Characterization of CD22 expression in acute lymphoblastic leukemia.

Abstract

BACKGROUND:

CD22 is a B-lineage differentiation antigen that has emerged as a leading therapeutic target in acute lymphoblastic leukemia (ALL).

PROCEDURE:

Properties of CD22 expression relevant to therapeutic targeting were characterized in primary samples obtained from children and young adults with relapsed and chemotherapy refractory B-precursor (pre-B) ALL.

RESULTS:

CD22 expression was demonstrated in all subjects (n = 163) with detection on at least 90% of blasts in 155 cases. Median antigen site density of surface CD22 was 3,470 sites/cell (range 349-19,653, n = 160). Blasts from patients with known 11q23 (MLL) rearrangement had lower site density (median 1,590 sites/cell, range 349-3,624, n = 20 versus 3,853 sites/cell, range 451-19,653, n = 140; P = <0.0001) and 6 of 21 cases had sub-populations of blasts lacking CD22 expression (22%-82% CD22 +). CD22 expression was maintained in serial studies of 73 subjects, including those treated with anti-CD22 targeted therapy. The levels of soluble CD22 in blood and marrow by ELISA were low and not expected to influence the pharmacokinetics of anti-CD22 directed agents.

CONCLUSIONS:

These characteristics make CD22 an excellent potential therapeutic target in patients with relapsed and chemotherapy-refractory ALL, although cases with MLL rearrangement require close study to exclude the presence of a CD22-negative blast population.

• Authors: Nirali N Shah, Maryalice Stetler Stevenson, Constance M Yuan, Kelly Richards, Cindy Delbrook, Robert J Kreitman, Ira Pastan, Alan S Wayne
• Journal: Pediatric blood & cancer (Pediatr Blood Cancer) Vol. 62 Issue 6 Pg. 964-9 (Jun 2015) ISSN: 1545-5017 [Electronic] United States
• PMID: 25728039 (Publication Type: Journal Article, Research Support, N.I.H., Intramural, Research Support, Non-U.S. Gov't)
• Copyright: Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Chemical References

• CD22 protein, human
• KMT2A protein, human
• Sialic Acid Binding Ig-like Lectin 2
• Myeloid-Lymphoid Leukemia Protein
• Histone-Lysine N-Methyltransferase

Topics

• Adolescent
• Adult
• Child
• Child, Preschool
• Chromosomes, Human, Pair 11
• Histone-Lysine N-Methyltransferase
• Humans
• Infant
• Myeloid-Lymphoid Leukemia Protein (genetics)
• Precursor Cell Lymphoblastic Leukemia-Lymphoma (drug therapy, immunology)
• Sialic Acid Binding Ig-like Lectin 2 (analysis, antagonists & inhibitors)