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Biomedical subjects

H P van Bever

Publications and source records attributed to H P van Bever.

6 recordsLinked to original sources
PubMed1998

Comparison between the in vitro cytokine production of mononuclear cells of young asthmatics with and without immunotherapy (IT)

BACKGROUND: The underlying mechanisms of immunotherapy (IT) are still unknown but may be related to modifications of cytokine production of T lymphocytes. OBJECTIVE: In this study we determined the in vitro allergen-induced production of IL-2, IL-4, IL-5, IL-12 and IFNgamma of peripheral blood mononuclear cells (PBMC) of eight young asthmatics, aged 15+/-2 years, receiving IT (IT group) and of eight comparable asthmatics, aged 13+/-3.5 years, who never received IT (non-IT group). METHODS: All patients suffered from perennial asthma and were allergic to house dust mite (HDM). They were selected if they showed a positive stimulation index (SI) of PBMC after in vitro incubation with HDM (i.e. SI > 2). Cells were incubated with and without HDM (10 microg/mL) during 24 h, 48 h and 7 days. Cytokines were determined in the supernatant at the three time points and are expressed as median values in pg/mL. RESULTS: In the IT group the secretion of IL-2 was lower compared with the non-IT group after 7 days incubation of PBMC with HDM (0 vs 33.2, P = 0.008). In both groups maximal secretion of IL-2 was observed after 48 h. In the non-IT group a high value of IL-2 persisted after 7 days, whereas in the IT group a significant decline of IL-2 occurred after 7 days. Although IL-4 secretion was low in all subjects, more patients of the non-IT group showed detectable IL-4 in the HDM cultures after 24 h and 48 h, although the difference was not statistically significant (P = 0.08 and P = 0.28, respectively). Furthermore, IL-4 secretion was lower in the HDM cultures after 24 h in the IT group (1.75 vs 4.1, P = 0.011) and 48 h (2.2 vs 4.1, P=0.035). IL-5 secretion was lower in the HDM cultures after 24h (12.4 vs 47.6, P = 0.035) and 48 h (26.8 vs 135, P = 0.046) in the IT group than in the non-IT group. After 7 days of incubation with HDM there was no difference between the groups. There was no difference between both groups in secretion of IFNgamma and IL-12. CONCLUSIONS: These results show a difference in vitro cytokine secretion of PBMC of asthmatics receiving IT compared with asthmatics who never received IT. PBMC of patients receiving IT secrete less IL-2 and IL-5 after in vitro incubation with HDM and show a tendency to secrete less IL-4. The efficacy of IT may be attributed to a modified cytokine secretion of PBMC.

Allergens↗
PubMed1995

Specific decrease of anti-pseudomonal IgA after anti-pseudomonal therapy in cystic fibrosis.

UNLABELLED: In patients with cystic fibrosis (CF) and chronic colonisation with Pseudomonas aeruginosa, specific anti-pseudomonal IgG and IgA, as well as serum immunoreactive protein C, WBC and differential count, ESR, pulmonary function and chest radiograph score were determined before and after a 2 week intravenous course of anti-pseudomonal antibiotics in 32 cases of acute exacerbation of pulmonary infection. Specific anti-pseudomonal IgA but not specific anti-pseudomonal IgG decreased significantly after treatment. Log of anti-pseudomonal IgA but not log anti-pseudomonal IgG correlated well with disease severity as assessed by the Brasfield chest radiograph score (r 0.57), forced expiratory volume in 1 s (r 0.6) as well as C-reactive protein (r 0.62). CONCLUSION: Specific anti-pseudomonal IgA may be a better parameter than specific IgG in the follow up of lung infection in patients with CF, probably because it more closely reflects ongoing endobronchial infection, the major pathology in CF lungs.

Antibodies, Bacterial↗
PubMed1993

Lymphocyte transformation test with house dust mite (Dermatophagoides pteronyssinus) in normal children, asthmatic children and asthmatic children receiving hyposensitization.

In the first part of this study the proliferative response of lymphocytes (lymphocyte transformation test) to house dust mite (HDM) stimulation in cultures was studied in normal children (n = 16), asthmatic children who never received hyposensitization (HS) (n = 50) and asthmatic children receiving HS with HDM for at least 6 months (n = 20). The results are expressed as disintegrations per minute (d.p.m.) and as stimulation index (SI = d.p.m. in the presence of the allergen/d.p.m. in the control culture). A positive SI (> 2) was found in 54% of the asthmatic children who never received HS, in 30% of the asthmatics receiving HS and in none of the normal children. Furthermore, between asthmatics with and without HS, the SI was not statistically different, although asthmatics without HS tended to have a higher SI (median value: 2.13 vs 1.38) (P = 0.10). In a second series of experiments the effect of adding interleukin-2 (IL-2) to the lymphocyte cell culture was studied in asthmatic children with and without HS. Interleukin-2 induced an additional stimulatory effect on the lymphoproliferative response to HDM and to phytohaemagglutinin in patients who never received HS, but had no effect in patients receiving HS. We conclude that HS treatment seems to have an inhibiting effect upon this proliferative response, not only inhibiting the degree of the allergen-induced lymphocyte proliferation, but also inhibiting the sensitivity of proliferating lymphocytes for IL-2. These inhibiting effects upon lymphocytic activation could be responsible for the anti-inflammatory effects (i.e. suppression of the late asthmatic reaction) of HS.

Allergens↗
PubMed1991

Measurement of total respiratory impedance in infants by the forced oscillation technique.

The forced oscillation technique according to Làndsér et al. (J. Appl. Physiol. 41:101-106, 1976) was modified for use in infants. Adaptations, including a flexible tube to connect the infant to the measuring system and a bias flow to avoid rebreathing, did not influence impedance values. The linearity of the respiratory system was assessed and confirmed by 1) applying pseudo-random noise oscillations at three different amplitudes to 7 infants and 2) comparing in 12 infants impedance values obtained with pseudo-random noise and with sinusoidal oscillations at 12 and 32 Hz. Intersubject variability, averaged for all frequencies, was 6%. In 17 infants the relative error (+/- SD) between two series of five measurements within a time interval of 15 min was 0.5 +/- 5.7%. No statistically significant difference was found between impedance values before and after repositioning of the infant's head, whereas rotation resulted in a decrease in resistance and no effect on reactance. Our results indicate that the infant-adapted forced pseudo-random noise oscillation technique has the potential to give valuable information about ventilatory lung function in infants.

Airway Resistance↗
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↗