Allergic & immunologic disease: A practical guide to the evaluation, diagnosis and management of allergic and immunologic disease

Most major human conditions, including cancer, infection, autoimmunity and allergy involve the immune system highlighting the important role of immunology as a system-based discipline with a central role in almost every speciality and sub-speciality of medicine. The last century witnessed landmark developments beginning with Ehrlich’s description of humoral immunity, Metchnikoff’s discovery of phagocytosis and cellular immunity leading to an understanding of the importance of lymphocytes in host immunity, Burnet’s self-versus non-self-hypothesis and theory of clonal selection, discovery of the major histocompatibility complex (MHC) first in the mouse system and then the human leucocyte antigen (HLA) system in man. These discoveries were followed by the description of MHC restriction that led to a greater understanding of immunobiology, and mechanism of antigen presentation and of host immunity. These developments were helpful in overcoming the immunological barrier in organ and haematopoietic stem-cell transplantation that laid the foundation for the establishment of transplant immunology and clinical immunogenetics as a distinct arm of immunology. The century also witnessed numerous Nobel Prizes to eminent stalwarts for their epoch-making discoveries.

Simultaneously, the field of allergy has witnessed remarkable discoveries. Several hitherto unknown allergic diseases that affect people globally in both developed and developing nations have recently been defined. Further, there have been impressive developments in laboratory diagnostics of allergy and immune-mediated diseases, vaccines formulations and therapeutics. Despite their important biological and clinical importance, the teaching of immunology and allergology in medical schools and the university system has sorely been inadequate. There is a critical need to augment human resources in these subjects and encourage young minds by making available quality books and monographs encompassing all subspecialities of immunology.

This book is a comprehensive and practical guide to basic understanding of the immune system as it applies to these group of diseases with a focus on laboratory diagnosis, clinical evaluation and finally management. For simplicity’s sake and better comprehension, the 55 chapters of the book have been divided into two volumes, each having three sections. Section A of the book includes chapters that are focused on providing background and history of allergy and immunology highlighting its role beyond simple protection against pathogens including shared diseases and the need to have a trained force of specialists for accurate diagnosis and management. There are chapters that provide the much-needed understanding on basic genetics and epigenetics for the immunologist and allergist, laboratory skills and basic technologies required for the diagnosis of common and rare diseases with focus on new and emerging genomic technologies including the Sanger and next-generation sequencing. The chapter also covers the data science and big data analytics through the application of bioinformatics.

Diagnosis of allergies is first and often documented by IgE-mediated allergy. Although the skin test provides crucial information about sensitization to a given allergen, it need not correlate with clinical reactivity. Section B is primarily devoted to the laboratory diagnosis of allergic diseases, for example, skin prick testing for foods, in vitro methods to assess allergy, oral food challenges with post-challenge management, techniques to evaluate allergic diseases such as urticaria, asthma, drug-induced allergy, rhinitis and rhinosinusitis and immunological aspects of allergic rash as well as evaluation of contact allergy by patch test. It provides the reader with much-needed basic information on various testing methods for the assessment of allergic reactions besides the physiologic evaluations. An important feature is the comparison between skin testing and other methods routinely used for the diagnosis of allergies including in vitro tests as well as allergen challenges. This is particularly useful for the diagnosis of food allergy since clinical history alone may not be sufficient to determine the causative allergen. It is important to distinguish between IgE-mediated and non-IgE-mediated conditions and those overlapping the two. For this, an algorithm is needed on the correcting timing of skin prick testing.

The book lays particular stress on laboratory skills for the immunologist with a special focus on allergy research. Chapter 6 describes the utility of laboratory techniques commonly employed in the research and diagnosis of immunologic diseases with emphasis of their application in the field of allergy. There is a description on the principles, procedure, data analysis, application and limitations of tests such as western blotting, ELISA, flow cytometry, basophil activation test, DNA and protein/peptide microarray. The chapter also describes the use of animal models that mimic human allergic reactions for a better understanding of the molecular processes involved and systemic responses.

In recent years, the genomics approach to the study of immune system disorders has gained credence. The book provides a good description on the use of emerging and novel technologies such as omics, use of bioinformatics and artificial intelligence along with their implications in the management of allergic diseases. For those designing research studies, an understanding of the nature of molecular targets under investigation as well as data mining resulting from high throughput method is imperative, so as to better comprehend the biological impact of the molecular variations. The chapter describes the infrastructure and staff requirements for implementing programmes focused on omics technologies.

An astute clinician often relies on in vitro methods for the evaluation of allergy. Chapter 11 of the book provides an overview on the indications for in vitro testing including an explanation and utility for the methods used. Sections covered in this chapter include environmental allergens, occupational allergens, foods, latex, venoms and drugs. Nevertheless, the author cautions that ‘a positive in vitro allergy test only indicates sensitization; it does not necessarily indicate clinical reactivity’.

A full chapter has been devoted to the importance of skin biopsies and their utility to immunologists and allergists for the diagnosis of a whole spectrum of diseases including eczematous and urticarial reactions, autoinflammatory syndromes, immunodeficiency and other skin inflammatory reactions. Key information has been tabulated to help the clinician in gauging the diagnostic utility of performing biopsy based on clinical differential diagnosis and histopathologic features.

A commonly occurring allergic disorder is asthma which is a chronic inflammatory obstructive lung disease with overlapping clinical features with other respiratory conditions or chronic dyspnoea causes. Such patients often report inaccurate histories owing to poor recall of symptoms and misreporting of wheezing sounds. Chapter 14 provides detailed information on the optical assessment of this disease using subjective, physiologic and mechanistic evaluations such as biomarkers that could characterize the type and severity of inflammation in the airway, all of which could guide a proper therapeutic intervention.

Allergic rashes are a set of diseases that have an important immunologic perspective. The commonly occurring rashes include eczematous, papulosquamous, urticarial, drug rashes and autoimmune bullous dermatoses, each of which have been comprehensively covered in chapter 17. Besides clinical characteristics, these require differential diagnostic and reference tools as aids for reaching the correct diagnosis. Often allergic contact dermatitis can coexist with atopic dermatitis and requires important consideration. The book provides a practical guide on the clinical diagnosis and treatment of this disease with a focus on skin patch tests and interpretation.

Similarly, there are chapters describing mast cell and eosinophilic-associated disorders, anaphylaxis, urticaria and angioedema. Mast cells play a central role in the precipitation of immediate hypersensitivity reactions. Their evaluation, activation status and knowledge about disorders associated with these cells are needed to make clinical diagnosis of mastocytosis. The use of biomarkers can aid in defining genetic variants involving these cells. Besides clinical evaluation, the section describes the whole range of other diagnostic methods and their interpretation.

Section C has nine chapters describing newborn screening and evaluation of immune function for severe combined immunodeficiencies with focus on laboratory evaluation and genetic testing. Special emphasis is laid on testing of innate and adaptive immune system dysregulations and the impact of infections on disease precipitation. The book has independent chapters describing HIV and AIDS, as well as immune regulatory and autoinflammatory disorders addressing their pathophysiology, clinical presentation, diagnosis and management. Similarly, description on autoimmune diseases has been well covered including differential autoantibody evaluation, HLA association and newer treatment strategies. A full chapter describes neurologic autoimmune diseases such as multiple sclerosis, Guillain–Barre syndrome, myasthenia gravis, autoimmune encephalitis and chronic inflammatory demyelinating polyneuropathy.

The Volume 2 of this book has two independent sections that describe the treatment of allergic and immunologic disorders, respectively. The former includes allergic reactions due to environmental allergens, drug-induced hypersensitivity and desensitization, food allergy, allergic rhinitis and conjunctivitis. Special emphasis is laid on the role of new biologics and monoclonals with action plans on asthma for ensuring a better quality of life. Similarly, the spectrum of immunologic diseases comprising antibody and complement deficiencies, phagocytic disorders, primary immune deficiencies and autoinflammatory diseases has been covered in this volume.

This is an exhaustive book that highlights both the basic and clinical aspects of allergic reactions as well as the associated host immunity. It serves as a practical guide for the clinical presentation and laboratory parameters needed for reaching the correct diagnosis and treatment of a whole spectrum of disorders associated with allergens and/or immune deviation. The presentation style of the book is user-friendly and the author has put in commendable effort in trying to resolve the complexities of allergy and immunology in understanding the pathophysiology of a huge number of diseases. This book is equally useful to basic scientists, researchers, clinicians and allied health professionals with interest in allergy and immunology. It fulfils the unmet need and its unique presentation style with appropriate figures, diagrams and tables is profoundly appealing. In my personal opinion, the book has covered every known aspect of these set of diseases and I am confident that the reader will enjoy its academic flavour and subject content.