Bringing immunoglobulin knowledge up to date: how should we treat today?

Recommendations for the management of secondary hypogammaglobulinaemia due to B cell targeted therapies in autoimmune rheumatic diseases

OBJECTIVES

The association of B cell targeted therapies with development of hypogammaglobulinaemia and infection is increasingly recognized. Our aim was to develop consensus recommendations for immunoglobulin replacement therapy for management of hypogammaglobulinaemia following B cell targeted therapies in autoimmune rheumatic diseases.

METHODS

A modified Delphi exercise involved a 17-member Taskforce committee, consisting of immunologists, rheumatologists, nephrologists, haematologists, a gastroenterologist, an immunology specialist nurse and a patient representative. The first round identified the most pertinent topics to address in the recommendations. A search string was agreed upon for the identification of publications in PubMed focusing on these areas, for a systematic literature review. Original data was presented from this review to the Taskforce committee. Recommendations from the British Society for Rheumatology, the UK Department of Health, EULAR, the ACR, and the American Academy of Allergy, Asthma, and Immunology were also reviewed. The evidence was discussed in a face-to-face meeting to formulate recommendation statements. The levels of evidence and statements were graded according to Scottish Intercollegiate Guidelines Network methodology.

RESULTS

Three overarching principles, eight recommendation statements and a research agenda were formulated. The Taskforce committee voted on these statements, achieving 82-100% agreement for each recommendation. The strength of the recommendations was restricted by the low quality of the available evidence, with no randomized controlled trial data. The recommendations cover risk factors, monitoring, referral for hypogammaglobulinaemia; indications, dosage and discontinuation of immunoglobulin replacement therapy.

CONCLUSION

These are the first recommendations specifically formulated for B cell targeted therapies related to hypogammaglobulinaemia in autoimmune rheumatic diseases. The recommendations are to aid health-care professionals with clinical decision making for patients with hypogammaglobulinaemia.

The history and evolution of immunoglobulin products and their clinical indications

The history of providing antibodies to treat diseases began in the 19th century with the discovery of tetanus and diphtheria toxins and the demonstration that immunity to tetanus and diphtheria infections could be transferred by immune sera. Characterization of the mediators of this immunity resulted in the discovery that antibodies are proteins that can be isolated and used to protect against infectious diseases. Development of a method to isolate antibodies from human plasma that could be safely injected into people initiated the development of human gamma globulin preparations to provide antibodies to patients with inherited antibody deficiencies. To overcome the limitations imposed by intramuscular injection of gamma globulin, intravenous gamma globulin preparations were developed that began to be used in a wide variety of clinical conditions. Thus the original clinical indication for infection prevention was expanded to several other indications that employ large doses to suppress inflammatory and autoimmune disorders. The most recent development in immunoglobulin therapy is the production of concentrated immune globulins for subcutaneous injection. Home infusions of subcutaneous immunoglobulin are increasingly used to treat immunodeficient patients and are being studied for other clinical applications.

Therapeutic immunoglobulin should be dosed by clinical outcome rather than by body weight in obese patients

There are currently no data to support the suggestion that the dose of therapeutic immunoglobulin (Ig) should be capped in obese patients for pharmacokinetic (PK), safety and economic reasons. We compared IgG trough levels, increment and efficiency in matched pairs of obese and lean patients receiving either replacement or immunomodulatory immunoglobulin therapy. Thirty-one obese patients were matched with a clinically equivalent lean patient across a range of indications, including primary antibody deficiency or autoimmune peripheral neuropathy. Comprehensive matching was carried out using ongoing research databases at two centres in which the dose of Ig was based on clinical outcome, whether infection prevention or documented clinical neurological stability. The IgG trough or steady state levels, IgG increments and Ig efficiencies at times of clinical stability were compared between the obese and lean cohorts and within the matched pairs. This study shows that, at a population level, obese patients achieved a higher trough and increment (but not efficiency) for a given weight-adjusted dose compared with the lean patients. However at an individual patient level there were significant exceptions to this correlation, and upon sub-group analysis no significant difference was found between obese and lean patients receiving replacement therapy. Across all dose regimens a high body mass index (BMI) cannot be used to predict reliably the patients in whom dose restriction is clinically appropriate.

Immunoglobulin replacement therapy for primary immunodeficiencies

Exogenous antibody therapy to protect patients against infections and toxins is over 100 years old, yet progress continues to be made in the manufacture, administration and application of this type of immunotherapy, known as therapeutic human immunoglobulin. For the majority of patients with primary immunodeficiencies, immunoglobulin replacement is the only life-saving therapy and treatment is life-long, since the vast majority of primary immunodeficiency patients have primary antibody failure. Successful treatment depends on multiple factors: the availability of products, the type of immunodeficiency and any comorbidities of the individual patient. Essential components include long-term follow-up, regular monitoring and a close relationship between the patient and the multidisciplinary clinical immunology team. In this article, we describe the current immunoglobulin products and the types of adverse reactions. We provide evidence for clinical decision-making regarding dosing, route of administration and location of therapy, highlighting current ‘best practice’ recommendations.

Evolution of vertebrate immunity

All multicellular organisms protect themselves against pathogens using sophisticated immune defenses. Functionally interconnected humoral and cellular facilities maintain immune homeostasis in the absence of overt infection and regulate the initiation and termination of immune responses directed against pathogens. Immune responses of invertebrates, such as flies, are innate and usually stereotyped; those of vertebrates, encompassing species as diverse as jawless fish and humans, are additionally adaptive, enabling more rapid and efficient immune reactivity upon repeated encounters with a pathogen. Many of the attributes historically defining innate and adaptive immunity are in fact common to both, blurring their functional distinction and emphasizing shared ancestry and co-evolution. These findings provide indications of the evolutionary forces underlying the origin of somatic diversification of antigen receptors and contribute to our understanding of the complex phenotypes of human immune disorders. Moreover, informed by phylogenetic considerations and inspired by improved knowledge of functional networks, new avenues emerge for innovative therapeutic strategies.

Broadening the translational immunology landscape

It is just over 5 years sinceClinical and Experimental Immunology came under the direction of a new team of Editors and made a concerted effort to refresh its approach to promoting clinical and applied immunology through its pages. There were two major objectives: to foster papers in a field which, at the time, we loosely termed ‘translational immunology’; and to create a forum for the presentation and discussion of immunology that is relevant to clinicians operating in this space. So, how are we doing with these endeavours? This brief paper aims to summarize some of the key learning points and successes and highlight areas in which translational gaps remain.

Subcutaneous immunoglobulin therapy: a new option for patients with primary immunodeficiency diseases

Since the 1950s, replacement of immunoglobulin G using human immunoglobulin has been the standard treatment for primary immunodeficiency diseases with defects in antibody production. These patients suffer from recurrent and severe infections, which cause lung damage and shorten their life span. Immunoglobulins given intravenously (IVIG) every 3-4 weeks are effective in preventing serious bacterial infections and improving the quality of life for treated patients. Administration of immunoglobulin subcutaneously (SCIG) is equally effective in preventing infections and has a lower incidence of serious adverse effects compared to IVIG. The tolerability and acceptability of SCIG has been demonstrated in numerous studies showing improvements in quality of life and a preference for subcutaneous immunoglobulin therapy in patients with antibody deficiencies.