Distribution of histamine among leukocytes and platelets

1. Platelets and lymphocytes free of other white elements of blood have beenanalysed for histamine by a microchemical method. Platelets were found to contain 1280 µg. per liter or .009 µg. per 10⁹ platelets, lymphocytes 2600 µg. perliter, or 0.6 µg. per 10⁹ cells.

2. The histamine content of neutrophilic, eosinophilic and basophilic granulocytes has been calculated by multiple regression from histamine measurementson one series of blood samples from normal adults and another from subjectswith chronic myelocytic leukemia. The normal values are 1080 µg. per l0⁹basophils and 160 µg. per 10⁹ eosinophils or 2,400,000 and 360,000 µg. per literrespectively. The corresponding values for neutrophils are 3 µg. per 10⁹ cellsand 7000 µg. per liter. The values for the histamine concentration per cell arestatistically significant for basophils and eosinophils, but not for neutrophils.

In the leukemia series, the values for neutrophils and basophils are respectively69 and 305 µg. per 10⁹ cells, and they are statistically significant. The differencefrom normal in the value for basophils was not statistically validated. There are,however, in chronic myelocytic leukemia, histological changes from the normalthat are consonant with a decreased histamine content in basophils and an increased histamine content in eosinophils and neutrophils.

3. Although definite values for the histamine content of monocytes and theimmature forms seen in chronic myelocytic leukemia have not been obtained,there is reason to believe that the histamine of these cell types does not exceedthat of neutrophils.

4. By centrifuging white cells in a specific gravity gradient column, partialsegregation of cell types was obtained. Peak concentrations were observed at thefollowihig specific gravities: lymphocytic leukemia lymphocytes, 1.063; myelocytes, normal lymphocytes and basophils, all near 1.070; neutrophils, 1.080,and eosinophils, 1.080 or higher. Although individual concentration peaks wereusually quite sharp, there was considerable overlapping at intermediate specificgravities.

5. About half of the histamine of normal blood is in the basophils, one-thirdin the eosinophils and the remaining one-sixth in all the other blood elementscombined. In blood samples from patients with chronic myelocytic leukemia,the fraction of blood histamine carried by each type of granulocyte varies widely.

Submitted on September 20, 1954 Accepted on October 11, 1954