title: Childhood T-cell acute lymphoblastic leukaemia expressing "Ia-like" antigen:" a case report.
abstract: A 4-year-old girl presenting with vomiting, abdominal pain, and renal failure was found to have gross hepatosplenomegaly, a renal mass, and bilateral pleural effusions. A diagnosis of acute lymphoblastic leukaemia (ALL) was suggested by a peripheral white cell count (WCC) of 119,000 x 10(6)mm3, 57% blasts, 22% lymphocytes, and confirmed by bone marrow examination. Lymphocyte surface marker studies at diagnosis enabled classification as a T-ALL, with a significant proportion of the T cells also bearing receptors for the third component of complement (C3). Seventy-two percent of the peripheral blood mononuclear cells reacted with anti-Ia monoclonal antibody (FMC44), and a smaller proportion (25%) carried receptors for the Fc portion of IgG. The T-classification of this ALL was verified at central nervous system (CNS) relapse and at a subsequent nodal relapse. Double-marker studies on cells from the infiltrated lymph node prepared in suspension confirmed the presence of Ia-positive T cells. The Ia marker is usually a useful discriminant between T and non-T cells in normal and ALL cell populations. The case described here highlights the need for a panel of markers to be used in classification of childhood ALL and supports the suggestion that there is a distinct subtype of Ia-positive T-ALL.
mesh_terms: D000954:Antigens, Surface / Q000032:analysis; D002462:Cell Membrane / Q000276:immunology; D002675:Child, Preschool; D005260:Female; D006681:HLA-D Antigens; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D006801:Humans; D007945:Leukemia, Lymphoid / Q000276:immunology*; D008213:Lymphocyte Activation; D011951:Receptors, Complement / Q000032:analysis; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology
chemical_list: D000954:Antigens, Surface; D006681:HLA-D Antigens; D000949:Histocompatibility Antigens Class II; D011951:Receptors, Complement