Common acute lymphoblastic leukemia in a girl with genetically confirmed LEOPARD syndrome.

Common acute lymphoblastic leukemia in a girl with genetically confirmed LEOPARD syndrome.
J Pediatr Hematol Oncol. 2008 Aug
Laux D, Kratz C, Sauerbrey A.
Pediatric Hematology and Oncology Unit, Department of Pediatrics, HELIOS Klinikum Erfurt, Erfurt, Germany. danilaux@yahoo.de

Germline mutations in PTPN11 gene cause Noonan syndrome and the clinically similar LEOPARD syndrome (LS). LS is a rare congenital developmental disorder characterized by multiple lentigines, cardiac abnormalities, facial dysmorphism, retardation of growth, and deafness. Mutations in exons 7 and 12 of the PTPN11 gene can be identified in nearly 90% of patients with LS. PTPN11 gene encodes for an ubiquitously expressed protein tyrosine phosphatase SHP-2 involved in a variety of intracellular signaling processes in development and hematopoiesis. Somatic PTPN11 mutations contribute to leukemogenesis in children with hematologic malignancies including juvenile myelomonocytic leukemia, acute lymphoblastic leukemia, acute myeloid leukemia, and myelodysplasia. Two cases of leukemia (acute myeloid leukemia) have been reported in children with LS. The authors describe for the first time a girl with genetically confirmed LEOPARD syndrome presenting with common acute lymphoblastic leukemia.

PMID: 18799937 [PubMed - indexed for MEDLINE]

B lymphocytes: how they develop and function

B lymphocytes: how they develop and function
Blood. 2008 Sep

LeBien TW, Tedder TF.
Department of Laboratory Medicine/Pathology, University of Minnesota Cancer Center, Minneapolis, MN 55455, USA. lebie001@umn.edu

The discovery that lymphocyte subpopulations participate in distinct components of the immune response focused attention onto the origins and function of lymphocytes more than 40 years ago. Studies in the 1960s and 1970s demonstrated that B and T lymphocytes were responsible primarily for the basic functions of antibody production and cell-mediated immune responses, respectively. The decades that followed have witnessed a continuum of unfolding complexities in B-cell development, subsets, and function that could not have been predicted. Some of the landmark discoveries that led to our current understanding of B lymphocytes as the source of protective innate and adaptive antibodies are highlighted in this essay. The phenotypic and functional diversity of B lymphocytes, their regulatory roles independent of antibody production, and the molecular events that make this lineage unique are also considered. Finally, perturbations in B-cell development that give rise to certain types of congenital immunodeficiency, leukemia/lymphoma, and autoimmune disease are discussed in the context of normal B-cell development and selection. Despite the significant advances that have been made at the cellular and molecular levels, there is much more to learn, and cross-disciplinary studies in hematology and immunology will continue to pave the way for new discoveries.

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