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Biomedical subjects

L Luyendijk

Publications and source records attributed to L Luyendijk.

13 recordsLinked to original sources
PubMed1992

Anti-retinal S-antigen antibodies in human sera: a comparison of reactivity in ELISA with human or bovine S-antigen.

Various studies have demonstrated anti-retinal S-antigen (S-ag) antibodies in uveitis sera in assays using bovine S-ag. Because of its molecular similarity and cross-reactivity with human S-ag, reactions with bovine S-ag have been considered a reliable indication of anti-S-ag autoimmunity. To test this assumption, the cross-reactivity of purified human and bovine S-ags was quantitated by ELISA titration of various anti-human and anti-bovine S-ag immune reagents raised in mice, rats and rabbits. Anti-human S-ag reagents appeared to be largely cross-reactive with bovine S-ag, whereas anti-bovine S-ag reagents were 6-10 times less reactive with the cross-reacting human S-ag than with bovine S-ag, thus showing a predominant role of species-specific epitopes on bovine S-ag. Furthermore, a large number of human control and uveitis sera was tested in ELISA with both human S-ag- and bovine S-ag-coated microwells. Both the numbers of positive sera and the levels of anti-S-ag antibodies in the two tests significantly correlated, but many exceptions were found, and the predictive value of reactions with bovine S-ag for the presence and levels of anti-S-ag autoantibodies was low. For individual human sera, assessment of anti-S-ag autoantibodies requires the use of human S-ag in immunoassays.

Animals↗
PubMed1992

Analysis of aqueous humour in uveitis by high performance liquid chromatography and sodium dodecyl sulphate-polyacrylamide gel electrophoresis.

Aqueous humour from patients with Fuchs' heterochromic cyclitis (FHC) and other types of uveitis was analysed by high performance liquid chromatography (HPLC) and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Using HPLC, the number of peaks and their respective elution times were similar for the FHC, uveitis and control groups. SDS-PAGE and silver staining showed immunoglobulin G migrating as two to four distinct bands in all non-reduced samples. In the reduced state, 1-5 unidentified low MW bands (10-19 kD) were seen. Two bands at 19 and 10 kD appeared to be specific for the uveitis group, and a band at 11 kD was present in 76% of uveitis and 19% of FHC patients. None of these three bands were detected in any of the control group. As yet the identity of these low MW proteins and their possible significance in the pathogenesis of intraocular inflammation are unknown.

Adult↗
PubMed1992

Uveitis and systemic disease.

A prospective study was conducted of 865 patients with uveitis to determine the frequency of associated systemic diseases and to assess the value of limited laboratory screening of these patients. All patients underwent a standard diagnostic protocol followed--when indicated--by special tests and procedures performed in order of likelihood ('tailored approach'). For 628 patients (73%) a specific diagnosis was established based on history, ophthalmologic examination, and laboratory and radiographic studies. A definite association with systemic disease was determined for 220 patients (26%). A relationship with a subclinical systemic disorder could be presumed in 201 cases (23%) and a well-established clinical uveitis entity without a recognisable systemic disorder was present in 207 cases (24%). For 237 patients (27%) a diagnosis could not be determined. The most frequently observed systemic diseases were sarcoidosis (7%) and HLA-B27-associated seronegative spondylarthropathies (6%). Presumed or definite toxoplasmosis was encountered in 10% of cases. HLA-B27-associated acute anterior uveitis was the most common clinical entity (17%). In the majority of cases the presence of a systemic disease was not suspected prior to eye involvement and was only recognised after the subsequent diagnostic procedures.

Adolescent↗
PubMed1992

Transient decrease of secretory IgA in tears during rigid gas permeable contact lens wear.

Decreased humoral defense mechanisms may be involved in the occurrence of keratic ulcerations after contact lens wear. To investigate the effect of contact lens wear on tear protein composition a prospective study was performed whereby tears were collected with Schirmer papers from 42 healthy individuals, before and at varying times after contact lens wear. Tear proteins were quantitated using HPLC analysis. Analysis of tear fluid by HPLC is a rapid and simple technique to detect the major tear proteins. Four separate peaks containing respectively IgA, lactoferrin, TSPA and lysozyme can easily be identified. The results show that the mean relative level of secretory IgA in the collected tear samples decreased significantly after the first months of contact lens wear but was not significantly altered after one year. The decrease in IgA was accompanied by a significant increase in the relative amount of lysozyme, whereas the levels of lactoferrin and TSPA remained the same. Certain individuals showed a marked decrease in their tear secretory IgA levels after wearing the lenses for more than one year. Future studies will clarify whether such individuals are at higher risk to develop corneal complications.

Adolescent↗
PubMed1991

Analysis of local antibody production in the vitreous humor of patients with severe uveitis.

We analyzed the local antibody production in vitreous humor samples collected during vitrectomy in patients with severe vision-threatening uveitis. In 24 patients, paired serum and undiluted vitreous humor samples were collected and tested for antibodies against Toxoplasma gondii, herpes simplex virus, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus, and Toxocara canis. Total IgG and the Goldmann-Witmer coefficient were determined. The initial diagnosis of ocular toxoplasmosis could be confirmed in six of the seven patients. The seventh patient showed a local antibody production against herpes simplex virus. One of the three patients with chronic panuveitis at initial diagnosis showed a local antibody production against T. gondii. These last two findings resulted in a change in medical treatment. Analysis of local antibody production in vitreous humor samples is a valuable diagnostic tool.

Animals↗
PubMed1991

The lifetime cumulative incidence of acute anterior uveitis in a normal population and its relation to ankylosing spondylitis and histocompatibility antigen HLA-B27.

The lifetime cumulative incidence of acute anterior uveitis (AAU) was determined in a sample of a large population (n = 10,500). Nine hundred seventeen subjects, who answered the question "Have you ever had a red eye" in the affirmative in 1977, were asked to participate in a follow-up study 10 years later. From the 917 respondents, 539 were studied completely. A questionnaire was used to collect historic data, and confirmation of these data was obtained from the treating ophthalmologists and physicians. From these data, subjects were selected for an ophthalmologic examination. The respondents also underwent a rheumatologic examination. The results revealed that the lifetime cumulative incidence of definite AAU is approximately 0.2% in the general population and 1% in the histocompatibility antigen HLA-B27-positive population. In one third of the definite AAU patients, the cause of the disease was known. The lifetime cumulative incidence of definite AAU of unknown cause was 0.15% in the general population. When possible and probable AAU are included, the lifetime cumulative incidence of AAU in the general population is about 0.4%. The observed frequency of the concurrence of AAU and ankylosing spondylitis (AS) was 0.4% in the HLA-B27-positive population and 0.02% in the HLA-B27-negative population. Comparison with the expected frequency of the concurrence of AAU and AS revealed that AAU and AS probably are related diseases irrespective of the association of both diseases with HLA-B27.

Acute Disease↗
PubMed1990

Laboratory tests in uveitis. New developments in the analysis of local antibody production.

Analysis of local intraocular antibody production is a valuable tool with which to confirm a suspected clinical diagnosis in uveitis. We have analysed paired serum and aqueous samples for the presence of specific antibodies against toxoplasma, cytomegalovirus, herpes simplex virus and varicella zoster virus. Of the patients retrospectively diagnosed as having toxoplasma chorioretinitis 75% had a positive antibody coefficient indicating specific antibody production in the eye. Local antibody production in the eye directed against CMV confirmed the suspected diagnosis of CMV retinitis in 50% of the AIDS patients investigated. So far we have not been able to demonstrate local antibody production against herpes simplex virus (26 samples tested). Two of three patients with acute retinal necrosis had a positive antibody coefficient against varicella zoster virus. Both of these patients had an even higher titer in the aqueous than in serum. Since the choice of therapy, in infectious uveitis, depends on the causative organisms, it is very important to confirm a suspected clinical diagnosis by means of aqueous humor analysis.

Antibodies, Protozoan↗
PubMed1990

Detection of locally produced antibodies to herpes viruses in the aqueous of patients with acquired immune deficiency syndrome (AIDS) or acute retinal necrosis syndrome (ARN).

Intraocular synthesis of IgG antibodies against HSV (herpes simplex virus), CMV (cytomegalovirus) and VZV (varicella zoster virus) is considered as an indirect proof of uveoretinal infection. Paired serum and aqueous samples obtained from 16 patients with retinitis associated with AIDS, 3 patients with ARN, 8 patients with posterior uveitis not related to AIDS or ARN and 5 patients with senile cataract were tested for total immunoglobulin G levels and antibodies to HSV, CMV and VZV by the fixed cell immunofluorescence technique. Since therapy must often be started before results of cultures are available, rapid detection of locally produced anti-Herpes Virus antibodies can be a precious tool in the diagnosis of ocular viral infection. Using this technique we were able to confirm the clinically suspected diagnosis in more than 50% of AIDS patients with retinitis and in two out of three patients with ARN.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Aqueous humour analysis in Fuchs' heterochromic cyclitis.

Aqueous humor from 23 patients with Fuchs' heterochromic cyclitis (FHC) was analysed by a number of immunological methods. Intraocular IgG synthesis was found in 65% of patients and oligoclonal IgG bands, mainly of the IgG1 subclass, identified in 57%. There was a relative increase in IgG1 (P less than 0.01) as compared to patients with senile cataract. Local production of the cytokine Interleukin-6 was demonstrated in 63% of patients (P less than 0.01). Analysis of aqueous by HPLC and SDS-PAGE failed to reveal any abnormalities specific for FHC. These findings add further evidence to the theory of immune dysregulation in this condition.

Adult↗
PubMed1990

Analysis of aqueous humor immunoglobulin G in uveitis by enzyme-linked immunosorbent assay, isoelectric focusing, and immunoblotting.

Immunoglobulin G (IgG) in aqueous humor from patients with various uveitis syndromes was analyzed using a number of immunologic techniques. Sixty-five percent of patients with Fuchs' heterochromic cyclitis (FHC), 70% of patients with other forms of uveitis, and 44% of controls showed local synthesis of IgG, as demonstrated by an elevated IgG:albumin relative concentration ratio. Using an enzyme-linked immunosorbent assay to measure the concentration of IgG subclasses 1-4, a relative excess of IgG1 was found in the aqueous compared with the serum in FHC. Isoelectric focusing and immunoblotting studies revealed oligoclonal IgG bands in the aqueous of 13 of 23 (57%) patients with FHC, most being of the IgG1 subclass. Oligoclonal bands were not found in 18 patients with other types of uveitis or 13 patients undergoing surgery for senile cataract. These findings indicate intraocular production of IgG of restricted specificity in FHC, providing further evidence for local immune dysfunction in this condition. As yet the antigenic stimulus for this oligoclonal B-cell response has not been identified.

Adult↗
PubMed1989

HPLC analysis of tear proteins in giant papillary conjunctivitis.

Giant papillary conjunctivitis (GPC) is a well defined entity seen in patients with deposits on their lenses. High performance liquid chromatography (HPLC) tear protein analysis was performed on 17 GPC patients and compared with healthy controls with and without contact lenses. The IgA levels are somewhat lower in GPC patients as compared with healthy controls not wearing lenses (P less than 0.05). A similar decrease was also seen in the control group wearing contact lenses. We were not able to identify a specific HPLC tear protein profile in GPC patients as compared with controls. The HPLC profile therefore gives no explanation for the lens deposits and is not suitable as a diagnostic or prognostic tool.

Adult↗
PubMed1989

Aqueous humor analysis as a diagnostic tool in toxoplasma uveitis.

Analysis of local toxoplasma antibody production to confirm a suspected clinical diagnosis of toxoplasma chorioretinitis is a valuable diagnostic tool. Determination of toxoplasma antibodies in the blood of the patient is of limited use. When blood toxoplasma tests are negative this indicates that toxoplasma as a causative organisms in the pathogenesis of uveitis is unlikely. A positive blood test is a sensitive test (100% patients positive) but not a specific test since so many healthy individuals already have undergone subclinical infection and have acquired humoral immunity against the parasite. We analysed 93 paired aqueous and serum samples for toxoplasma antibodies and total IgG and determined the Goldmann-Wittmer coefficient. In patients retrospectively diagnosed as having toxoplasma chorioretinitis 16 out of 22 had a positive coefficient, indicating local parasite antibody production. In one patient with AIDS we also found a positive toxoplasma coefficient. Three out of 15 patients with posterior uveitis of unknown origin also had a positive coefficient. None of the cataract patients tested (n = 32) had a positive coefficient. Major drawbacks of aqueous humor analysis are that a false negative antibody coefficient can occur when a massive blood aqueous barrier breakdown has occurred.

Antibodies, Protozoan↗