AUTOIMMUNE DISEASES

INTRODUCTION:  Autoimmunity is the body's malfunctioning of destroying it's own tissues.  In this natural phenomenon, the immune system tend to mistakenly recognize body tissues as foreign and it wedges attack against it.  The root causes of this destructive auto process is as a result of body's previous exposure to molecules that resemble the body's human leukocyte antigen discussed in some of our previous chapters. In our discussion here, let us look at the most common autoimmune disease that we encounter and their common presentation.  If you did not follow us on the discussion on the pathophysiology of autoimmunity, click on the link below to get the details about the condition.  The human leukocyte antigen and development of autoimmunity

HASHIMOTO’S THYROIDITIS:  This was the first disease that satisfied Witebsky’s criteria for an autoimmune disease.  Hashimoto’s disease is characterised physiologically by a deficiency in thyroid hormone and anatomically by an enlarged thyroid gland infilterated with plasma cells and lymphocytes.

THROMBOCYTOPENIC PURPURA:  Thrombocytopenic purpura is an illness characterised by thrombocytopenia and the appearance of purpuric or petechial haemorrhages in the skin and tissues.  If you have not been following us click here to read about thrombocytopenia.  In infants, this condition can arise through allo-immunisation in much the same way that erythroblastosisfetalis develops.  An autoimmune form of thrombocytopenic purpura is seen in adults as well in which in most cases, it is drug-induced.  Invariably the afflicted person is on a continued drug regimen of some sort.  The offending drug may be aspirin, sulfonamide, quinine, antihistaminics, and many others.

MYASTHENIA GRAVIS:  This is a disease in which a gradual progressive weakness of striated muscle is a prominent external sign and which becomes so severe that even eating is laborious.  Myasthenia gravis patients exhibit a number of immunologic aberrations. Antinuclear antibodies, rheumatoid factors and antibodies that react with striated muscles are frequently detected.  Commonest immunopathological feature is presence of antibody to acetylcholine receptor.

MULTIPLE SCLEROSIS:  Partial loss of vision, nystagmus, facial palsy and muscular incoordination are a few of the varied symptoms of multiple sclerosis.  Remissions and exacerbations are characteristics of this disease. The major pathologic feature is an inflammatory lesion of the myelin in the central nervous system.

GLOMERULONEPHRITIS:  There are three forms of immune diseases that involve the glomerulus.  One is associated with antecedent group A streptococcal infection, second is involved with heterologous antibodies versus glomerular basement membrane antigens and third is based on immune complex formation with foreign antigens, as in serum sickness or alloantigens, as in SLE.

RHEUMATOID ARTHRITIS:  It is inflammatory disease of joints and connective tissue, amyloid deposition of tissues and permanent deformity of the joints may result.  An autoantibody seen in this condition is an agglutinating agent known as rheumatoid factor (RF) which is a 19S Ig compatible in all respects with IgM.

GRAVES’ DISEASE:  This disease is a form of hyperthyroidism and more common than Hashimoto’s disease.  It is now believed to be caused by a long acting thyroid stimulator (LATS) an immunoglobulin found in the sera of majority of patients with Graves’ disease.  The LATS autoantibody is a type of enhancing antibody that operates at the cellular level, much like the thyroid stimulating hormone, to stimulate thyroid hormone release and thyrotoxicosis.  

RELATED;

1.  Thrombocytopenia

2.  Specific immunity

3.  Passive immunisation

4.  Thrombocytopenia

5.  Hemorrhagic disease of the new born