Fatal nonneurological EHV-1 infection in a yearling filly.

A case of fatal nonneurological equine herpesvirus 1 (EHV-1) infection in a yearling filly is described. Gross lesions included extensive pulmonary edema, prominent laryngeal lymphoid follicles, and congestion and edema of the dorsal third ventricle choroid plexus. Histologically, there was vasculitis, hemorrhage, and edema in the lungs and dorsal third ventricle choroid plexus as well as mild intestinal crypt necrosis with occasional intranuclear inclusion bodies. The perivascular and vascular inflammatory infiltrates were comprised mainly of T lymphocytes and macrophages. EHV-1 antigen was identified within the nucleus and cytoplasm of endothelial cells, dendritic-like cells of the pharyngeal lymphoid follicles, pharyngeal glandular epithelium, crypt enterocytes, and monocytes. Attempted virus isolation was negative. Weak seroconversion for EHV-1 was observed. Herpesvirus-like particles were identified within pharyngeal endothelial cells by transmission electron microscopy. Polymerase chain reaction amplified 369 and 188 base-pair fragments specific for EHV-1. The scarcity of pathognomonic viral inclusions and lesions in this case suggests that this disease may not be recognized, particularly in situations when ancillary laboratory procedures are limited.

Autoimmune neutropenia and Hodgkin's disease: successful treatment with intravenous gammaglobulin.

We describe a child with Hodgkin's disease (HD) who presented with profound neutropenia, secondary to an antineutrophil antibody. The patient responded to intravenous immunoglobulin (IVIG), with prompt and sustained improvement in total white blood cell count (WBC) and absolute neutrophil count (ANC). The literature pertaining to autoimmune cytopenias complicating HD is reviewed, as well as the role of IVIG in management of these disorders.

Successful treatment of severe aplastic anemia by bone marrow transplantation from HLA nonidentical family members: preliminary results utilizing cyclophosphamide and 600 cGY fractionated total body irradiation.

We have performed bone marrow transplants on four children with severe aplastic anemia who lacked an human leukocyte antigen (HLA)-identical sibling donor. Patients were prepared with cyclophosphamide and 600 cGy fractionated total body irradiation, and then received marrow from a parent donor mismatched for one (two patients), two (one patient), or three (one patient) HLA antigens. All four patients engrafted. One died early of acute graft-versus-host disease. The three others showed sustained complete hematopoietic reconstitution. Two are alive and hematologically normal 43-87 months after transplant. Both have had acute and chronic graft-versus-host disease (CGVHD), and one of the two remains on immunosuppressive drugs. The fourth died at 48 months after transplant of CGVHD. The previous experience with HLA-incompatible marrow transplants is reviewed, and the rationale for this preparative regimen is discussed. Cyclophosphamide and 600 cGy fractionated total body irradiation is an effective preparative regimen for children with severe aplastic anemia receiving transplants from HLA-nonidentical parental donors, allowing engraftment and full hematologic reconstitution.

Studies on the ability of monoclonal antibodies to selectively mediate complement-dependent cytotoxicity of human myelogenous leukemia blast cells.

A panel of monoclonal antibodies that bind to leukemic blast cells from patients with acute myelocytic leukemia and chronic myelocytic leukemia in blast crisis was studied for their ability to mediate complement-dependent lysis of a variety of cell populations from patients with leukemia, normal blood cells, and human leukemia cell lines. Several of these monoclonal antibodies were selectively cytotoxic to myeloid leukemia cells (AML-1-99, AML-1-211, AML-2-30, CML-75, CML-115, and CML-150). Although they were all capable of binding to normal cell populations, none of these hybridomas were cytotoxic to normal cells. Three of these antibodies (AML-1-211. CML-75, and CML-150) were cytotoxic to some leukemia cell samples only after dilution of the hybridoma supernatant, i.e., they showed a prozone. Binding of these three antibodies, as well as another, AML-1-201, as determined in a radioimmunoassay, also showed a prozone. Other monoclonal antibodies are described (AML-2-23 and AML-2-9) that mediate complement-dependent cytotoxicity to myeloid leukemia cells as well as selected normal cell types (monocytes and lymphocytes, respectively). The potential clinical utility of these monoclonal antibodies is considered in the context of recently encountered problems in the use of monoclonal antibodies to mediate leukemia cell lysis in vivo.

Family studies of neutrophil alloantigens in bone marrow transplantation.

In order to evaluate the utility of the neutrophil specific antigens NA1, NA2, Vaz (NC1), NB1 and 9a in the documentation of bone marrow chimeras in recipients of allogeneic bone marrow grafts, neutrophil antigen typing was performed by EDTA microagglutination on the families of 17 patients with hematopoietic disorders under evaluation for bone marrow transplantation. Mendelian segregation independent of HLA and mutually independent was noted for the NA, NB and 9a systems. Vaz (NC1) segregated with and was included in NA2. Serological complexity was noted for NA1 and NA2. Typing for neutrophil antigens was achieved for 13 of 17 patients. Eight of 10 patients with HLA identical siblings had neutrophil antigen markers differing between donor and recipient. Conversion to donor neutrophil phenotype was documented for four recipients of bone marrow grafts. The neutrophil antigens, particularly of the NA system, appear to be useful additional markers for allogeneic bone marrow engraftment.