AUTOIMMUNE DISEASES

AUTOIMMUNE DISEASES Martin Liška

Autoimmune disease • Results from a failure of self-tolerance • Immunological tolerance is specific unresponsiveness to an antigen • All individuals are tolerant of their own (self) antigens

Autoimmunity • is defined as an immune response against self antigens • The principal factors in the development of autoimmunity are the inheritance of susceptibility genes and environmental triggers, such as infections • Most autoimmune diseases are polygenic and are asssociated wih multiple gene loci, the most important of which are the MHC genes • Infections may activate self-reactive lymphocytes, thereby triggering the development of autoimmune diseases

AUTOIMMUNE PATOLOGICAL RESPONSE- ETIOLOGY • the diseases are chronic and usually irreversible • incidence: 5%-7% of population, higher frequencies in women, increases with age • factors contribute to autoimmunity: - internal (HLA association, polymorphism of cytokine genes, defect in genes regulating apoptosis, polymorphism in genes for TCR a H immunoglobulin chains, association with immunodeficiency, hormonal factors) - external (infection, stress by activation of neuroendocrine‘s line and hormonal dysbalance, drug and ionization through modification of autoantigens)

CLINICAL CATEGORIES • systemic - affect many organs and tissue • organ localized - affect predominantly one organ accompanied by affection of other organs (inflammatory bowel diseases, celiac disease, AI hepatitis, pulmonary fibrosis) • organ specific - affect one organ or group of organs connected withdevelopment or function

EXAMPLES OF SYSTEMIC AUTOIMMUNE DISEASES examples autoantibodies

SYSTEMIC AUTOIMMUNE DISEASES • Systemic lupus erythematosus • Rheumathoid arthritis • Sjögren‘s syndrome • Dermatopolymyositis • Systemic sclerosis • Mixed connective tissue disease • Vasculitis

SYSTEMIC LUPUS ERYTHEMATOSUS • chronic, inflammatory, multiorgan disorder • autoantibodies react with nuclear material and attack cell function, immune complexes with dsDNA deposit in the tissue • general symptoms: include malaise, fever, weight loss • multiple tissueare involved including the skin, mucosa, kidney, joints, brain and cardiovascular system • characteristic features: butterfly rash, renal involvement, CNS manifestation, pulmonary fibrosis

DIAGNOSTIC TESTS • a elevated ESR (erythrocyte sedimentation rate), low CRP, trombocytopenia, leucopenia, hemolytic anemia, decreased levels of complement compounds(C4, C3), elevated serum Ig levels, immune complexes in serum

AUTOANTIBODIES • Autoantibodies: ANA, dsDNA (double-stranded), ENA (SS-A/Ro, SS-A/La), Sm, against histones, phospholipids

RHEUMATOID ARTHRITIS • chronic, inflammatory disease with systemic involvement • characterized by an inflammatory joint lesion in the synovial membrane, destruction of the cartilage and bone, results in the joint deformation • clinical features: arthritis, fever, fatigue, weakness, weight loss • systemic features: vasculitis, pericarditis, uveitis, nodules under skin, intersticial pulmonary fibrosis • diagnostic tests: elevated C- reactive protein and ESR, elevated serum gammaglobulin levels - autoantibodies against IgG = rheumatoid factor (RF), a-CCP (cyclic citrulline peptid), ANA - X-rays of hands and legs- show a periarticular porosis, marginal erosion

SJÖGREN‘S SYNDROME • chronic inflammatory disease affecting exocrine glands • the primary targetsare the lacrimal and salivary gland duct epithelium • general features: malaise, weakness, fever • primary syndrome - features: dry eyes and dry mouth, swollen salivary glands, dryness of the nose, larynx, bronchi and vaginal mucosa, involvement kidney, central and periferal nervous system, arthritis • secondary syndrome – is associated with others AI diseases (SLE, RA, sclerodermia, polymyositis, primary biliary cirhosis,AI thyroiditis) • autoantibodies against ENA (SS-A, SS-B), ANA, RF • The Schirmer test - measures the production of tears

Systemic sclerosis • sclerosis in the skin or other organs • Diffuse scleroderma (progressive systemic sclerosis) is the most severe form, involves skin, will generally cause internal organ damage (specifically the lungs and gastrointestinal tract) • The limited form is much milder • The limited form is often referred to as CREST syndrome(CREST is an acronym for the five main features: Calcinosis, Raynaud's syndrome, Esophageal dysmotility, Sclerodactyly, Telangiectasia

Immunological findings • ANA, ENA - anti-Scl-70 (fluorescence of nucleolus), anti-centromers

Mixed connective tissue disease • combines features of polymyositis, systemic lupus erythematosus, scleroderma, and dermatomyositis (overlap syndrome) • Causes : joint pain/swelling, malaise, Raynaud phenomenon, muscle inflammation and sclerodactyly (thickening of the skin of the pads of the fingers) • Distinguishing laboratory characteristics: a positive, speckled anti-nuclear antibody (ANA) and anti-U1-RNP antibody (ENA)

Dermatopolymyositis • a connective-tissue disease related to polymyositis (PM) that is characterized by inflammation of the muscles and the skin. Gottron's sign is an erythematous, scaly eruption occurring in symmetric fashion over the MCP and interphalangeal joints Heliotrope rash is a violaceous eruption on the upper eyelids, often with swelling

Dermatopolymyositis • Elevated creatine phosphokinase (CPK) • muscle biopsy (a mixed B- and T-cell perivascular inflammatory infiltrate, perifascicular muscle fiber atrophy) • EMG (electromyogram) • autoantibodies - ENA (Jo-1)

Vasculitis • characterized by inflammatory destruction of vessels leading to thrombosis and aneurysms • proliferation of the intimal part of blood-vessel wall and fibrinoid necrosis • affect mostly lung, kidneys, skin • diagnostic tests: elevated ESR, CRP, leucocytosis, biopsy of affected organ (necrosis, granulomas), angiography

Vasculitis • p- ANCA (myeloperoxidase) positivity (Polyarteritis nodosa, Churg- Strauss, Microscopic polyarteritis nodosa) • c- ANCA (serin proteinase) positive (Wegener granulomatosis, Churg- Strauss syndrome)

Classification • Large vessel vasculitis (Takayasu arteritis, Giant cell (temporal) arteritis) • Medium vessel vasculitis (Polyarteritis nodosa, Wegener's granulomatosis, Kawasaki disease) • Small vessel vasculitis (Churg-Strauss arteritis, Microscopic polyarteritis, Henoch-Schönlein purpura) • Symptoms: fatigue, weakness, fever, arthralgias, abdominal pain, hypertension, renal insufficiency, and neurologic dysfunction

EXAMPLES OF ORGAN- SPECIFIC AUTOIMMUNE DISEASES diseases autoantibodies

ORGANOLEPTIC AUTOIMMUNE DISEASES • Ulcerative colitis • Crohn‘s disease • Autoimmune hepatitis • Primary biliary cirhosis • Pulmonary fibrosis

Ulcerative colitis • chronic inflammation of the large intestine mucosa and submucosa • features: diarrhea, bloody and mucus stools • extraintestinal features (arthritis, uveitis) • autoantibodies against pANCA, a- large intestine

Crohn‘s disease • the granulomatous inflammation of whole intestinal wall with ulceration and scarring that can result in abscess and fistula formation • the inflammation of Crohn's disease the most commonly affects the terminal ileum, presents with diarrhea and is accompanied by extraintestinal features - iridocyclitis, uveitis, artritis, spondylitis • antibodies againstSaccharomyces cerevisiae (ASCA), a- pancreas

Primary biliary cirhosis autoimmune disease of the liver marked by the slow progressive destruction of the small bile ducts; can lead to cirrhosis AMA= antimitochondrial autoantibodies

AUTOIMMUNE HEPATITIS • typeI – association with autoantibodies against smooth muscles SMA, ANA, ANCA, SLA • type II – autoantibodies against microsomes LKM-1 = liver-kidney microsomes • type III – autoantibodies against SLA (solubile liver antigen) • type IV – overlap syndrome with PBC – autoantibodies against mitochondries AMA

Pulmonary fibrosis • isassociated with SLE, RA, systemic sclerosis, polymyositis • autoantibodies nonspecific- RF, ANA • biopsy, lung function testing, X-ray

ORGAN SPECIFIC AUTOIMMUNE DISEASES • Autoimmune endocrinopathy • Autoimmune neurological diseases • Autoimmune cytopenia

AUTOIMMUNE ENDOCRINOPATHY • Hashimoto‘s thyroiditis • Graves-Basedow disease • Diabetes mellitus I. type • Addison‘s disease • Autoimmune polyglandular syndrome • Pernicious anemia

Hashimoto‘s thyroiditis • thyroid disease result to hypothyroidism on the base of lymphocytes and plasma cells infiltrate • autoantibodies against thyroidal peroxidase (a-TPO) and/or against thyroglobulinu (a-TG)

Grave‘s disease • thyrotoxicosis from overproduction of thyroid hormone (patient exhibit fatigue, nervousness, increased sweating, palpitations, weight loss, exophtalmus) • autoantibodies against thyrotropinreceptor, autoantibodies cause thyroid cells proliferation

Diabetes mellitus (insulin- dependent) • characterized by an inability to process sugars in the diet, due to a decrease in or total absence of insulin production • results from immunologic destruction of the insuline- producing β-cells of the islets of Langerhans in the pancreas • autoantibodies against GAD- glutamic acid decarboxylase = primary antigen), autoantibodies anti- islet cell, anti- insulin • islets are infiltrated with B and T cells

Polyglandular autoimmune syndrome • combination of several different AI endocrinopathies • autoantibodies appear in according with the connected disorders

Pernicious anemia • the deficiency of the intrinsic factor results in inadequate and abnormal formation of erythrocytes and failure to absorb vitamin B12 • clinical feature- atrophic gastritis, macrocytic anemia • autoantibodies against parietal cells of gastric mucose, against intrinsic factor (transportation of B12 vitamin)

AUTOIMMUNE NEUROPATHY • Guillain-Barré syndrome (acute idiopathic polyneuritis) • Myasthenia gravis • Multiple sclerosis

Guillain-Barré syndrome • inflammation demyelinates peripheral neuropathy that causes progressive muscle weakness and paralysis • the cause is the loss of myelin • occurs often 1-3 weeks after infection (Campylobacter jej.) • features: progressive weakness and paresthesia of the lower and later upper extremitas and respiratory muscles, weakness can leads to paralysis and respiratory failure • immunologic findings: autoantibodies against ganglioside membrane

Myasthenia gravis • chronic disease with impaired neuromuscular transmission • characterized by muscle weakness and fatigue • the muscle weakness and neuromuscular dysfunction result from blockage and depletion of acetylcholine receptors at the myoneural junction • immunological findings: autoantibodies against Ach receptors • ptosis of the eye

Multiple sclerosis • chronic demyelinizing disease with abnormal reaction T cells to myeline protein on the base of mimicry between a virus and myeline protein • features: weakness, ataxia, impaired vision, urinary bladder dysfunction, paresthesias, mental abberations • autoantibodies against MOG (myelin-oligodendrocyte glycoprotein) • Magnetic resonance imaging of the brain and spine shows areas of demyelination • The cerebrospinal fluid is tested for oligoclonal bands, can provide evidence of chronic inflammation of the central nervous system

AUTOIMMUNE CYTOPENIA • AI hemolytic disease- autoantibodies against membrane erythrocyte antigens • AI trombocytopenia - autoantibodies against trombocyte antigens (GPIIb/IIIa) • AI neutropenia - autoantibodies against membrane neutrofil antigens

IMMUNOSUPPRESSION non-specific treatment examples of drugs indication risks

Immunosuppressants • Drugs that inhibit or prevent activity of the immune system • They are used in immunosuppressive therapy to: • Prevent the rejection of transplanted organs and tissues (bone marrow, heart, kidney, liver) • Treat autoimmune diseases or diseases that are most likely of autoimmune origin (rheumatoid arthritis, multiple sclerosis, myasthenia gravis, systemic lupus erythematosus, Crohn's disease, pemphigus, ulcerative colitis). • Treat some other non-autoimmune inflammatorydiseases (allergic asthma, atopic eczema).

Glucocorticoids • suppress the cell-mediated immunity- act by inhibiting genes that code for various cytokines (e.g.IL-2) • decrease cytokine production reduces the T cell proliferation. • suppress the humoral immunity, causing B cells to express smaller amounts of IL-2 and IL-2 receptors- this diminishes both B cell clone expansion and antibody synthesis.

Glucocorticoids • leads to diminished eicosanoid production, suppression of the cyclooxygenase expression • Glucocorticoids also stimulate the lipocortin-1 escaping to the extracellular space, where it binds to the leucocyte membrane receptors and inhibits : epithelial adhesion, migration, chemotaxis, phagocytosis, respiratory burst, and the release of various inflammatory mediators from neutrophils, macrophages, and mastocytes. • side-effects: hypertension, dyslipidemia, hyperglycemia, peptic ulcers, osteoporosis, disturbed growth in children

Drugs affecting the proliferation of both T cells and B cells • Cyclophosphamide -very efficient in the therapy of systemic lupus erythematosus, autoimmune hemolytic anemias • high doses cause pancytopenia and hemorrhagic cystitis • Methotrexate is a folic acid antagonist, acts during DNA and RNA synthesis, and thus it is cytotoxic during the S-phase of the cell cycle; used in the treatment of autoimmune diseases (RA, Crohn's disease) and in transplantations.

Drugs affecting the proliferation of both T cells and B cells • Azathioprine is a purine synthesis inhibitor, inhibiting the proliferation of cells, especially leucocytes; SLE, RA, sclerosis multiplex, transplantation • Mycophenolate mofetil – affects the enzyme that controls the purine synthesis • Used in transplantation of solid organ

Drugs blocking the activation of lymphocytes • Tacrolimus - prevents the cell from transitioning from the G0 into G1 phase of the cell cycle • Used to prevent rejection reactions, atopic eczema • Cyclosporin A- inhibits calcineurin, which is responsible for activating the transcription of interleukin-2; inhibits cytokines production and interleukin release • Used to prevent rejection reactions • Side effects: nephrotoxicity, neurotoxicity, hypertension, dyslipidemia, hyperglycemia

Monoclonal antibodies • Monoclonal antibodies are directed towards exactly defined antigens • Daclizumab - acts by binding the IL-2a receptor's α chain, preventing the IL-2 induced clonal expansion of activated lymphocytes and shortening their survival • used in the prophylaxis of the acute organ rejection after the bilateral kidney transplantation

AUTOIMMUNE DISEASES