Damage to thymus in a child may lead to

Thymus gland is found in the upper part of thorax near the heart. It is a bilobed pinkish gland. At the time of birth, it is a prominent gland but in the adult it gradually atrophies. This gland secretes thymosin hormone, thymic humoral factor, thymic factor and thymopoietin. Proliferation of lymphocytes and differentiation of these lymphocytes into a variety of clones are induced by these factors. These clones are differentially specialized to destroy different specific category of antigens and pathogens. Thus thymus gland brings fourth T-Lymphocytes for cell mediated immunity.