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Biomedical subjects

A Kijlstra

Publications and source records attributed to A Kijlstra.

At least 37 records · Page 2Linked to original sources
PubMed2000

Analysis of the cellular infiltrate in the iris during experimental autoimmune encephalomyelitis.

PURPOSE: Previous studies have shown that experimental autoimmune encephalomyelitis (EAE) and anterior uveitis (AU) develop in Lewis rats immunized with myelin basic protein (MBP). The purpose of this study was to characterize the dynamics, distribution, and phenotype of infiltrating cells in the iris during EAE-associated AU. METHODS: Lewis rats were immunized with MBP emulsified in complete Freund's adjuvant (CFA) or with CFA alone. Cellular infiltration of the iris was analyzed at various time points by immunohistochemistry of wholemounts, flow cytometry, and immunoelectron microscopy, by using monoclonal antibodies specific for monocytes/macrophages (ED1), T lymphocytes (R73, W3.25, OX8), T-cell activation markers (OX39, OX40), granulocytes (HIS48), major histocompatibility complex (MHC) class II (OX6), and neurofilament (2H3). RESULTS: MBP-immunized rats showed development of characteristic monophasic EAE, followed, after resolution of paralysis, by mild self-limited AU. Initially, focal infiltrates of round MHC class II(+) and ED1(+) cells were found in the iris. During the course of AU, the midiris became massively infiltrated with ED1(+) monocytes-macrophages, R73(+) T cells, granulocytes (HIS48(+)), and MHC class II(+) cells. The influx of T cells consisted of CD4(+) and CD8(+) cells, of which only a small fraction (<14 and 11%, respectively) expressed activation markers. The infiltrating cells accumulated in proximity to myelinated and nonmyelinated nerve bundles and in the vicinity of blood vessels in the iris. No evidence was found for demyelination or nerve degradation. Neither EAE nor AU developed in CFA-treated control rats. CONCLUSIONS: These data show that EAE-associated AU is characterized by a transient mixed cellular infiltrate consisting of monocytes-macrophages, granulocytes, and CD4 and CD8 T cells. The preferential accumulation of inflammatory cells in the vicinity of nerve fibers suggests that AU in this model may result from autoreactivity to nerve antigens.

Animals↗
PubMed2000

Localization and characterization of immunocompetent cells in the human retina.

PURPOSE: Recent studies have shown that experimental uveitis can be induced by the appropriate administration of various retinal antigens. Little is known about the in-situ interactions between immune cells in the retina as a prerequisite for understanding the mechanisms involving the presentation of antigens by local antigen-presenting cells (APC) to invading T cells. The study described here was therefore designed to investigate the presence of immunocompetent cells with a focus on the characterization of retinal APCs. MATERIALS AND METHODS: Retinal wholemounts, cytospins, and ocular sections were prepared from eyebank eyes obtained within 24 hours postmortem. Immunohistochemistry (single staining and double staining) was performed on the retinal wholemounts, cytospins, and the ocular sections using monoclonal antibodies specific for HLA-DR (MHC class II), CD45 (leukocytes), CD68 (macrophages), CD22 (B cells), CD3 (T cells), and CD1a (dendritic cells). RESULTS: CD68-positive macrophages were observed in one layer of the retina, whereas HLA-DR(+) and CD45(+) cells were seen in two distinct planes: one mainly at the level of the inner nuclear layer to outer plexiform layer (deep layer) and the other mainly at the nerve fiber and ganglion cell layer (shallow layer). There was a significant difference between the different parts of the retina with regard to the density of these cells. Cell density decreased when going from the peripheral to the posterior areas of the retina. The positive cells in the deep layer were frequently associated with blood vessels, whereas the cells in the shallow layer were distributed evenly throughout the retina. Most positive cells displayed a dendritiform appearance, whereas few cells showed a pleiomorphic morphology. Very few CD1a-positive cells were noted in the retina. Neither T cells (CD3) nor B cells (CD22) could be detected in the normal human retina. Double staining showed that the majority (83. 7%) of the CD45(+) cell population was HLA-DR-positive, whereas approximately half (56.8%) the CD68(+) cell population was HLA-DR-positive. CONCLUSIONS: This study shows that the human retina contains a number of different microglia populations, some of which express HLA-DR and could thus be involved in antigen presentation. Marked differences in cell density can be observed within the retina, with the most abundant presence seen in the peripheral retina. The normal retina contains few professional antigen-presenting cells (CD1(+)).

Adult↗
PubMed2000

Apoptosis of infiltrating cells in experimental autoimmune uveoretinitis.

OBJECTIVE: To investigate the cellular phenotype and apoptosis of infiltrating cells involved in experimental autoimmune uveoretinitis (EAU). METHODS: Immunohistochemical staining and in situ apoptosis staining were performed using monoclonal antibodies to monocytes and macrophages (ED1), major histocompatibility complex (MHC) class-II antigen (OX6), T lymphocytes (R73) and TACS 1 Klenow kit on both ocular sections and wholemounts from Lewis rats after immunization with interphotoreceptor retinoid-binding protein (IRBP). RESULTS: EAU was induced in 12 of 16 Lewis rats with a mean clinical inflammation score of 1.29 +/- 0.7. Influx of monocytes, lymphocytes and MHC class II-positive cells into the uvea and retina was noted after immunization with IRBP. Apoptosis of infiltrating cells was observed in the uvea and retina, and more apoptotic cells were present in the iris and ciliary body compared with those in the choroid and retina. CONCLUSION: Apoptosis of infiltrating cells occurs at the early stage of EAU, which may greatly contribute to the rapid regression of the inflammation induced by IRBP.

Animals↗
PubMed1999

Incidence of contact-lens-associated microbial keratitis and its related morbidity.

BACKGROUND: The incidence of contact-lens-associated microbial keratitis is uncertain and its related morbidity in the general population of contact-lens wearers is not known. We examined these issues in a prospective epidemiological study. METHODS: We surveyed all practising ophthalmologists in the Netherlands to identify all new cases of microbial keratitis reported during a 3-month period in 1996. Follow-up telephone calls were made to examine ocular morbidity. We undertook annual nationwide telephone surveys between 1994 and 1997 to estimate the prevalence of contact-lens wear. FINDINGS: Of 440 ophthalmologists contacted, 379 provided information. There were 92 cases of microbial keratitis; 17 used daily-wear rigid gas-permeable lenses, 63 daily-wear soft lenses, and 12 extended-wear soft lenses. The estimated annualised incidence of microbial keratitis was 1.1 per 10,000 (95% CI 0.6-1.7) users of daily-wear rigid gas-permeable lenses, 3.5 per 10,000 (2.7-4.5) users of daily-wear soft lenses, and 20.0 per 10,000 (10.3-35.0) users of extended-wear soft lenses (p<0.00001 for comparison between all groups), Five of the 92 patients achieved a final visual acuity of 20/70 or less. Pseudomonas and Serratia spp were the organisms most commonly isolated. Pseudomonas keratitis accounted for the largest mean diameter of corneal ulcers, the highest mean number of days in hospital, the greatest number of mean outpatients visits, and the poorest visual acuity outcome. INTERPRETATION: The incidence of microbial keratitis among users of extended-wear soft contact lenses in the Netherlands is similar to that reported in the USA during 1989. Awareness of risk factors and improvement in contact-lens materials have not led to a decrease in incidence. Overnight wear should be strongly discouraged.

Adolescent↗
PubMed1999

Expression of multiple forms of IL-1 receptor antagonist (IL-1ra) by human retinal pigment epithelial cells: identification of a new IL-1ra exon.

The eye is considered an immunologically privileged organ and is separated from the rest of the body by blood-ocular barriers. Part of the blood-retina barrier consists of the retinal pigment epithelium (RPE). In addition to the physical barrier which the monolayer of RPE cells forms, these cells contribute to ocular immune privilege by producing anti-inflammatory molecules that down-regulate potential damaging immune reactions. In this study the mRNA expression of IL-1 receptor antagonist (IL-1ra) by RPE cells was studied in 15 donor-derived cell lines. Expression of both the intracellular and secreted IL-1ra was detected in unstimulated and IL-1beta- or phorbol 12-myristate 13-acetate-exposed RPE. Analysis of IL-1ra protein in RPE cell lysates and cell culture supernatants indicated that these cells produce mainly intracellular IL-1ra. No correlation between IL-1ra expression levels and the IL-1ra gene polymorphism could be detected. In addition to the two known intracellular IL-1ra variants (intracellular IL-1ra type I and type II) evidence is provided for the expression of a hitherto unknown splice variant of the IL-1ra mRNA by RPE cells. Expression was not confined to RPE cells and could also be detected in cultured human fibroblasts and macrophages. This variant, which we have tentatively named intracellular IL-1ra type III, encodes a C-terminally truncated protein of only 27 amino acids.

Amino Acid Sequence↗
PubMed1999

Intraocular anti-Toxoplasma gondii IgA antibody production in patients with ocular toxoplasmosis.

PURPOSE: To investigate the immunoglobulin classes associated with the intraocular anti-Toxoplasma gondii antibody response during clinical ocular toxoplasmosis and to determine which immunoglobulin class is most helpful in the diagnosis of this disease. METHODS: Paired serum and intraocular fluid samples from 155 patients who had uveitis were tested for intraocular anti-T. gondii IgG, IgA, and IgM antibody production. The presence of T. gondii DNA was determined by polymerase chain reaction. Patients were divided into two groups, based on the initial clinical diagnosis; group 1 included 78 patients with presumed ocular toxoplasmosis, and group 2 included 77 patients with uveitis that was not clinically suspected to be ocular toxoplasmosis. Samples from 27 nonuveitis patients who underwent intraocular surgery were used as control subjects. The final diagnosis was based on the clinical course and interpretation of laboratory tests. RESULTS: A final diagnosis of ocular toxoplasmosis was made in 88 of 155 patients (group 1, 68; group 2, 20). Among these patients, 65% had intraocular IgG production, 52% had intraocular IgA production, 37.5% had both IgG and IgA production, 27% had IgG production only, and 15% had IgA production only. Of the 13 patients tested, only one had intraocular IgM production. Intraocular IgA could not be detected in patients who had final diagnoses other than ocular toxoplasmosis or in control subjects. A positive polymerase chain reaction combined with a test that was positive for intraocular IgG production had a sensitivity of 77%, which increased to 91% after the detection of intraocular IgA production was added. CONCLUSIONS: Immunoglobulin G is the major class involved in the humoral immune response against the T. gondii parasite, followed by IgA. The determination of IgA production is useful as an additional test in the diagnosis of ocular toxoplasmosis.

Adolescent↗
PubMed1999

Serologic evaluation of patients with primary and recurrent ocular toxoplasmosis for evidence of recent infection.

PURPOSE: To identify the frequency of recently acquired vs chronic systemic Toxoplasma gondii infections in patients with ocular toxoplasmosis. METHODS: Serum samples from 22 patients with primary ocular toxoplasmosis (not from scars) and 42 patients with recurrent ocular toxoplasmosis were tested for the presence of anti-T. gondii IgM, IgG, and IgA antibodies and compared with samples from 24 patients with other causes of uveitis. Intraocular production of anti-T. gondii IgG and IgA, and the presence of T. gondii DNA was determined in patient s and control subjects from whom ocular fluid was available. RESULTS: Serologic evidence of recently acquired infection was found for 11 (50%) of 22 patients with primary ocular toxoplasmosis and for one (2%) of 42 with recurrent ocular toxoplasmosis. In the uveitis control group, anti-T. gondii IgM antibodies could be detected in two (8%) of 24 patients, but anti-T. gondii IgA antibodies were not detectable. Patients with primary ocular toxoplasmosis and serologic markers of recently acquired systemic infection were significantly older than those with chronic infection (P = .008). Intraocular production of anti-T. gondii IgG was more frequently noted in patients with recurrent than primary ocular toxoplasmosis (81% vs 41%; P < .001), but intraocular T. gondii DNA was more frequently found in patients with primary ocular toxoplasmosis than in those with recurrent ocular toxoplasmosis (37% vs 4%; P < .01). CONCLUSIONS: Primary ocular toxoplasmosis can be seen in either recently acquired or chronic T. gondii infection. Patients with ocular disease and recently acquired infection were older and more likely to have T. gondii DNA in intraocular fluids.

Adolescent↗
PubMed1999

Polarized vascular endothelial growth factor secretion by human retinal pigment epithelium and localization of vascular endothelial growth factor receptors on the inner choriocapillaris. Evidence for a trophic paracrine relation.

The retinal pigment epithelium (RPE) maintains the choriocapillaris (CC) in the normal eye and is involved in the pathogenesis of choroidal neovascularization in age-related macular degeneration. Vascular endothelial growth factor-A (VEGF) is produced by differentiated human RPE cells in vitro and in vivo and may be involved in paracrine signaling between the RPE and the CC. We investigated whether there is a polarized secretion of VEGF by RPE cells in vitro. Also, the localization of VEGF receptors in the human retina was investigated. We observed that highly differentiated human RPE cells, cultured on transwell filters in normoxic conditions, produced two- to sevenfold more VEGF toward their basolateral side as compared to the apical side. In hypoxic conditions, VEGF-A secretion increased to the basal side only, resulting in a three- to 10-fold higher basolateral secretion. By immunohistochemistry in 30 human eyes and in two cynomolgus monkey eyes, KDR (VEGFR-2) and flt-4 (VEGFR-3) were preferentially localized at the side of the CC endothelium facing the RPE cell layer, whereas flt-1 (VEGFR-1) was found on the inner CC and on other choroidal vessels. Our results indicate that RPE secretes VEGF toward its basal side where its receptor KDR is located on the adjacent CC endothelium, suggesting a role of VEGF in a paracrine relation, possibly in cooperation with flt-4 and its ligand. This can explain the known trophic function of the RPE in the maintenance of the CC and its fenestrated permeable phenotype and points to a role for VEGF in normal eye functioning. Up-regulated basolateral VEGF secretion by RPE in hypoxia or loss of polarity of VEGF production may play a role in the pathogenesis of choroidal neovascularization.

Adolescent↗
PubMed1999

Influence of highly active antiretroviral therapy on the development of CMV disease in HIV positive patients at high risk for CMV disease.

BACKGROUND/AIMS: In the pre-HAART era, HIV positive patients with CD4+ cell counts below 50 cells x10(6)/l, and those with detectable cytomegalovirus (CMV) DNA in their peripheral blood, were considered to be at high risk for the development of CMV disease. With the start of highly active antiretroviral therapy (HAART), a restoration of immune function occurred in these patients, and as a consequence patients became less vulnerable to CMV disease. Since it is not exactly known how HAART influences CMV viral load in peripheral blood and the incidence of CMV disease in high risk HIV positive patients a group of patients was followed before and after initiation of HAART. METHODS: 29 HIV positive patients, seen in the first 3 months of 1996 at the AIDS clinic of the Academic Medical Centre, at high risk for development of CMV disease (positive CMV DNA assay in blood and/or CD4+ cell count below 50 cells x10(6)/l), not receiving anti-CMV maintenance therapy, were included in a prospective cohort study. HAART was started in the second trimester of 1996. Patients were evaluated for the occurrence of CMV retinitis, or CMV disease elsewhere, comparing the incidence of CMV events before and after the start of HAART. Following the introduction of HAART, CD4+ cell counts and quantitative polymerase chain reaction (PCR) for CMV DNA in blood were monitored in all patients who remained alive and were not receiving anti-CMV maintenance therapy (n=22). Follow up was performed until August 1998; the mean follow up after the start of HAART was 14.9 months (range 8-22 months). RESULTS: In the pre-HAART period four patients developed CMV disease, and four died (without clinically manifest CMV disease). After the start of HAART no patient developed CMV disease or died. With HAART, the mean CD4+ cell counts increased from 34 cells x10(6)/l to 194 cells x10(6)/l at the end of follow up. CMV DNA could be detected in the blood of 11 patients. Quantification showed a decline in the amount of detectable DNA during follow up. At the last examination only one patient showed a positive PCR assay. This was the only patient with a CD4+ cell count remaining below 100 cells x10(6)/l. CONCLUSION: In HIV positive patients at high risk of CMV retinitis, either with a positive CMV PCR assay in blood and/or with CD4+ cell counts below 50 cell x10(6)/l, HAART causes a dramatic decrease in the occurrence of CMV disease. This decrease is paralleled by an increase in CD4+ cell count, and a decrease in the amount of CMV DNA in the blood, which was below detection levels in all patients with CD4+ cell counts above 100 cells x10(6)/l.

AIDS-Related Opportunistic Infections↗
PubMed1999

Aetiological study of the presumed ocular histoplasmosis syndrome in the Netherlands.

AIM: To investigate whether presumed ocular histoplasmosis syndrome in the Netherlands is caused by Histoplasma capsulatum and whether other risk factors might play a role in the pathogenesis of this syndrome. METHODS: 23 patients were clinically diagnosed as having presumed ocular histoplasmosis syndrome based on the following criteria: peripapillary atrophy, punched out lesions, a macular disciform lesion or scar in one eye without vitritis. As controls, 66 sex and age matched healthy volunteers were used. Serum samples from both patients and controls were tested for the presence of antibodies against H capsulatum, Toxoplasma gondii, Toxocara canis et cati, Ascaris sp, and for the presence of antigens of Cryptococcus neoformans. Serum samples were also tested for the presence of autoantibodies against retinal or choroidal proteins. To investigate other risk factors, patients and controls were asked to fill in a health and travel related questionnaire. Ten patients with ocular toxoplasmosis were used as a disease control group. RESULTS: None of the patients with presumed ocular histoplasmosis syndrome or controls had circulating antibodies directed against H capsulatum. No risk factors could be identified and no indications for autoimmunity and no evidence for the role of the other infectious agents could be demonstrated. CONCLUSIONS: In a Dutch group of patients fulfilling the criteria of a disease currently named presumed ocular histoplasmosis syndrome, no risk factors or relation with the fungus H capsulatum could be detected.

Adult↗
PubMed1999

Soluble ICAM-1 serum levels in patients with intermediate uveitis.

AIM: To investigate whether serum levels of soluble intercellular adhesion molecule 1 (sICAM-1) can serve as a marker of the presence of systemic disease in intermediate uveitis. METHODS: In a multicentre study sICAM-1 serum levels were measured in 61 patients with idiopathic intermediate uveitis, controls included 56 uveitis patients with a systemic disease (26 sarcoid associated uveitis and 30 HLA-B27 positive acute anterior uveitis), 58 uveitis patients without systemic disease (30 toxoplasma chorioretinitis and 28 Fuchs' hetrochromic cyclitis), and 21 normal controls. The clinical records of the patients with intermediate uveitis were analysed for disease characteristics at the time of blood sampling and for a relation with the development of a systemic disease after a mean follow up of 4.5 years. RESULTS: Increased serum levels of sICAM-1 were found in 34 out of 61 patients with intermediate uveitis and were significantly different when compared with toxoplasmosis, Fuchs' cyclitis, and healthy controls (p<0.001). Elevated sICAM-1 levels were also found in 18 out of 26 patients with sarcoid uveitis and in 11 out of 30 patients with HLA-B27 associated anterior uveitis. Raised sICAM-1 levels in the intermediate uveitis group were significantly associated with active ocular disease (p<0.01) and the presence of vitreous exudates (p<0.05). Increased levels of sICAM-1 correlated with interleukin 8 levels (IL-8) (tested in a previous study in the same group of intermediate uveitis patients) in patients with active systemic involvement. Follow up of the patients showed that an established or suspected systemic disease was found more often in the 21 intermediate uveitis patients with increased sICAM-1 and IL-8 levels compared with the other 40 patients with intermediate uveitis (p<0.01). CONCLUSIONS: The measurement of both sICAM-1 and IL-8 can be used as a marker for ocular disease activity and for a predisposition of developing an associated systemic disease in intermediate uveitis patients.

Adult↗
PubMed1999

Interleukin 10 treatment does not prolong experimental corneal allograft survival.

In view of the known anti-inflammatory activities of interleukin (IL) 10, we investigated whether the administration of recombinant murine IL-10 prolonged corneal graft survival. A major histocompatibility complex mismatched rat model with AO rats as recipients of PVG donor corneas was used. A total of 39 corneal allografts was included in this study and divided into 7 groups for different treatments. Group I (n = 6), II (n = 8), III (n = 6) and IV (n = 7) were injected subconjunctivally with saline (control), 0. 5 ng, 5 ng or 50 ng of IL-10, respectively, on the day of transplantation and then on postoperative days (POD) 2, 4, 6, 8 and 10. Group V (n = 4) and group VI (n = 4) were injected intraperitoneally with saline (control) or 1 microg of IL-10, respectively, on the day before surgery, the day of grafting and then on POD 2, 4 and 6. Finally, group VII (n = 4) was injected with both subconjuctival 5 ng of IL-10 and intraperitoneal 1 microg of IL-10 on the same days as the previous groups. The median days for corneal rejection in the various groups were: group I, 11.3 +/- 0.9; group II, 11.5 +/- 0.9; group III, 11.6 +/- 0.8, and group IV, 10 +/- 1.0. Statistical analysis revealed a trend towards rejection (p = 0.08) in group IV (compared to group I). In groups V and VI, corneal rejection was evident on day 12 and in group VII the median time for rejection was 10.5 +/- 0.8 days. These results indicate that IL-10 treatment does not prolong corneal allograft survival and may even accelerate rejection.

Animals↗
PubMed1999

Changes in cytokine mRNA levels in experimental corneal allografts after local clodronate-liposome treatment.

PURPOSE: Corneal allograft rejection in rats can be prevented by subconjunctival injections of liposomes containing dichloromethylene diphosphonate (clodronate-LIP), which selectively eliminate macrophages. In this study, the effect of clodronate-LIP treatment on cytokine mRNA levels in corneal allografts was examined. METHODS: AO rats received corneal grafts of PVG rats. Rats were either not treated or injected subconjunctivally with clodronate-LIP on the day of transplantation and on postoperative days (PODs) 2, 4, 6, and 8. RNA was isolated from the graft and rim of corneas at different times after transplantation and from normal controls. Interleukin (IL)-1beta, IL-1 receptor antagonist (IL-1RA), IL-2, IL-4, IL-6, IL-10, IL-12p40, tumor necrosis factor (TNF)-alpha, TNF-beta/lymphotoxin (LT), interferon (IFN)-gamma, monocyte chemotactic protein 1 (MCP-1), and macrophage inflammatory protein 2 (MIP-2) mRNA levels were analyzed by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Corneal rejection, observed in all untreated rats by POD 12, was associated with increased mRNA levels of all cytokines investigated in grafts and rims. Clodronate-LIP treatment prevented allograft rejection and strongly decreased the levels of IL-1beta, IL-1RA, IL-2, IL-4, IL-6, IL-10, IFN-gamma, TNF-beta/LT, MCP-1, and MIP-2 mRNA in grafts and IL-1 beta, IL-2, IL-4, IL-6, and IFN-gamma mRNA in rims. Interleukin-12p40 mRNA levels were unaltered in clodronate-treated rats, except for a transient increase in grafts at POD 3. TNF-alpha mRNA levels were increased by clodronate-LIP in grafts and rims early after transplantation (PODs 3 and 7). Despite a normal appearance, long-term accepted corneal grafts (POD 100) contained mRNA for IL-10, IL-12p40, TNF-alpha, MCP-1, and MIP-2. CONCLUSIONS: Clodronate-liposome treatment markedly altered the mRNA levels of all cytokines investigated in corneal allografts. These results may explain in part the mechanism by which clodronate-LIP treatment prevents corneal allograft rejection.

Animals↗
PubMed1999

In vivo human corneal hydration control dynamics: a new model.

PURPOSE: To introduce a new model describing human in vivo corneal deswelling after hypoxic contact lens wear, based on a damped harmonic oscillator, which can describe an overshoot in corneal deswelling, to compare this new model with the currently used exponential model, and also to test whether a diurnal variation in baseline corneal thickness exists that would have to be taken into consideration when calculating corneal deswelling curves. METHODS: In nine healthy young adults, corneal thickness was measured every 30 minutes for 11.5 hours on average using modified optical pachometry (natural test). On another day, corneal deswelling was monitored for 11.1 hours on average after 2 hours of hypoxic contact lens wear (stress test). The damped harmonic oscillator model and the exponential model were used to calculate best-fitting deswelling curves. Natural test data were analyzed for the presence of a trend. Goodness of fit of the curves to the experimental data was analyzed using the F test. RESULTS: In 82% of the deswelling curves the new damped harmonic oscillator model provided a better fit to the data than the exponential model (P < 0.05). An average overshoot in corneal thickness recovery of 5 microm (range, 0-11 microm) was found. In 50% of the natural tests significant trends were found, without any consistent similarities. The overshoot could not be explained by these trends. CONCLUSIONS: The new damped harmonic oscillator model describes corneal deswelling after hypoxic contact lens wear more accurately than the exponential model. No consistent diurnal variation could be demonstrated.

Adult↗
PubMed1998

Cytomegalovirus (CMV) strain differences between the eye and blood in AIDS patients with CMV retinitis.

OBJECTIVE: To investigate possible differences in cytomegalovirus (CMV) strain distribution between the eye and blood in AIDS patients with CMV retinitis. METHODS: CMV DNA sequences from aqueous humour and peripheral blood leukocytes (PBL), obtained from 13 AIDS patients with CMV retinitis, were compared. DNA was isolated and the CMV IE-1 sequence (part of the immediate early-1 gene) and the a-sequence (located in the a-region) were amplified by polymerase chain reaction (PCR). The PCR products of the a-sequence were analysed by Southern blotting for amplified fragment-length polymorphisms. The level of divergence between the a-sequences of aqueous humour- and PBL-derived CMV was studied in two patients by cloning these sequences followed by sequence analysis. RESULTS: CMV DNA could be detected in all aqueous humour samples and in 10 out of 13 paired blood samples. In the 10 patients, with CMV DNA detectable in both aqueous humour and PBL, seven cases showed differences between the amplified products of both compartments. Sequence analysis in two patients revealed that the aqueous humour and PBL of the same patient can harbour both identical, similar and highly divergent CMV a-sequences. CONCLUSION: These results indicate that despite the haematogenous spread of CMV, the eye, being a relatively shielded organ, may contain CMV strains different from those found in the blood.

AIDS-Related Opportunistic Infections↗
PubMed1998

Differences between intraocular and serum antibody responses in patients with ocular toxoplasmosis.

PURPOSE: To investigate the antigen specificity of the intraocular anti-Toxoplasma gondii antibody response in patients with ocular toxoplasmosis. METHODS: Paired ocular fluid and serum samples were collected from 13 patients with active ocular toxoplasmosis. Serum IgM anti-T. gondii antibodies were tested to distinguish recently-acquired from chronic infection. Anti-T. gondii IgG specificity was analyzed by immunoblotting using a crude T. gondii extract. RESULTS: Two of the 13 patients tested were IgM positive and considered to have acquired ocular toxoplasmosis. The antibody specificity in ocular fluid and serum of these two patients was similar, whereas in the patients with presumed chronic disease, marked differences could be observed. Most ocular fluid samples contained antibodies that stained a 28-kD antigen more intensely than did antibodies from paired serum samples. Using absorption and elution experiments, we demonstrated that this 28-kD protein was identical to the GRA-2 antigen, which is expressed in both the tachyzoite and the bradyzoite stages of the parasite. CONCLUSIONS: Our results show that the intraocular T. gondii antibody response of patients with recurrent ocular toxoplasmosis differs from the systemic response. This finding may have implications for our understanding of the immunopathogenesis of ocular toxoplasmosis and could be employed to improve diagnosis of the disease.

Adult↗