Immunology is a study of immune systems in all organisms. Immunology consist charts, measures, and contextualizes the functioning of the immune system in terms of health and diseases, malfunctions of the immune system in immunological disorders (such as autoimmune diseases, hypersensitivities, immune deficiency, and transplant rejection and the physical, chemical, and physiological properties of the components of the immune system in vitro and in vivo. Immunology has applications in various parts of medicine, in the fields of organ transplantation, oncology, rheumatology, virology, parasitology, bacteriology, psychiatry, and dermatology.

An immune disorder is defined as dysfunction of the immune system. Those disorders are characterized in several different ways:

• If the components of the immune system affected
• If the immune system is overactive or underactive
• If the condition is congenital or acquired

List of some autoimmune disorders

• Lupus
• Scleroderma
• Certain types of hemolytic anemia
• Vasculitis
• Type 1 diabetes
• Graves' disease
• Rheumatoid arthritis
• Multiple sclerosis
• Goodpasture syndrome
• Pernicious anemia
• Some types of myopathy
• Lyme disease (Late)

Primary immune deficiencies

Primary immune deficiency disorders are caused by inherited genetic mutations. Secondary deficiencies are also known as acquired immune deficiencies and caused by something outside the body like virus or immune suppressing drugs.

Primary immune diseases have risk to increased susceptibility, and recurrent ear infections, pneumonia, sinusitis, bronchitis or skin infections. Patients with immunodeficiency may less frequently develop abscesses in internal organs, autoimmune or rheumatologic and gastrointestinal problems.

Primary immune deficiencies

• Severe combined immunodeficiency (SCID)
• DiGeorge syndrome
• Hyperimmunoglobulin E syndrome
• Common variable immunodeficiency (CVID): In this level of B-cell are normal in circulation with decreased production of IgG throughout the years, so this is the only primary immune disorder which presents onset in the late teens years.
• Chronic granulomatous disease (CGD): deficiency in the NADPH oxidase enzyme, this causes failure to generate oxygen radicals. The catalase positive bacteria and fungi results in the Classical recurrent infection.
• Wiskott–Aldrich syndrome (WAS)
• Autoimmune lymphoproliferative syndrome (ALPS)
• Hyper IgM syndrome
• Leukocyte adhesion deficiency (LAD)
• NF-κB Essential Modifier (NEMO) Mutations
• Selective immunoglobulin A deficiency: This is the most common defect in the humoral immunity which is characterized by a deficiency of IgA and produces repeating sino-pulmonary and gastrointestinal infections.
• X-linked agammaglobulinemia (XLA; This is also known as Bruton type agammaglobulinemia) and characterized by a deficiency in tyrosine kinase enzyme which blocks the B-cell maturation in bone marrow. B-cells are unable to produce circulation and results in no immunoglobulin classes although they tends to be a normal cell-mediated immunity.
• X-linked lymphoproliferative disease (XLP)
• Ataxia–telangiectasia

Secondary immune deficiencies

• AIDS

An allergy is an abnormal immune reaction to a harmless antigen.

• Seasonal allergy
• Mastocytosis
• Perennial allergy
• Anaphylaxis
• Food allergy
• Allergic rhinitis
• Atopic dermatitis