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.

Elevated serum IL-8 levels are associated with disease activity in idiopathic intermediate uveitis.

AIM: To find a laboratory indicator for systemic involvement in intermediate uveitis. METHODS: Interleukin 8 (IL-8) and C reactive protein (CRP) serum levels were measured in patients with idiopathic intermediate uveitis (n = 61), uveitis controls (n = 143), and normal controls (n = 29). The records of those with intermediate uveitis were reviewed with the emphasis on disease activity and severity as characterised by the presence of cystoid macular oedema, vitreous exudates or snowbank formation, papillitis, and periphlebitis. RESULTS: Increased serum IL-8 (> or = 20 pg/ml) was found in 27 out of 61 patients with intermediate uveitis (p < 0.01), 12 of 27 patients with sarcoid uveitis (p < 0.05), in 19 of 30 patients with HLA-B27 associated acute anterior uveitis (p < 0.05), and in five of 29 healthy controls. Raised IL-8 levels in intermediate uveitis were significantly associated with active disease (p < 0.001) and the presence of vitreous exudates (p < 0.001), papillitis, and periphlebitis (p < 0.01). Elevated CRP levels were found in 12 of the 143 uveitis controls but in none of the intermediate uveitis patients or normal controls. During follow up an associated systemic disease was more frequently noticed in patients with an elevated serum IL-8 at entry into the study. CONCLUSIONS: Elevated IL-8 serum levels were found in patients with active intermediate uveitis of unknown origin. An elevated IL-8 level seems to predispose the patient to a later development of associated systemic disease.

Aetiology of uveitis in Sierra Leone, west Africa.

BACKGROUND: In 1992, non-onchocercal uveitis caused 9% of blindness, 8% of visual impairment, and 11% of uniocular blindness among patients visiting an eye hospital in Sierra Leone, west Africa. The aim of this study was to determine the aetiology of uveitis in this population. METHODS: General and ophthalmic examination complemented by serum and aqueous humour analyses for various infectious agents was performed for 93 uveitis patients and compared with serum (n = 100) and aqueous humour (n = 9) analysis of endemic controls. RESULTS: At the initial examination, 45 patients (48%) proved to be severely visually handicapped. After clinical and laboratory analyses, an aetiological diagnosis was established for 49 patients (52%). Toxoplasma gondii was the most important cause of uveitis (40/93; 43%). Anti-toxoplasma IgM antibodies were detected in serum samples of seven of 93 patients (8%) compared with one of 100 controls (1%, p < 0.05). At least six patients (15%) with ocular toxoplasmosis had acquired the disease postnatally. Antibodies against Treponema pallidum were detected in 18 of 92 patients (20%) and in 21 controls (21%). Other causes of uveitis were varicella zoster virus (one patient), herpes simplex virus (two patients), and HLA-B27 positive acute anterior uveitis with ankylosing spondylitis (one patient), while one patient had presumed HTLV-I uveitis. CONCLUSIONS: In a hospital population in Sierra Leone, west Africa, uveitis was associated with severe visual handicap and infectious diseases. Toxoplasmosis proved to be the most important cause of the uveitis. Although the distribution of congenital versus acquired toxoplasmosis in this population could not be determined, the results indicate an important role of postnatally acquired disease. The results further suggested minor roles for HIV, tuberculosis, toxocariasis, and sarcoidosis as causes of uveitis in this population.

Serological and polymerase chain reaction-based analysis of aqueous humour samples in patients with AIDS and necrotizing retinitis.

OBJECTIVE: To evaluate the measurement of intraocular antibody production and detection of DNA by the polymerase chain reaction (PCR) for diagnosis of the causative microorganism in patients with AIDS and necrotizing retinitis. METHODS: Paired serum and aqueous humour samples obtained from 28 patients with AIDS and necrotizing retinitis, seen between January 1987 and March 1992, were analysed for intraocular antibody production against cytomegalovirus (CMV), varicella zoster virus, herpes simplex virus, Epstein-Barr virus, and Toxoplasma gondii. Specific antibody titres in the inflamed eye and in the circulation were related to total immunoglobulin G content in the aqueous humour and serum. In addition, PCR analysis was performed in 15 samples. Results were compared to the final diagnosis, which was based on the subsequent clinical course. Results were also related to parameters describing the immune state of the patients: CD4 count, time between diagnosis of an AIDS-defining illness and retinitis, and time of survival following the diagnosis of retinitis. RESULTS: In 11 (39%) out of 28 patients we found local intraocular antibody production which correlated with the final diagnosis (one out of two cases with acute retinal necrosis, three out of five cases with toxoplasma retinitis, and eight out of 21 patients with CMV retinitis). In all 13 patients with CMV retinitis PCR analysis detected CMV DNA. In one patient with the clinical diagnosis of Toxoplasma retinitis, Toxoplasma DNA could be determined, whereas in the same sample CMV DNA was also found. In yet another patient with Toxoplasma retinitis only CMV DNA could be detected. A relationship between results of local antibody determination with either CD4 counts, or the time interval between AIDS-defining illness and retinitis, or survival time after diagnosis of retinitis could not be established. CD4 counts were higher than 50 x 10(6)/l in eight out of 19 patients with CMV retinitis. No complications of paracentesis were seen. CONCLUSIONS: Detection of intraocular antibody production and PCR analysis are quick and safe procedures and helpful tools for diagnosis of the involved pathogen in AIDS patients with a necrotizing retinitis. Negative results of local antibody production, even in the presence of detectable viral DNA, could not be related to the parameters of a more deteriorated immune status of these patients.

Presumed acquired ocular toxoplasmosis.

OBJECTIVE: To describe the clinical characteristics and laboratory findings of eight patients with focal chorioretinitis presumably caused by acquired toxoplasmosis. DESIGN: Case series. SETTING: Referral hospitals in the Netherlands. PATIENTS: Eight patients, aged 42 to 75 years, with unilateral focal chorioretinitis and laboratory evidence of a recently acquired infection with Toxoplasma gondii. MAIN OUTCOME MEASURES: Findings from ocular examination and analysis of both serum and aqueous humor samples for Toxoplasma and viral antibodies. RESULTS: All patients had unilateral focal chorioretinitis without associated old scars in the posterior pole. Patients treated with systemic or periocular corticosteroids not accompanied by antiparasitic medication showed a rapid increase of inflammation. All eight patients had Toxoplasma IgM antibodies in their serum samples, seven of whom had high Toxoplasma IgG titers. Five of eight patients had increased intraocular production of IgG antibodies against T gondii. CONCLUSION: Unilateral focal chorioretinitis in patients of any age should alert the clinician to consider acquired ocular toxoplasmosis in the differential diagnosis.

C-reactive protein and interleukin-6 are elevated in onchocerciasis patients after ivermectin treatment.

Ivermectin treatment of onchocerciasis can induce adverse reactions. Mechanisms underlying these reactions are poorly understood but may include activation of neutrophils. This study investigated the acute-phase response in onchocerciasis patients during 2 days after ivermectin treatment. The acute-phase protein C-reactive protein (CRP) and cytokines that mediate the acute-phase response (tumor necrosis factor-alpha [TNF alpha] and interleukin-6 [IL-6]) were measured in 144 skin snip-positive onchocerciasis patients and 12 skin snip-negative controls who received one dose of ivermectin (150 micrograms/kg). No elevated TNF alpha levels were found, but IL-6 and CRP were elevated in 25.7% and 50.7% of the patients, respectively, after ivermectin treatment. Most patients (89.2%) with raised IL-6 also had raised CRP. Such increases were not observed in controls and in patients were correlated with adverse reactions and microfilarial densities. These findings suggest a possible role of the acute-phase response in microfilarial destruction following ivermectin treatment.

Detection of intraocular antibody production to herpesviruses in acute retinal necrosis syndrome.

In order to improve the determination of the causative agent in acute retinal necrosis syndrome, we evaluated the detection of intraocular antibody production to herpesviruses in 28 patients with this disease. Intraocular antibody production was determined by calculation of the Goldmann-Witmer coefficient whereby specific antibody titers in the inflamed eye and circulation are related to the total IgG content in ocular fluid and serum. Specific antibody titers to herpesviruses and Toxoplasma were determined by the indirect immunofluorescence technique. Thirty-five patients with ocular toxoplasmosis, cataract, or proliferative vitreoretinal disorders were tested as controls. By this technique, intraocular antibody production to varicella zoster virus or herpes simplex virus could be established in 16 (57%) of the patients with the typical clinical features of acute retinal necrosis, compared to none of the controls. Of the 33 affected eyes, 21 (64%) had a visual outcome of less than 20/200. We concluded that detection of intraocular antibody production to herpesviruses may be a useful diagnostic tool in establishing the causative agents in acute retinal necrosis.

Uveitis and Lyme borreliosis.

In a retrospective study 56 consecutive patients with uveitis of unknown origin and 56 consecutive patients suffering from uveitis of established aetiology were investigated. The purpose of this study was to determine the frequency of positive serological tests for Lyme borreliosis among patients with uveitis and to relate laboratory data to clinical findings. The antibody titre for Borrelia burgdorferi was determined by two assays: the indirect immunofluorescence assay and the enzyme linked immunosorbent assay. A positive result according to one or both assays was found for eight patients with uveitis of unknown aetiology (14%) and three patients with uveitis of established cause (5%). On clinical examination, none of the patients fulfilled the CDC criteria for diagnosis of Lyme borreliosis.

Birdshot chorioretinopathy and Lyme borreliosis.

Two patients in whom ocular Lyme disease was suspected and who had antibodies to Borrelia burgdorferi developed birdshot chorioretinopathy and carried the HLA-A29 antigen. In a series of 11 patients with birdshot chorioretinopathy who carried the HLA-A29 antigen, three patients had antibodies against B. burgdorferi as determined by either immunofluorescence assay, enzyme-linked immunosorbent assay, Western blot analysis, or a combination of these tests. Further studies will be necessary to evaluate whether this is a false-positive reaction or whether B. burgdorferi has a causative role in the pathogenesis of birdshot chorioretinopathy.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.