Antibody, Complement, Neutrophil, Deficiencies Antibody, Complement, Neutrophil, Deficiencies Dr J. North Aims and Objectives To understand the clinical features and management of patient's with antibody, complement or neutrophil deficiences. Antibody Deficiency Antibodies provide a means of specifically recognising foreign antigens. The action of antibodies can be direct e.g. blocking the action of toxins, blocking the binding of pathogenic organisms to host cells, or indirect e.g. opsonisation of bacteria either alone or by activating the classical complement pathway. Deficiency of antibodies can be secondary to diseases such as leukaemia which suppress B cell production by the bone marrow or due to loss, especially through the kidneys in conditions such as the nephrotic syndrome.
Antibody deficiency is usually secondary to other causes in older patients.
Primary antibody deficiency is usually seen in children and is due to defects in B cells. Although B cells are present in this condition they do not differentiate into plasma cells and hypogammaglobulinaemia is present to a variable degree. This condition can present in adults as well as children. The hallmark of significant antibody deficiency is recurrent infection. A small number of other organisms can also cause infection in patients with hypogammaglobulinaemia, e.g. diarrhoea caused by Giardia lambia, encephalitis caused by Echo virus.