autoimmune diseases and immune-mediated neurological diseases [12,14,15, 25-28]. Currently, subcutaneous immunoglobulin infusions administered by a special pump has become an alternative to IVIG treatment. It has been demonstrated that this product is safe and has some clinical advantages over intravenous preparations. It has been recommended especially for selected patients with primary immunodeficiencies [29,30].
