Focal enterocyte vacuolization. A new microscopic finding in the acquired immune deficiency wasting syndrome.

Vacuolization of duodenal enterocytes was found by light microscopic examination in five patients meeting the Centers for Disease Control criteria for the acquired immunodeficiency wasting syndrome. Four of these patients had chronic diarrhea and malabsorption as documented by an abnormal D-xylose test, whereas one patient had no diarrhea or malabsorption. Enterocyte vacuolization was patchy in distribution, although affected cells were most notable on villous tips. Staining with period acid-Schiff, acid-fast bacilli, periodic acid-Schiff following diastase treatment, Congo red, and alcian blue were negative, suggesting that vacuolization is due to lipid accumulation. Immunoperoxidase staining for the human immunodeficiency virus envelope protein gp41 was positive in lamina propria mononuclear cells in all five patients. The authors hypothesize that lipid accumulation represents an enterocyte response to injury, possibly by an indirect effect of the human immunodeficiency virus.