Question

what are some of the most common clinical and pathological manifestations of human immunity

Answer 1

The carious types of immune system diseases are of following tyoes:

1) hypersensitivity reactions

Hypersensitivity reactions are of four types (types I–IV). It leads to fatal reactions produced by the normal immune system

Type I – allergy (immediate hypersensitivity)

It’s caused by an antigen binding to IgE antibodies that are bound to the surface of mast cells. The antigen bridges the IgE antibodies, triggering release of mediators (like histamine) from the mast cell.It results in vessels dilation, smooth muscle contraction, and inflammation.

Type II – antibody-mediated hypersensitivity

In this type of hypersensitivity antibodies bind to antigens on a cell surface (any cell surface). Macrophages come in and eat up the cells. Complement gets activated, inflammation comes in (harming tissue) and cells end up dying. Examples of this type of hypersensitivity include: autoimmune hemolytic anemia, pemphigus vulgaris, Goodpasture syndrome, myasthenia gravis, and Graves disease

Type III – immune-complex-mediated hypersensitivity

In this one, antibodies bind to antigens, forming complexes. These antigen-antibody complexes circulate (either throughout the whole body, or within one area of the body), get stuck in vessels, and stimulate inflammation, the end result being inflammation-mediated tissue damage and necrotizing vasculitis. Examples of this type of hypersensitivity include: systemic lupus erythematosus, post-streptococcal glomerulonephritis, polyarteritis nodosa, serum sickness, and the Arthus reaction
Type IV – T cells mediated hypersensitivity

This type of hypersensitivity has two subtypes. In one subtype, called delayed-type hypersensitivity, helper T cells secrete cytokines that activate macrophages (which eat the antigen) and induce inflammation (which damages tissue). A good example of delayed-type hypersensitivity is poison ivy. The other subtype, called T-cell-mediated cytotoxicity, involves cytotoxic T cells coming and killing target cells (like the cells of a transplanted organ, or the pancreatic islet cells in a patient with type I diabetes)

Some common auto-imune disorders:

a. Type 1 Diabetes

The pancreas produces the hormone insulin, which helps regulate blood sugar levels. In type 1 diabetes, the immune system attacks and destroys insulin-producing cells in the pancreas.

High blood sugar can damage blood vessels, as well as organs like the heart, kidneys, eyes, and nerves.

b.  Rheumatoid arthritis

In rheumatoid arthritis (RA), the immune system attacks the joints. This attack causes redness, warmth, soreness, and stiffness in the joints.

c. Psoriasis/psoriatic arthritis

Skin cells normally grow and then shed when they’re no longer needed. Psoriasis causes skin cells to multiply too quickly. The extra cells build up and form red, scaly patches called scales or plaques on the skin

d. Multiple sclerosis

Multiple sclerosis (MS) damages the myelin sheath — the protective coating that surrounds nerve cells. Damage to the myelin sheath affects the transmission of messages between your brain and body.

e.  Graves’ disease

Graves’ disease attacks the thyroid gland in the neck, causing it to produce too much of its hormones. Thyroid hormones control the body’s energy usage, or metabolism.

Having too much of these hormones revs up your body’s activities, causing symptoms like nervousness, a fast heartbeat, heat intolerance, and weight loss.

One common symptom of this disease is bulging eyes, called exophthalmos. It affects up to 50 percent of people with Graves’ disease.