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March 1967

Leukocyte Alkaline Phosphatase and the Philadelphia Chromosome

Author Affiliations

Los Angeles

From the Department of Medicine, University of California at Los Angeles School of Medicine, Los Angeles. Dr. Winkelstein is a US Public Health Service Special Post-doctoral Fellow in Hematology and Dr. Goldberg is a US Public Health Service trainee in Hematology.

Arch Intern Med. 1967;119(3):291-296. doi:10.1001/archinte.1967.00290210123012

CHRONIC myelogenous leukemia (CML) is the only malignancy in which a specific and consistent chromosome abnormality has been consistently documented.1 This cytogenetic abnormality, designated the Philadelphia (Ph') chromosome, appears to be limited to CML2-5 or closely related variants.6 Therefore, its demonstration may be regarded as at least presumptive evidence for this disease.

Another characteristic of CML is the depressed level of the leukocyte alkaline phosphatase activity (LAP).7 An elevated LAP in a myeloproliferative disorder has been generally assumed to exclude a diagnosis of CML.8 Recently, however, both Rosen and Teplitz9 and Heath and Moloney10 have reported elevated LAP levels in patients with Ph' positive CML coexisting with a second disorder. These two reports suggest that elevated enzyme values may occur in CML if the leukemic process is accompanied by another disease. The present paper describes the third case of an elevated LAP in a Ph' positive CML in the presence