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Biomedical subjects

W J Stevens

Publications and source records attributed to W J Stevens.

At least 109 records · Page 6Linked to original sources
PubMed1989

Immunohistochemical characterization of the mononuclear cells in the brain of the rat with an experimental chronic Trypanosoma brucei gambiense infection.

The distribution of T-cell subsets, B cells, and class II MHC antigens was examined within the CNS of rats chronically infected with Trypanosoma brucei gambiense, using appropriate mouse monoclonal antibodies. The mononuclear infiltrates of the leptomeninges and the perivascular areas (Virchow-Robin spaces) were composed of IgM-producing plasma cells and Mott cells and T-helper/inducer cells. Cells defined phenotypically as suppressor/cytotoxic T cells were rare. Anti-Ia reactive cells were also abundant in these inflammatory lesions and in the white matter, representing Ia-expressing neuroglial cells, B cells, activated T cells, and macrophages. The Ia-positive neuroglial cells, possibly acting as accessory cells, associated with numerous T-helper/inducer cells and cells from the B-cell lineage, suggest that a T-dependent B-cell immune response can be initiated within the CNS of rats with a chronic T. b. gambiense infection.

Animals↗
PubMed1989

Pitfalls with anti-neutrophil cytoplasmic antibodies (ANCA).

A 39-year-old Ugandan student is described presenting with general malaise, fever and a pulmonary infiltrate. Open lung biopsy showing infarction and positive ANCA lead to a diagnosis of Wegener's granulomatosis and a treatment with immunosuppressive drugs was instituted. Five weeks after admission, however, sputum cultures turned out to be positive for Mycobacterium tuberculosis. The importance of ANCA-interpretation and the possibility of false positive results is discussed.

Adult↗
PubMed1989

Inhibition of natural killer cell activity by retroplacental sera as compared to peripheral sera. Lack of influence of immune complexes.

A decrease of natural killer cell activity (NKCA) during human pregnancy might contribute to the acceptance of the allogeneic fetus by the maternal host. The inhibition of NKCA might be due to serum factors derived from the trophoblast. We focused especially on the role of immune complexes, as it has already been described that these complexes depress NKCA and as they are found frequently in retroplacental serum. We have compared the influence of 19 paired retroplacental and peripheral blood sera on NKCA of normal donors. One peripheral and eight retroplacental sera contained immune complexes. Normal donor mononuclear cells were incubated with carboxyfluorescein-labeled K562 cells in the presence of retroplacental serum or peripheral serum. NKCA was measured on a FACS Analyzer. Ten of 19 retroplacental sera inhibited NKCA significantly in comparison to the corresponding peripheral serum (P = 0.003). There was no correlation between NKCA and the immune complex level. We conclude that, as compared to peripheral serum taken at delivery, there is a retroplacental serum-induced inhibition of NKCA, which is not correlated with the presence of immune complexes.

Antigen-Antibody Complex↗
PubMed1989

Suppression of the late asthmatic reaction by hyposensitization in asthmatic children allergic to house dust mite (Dermatophagoides pteronyssinus).

In this study, we wanted to test the hypothesis that hyposensitization (HS) abrogates the late asthmatic reaction (LAR). We therefore selected 15 asthmatic children (subjects) sensitized to house dust mite (HDM), as proven by positive prick tests and/or specific IgE via the RAST. All children demonstrated a positive bronchial provocation test (BPT) to HDM; 14 showed a dual asthmatic reaction and one child showed an isolated LAR. All children were treated with anti-asthmatic drugs and received HS. They were rechallenged after 1 yr of HS while their anti-asthmatic medication was not changed, except for beta-agonists which were used only for relief of symptoms. Two BPTs, with a mean interval of 6.4 months, were also performed in eight asthmatic children (controls), who did not receive HS. In the controls, the same reaction pattern was observed during both BPTs. In the subjects, the LAR completely resolved in 5/15 after 1 yr of HS (P = 0.04). Furthermore, as a group, the subjects showed a less severe LAR after 1 yr of HS (expressed as mean fall of FEV1) (P less than 0.0001). The PD20 of the immediate asthmatic reaction (IAR) was the same as before HS was started, but the IAR was also less severe after 1 yr of HS (expressed as mean fall of FEV1) (P = 0.028). From these observations it is concluded that, in asthmatic children, HS may resolve and/or reduce the severity of the LAR. Although the PD20 of the IAR is not changed, the severity of the IAR is also reduced after 1 yr of HS.

Adolescent↗
PubMed1989

Frequency and intensity of late asthmatic reactions after bronchial allergen challenge in asthma and rhinitis.

The occurrence of late asthmatic reactions after bronchial allergen challenge was studied in 50 house dust mite allergic patients subdivided in three groups: one group had asthma without nasal symptoms, another group had rhinitis without pulmonary symptoms and a third group had a combination of both asthma and rhinitis. Late asthmatic reactions were present in 80% of asthmatic patients and in 18.7% of rhinitis patients. The degree of non-specific bronchial reactivity to histamine (provocative dose 15 or PD15 histamine) and the degree of immediate reactivity to allergen (PD15 house dust mite) did not differ significantly between patients with and without late asthmatic reactions. These findings suggest that an important difference between asthma and rhinitis is the lack of late asthmatic reactions in rhinitis patients, whereas the degree of immediate bronchial reactivity to the allergen is similar in asthma and rhinitis.

Adolescent↗
PubMed1989

Food and food additives in severe atopic dermatitis.

In this study the role of food additives, tyramine and acetylsalicylic acid, was investigated by double-blind placebo-controlled challenges (DBPCC) in 25 children with severe atopic dermatitis (AD). All children challenged with foods (n = 24), except one, showed one or more positive reactions to the DBPCC with foods. Positive reactions presented as different combinations of flares of skin symptoms, intestinal symptoms and respiratory symptoms. Seventeen children (70.8%) showed a positive challenge to egg, 12 to wheat (50%), eight to milk (33.3%) and eight to soya (33.3%). Six children underwent DBPCC with food additives, tyramine and acetylsalicylic acid. All were found to demonstrate positive skin and/or intestinal reactions to at least one of the food additives. Two children reacted to tartrazine, three to sodium benzoate, two to sodium glutamate, two to sodium metabisulfite, four to acetylsalicylic acid and one to tyramine. It is concluded that some foods, food additives, tyramine and acetylsalicylic acid, can cause positive DBPCC in children with severe AD.

Animals↗
PubMed1989

Magnetic resonance imaging in the evaluation of patients with eosinophilic fasciitis.

Two cases of eosinophilic fasciitis are described, in which magnetic resonance imaging (MRI) clearly demonstrated thickening of the fascia and increased signal intensity in the superficial muscle fibers correlating with inflammation. MRI is a useful noninvasive imaging technique in the diagnosis of eosinophilic fasciitis and can guide biopsy of selected abnormal areas.

Biopsy↗
PubMed1988

A useful method for determining class-specific rheumatoid factors with computerized analyses of data.

A simple and sensitive enzyme-linked immunosorbent assay (ELISA) was developed to determine rheumatoid factors (RFs) of IgG, IgA and IgM class. Standardisation was performed with a standard reference serum for IgM-RF, calibrated according to the WHO preparation, and with the serum of a patient containing high levels of IgA- and IgG-RF. The sigmoidal shaped calibration curve was fitted with a computerized four parameter logistic model with simplified mathematical computations. This method provided to be more accurate for measuring RF levels, as judged by the smaller residuals, than logit or log-linear transformations. The considerable reduction in processing time, which is obtained by the computerized analysis of data, makes this method of class-specific RF determination suitable for routine analysis.

Enzyme-Linked Immunosorbent Assay↗
PubMed1988

Diagnosis of Sjögren's syndrome in children.

We treated four children with clinical symptoms and laboratory findings suggestive of Sjögren's syndrome (SS). We also review the findings in 23 children with the diagnosis of SS whose cases were reported in the literature. We propose that the following criteria for the diagnosis of SS, which are mostly used in adults, should also be applied to children: (1) keratoconjunctivitis evidenced by a Schirmer test and a quantitative rose bengal test; (2) xerostomia shown by a decreased basal and stimulated salivary flow; (3) lymphocytic infiltration in a minor salivary gland biopsy specimen with at least two foci per 4 mm2; (4) laboratory evidence of a systemic autoimmune disorder on the basis of a rheumatoid factor of 1/160 or greater, antinuclear antibody of 1/160 or greater, or extractable nuclear antigen antibodies. Only close observation and long-term follow-up of these patients will allow a better insight in the natural history of SS in children. Those children who do not fulfill these diagnostic criteria also need close and prolonged follow-up study: one of the possibilities is that their conditions will ultimately evolve toward definite SS.

Child, Preschool↗
PubMed1988

Acquired immunodeficiency syndrome mimicking Sjögren's syndrome and systemic lupus erythematosus.

We describe a patient in whom the diagnosis of transfusion-associated acquired immunodeficiency syndrome (AIDS) was delayed because her clinical symptoms were similar to those of systemic lupus erythematosus and Sjögren's syndrome and because of a false-negative result on a Western blot test for human immunodeficiency virus. The importance of using different diagnostic tests for AIDS and the pitfalls in diagnosing AIDS in patients who appear to have connective tissue disease are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Neutrophil activation by IgE-containing circulating immune complexes of patients with connective tissue diseases.

In an earlier study, we reported IgE-containing circulating immune complexes (CICs) in 66.6% of the patients with rheumatoid arthritis who were studied, especially in those with extra-articular manifestations. The present study was undertaken to examine the possible role of these immune complexes in inflammatory cell activation. Twelve patients with classic or definite rheumatoid arthritis, two with primary Sjögren's syndrome, and three patients with systemic lupus erythematosus were studied. Of these 17 patients, 10 were IgE-containing CIC positive, and seven patients were IgE-containing CIC negative. Polyethylene glycol-precipitated IgE-containing CICs and IgG-containing CICs of these patients were coated on plastic wells and incubated with suspensions of neutrophils. As a parameter of cell activation, superoxide release (SOR) was measured by cytochrome C reduction in the supernatant after 30, 60, and 90 minutes. There was a significant SOR up to 38% of the zymosan control when IgE-containing CICs were incubated with neutrophils. Furthermore, there was a significant correlation between the level of IgE-containing CICs and the amount of SOR, but not between the level of IgG-containing CICs and the amount of SOR. These results suggest a possible role for IgE-containing CICs in the activation of inflammatory cells in connective tissue diseases.

Antigen-Antibody Complex↗
PubMed1988

Modification of the late asthmatic reaction by hyposensitization in asthmatic children allergic to house dust mite (Dermatophagoides pteronyssinus) or grass pollen.

The frequency and severity of the late asthmatic reaction (LAR) was studied in asthmatic children allergic to house dust mite (HDM) or grass pollen (GP) with and without hyposensitization (HS). The four groups were comparable according to their severity of asthma. All children were allergic to HDM (Dermatophagoides pteronyssinus) or GP according to history, skin testing and specific IgE determination via the RAST. The LAR occurred less frequently (29% versus 73%) (P less than 0.001) and was less severe in children receiving HS. The difference was significant between the children allergic to HDM as well as between children allergic to GP. The immediate asthmatic reaction (IAR) was also less severe in children allergic to HDM who received HS, compared to those who never received HS, (P = 0.033) although the PD20 of the HDM challenge (PD20HDM) was not different between the two groups. In children allergic to GP, there was no difference in PD20 of the GP challenge (PD20GP) or in severity of the IAR, whether the children received HS or not. There was no difference between the PD20HDM in patients who developed a LAR and in patients who did not. There was no relation between the type of asthmatic reaction following the allergen provocation test and the level of circulating immune complexes (CIC) and the level of house dust mite-specific IgG (IgGHDM) or grass pollen-specific IgE (IgGGP) in the different groups, determined before the challenge. There was a decrease in the level of IgG containing CIC (IgGCIC) during the LAR. It is concluded that the LAR occurs less frequently and is less severe in asthmatic children who receive HS.

Adolescent↗
PubMed1988

Immune complexes and Pseudomonas aeruginosa antibodies in cystic fibrosis.

Serum samples from 57 patients with cystic fibrosis were tested for the presence of IgG, IgA, IgM, IgE, and circulating immune complexes containing IgG, IgA, and IgM. Titres of class specific antibodies to Pseudomonas aeruginosa, and class specific antibodies to Ps aeruginosa in circulating immune complexes, were also measured. According to the Shwachman score the patients were divided into three clinical groups: group 1-moderate and severe disease, group 2-mild disease, and group 3-well. The results of the immunological investigations were correlated with the clinical state of the patients as assessed by the Shwachman score. Serum concentrations of IgG, IgA, and IgM were inversely correlated with the Shwachman score, but the differences between the groups were only significant for IgG and IgA. The same correlations were found for circulating immune complexes containing IgG and IgA. Antibodies to Ps aeruginosa could be detected in most of the patients' serum samples. IgA antibody specific to Ps aeruginosa was the most often raised, even in patients in group 3. It is therefore suggested that IgA antibody specific to Ps aeruginosa could be an early marker of colonisation by Ps aeruginosa and a sensitive measurement of infection with Ps aeruginosa in young children with cystic fibrosis. Moreover, in the circulating immune complexes, class specific antibodies to Ps aeruginosa were found in nearly half the patients. The highest titres of IgG and IgA antibodies specific to Ps aeruginosa in the circulating immune complexes were detected in the patients with the worst clinical state (group 1).

Adolescent↗
PubMed1988

Ultrasonography and computer tomography of the salivary glands in the evaluation of Sjögren's syndrome. Comparison with parotid sialography.

Ultrasonography (US) and computed tomography (CT) were studied as noninvasive methods to determine salivary gland involvement and compared with parotid sialography in patients with Sjögren's syndrome (SS) and patients with only objective xerostomia and/or xerophthalmia. Patients with complaints of dry eyes and dry mouth but with no objective abnormalities served as controls. CT was not discriminative between the 2 groups. In contrast, US revealed decreased parotid gland echogenicity in most of the patients with SS, compared with only 1 patient in the group with sicca complaints only (p = 0.005). Our study suggests that US can be a useful, noninvasive method in the diagnostic investigation of patients with sicca complaints.

Humans↗
PubMed1988

Role of IgM-rheumatoid factor interference in the determination of total serum IgE and IgE-containing circulating immune complexes.

IgM-rheumatoid factor (RF) interference in the determination of total serum IgE and IgE-containing circulating immune complexes (IgE-CIC) was studied by inhibition experiments in vitro comparing a new ELISA technique free of IgM-RF interference with more widely used RIA methods. It was shown that a considerable overestimation of the IgE content in CIC can exist when high levels of IgM-RF are present in the same serum. The clinical part of this study revealed a dramatic fall in prevalence of IgE-CIC in patients with rheumatoid arthritis (RA) with the ELISA technique, compared with the more conventional RIA method (respectively 1/20 compared to 12/20 positive for IgE-CIC). In these patients, there was a good correlation between the level of IgM-RF and the amount of IgE detected in the CIC by the RIA method (r = 0.87) whereas the RF-interference free ELISA method showed no correlation between these two parameters (r = 0.06). Total serum IgE determination with a solid phase RIA was also influenced by IgM-RF interference, whereas the PRIST method was not affected by the presence of IgM-RF. In conclusion, in patients with rheumatic diseases, IgE-assays using polyclonal rabbit or sheep anti-IgE antibodies are not appropriate and monoclonal anti-IgE antibodies that have been proved not to interfere with IgM-RF should be advocated.

Antigen-Antibody Complex↗