Absence of human T-cell lymphotropic virus type I coinfection in human immunodeficiency virus-infected hemophilic men

Concern for transmission of human T-cell lymphotropic virus, type 1 (HTLV-1) infection to recipients of infected cellular blood products has prompted development of tests to eliminate blood units with HTLV-I antibodies. Most hemophilic men from the United States became infected with human immunodeficiency virus (HIV) before HIV donor screening and before blood products were processed to inactivate the virus. To assess whether these men might also be infected with HTLV-I, we examined the HTLV-I antibody status of 127 factor VIII (hemophilia A) recipients and 71 factor IX (hemophilia B) recipients. One HIV-seronegative and four HIV-seropositive persons were HTLV-I reactive by enzyme-linked immunosorbent assay (ELISA). Four of five ELISA-reactive serum samples were negative by HTLV-I immunoblot assay (IB); 1 reactive and 1 borderline reactive serum were indeterminate on IB (p19 reactivity), but negative by radioimmunoprecipitation assay (RIPA). Peripheral blood mononuclear cells from one patient with indeterminate HTLV-I IB were negative for HTLV-I genomic sequences by polymerase chain reaction. The other indeterminate patient's serum antibody pattern was stable over a 2-year period, suggesting this was not an instance of early HTLV-I seroconversion. These results reaffirm the safety of factor components in the United States with regard to HTLV-I but emphasize the importance and need for further testing of reactive HTLV-I ELISA results with a second more specific technique.     

Transformed T lymphocytes infected by a novel isolate of human T cell leukemia virus type II

Human T cell leukemia virus type II (HTLV-II) has been isolated from a patient (Mo) with features of leukemic reticuloendotheliosis (LRE) and from a patient with acquired immunodeficiency syndrome (AIDS). We have obtained another isolate of HTLV-II from a patient (CM) with severe hemophilia A, pancytopenia, and a 14-year history of staphylococcal and candidal infections but no evidence of T cell leukemia/lymphoma, AIDS, or LRE. Fresh mononuclear cells and cultured lymphocytes from CM express retroviral antigens indistinguishable by molecular criteria from HTLV-IIMo. Leukocyte cultures from CM yield hyperdiploid (48,XY, +2, +19) continuous lymphoid lines; human fetal cord blood lymphocytes (CBL) are transformed by cocultivation with these CM cell cultures but retain normal cytogenetic constitution. Electron microscopic examination of the CM cultures and transformed CBL reveals budding of extracellular viral particles, intracellular tubuloreticular structures, and viral particles contained within intracellular vesicles. CM cell cultures and the transformed CBL do not require exogenous interleukin 2, have T cell cytochemical features and mature T helper phenotypes, and exhibit minimal T helper and profound T suppressor activity on pokeweed mitogen-stimulated differentiation of normal B cells. These characteristics, which are similar to those observed with the first HTLV-II isolate, may represent properties of all HTLV-II-infected T cells.     

Tumor necrosis factor-alpha downregulates protein S secretion in human microvascular and umbilical vein endothelial cells but not in the HepG- 2 hepatoma cell line

Protein S deficiency, which is associated with thrombosis, can either be inherited or acquired. Recently, we reported that a decrease in free protein S was observed in 19 of 25 persons with HIV/AIDS. The proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), has been reported to be elevated in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) patients and has been shown to induce a procoagulant state on the surface of endothelial cells. We report here that recombinant TNF-alpha (rTNF-alpha) downregulated protein S synthesis in the SV-40T transfected human microvascular endothelial cell line (HMEC-1) model system by approximately 70% and in primary human umbilical vein and dermal microvascular endothelial cell cultures by approximately 50%. Using the HMEC-1 model, Northern blot analysis showed a decrease in protein S RNA at 24 hours that was corroborated by Western blot analysis and enzyme- linked immunosorbent assay (ELISA) quantification. Evidence supporting the specificity of the TNF-alpha effect included the following: (1) TNF- alpha down-regulation of protein S was completely blocked by TNF neutralizing antibody; (2) the effect was transient, and protein S was restored to near normal levels after TNF was removed from cell cultures; (3) an antibody directed to the TNF RI (55-kD receptor) was shown to mimic the action of TNF-alpha on HMEC-1 cells; and (4) other proinflammatory cytokines, interleukin (IL)-1, IL-6, and TGF-beta, had no effect on protein S secretion. However, TNF-alpha showed no regulatory control over protein S synthesis in the human hepatocellular carcinoma cell line HepG-2. We suggest that TNF-alpha downregulation of protein S may be a mechanism for localized procoagulant activity and thrombosis recently reported in some AIDS patients with associated protein S deficiency.     

Suppression of B-cell development as a result of selective expansion of donor T cells during the minor H antigen graft-versus-host reaction

A murine model of bone marrow (BM) transplantation in which donor (B10.D2) and recipient (BALB/c) mice were major histocompatibility complex (MHC) (H-2d) and Mls-1 identical, but incompatible at multiple non-MHC minor histocompatibility (H) antigens, and at Mls-2,3 was used to examine regeneration of B-cell development during the minor H antigen graft-versus-host reaction (GVHR). Mice that received T-cell- depleted allogeneic BM regained significant pre-B cells (sIg- 14.8+) in their BM. Mice undergoing GVHR after transplantation with allogeneic BM + T cells had less than 2% pre-B cells in their BM at day 7 and only 12% to 14% pre-B cells at days 21 and 28 compared with greater than 20% pre-B cells in the allogeneic controls. After partial recovery, the pre- B cells in the BM of GVH mice again decreased to less than 3% by day 42. This abnormal pattern of pre-B cell development in mice undergoing GVHR was associated with a reduced response to interleukin-7 (IL-7) in vitro. The delay in B-lineage cell reconstitution in mice with GVHR correlated with the expansion of donor V beta 3+ T cells in both the spleen and BM. BM T cells from mice with GVHR as well as isolated V beta 3+ T cells inhibited IL-7 colony-forming units from normal BM in co-culture assays. This inhibition could be reversed with anti- interferon gamma (IFN gamma) antibody. These data suggest that the delay in appearance and the reduction in proportion and number of pre-B cells observed early during the GVH reaction in this model is caused, in part, by the inhibitory actions of IFN gamma derived from donor V beta 3+ T cells on B-lineage cell development.     

Metabolic and energy balance in small- and appropriate-for-gestational-age, very low-birth-weight infants

This study compared nutrient utilization and postnatal weight gain composition in eight appropriate for gestational age (AGA: birth weight 1293 ± 107 g; gestational age 28.8 ± 1.4 weeks) and eight symmetrically growth-retarded (SGA: birth weight 1110 ± 230 g; gestational age 32.7 ± 1.9 weeks), very low-birth-weight (VLBW) infants. There was no significant difference in protein, mineral and energy intake between AGA and SGA infants. Nitrogen absorption (84 ± 3 and 83 ± 4%) and nitrogen retention (356 ± 48 and 352 ± 43 mg/kg/day) were similar in both groups. Fat absorption tended to be lower in AGA (78 ± 15%) than in SGA (87 ± 4%) infants. Calcium, phosphorus and magnesium absorptions were similar in AGA and SGA infants. Metabolizable energy utilization was similar in both groups; about 55% was expended and 45% stored in new tissues. Energy expenditure was 58 ± 4 kcal/kg/day in SGA infants and 61 ± 9 kcal/kg/day in AGA infants. Weight gain and its composition were similar in both groups. We conclude that nutrient and energy utilization are similar in AGA and symmetrically growth-retarded, VLBW infants.     

Whole body bone mineral content in healthy children and adolescents

Data from healthy children are needed to evaluate bone mineralisation during childhood. Whole body bone mineral content (BMC) and bone area were examined by dual energy x ray absorptiometry (Hologic 1000/W) in healthy girls (n = 201) and boys (n = 142) aged 5-19 years. Centile curves for bone area for age, BMC for age, bone area for height, and BMC for bone area were constructed using the LMS method. Bone mineral density calculated as BMC/bone area is not useful in children as it is significantly influenced by bone size. Instead, it is proposed that bone mineralisation is assessed in three steps: height for age, bone area for height, and BMC for bone area. These three steps correspond to three different causes of reduced bone mass: short bones, narrow bones, and light bones.