SINCE the original work on vitamin B12 was reported in 1948, numerous articles have appeared confirming the effectiveness and potency of vitamin B12 in producing remissions in pernicious anemia. The original work1 was done in the laboratories of the Merck Company, who generously supplied the material used in our cases. It was shown by Shorb2 and West3 that a factor, the LLD, could be found in liver extracts in direct proportion to the unit potency of the extracts used in pernicious anemia. As hypothesized by Rickes et al, 1 unit of vitamin B12 is equivalent to 1 USP unit of liver extract, and may produce equivalent hematopoietic response. This material has been isolated from whole liver and is believed to contain cobalt, phosphorus, and nitrogen. It is commercially obtained from the growth of Streptomyces griseus. It has been shown, too, that satisfactory responses may be expected to occur neurologically. Vitamin B12 is ineffective when given orally, yet when mixed with gastric juice passed through a Berkefeld filter, its effectiveness in preventing a megaloblastic arrest is complete.4
The present communication deals with the first 5 cases whom we now have under observation and treatment for pernicious anemia with vitamin B12.
Case 1. A woman, aged 55, was seen initially on February 19, 1949, with a chief complaint of “something eating my blood.” She first consulted her physician in 1940 because of paleness and weakness and was found to be anemic. Treatment by pills and injections of iron was ineffective.