Clinical Immunology deals with studies of diseases caused due to disorders of immune system disorders ie.,abnormal growth of any cellular tissues of the system, hypersensitivities such as in asthma and other allergies, immune system failure. It also includes the diseases of other systems, where immune reactions plays a vital role in the clinical aspects and pathology. Clinical Immunology divided into two categories : Immunodeficiency is a category in which inadequate response is attained by the immune system,whereas in autoimmunity host body own itself attacks the immune system.