Severe illness or human immunodeficiency virus infection may also result in involution. Macrophages also play a role in human immunodeficiency virus (HIV) infection. Infection with the human immunodeficiency virus (HIV) is not uncommon. Angular cheilitis may be present in human immunodeficiency virus infection, neutropenia, or diabetes. Omenn syndrome is an autosomal recessive severe combined immunodeficiency. Bacterial myocarditis is rare in patients without immunodeficiency. The viral spike of the human immunodeficiency virus is heavily glycosylated. Defective synthesis of the sialyl Lewis antigen results in immunodeficiency (leukocyte adhesion deficiency type 2). Molecular techniques are used for the diagnosis of cystic fibrosis and severe combined immunodeficiency. It is 50 to 100 times more infectious than human immunodeficiency virus (HIV). Defects of either protein confers severe immunodeficiency. Familial hemophagocytic lymphohistiocytosis, an autosomal recessive primary immunodeficiency, is another example. A person who has an immunodeficiency of any kind is said to be immunocompromised. Other causes include inherited immunodeficiency conditions, such as common variable immunodeficiency, IgA deficiency, and hypogammaglobulinemia. In addition, bites are probably the main route of transmission of feline immunodeficiency virus.