Question

The causes of autoimmune diseases are
A. defects in the cell's immune system.
B. Defects in the immune system mediate antibodies.
C. defects in thymus development.
D. Immune response to self-antigens.
E. T cell defects.

Answer 1

Answer is option (d) immune response to self antigens.

Normally, adaptive immune responses are targeted against a foreign antigen. It results in the destruction and clearance of that foreign antigen from the body.
But when there is an autoimmune disorder, adaptive immune system cannot recognize body's own antigens and it will mount immune response against them.

*self antigens are molecules which acts as antigen and induce antibody formation in other organisms but to which immune system of parent organism is tolerant.

Lymphocytes in our body can recognize non-self antigen and that's why immune system does not respond to self antigen.

But sometimes, our immune system fails to recognize self antigens and starts to produce antibody against them. This will lead to development of autoimmune diseases.