Impaired chemiluminescence and bactericidal killing by neutrophils from patients with severe cobalamin deficiency.

Neutrophil function was examined in 24 patients with megaloblastic haemopoiesis due to vitamin B12-or folate deficiency. Defective bactericidal activity was demonstrated in the B12-deficient group only and was associated with normal phagocytic activity but impaired intracellular killing. Luminol amplified luminescence was consistently low in B12-deficient subjects with RBC counts of less than 2 X 10(12)/l. These defects were not seen in the folate-deficient cases although isolated abnormalities were present in those who were also alcoholic.