Granulocyte colony-stimulating factor administration to healthy volunteers: analysis of the immediate activating effects on circulating neutrophils

In four healthy volunteers, we analyzed in detail the immediate in vivo effects on circulating neutrophils of subcutaneous administration of 300 micrograms of granulocyte colony-stimulating factor (G-CSF). Neutrophil activation was assessed by measurement of degranulation. Mobilization of secretory vesicles was shown by a decrease in leukocyte alkaline phosphatase content of the circulating neutrophils. Furthermore, shortly postinjection, Fc gamma RIII was found to be upregulated from an intracellular pool that we identified by immunoelectron microscopy as secretory vesicles. Intravascular release of specific granules was shown by increased plasma levels of lactoferrin and by upregulation of the expression of CD66b and CD11b on circulating neutrophils. Moreover, measurement of fourfold elevated plasma levels of elastase, bound to its physiologic inhibitor alpha 1- antitrypsin, indicated mobilization of azurophil granules. However, no expression of CD63, a marker of azurophil granules, was observed on circulating neutrophils. G-CSF--induced mobilization of secretory vesicles and specific granules could be mimicked in whole blood cultures in vitro, in contrast to release of azurophil granules. Therefore, we postulate that the most activated neutrophils leave the circulation, as observed shortly postinjection, and undergo subsequent stimulation in the endothelial microenvironment, resulting in mobilization of azurophil granules. Our data demonstrate that G-CSF should be regarded as a potent immediate activator of neutrophils in vivo.     

High-dose etoposide and cyclophosphamide without bone marrow transplantation for resistant hematologic malignancy

Seventy-five patients with resistant acute leukemia or lymphoma received high-dose cyclophosphamide and etoposide to explore the activity of this combination in resistant hematologic malignancies, and to determine the maximum doses of these drugs that can be combined without bone marrow transplantation. Etoposide was administered over 29 to 69 hours by continuous infusion corresponding to total doses of 1.8 g/m2 to 4.8 g/m2. Cyclophosphamide, 50 mg/kg/d, was administered on 3 or 4 consecutive days total 150 to 200 mg/kg ideal body weight). At all dose levels myelosuppression was severe but reversible. Mucosal toxicity was dose-limiting with the maximum tolerated dose level combining etoposide 4.2 g/m2 with cyclophosphamide 200 mg/kg. Continuous etoposide infusion produced stable plasma levels that were lower than would be achieved after administration by short intravenous infusion, and this could explain our ability to escalate etoposide above the previously reported maximum tolerated dose. There were 28 complete (35%) and 12 partial (16%) responses. Median duration of complete response (CR) was 3.5 months (range 1.1 to 20+). Seventeen of 40 patients (42%) with acute myelogenous leukemia (AML) achieved CR, including 6 of 20 (30%) with high-dose cytosine arabinoside resistance. We conclude that bone marrow transplantation is not required after maximum tolerated doses of etoposide and cyclophosphamide. This regimen is active in resistant hematologic neoplasms, and the occurrence of CR in patients with high-dose cytosine arabinoside-resistant AML indicates a lack of complete cross-resistance between these regimens.     

Diarrhea associated with rotavirus in rural Guatemala: a longitudinal study of 24 infants and young children.

A population of 24 infants and young children followed prospectively during the first 3 years of life was studied for the occurrence of rotavirus infection by using enzyme-linked immunosorbent assay to detect virus in stools. Infection with rotavirus was associated with 26 (14.2%) of 183 selected diarrheal episodes. Twenty of the 24 infants and young children had diarrhea associated with rotavirus on at least one occasion and six had two such episodes. Rotavirus infection was documented in over 50% of the dehydrating episodes studied, thus further indicating the importance of rotavirus in this population.     

Influence of maternal infections on neonatal acute phase proteins and their interaction in the development of non-affective psychosis

Although primary infections with Toxoplasma gondii or herpes viruses during pregnancy are established teratogens, chronic maternal infections with these pathogens are considered far less serious. However, such chronic infections have been associated with neuropsychiatric disorders in the offspring. The risks of non-affective psychoses, including schizophrenia, in offspring associated with these exposures during pregnancy have not been completely defined. We used data from neonatal dried blood samples from 199 cases of non-affective psychosis and 525 matched controls (born 1975–1985). We measure immunoglobulin G antibodies directed at T. gondii, cytomegalovirus and herpes simplex virus type-1 and -2, as well as levels of nine acute phase proteins (APPs). We assessed the interaction between maternal antibodies and neonatal APP in terms of risk of non-affective psychosis. Among controls, maternal exposure to T. gondii or cytomegalovirus, but not to the other herpes viruses, was associated with significantly higher levels of neonatal APPs. Among cases, none of the maternal exposures were associated with any significant change in APPs. We observed increased RR for non-affective psychosis associated with maternal infection with T. gondii (odds ratio 2.1, 95% confidence interval 1.1–4.0) or cytomegalovirus (1.7, 0.9–3.3) only among neonates with low APP levels. These findings suggest that chronic maternal infection with T. gondii or cytomegalovirus affect neonatal markers of innate immunity. Deficient fetal immune responses in combination with maternal chronic infections may contribute to subsequent risk for psychosis. A greater understanding of the maternal–fetal immunological interplay may ultimately lead to preventive strategies toward neuropsychiatric disorders.     

Identification of glycoprotein Ib as a target for autoantibody in idiopathic (autoimmune) thrombocytopenic purpura

An antibody (DIL) from a patient with idiopathic thrombocytopenic purpura (ITP) was shown to have autospecificity on the basis of reactions with autologous platelets that were identical to those obtained with platelets from normal subjects. DIL antibody also reacted strongly in an immunofluorescence test with platelets from a patient with Glanzmann's thrombasthenia, but failed to react with platelets from a patient with the Bernard-Soulier syndrome who was known to be deficient in glycoprotein Ib (GPIb). Purified GPIb and control platelets, but not Bernard-Soulier platelets, inhibited the lytic activity of DIL. Using the GPIb-specific monoclonal antibody AP1 and one-dimensional rocket electrophoresis into gels containing rabbit antihuman platelet membrane antibody, it was shown that staphylococcal protein A-Sepharose beads coated with DIL antibody selectively remove GPIb from solubilized platelet preparations. By crossed immunoelectrophoresis it was found that DIL recognizes a determinant on GPIb on the membrane side of the cleavage site of the platelet calcium- activated protease (calpain). These studies provide direct evidence for binding of a platelet autoantibody to a determinant on GPIb relatively close to the site of insertion of this protein into the platelet membrane.     

Strain hypothesis of Toxoplasma gondii infection on the outcome of human diseases

The intracellular protozoan Toxoplasma gondii is an exceptionally successful food and waterborne parasite that infects approximately 1 billion people worldwide. Genotyping of T. gondii isolates from all continents revealed a complex population structure. Recent research supports the notion that T. gondii genotype may be associated with disease severity. Here, we (1) discuss molecular and serological approaches for designation of T. gondii strain type, (2) overview the literatures on the association of T. gondii strain type and the outcome of human disease and (3) explore possible mechanisms underlying these strain‐specific pathology and severity of human toxoplasmosis. Although no final conclusions can be drawn, it is clear that virulent strains (e.g. strains containing type I or atypical alleles) are significantly more often associated with increased frequency and severity of human toxoplasmosis. The significance of highly virulent strains can cause severe diseases in immunocompetent patients and might implicated in brain disorders such as schizophrenia should led to reconsideration of toxoplasmosis. Further studies that combine parasite strain typing and human factor analysis (e.g. immune status and genetic background) are required for better understanding of human susceptibility or resistance to toxoplasmosis.     

Exposure to herpes simplex virus,type 1 and reduced cognitive function

Herpes simplex virus, type 1 (HSV-1) causes cold sores, keratitis and rarely, fatal encephalitis. The infection is lifelong, with sensory ganglia serving as reservoirs of latent infection. Recently, exposure to HSV-1 has also been repeatedly associated with reduced cognitive function among healthy individuals without prior encephalitis. Though HSV-1 does not elevate risk for schizophrenia (SZ) per se, exposure is likewise associated with impaired cognitive functions among SZ patients. The range of cognitive changes observed in HSV-1 exposed persons has not been investigated systematically, nor is it known whether interaction between HSV-1 exposure and SZ related factors contributes to the impairment among SZ patients. Persons with or without schizophrenia/schizophreniform disorder (N = 298 total, DSM IV criteria) were assessed for HSV-1 exposure using serum HSV-1 antibody titers. The Penn Computerized Neurocognitive battery was used to assess eight cognitive domains with respect to accuracy and speed. There were no significant case–control differences in HSV-1 exposure. The SZ/schizophreniform disorder cases were significantly impaired in all cognitive domains compared with the controls. HSV-1 exposure was also associated with reduced cognitive function in the entire sample, but the magnitude of the effects and their patterns differed from the SZ related changes. Further, statistically significant interactions between HSV-1 exposure and SZ case status were not detected. HSV-1 exposure does not elevate risk for SZ, but it is associated with reduced function in specific cognitive domains regardless of SZ diagnostic status. An ‘epidiagnostic’ model for the association is proposed to explain the results.     

A two-year study of bacterial, viral, and parasitic agents associated with diarrhea in rural Bangladesh

Enteric pathogens associated with diarrhea were studied for two years at a diarrhea treatment center in rural Bangladesh. Enterotoxigenic Escherichia coli (ETEC) was the most frequently identified pathogen for patients of all ages. Rotavirus and ETEC were isolated from approximately 50% and approximately 25%, respectively, of patients less than two years of age. A bacterial or viral pathogen was identified for 70% of these young children and for 56% of all patients with diarrhea. Most ETEC isolates were obtained in the hot dry months of March and April and the hot wet months of August and September. Rotavirus identification peaked in the cool dry months of December and January, but infected patients were found year-round. The low case-fatality rates for patients with watery diarrhea and substantial dehydration further document the usefulness of treating patients with diarrhea with either a glucose- or sucrose-base electrolyte solution such as those used in this treatment center.