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September 1989

Vitamin B12 Malabsorption in Patients With Acquired Immunodeficiency Syndrome

Author Affiliations

From the Laboratories of Clinical Investigation (Dr Harriman) and Immunoregulation (Drs Koenig, Lane, and Faci), National Institute of Allergy and Infectious Diseases; the Laboratory of Microbiology and Immunology, National Institute of Dental Research (Dr Smith); the Department of Clinical Pathology, Warren Grant Magnuson Clinical Center (Dr Horne); and the Laboratory of Pathology, Division of Cancer Biology and Diagnosis (Drs Fox and Lack), National Cancer Institute, National Institutes of Health, Bethesda, Md.

Arch Intern Med. 1989;149(9):2039-2041. doi:10.1001/archinte.1989.00390090091018

• We have examined 11 patients with the acquired immunodeficiency syndrome (AIDS) for evidence of subclinical vitamin B12 malabsorption. Three subjects (27%) had low levels of vitamin B12. Eight subjects (73%), including these 3 subjects plus 5 others with normal vitamin B12 levels, had abnormal Schilling test results. In addition, 15% of an unselected population of 121 patients with AIDS and 7% of 27 patients without AIDS who were seropositive for human immunodeficiency virus type 1 (HIV-1) had low serum vitamin B12 levels. Stool cultures from the 8 subjects with abnormal Schilling test results revealed no pathogens. Intestinal involvement by Kaposi's sarcoma was found in only 1 patient. Biopsy specimens from 5 of 6 patients with vitamin B12 malabsorption, however, contained mononuclear cells harboring HIV-1, as indicated by in situ hybridization studies. Our observations suggest that vitamin B12 malabsorption is common in patients with AIDS and may be a very early manifestation of infection with HIV-1.

(Arch Intern Med. 1989;149:2039-2041)

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