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Greet J Boland

Publications and source records attributed to Greet J Boland.

10 recordsLinked to original sources
PubMed2004

Long-term persistence of T cell memory to HBsAg after hepatitis B vaccination.

AIM: To determine if the T cell memory to HBsAg can persist for a long time after hepatitis B (HB) vaccination. METHODS: Thirty one vaccine recipients who were healthcare workers (18 females and 13 males aged 34-58 years) from Utrecht University Hospital, Netherlands, and had previously received a standard course of vaccination for hepatitis B were investigated and another 9 unvaccinated healthy volunteers from the same hospital were used as the control. Blood samples were taken just before the experiment to test serum anti-HBs levels and the subjects were classified into different groups according to their serum titers of anti-HBs and vaccination history. Their peripheral blood mononuclear cells (PBMC) were isolated from freshly heparinized venous blood and the proliferative response of T lymphocytes to the recombinant hepatitis B surface antigen (HBsAg) was investigated. RESULTS: Positive serum anti-HBs was found in 61.3% (19/31) vaccine recipients and a significant in vitro lymphocyte proliferative response to recombinant HBsAg was observed in all the vaccinees with positive anti-HBs. Serum anti-HBs level < or =10 IU/L was found in 38.7% (12/31) subjects. In this study, we specially focused on lymphocyte proliferative response to recombinant HBsAg in those vaccine recipients with serum anti-HBsAg less than 10 IU/L. Most of them had received a standard course of vaccination about 10 years before. T lymphocyte proliferative response was found positive in 7 of the 12 vaccine recipients. These results confirmed that HBsAg-specific memory T cells remained detectable in the circulation for a long time after vaccination, even when serum anti-HBs level had been undetectable. CONCLUSION: The T cell memory to HBsAg can persist for at least 10 years after HB vaccination. Further booster injection is not necessary in healthy responders to HB vaccine.

Adult↗
PubMed2003

Cytokine polymorphisms play a role in susceptibility to ultraviolet B-induced modulation of immune responses after hepatitis B vaccination.

UVB exposure can alter immune responses in experimental animals and humans. In an earlier human volunteer study, we demonstrated that hepatitis B-specific humoral and cellular immunity after vaccination on average were not significantly affected by UVB exposure. However, it is known that individuals differ in their susceptibility to UVB-induced immunomodulation, and it was hypothesized that polymorphisms in specific cytokines may play a role in this susceptibility. In this respect, we previously demonstrated that immune responses after hepatitis B vaccination are influenced by the minor allelic variant of IL-1 beta in the general population. For all volunteers, single nucleotide polymorphisms were determined for the following UV response-related cytokines: IL-1 receptor antagonist (+2018), IL-1 alpha (+4845), IL-1 beta (+3953), TNF-alpha (-308), and TNF-alpha (-238). Exposure to UVB significantly suppressed Ab responses to hepatitis B in individuals with the minor variant for the IL-1 beta polymorphism. Increased minimal erythema dose values (just perceptible), which resulted in higher absolute UVB exposures, were observed in the same individuals. There were no associations observed between UVB-induced immunomodulation and the other cytokine polymorphisms examined. This study indicates that individual susceptibility to UVB radiation needs to be considered when studying the effects of UVB in humans.

Adult↗
PubMed2003

Transmission profile of hepatitis B virus infection in the Batam region, Indonesia. Evidence for a predominantly horizontal transmission profile.

The aim of this study was to describe the distribution of hepatitis B virus markers among the autochthonous and immigrant multicultural populations of Riau province, Indonesia, in order to define the groups at risk and their infrastructure. This investigation was part of a large hepatitis B vaccination study. A total of 9701 healthy individuals, aged 5 years or older and living in the urbanised area of Batam, near Singapore, and on the surrounding islands were included. Socio-epidemiological data were collected, blood was drawn, and sera were tested for antibodies to hepatitis B core (anti-HBc) and surface antigen (anti-HBs). Anti-HBc-positive sera were tested against hepatitis B surface antigen (HBsAg). All tests comprised immunoassays from Roche (Germany) using Elecsys 2010. Complete data were available from 9314 subjects. The results showed relatively low prevalences of anti-HBc (a marker of a previous hepatitis B infection) and HBsAg in the 5-year-old chiLdren (5.8 and 1.9%, respectively) that increased continuously with increasing age. High anti-HBs levels (>1000 IU/L) were found in all age cohorts, indicating a lifelong threat of active hepatitis B infection. In conclusion, the transmission profile of hepatitis B appeared to be mainly horizontal (person-to-person) in the highly endemic region studied. Vertical transmission was less than 5%. The horizontal transmission routes included non-sexual activities of life since children <10 years of age also showed considerable infection rates. The results underline the need for catch-up hepatitis B vaccination programs for children and adults.

Adolescent↗
PubMed2003

Prevention of cytomegalovirus disease in recipients of allogeneic stem cell transplants.

The main risk factors for cytomegalovirus (CMV) disease in recipients of allogeneic stem cell transplants (SCT) are recipient CMV seropositivity and acute graft-versus-host disease. Currently, two antiviral strategies, prophylactic or preemptive antiviral treatment, are used for prevention of CMV disease. Preemptive treatment is most favorable when short-term (14-day) treatment is applied. Several methods are available for monitoring of CMV reactivation. PCR-based CMV DNA detection assays are the most sensitive methods; however, the clinical benefit of this high sensitivity is unclear. Even more, there is lack of clarity whether PCR tests can better be performed with plasma, whole blood, or peripheral blood leukocyte samples. Recovery of a CMV-specific CD8(+) cytotoxic-T-lymphocyte (CTL) response is necessary for preventing CMV reactivation and disease. Reconstitution of absolute CMV-specific CTL counts to values above 10 x 10(6) to 20 x 10(6) CTLs/liter is associated with protection from CMV disease. In the near future, preemptive therapy might be withheld in patients with CMV reactivation who are shown to have adequate CMV-specific cytotoxic T-cell levels. Antiviral therapy with (val)acyclovir has been studied only as prophylactic treatment for prevention of CMV infection. High-dose oral valacyclovir is more effective than acyclovir when used in addition to preemptive treatment of CMV reactivation with ganciclovir or foscarnet. Three antiviral drugs have been tested for preemptive therapy of CMV reactivation and/or treatment of CMV disease. Although intravenous ganciclovir is considered the drug of choice, foscarnet has similar efficacy and less toxicity, especially hematologic toxicity. Cidofovir has not been tested extensively, but so far the results are disappointing. Oral valganciclovir for preemptive treatment of SCT recipients is currently being studied. In addition to antiviral therapy, adoptive immunotherapy with CMV-specific cytotoxic T cells as prophylactic or preemptive therapy is a very elegant strategy; however, generation of these cells is expensive and time-consuming, and therefore the therapy is not available at every transplantation center. Magnetic selection of CMV-specific CD8(+) T cells from peripheral blood by using HLA class I-peptide tetramers may be very promising, making this strategy more accessible.

Antiviral Agents↗
PubMed2003

Epidermal cis-urocanic acid levels correlate with lower specific cellular immune responses after hepatitis B vaccination of ultraviolet B-exposed humans.

Urocanic acid (UCA) is a major UV-absorbing chromophore in the epidermis and has been suggested to act as one of the initiators of UV-induced immunosuppression. cis-UCA, the isomer from UCA that is formed upon UV exposure, has been shown to impair some cellular immune responses. cis-UCA levels were determined in a study in which the influence of ultraviolet B (UVB) exposure on immune responses after hepatitis B vaccination in human volunteers was established. A significant increase in cis-UCA levels was found in the skin of UVB-exposed volunteers compared with controls. cis-UCA levels, calculated as the percentage of the total UCA amount, in UVB-exposed volunteers correlated significantly with the cumulative UVB dose received in 5 consecutive days, i.e. the higher the UVB dose (J/m2), the higher the cis-UCA levels (until a cis-UCA plateau was reached in the so-called photostationary state). Correlations between skin cis-UCA levels and immune responses were determined, and they revealed no statistically significant correlations among lymphocyte proliferation responses after either mitogenic stimulation or stimulation with recall antigens. No correlation was found between cis-UCA levels and hepatitis B-specific antibody titers. However, we found a statistically significant negative correlation between cis-UCA levels and hepatitis B-specific lymphocyte proliferation responses when volunteers were irradiated with UVB before hepatitis B vaccination. In other words, volunteers with high cis-UCA levels caused by UVB exposure showed lower cellular immune responses against hepatitis B antigen after hepatitis B vaccination.

Adult↗
PubMed2002

IL-1beta gene polymorphisms influence hepatitis B vaccination.

Considerable variability exists in the vaccine response to hepatitis B with 5-10% of healthy young adults demonstrating no or inadequate responses following a standard vaccination schedule. As the interleukin-1beta (IL-1beta) cytokine has been shown to be important in the development of immune responses, we determined whether vaccine efficacy is influenced by genetic polymorphisms associated with IL-1beta expression. Ninety-two healthy individuals who were negative for antibodies to hepatitis B antigen (anti-HBs) were vaccinated against hepatitis B according to a standardized schedule. At selected times, antibody titers and lymphoproliferative capacity to hepatitis B surface antigen (HBsAg) were determined. DNA genotyping for IL-1beta polymorphisms using a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) technique demonstrated that both the anti-HBs titer and the T-cell lymphoproliferative response to HBsAg are significantly increased in individuals possessing the IL-1beta (+3953) minor allelic variant.

Adult↗
PubMed2002

UVB exposure impairs immune responses after hepatitis B vaccination in two different mouse strains.

Ultraviolet light exposure can impair immune responses that are not restricted to the exposed skin but is also found at other sites, i.e. systemic immunosuppression. Therefore, we investigated the UV-induced modulating effects on vaccination against hepatitis B in a mouse model. Two different mouse strains, BALB/c and C57B1/ 6, were vaccinated intramuscularly against hepatitis B. Mice were exposed to different doses of ultraviolet B (UVB) for five consecutive days on shaved back skin before the vaccination. Vaccination against hepatitis B induced cellular (delayed-type hypersensitivity [DTH] and lymphocyte stimulation test) as well as humoral immune responses in both mouse strains. The DTH responses in C57BB1/6 mice were statistically significantly higher compared with BALB/c mice. UVB exposure induced a dose-dependent suppression of cellular immunity in both strains of mice. C57B1/6 mice seemed to be more susceptible to this suppression. Anti-hepatitis B surface antibodies (total-Ig) were only marginally suppressed after UVB exposure. IgG2a and interferon-gamma levels, both indicators for Th1 immune response, were suppressed in both mouse strains after UVB exposure. In summary, UVB exposure induced a dose-dependent suppression of both cellular and humoral immune responses after hepatitis B vaccination, although the suppressive effects on humoral immunity were limited to IgG2a production. Susceptibility to UVB-induced immunomodulation depended on the strain of mice and their predilection for developing different T cell responses.

Animals↗