Pulmonary surfactant is a surface-active lipoprotein complex (phospholipoprotein) formed by type II alveolar cells. The proteins and lipids that make up the surfactant have both hydrophilic and hydrophobic regions.
Antibody deficiencies, also called immunoglobulin deficiency syndromes, are immune system disorders that are characterized by low or absent levels of immunoglobulin in the blood.Immunoglobulins (Ig) are antibodies that play an essential role in the body's immune system.he antibodies are present in the bloodstream or bound to the outer surfaces of B-cells or plasma cells. There are five classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM. Patients who have antibody deficiencies may have reduced or absent levels of one or more types of immunoglobulin.
The clinical manifestations of this group of diseases, called autoimmune hemolytic anemia (AIHA), depend greatly upon the type of antibody that is produced by the abnormal immune reaction. This topic will review the mechanisms underlying AIHA due to cold agglutinins [1].