Seropositive Healthy Subjects Research Articles

Impact of Toxoplasmosis in Im-mune Respons in Hemodialysis Patients

Background:Toxoplasma gondii is the most common infection of protozoa, affecting a wide range of hosts. Toxoplasmosis is usually asymptomatic in immu-nocompetent persons, but in immunocompromised persons (ex:patients on dialysis) significant problems can ensure, and may progress to a life-threatening infection. Objective: To investigate the seroprevalence of anti-Toxoplasma anti-bodies in patients undergoing hemodialysis in Baquba / Iraq . Patients and Methods: A group of blood samples, consisting of 75 dial-ysis patients and 50 healthy controls, were examined for the detection of anti-toxoplasma antibodies in Baquba Governorate from November 2020 to April 2021 using enzyme-linked immunosorbent assay (ELISA) for IgG and IgM. Results: The total numbers of the 125 samples were examined, 32 (44.0%) and 2 (4.0%) were IgG-positive for both patients and healthy individual respectively, and the results of the current study showed only 1 (1.33%) was seropositive IgM for patient group, while no seroposi-tive healthy subjects was found for IgM . The results showed that the percentage of seropositivity was higher in 17 males (40.47%) than in females 15 (45.45%) in the group of patients, but the differences were not statistically significant . As for the age groups, a positive increase was observed in the age group 11-30 years when comparing patients and healthy people, as the percentage reached 5 (29.41%). It was also ob-served that the highest seropositivity in the education levels was in the group of patients at the educational level 6-12 (45.45%) than in the healthy controls group, but the differences were not statistically signifi-cant between education levels. Patients living in urban areas had signifi-cantly higher serum (P = 0.0041) than patients in rural areas, and the odds ratio was 22,000. And those who had contact with cats showed a significant increase in seropositivity p = 0.0466 and odds ratio was 20.5789. Conclusion: Dialysis patients are at risk for toxoplasmosis and should be screened on a regular basis to prevent the disease from spreading dur-ing hemodialysis. Keywords: Toxoplasma gondii, Hemodialysis, Antibodies ,IgG

Pharmacokinetics and Immunogenicity of ASP0113 in CMV-Seronegative Dialysis Patients and CMV-Seronegative and -Seropositive Healthy Subjects.

Cytomegalovirus (CMV) infection causes significant morbidity and mortality in immunocompromised transplant patients. ASP0113, a first-in-class DNA vaccine containing plasmids encoding CMV phosphoprotein 65 and glycoprotein B (gB), was evaluated in a phase 1b, subject-blinded study in CMV-seropositive (n=13) and CMV-seronegative (n=12) healthy and CMV-seronegative dialysis subjects (n=12) randomized to ASP0113 or placebo. End points included pharmacokinetics, anti-gB antibody levels, phosphoprotein 65-specific T-cell responses measured by ex vivo enzyme-linked immune absorbent spot (ELISpot) assay and 10-day cultured ELISpot and Stat T-cell activation assays, and safety. ASP0113 concentrations peaked at 2-10 and 24-48 hours; the pharmacokinetics were similar across groups. No group demonstrated significant anti-gB antibody responses. T-cell responder rates in the cultured ELISpot assay were 8/12 (66.7%, 95%CI 35% to 90%) and 4/12 (33.3%, 95%CI 10% to 65%) in CMV-seronegative healthy subjects and dialysis patients, respectively, whereas ex vivo ELISpot assay response rates were 4/11 (36.4%, 95%CI 11% to 69%) and 0/12, respectively. Responses peaked at week 27, with lower magnitude observed in CMV-seronegative dialysis patients versus CMV-seronegative healthy subjects. No serious adverse events occurred; the most common adverse event in ASP0113-vaccinated patients was injection-site pain (64.9%). Some CMV-seronegative healthy subjects and dialysis patients had T-cell responses; no humoral responses were detected.

From crystal structure to in silico epitope discovery in the Burkholderia pseudomallei flagellar hook-associated protein FlgK.

Melioidosis, caused by the Gram-negative bacterium Burkholderia pseudomallei, is a potentially fatal infection that is endemic in Southeast Asia and Northern Australia that is poorly controlled by antibiotics. Research efforts to identify antigenic components for a melioidosis vaccine have led to the identification of several proteins, including subunits forming the flagella that mediate bacterial motility, host colonization, and virulence. This study focuses on the B. pseudomallei flagellar hook-associated protein (FlgK(Bp)), and provides the first insights into the 3D structure of FlgK proteins as targets for structure-based antigen engineering. The FlgK(Bp) crystal structure (presented here at 1.8-Å resolution) reveals a multidomain fold, comprising two small β-domains protruding from a large elongated α-helical bundle core. The evident structural similarity to flagellin, the flagellar filament subunit protein, suggests that, depending on the bacterial species, flagellar hook-associated proteins are likely to show a conserved, elongated α-helical bundle scaffold coupled to a variable number of smaller domains. Furthermore, we present immune serum recognition data confirming, in agreement with previous findings, that recovered melioidosis patients produce elevated levels of antibodies against FlgK(Bp), in comparison with seronegative and seropositive healthy subjects. Moreover, we show that FlgK(Bp) has cytotoxic effects on cultured murine macrophages, suggesting an important role in bacterial pathogenesis. Finally, computational epitope prediction methods applied to the FlgK(Bp) crystal structure, coupled with in vitro mapping, allowed us to predict three antigenic regions that locate to discrete protein domains. Taken together, our results point to FlgK(Bp) as a candidate for the design and production of epitope-containing subunits/domains as potential vaccine components.

Decreased T cell reactivity to Epstein–Barr virus infected lymphoblastoid cell lines in multiple sclerosis

Objective: To investigate T cell and antibody immunity to Epstein–Barr virus (EBV) in multiple sclerosis (MS). Methods: Immunoglobulin G (IgG) immunity to EBV nuclear antigen 1 (EBNA1) and viral capsid...

Impact of Cytomegalovirus and Grafts versus Host Disease on the Dynamics of CD57+CD28−CD8+ T Cells After Bone Marrow Transplant

OBJECTIVESThe present study aimed to evaluate the dynamics of CD28 and CD57 expression in CD8+ T lymphocytes during cytomegalovirus viremia in bone marrow transplant recipients.METHODSIn a prospective study, blood samples were obtained once weekly once from 33 healthy volunteers and weekly from 33 patients. To evaluate the expression of CD57 and CD28 on CD8+ T lymphocytes, flow cytometry analysis was performed on blood samples for four months after bone marrow transplant, together with cytomegalovirus antigenemia assays.RESULTSCompared to cytomegalovirus-seronegative healthy subjects, seropositive healthy subjects demonstrated a higher percentage of CD57+ and a lower percentage of CD28+ cells (p<0.05). A linear regression model demonstrated a continuous decrease in CD28+ expression and a continuous increase in CD57+ expression after bone marrow transplant. The occurrence of cytomegalovirus antigenemia was associated with a steep drop in the percentage of CD28+ cells (5.94%, p<0.01) and an increase in CD57+ lymphocytes (5.60%, p<0.01). This cytomegalovirus-dependent effect was for the most part concentrated in the allogeneic bone marrow transplant patients. The development of acute graft versus host disease, which occurred at an earlier time than antigenemia (day 26 vs. day 56 post- bone marrow transplant), also had an impact on the CD57+ subset, triggering an increase of 4.9% in CD57+ lymphocytes (p<0.05).CONCLUSIONWe found continuous relative changes in the CD28+ and CD57+ subsets during the first 120 days post- bone marrow transplant, as part of immune system reconstitution and maturation. A clear correlation was observed between the expansion of the CD57+CD28−CD8+ T lymphocyte subpopulation and the occurrence of graft versus host disease and cytomegalovirus viremia.

HSV1 exposure affects prefrontal cortical structure in schizophrenia patients

Differences in grey matter among herpes simplex virus 1 (HSV1)-seropositive and HSV1-seronegative schizophrenia patients and healthy subjects: the left panel shows grey matter differences within schizophrenia and healthy subjects groups by HSV1 serological status. Significant reductions in grey matter in the prefrontal region can be seen in schizophrenia patients with serological evidence of exposure to HSV1 compared to those with no evidence of exposure but not within healthy subjects. The right panel shows significant changes in grey matter in the prefrontal region in HSV1-seropositive patients compared to seropositive healthy subjects. Such differences were not observed between. For more information on this topic, please refer to article by Prasad et al. on pages 105–113. Molecular Psychiatry (2007) 12, 1 & 2007 Nature Publishing Group All rights reserved 1359-4184/07 $30.00

Role of seroconversion in confirming cure of Helicobacter pylori infection.

The role of serologic testing to confirm cure of Helicobacter pylori infection after antimicrobial therapy is not completely defined. To determine the utility of serologic testing in confirming cure of H pylori infection more than 1 year after therapy. A prospective, before-after interventional trial. An outpatient clinical research laboratory in an academic, urban Veterans Affairs medical center. Twenty-three otherwise healthy men and women with active H pylori infection demonstrated by gastric biopsy and with positive H pylori serologic findings. A 14-day course of bismuth, tetracycline, and metronidazole. Determination of IgG serum antibodies to H pylori at baseline, 1 month, 3 months, and approximately 18 months after completion of therapy compared with serial gastric mucosal biopsy specimens with stains for H pylori and for histologic examination as the criterion standard. Fifteen (65%) of 23 subjects were cured of their H pylori infection as assessed by gastric biopsy, with elimination of gastritis; median antibody levels declined from 92.5 U/mL at baseline to undetectable levels at 18 months. The other 8 subjects (35%) were not cured and had persistent gastritis at 18 months; median antibody levels declined from 130.6 U/mL at baseline to 89.7 U/mL at 18 months. Sensitivity and specificity of seroconversion (from a positive to negative test result) in detecting cure of H pylori infection were 60% and 100%, respectively. Undetectable antibody levels beyond the first year of therapy accurately confirm cure of H pylori infection in initially seropositive healthy subjects, with reasonable sensitivity.

Demonstration of Borrelia burgdorferi DNA in urine samples from healthy humans whose sera contain B. burgdorferi-specific antibodies

Since the possibility of asymptomatic infection with Borrelia burgdorferi has been suggested by a positive serology found in healthy subjects, we hypothesized that these subjects might excrete borrelial DNA sequences in urine as happens in patients with Lyme borreliosis. We found borrelial sequences by nested PCR in the urine samples from 3 of 13 healthy B. burgdorferi antibody-positive adults but not in urine samples from 79 antibody-negative healthy controls. After therapy with doxycycline, the urine samples were repeatedly negative for B. burgdorferi DNA. We conclude that urinary excretion of borrelial DNA sequences may occur in seropositive healthy subjects during asymptomatic infection. Demonstration of such sequences in urine must be interpreted cautiously and may not necessarily prove a borrelial cause of disease.

Current seroepidemiological status of hepatitis A with a comparison of antibody titers after infection and vaccination

The overall prevalence of anti-hepatitis A virus antibodies was 49.6% in 385 inhabitants in Honda City, Japan in 1991. An approximately 50% prevalence rate occurred between 40 and 49 years of age. The prevalence of anti-HAV antibodies was significantly lower in 1991 than in 1982 in the age groups 20 to 29 years and 30 to 39 years (p < 0.01), suggesting there has been no significant HAV infection since 1982. In addition, anti-HAV antibody titers of sera from convalescent hepatitis. A patients were compared with those from seropositive healthy subjects and from healthy subjects following administration of a lyophilized inactivated hepatitis A vaccine or immune serum globulin. Titers after vaccine administration were considerably higher than after immune serum globulin and, although lower than those obtained after natural infection, should be sufficient for protection against hepatitis A virus.

Serum immunoglobulin G antibody to Porphyromonas gingivalis in rapidly progressive periodontitis: titer, avidity, and subclass distribution.

Porphyromonas gingivalis is a suspected pathogen in rapidly progressive periodontitis (RPP). We have determined the anti-P. gingivalis serum immunoglobulin G (IgG) isotype response and avidity and the subclass titer distributions for 30 RPP patients and 30 age-, sex-, and race-matched healthy subjects by using enzyme-linked immunosorbent assay technology. Patients and control subjects were classified as seropositive if their total IgG response to P. gingivalis was twofold or more than the median response in healthy subjects. The predominant antibody responses for both patients and healthy subjects were IgG2 and IgG3, with a subclass order of IgG2 greater than IgG3 greater than IgG1 greater than IgG4. The avidity of the IgG response was highest for the seropositive healthy subjects and was no different between seronegative and seropositive RPP patients. The subclass antibody responses did not depend on gender, and there were no correlations between titer, avidity, or subclass with disease severity in the RPP patients as measured by pocket depth or bone loss on dental X rays. The seronegative RPP patients exhibited antibody responses that were greater than the responses of seronegative healthy subjects for all four subclasses, while the seropositive RPP patients had higher IgG1 and IgG4 levels than seropositive healthy subjects. These findings are consistent with the hypothesis that both carbohydrate and protein antigens are important in the IgG response to P. gingivalis. The relative predominance of IgG2, a subclass which lacks strong complement fixation and opsonic properties, and the low avidity of patient anti-P. gingivalis IgG antibodies suggest that humoral responsiveness to infection with P. gingivalis may be ineffective in clearing this organism.