TAILIEUCHUNG - Chapter 100. Megaloblastic Anemias (Part 9)

Serum Antibodies Two types of IF immunoglobulin G antibody may be found in the sera of patients with PA. One, the "blocking," or type I, antibody, prevents the combination of IF and cobalamin, whereas the "binding," or type II, antibody prevents attachment of IF to ileal mucosa. Type I occurs in the sera of ~55% of patients and type II in 35%. IF antibodies cross the placenta and may cause temporary IF deficiency in the newborn infant. Patients with PA also show cellmediated immunity to IF. Type I antibody has been detected rarely in the sera of patients without. | Chapter 100. Megaloblastic Anemias Part 9 Serum Antibodies Two types of IF immunoglobulin G antibody may be found in the sera of patients with PA. One the blocking or type I antibody prevents the combination of IF and cobalamin whereas the binding or type II antibody prevents attachment of IF to ileal mucosa. Type I occurs in the sera of 55 of patients and type II in 35 . IF antibodies cross the placenta and may cause temporary IF deficiency in the newborn infant. Patients with PA also show cell-mediated immunity to IF. Type I antibody has been detected rarely in the sera of patients without PA but with thyrotoxicosis myxedema Hashimoto s disease or diabetes mellitus and in relatives of PA patients. IF antibodies have also been detected in gastric juice in 80 of PA patients. These gastric antibodies may reduce absorption of dietary cobalamin by combining with small amounts of remaining IF. Parietal cell antibody is present in the sera of almost 90 of adult patients with PA but is frequently present in other subjects. Thus it occurs in as many as 16 of randomly selected female subjects aged 60 years. The parietal cell antibody is directed against the a and 0 subunits of the gastric proton pump H K -ATPase . Juvenile Pernicious Anemia This usually occurs in older children and resembles PA of adults. Gastric atrophy achlorhydria and serum IF antibodies are all present although parietal cell antibodies are usually absent. About one-half of these patients show an associated endocrinopathy such as autoimmune thyroiditis Addison s disease or hypoparathyroidism in some mucocutaneous candidiasis occurs. Congenital Intrinsic Factor Deficiency or Functional Abnormality The affected child usually presents with megaloblastic anemia in the first to third year of life a few have presented as late as the second decade. The child has no demonstrable IF but has a normal gastric mucosa and normal secretion of acid. The inheritance is autosomally recessive. Parietal cell and IF .

• Y học thường thức
• Megaloblastic Anemias
• bệnh học và điều trị
• bài giảng bệnh học
• tài liệu học ngành y
• Harrisons Internal Medicine
• medical books
• pharmacology
• epidemiologic
• Obstetrics
• anatomy
• Preventing Morbidity
• Multidisciplinary Care