What happens when antibodies that should protect you attack your blood cells?

Bleeding disorders are never easy to handle. The mental agony associated with bleeding it a traumatic experience. Such is the case with ITP or Immune Thrombocytopenic Purpura. It is an autoimmune disease, wherein antibodies are produced in the body attacking its own platelets.

The immune system is the defence system, which protects the body against any outside agent. The body organs such as spleen, thymus, bone marrow and lymph nodes constitute the immune system. In case any microbes attack the body, these organs produce antibodies that help destroy these microbes.

In an autoimmune disease, antibodies are produced not against the external harmful agents but against the body's own cells.

ITP occurs when the immune system destroys platelets that help normal blood clotting. It is characterised by increased platelet destruction and impaired platelet production. A reduction in platelet counts is medically termed as Thrombocytopenia. The production of platelets (in the bone marrow) is regulated by a hormone called Thrombopoietin (TPO). The antibodies cause the suppression of bone marrow cells, thereby adversely affecting platelet production.

Double whammy

So, it is a double whammy for a person with ITP; platelets are being destroyed and the production of platelets that would normally replace the destroyed ones is seriously hampered. The overall result is a fall in the platelet count. Since platelets are essential for clotting of blood, these people may develop bleeding tendencies.

In chronic ITP, the quality of life is adversely affected with a fear of bleeding limiting the patients' daily activities.

Patients with ITP who have very low platelet counts (<20,000/cumm) are at an increased risk of spontaneous bleeding, and may develop bruises and experience nose or gum bleeds. Women suffering from ITP may suffer from abnormally heavy menstrual bleeding. Although very rare, bleeding in the brain or gastrointestinal tract may also occur and may be potentially fatal. In children, the condition is mostly acute, commonly following a viral illness, whereas it acquires a chronic stage in adults. It is more frequent in females than males. This disease is not contagious. The diagnosis may be confusing since low platelet counts are seen in a number of diseases such as leukaemia, lymphoma and bone marrow failure diseases such as aplastic anaemia. In addition, immune thrombocytopenia can occur with other diseases such as Hepatitis C and HIV and in autoimmune diseases such as SLE. Some patients have the disease in the latent stage and are asymptomatic, while others show heavy bleeding and petechiae or purple-coloured skin rash.

The presence or absence of bleeding symptoms often depends upon the platelet count. The symptoms manifest as per the dip in the platelet count.