The jejunal mucosa was studied in infantile marasmic malnutrition in the early phase
after treatment was begun and before the onset of significant weight gain. In 7 infants
light microscopy before recovery showed that the mucosa was normal or mildly abnormal
in 4, and moderately abnormal in 3 cases. The electron microscope disclosed abnormalities of the brush border, large autophagosomes and residual bodies, and the deposition of
collagen, filaments, and a dense, finely granular material below the basal lamella. Three
of the infants were studied again during recovery. Although the histology remained
unchanged, electron microscopy revealed improvement of the brush border, disappearance of the autophagosomes, and smaller and fewer residual bodies. The dense material
below the basal lamella was absent whereas the fibrillar components remained. It is
postulated that the fine structural lesions observed may be due to the derangements in
cell metabolism caused by the severe, prolonged restriction of protein and caloric intake.