Biomedical subjects

M Gaga

Publications and source records attributed to M Gaga.

28 records · Page 2Linked to original sources

PubMed1993

Influence of grass pollen immunotherapy on cellular infiltration and cytokine mRNA expression during allergen-induced late-phase cutaneous responses.

We have studied the influence of grass pollen immunotherapy on cellular infiltration and cytokine mRNA expression during allergen-induced late-phase cutaneous responses. In a double-blind, placebo-controlled trial of immunotherapy in 40 adult hay fever sufferers, clinical improvement was accompanied by a decrease in the size of the late-phase skin response. When the immunotherapy-treated group was compared with the placebo group, analysis of skin biopsies obtained 24 h after intradermal allergen revealed a significant reduction in the number of infiltrating CD3+ (P = 0.04) and CD4+ (P = 0.009) cells and a trend for a decrease in EG2+ eosinophils (P = 0.08). Treatment did not influence allergen-induced recruitment of CD8+ cells, neutrophils, or macrophages. Unexpected increases in expression of CD25 (P = 0.006) and HLA-DR (P = 0.007) were observed in the actively treated group. In situ hybridization using a panel of riboprobes demonstrated "TH2-type" (IL-4, IL-5) cytokine mRNA responses in both groups of patients. In contrast, significant hybridization for IL-2 (8/16 patients, P = 0.02) and for interferon-gamma (6/16 patients, P = 0.04) was observed only in the actively treated group. These findings indicate that immunotherapy is associated with suppression of allergen-induced CD4+ T lymphocyte infiltration, but among the cells that are recruited, there is upregulation of CD25 and HLA-DR. At least in this model, immunotherapy does not appear to affect expression of TH2-pattern cytokines in response to allergen exposure, but expression of mRNA for Th1-type cytokines was enhanced in half of the patients. The results support the view that immunotherapy may possibly be working through induction of T cell tolerance.

Adult↗

PubMed1992

The effect of a single oral dose of prednisolone or cetirizine on inflammatory cells infiltrating allergen-induced cutaneous late-phase reactions in atopic subjects.

The effect of a single dose of prednisolone (20 mg) or cetirizine (10 mg) on the immunohistology of the cutaneous late-phase reaction was determined in a double-blind, placebo-controlled, cross-over study in 12 atopic allergic individuals. The subjects were challenged with intradermal allergen (30 BU) 2 hr after ingestion of the drugs or placebo. The magnitude of the cutaneous reactions were determined at 15 min, 6 and 24 hr, and skin biopsies performed at 24 hr. Cetirizine produced a 50% average inhibition of the immediate weal and flare response (P = 0.001) and a 27% average inhibition of the 6 hr late-phase induration (NS). Prednisolone reduced the immediate (27%, P = 0.03) and significantly inhibited the late-phase reaction (53%, P = 0.02). Prednisolone significantly inhibited infiltration of CD45+ (total leucocytes), neutrophil elastase+, EG2+ (activated eosinophils) and CD25+ (IL-2R) cells (P = 0.017, 0.005, 0.005 and 0.032 respectively). CD3, CD4, CD8 and HLA-DR expression was also inhibited but this was not significant. Cetirizine also reduced the numbers of EG2+ cells, particularly those with high counts before treatment but the overall results were not significant. No other changes in the cellular infiltrate were demonstrated when cetirizine was compared with placebo. These findings indicate a single dose of prednisolone significantly reduces leucocyte infiltration and activation as well as the magnitude of the cutaneous late-phase reaction.

Administration, Oral↗

PubMed1991

Eosinophil activation and T lymphocyte infiltration in allergen-induced late phase skin reactions and classical delayed-type hypersensitivity.

T lymphocyte infiltration is a well documented feature of classical delayed-type hypersensitivity (DTH) reactions. Recently, we have shown that T lymphocytes and activated (EG2+) eosinophils accumulate in the allergen-induced late phase skin reaction (LPR). To compare the kinetics and phenotypic composition of these T lymphocyte responses, LPR and DTH reactions of comparable induration size were induced in atopic subjects. In addition, DTH and LPR were compared between atopic and nonatopic subjects. In atopic individuals, allergen challenge elicited a perivascular influx of T lymphocytes that was predominantly CD4+. Eosinophil accumulation and activation were also prominent. There was no cellular response to allergen challenge in the nonatropic group. In both groups, DTH responses showed an intense T cell infiltrate which was more dense and dispersed than in the LPR. CD4+ T cells predominated but at 48 h CD8+ numbers were also significantly increased. In DTH, total leukocyte numbers (CD45+) were increasing at 48 h, whereas in the LPR, cell numbers reached a plateau between 24 and 48 h. T cell activation (shown by expression of IL-2R) was more prominent in DTH. Endothelial expression of HLA-DR was increased in both LPR and DTH, implying the local release of inflammatory cytokines in both reactions. Small but significant numbers of activated eosinophils (EG2+) were detected in atopics and non-atopics at 24 h in DTH but not at 48 h. These findings suggest that the allergen-induced LPR induced in atopic subjects is, at least in part, a form of cell-mediated hypersensitivity but with T cell kinetics that differ from classical DTH.

Adolescent↗

PubMed1991

Messenger RNA expression of the cytokine gene cluster, interleukin 3 (IL-3), IL-4, IL-5, and granulocyte/macrophage colony-stimulating factor, in allergen-induced late-phase cutaneous reactions in atopic subjects.

Cryostat sections from skin biopsies from 24-h allergen-induced late-phase cutaneous reactions (LPR) in 14 human atopic subjects were hybridized with 35S-labeled RNA probes for a number of cytokines. mRNA was detected for interleukin 3 (IL-3) (8/14), IL-4 (10/14), IL-5 (11/14), and granulocyte/macrophage colony-stimulating factor (GM-CSF) (13/14). Only 5 of 14 gave hybridization signals for IL-2, and 0 of 14 for interferon gamma. Biopsies from diluent controls gave only occasional weak signals. These results suggest that cells infiltrating the site of the 24-h LPR transcribe mRNA for the IL-3, IL-4, IL-5, and GM-CSF gene cluster and support the hypothesis that atopy is associated with preferential activation of cells having a similar cytokine profile to the murine T helper type 2 subset.

Adolescent↗

PubMed1991

Usefulness of immunotherapy in patients with severe summer hay fever uncontrolled by antiallergic drugs.

OBJECTIVE: To evaluate the efficacy and safety of immunotherapy (hyposensitisation) in patients with severe summer hay fever. DESIGN: A randomised, double blind, placebo controlled study of a biologically standardised depot grass pollen extract. SETTING: Allergy clinic, Royal Brompton and National Heart Hospital, London. PATIENTS: 40 adults (mean age 35 years) with a history of severe grass pollen allergy uncontrolled by standard antiallergic drugs. Patients with perennial asthma were specifically excluded. INTERVENTION: Patients were randomised to receive either an active preparation (Alutard SQ, a grass pollen (Phleum pratense) extract) or placebo at a rate of two subcutaneous injections a week in increasing doses until a maintenance dose was reached. This maintenance dose was given once a month. MAIN OUTCOME MEASURES: Clinical efficacy was evaluated by symptom and drug diary cards, visual analogue scores during the grass pollen season, and a postseasonal assessment by the patients and a doctor. Conjunctival and skin sensitivity to local allergen provocation was measured before and after eight months of treatment. RESULTS: There was a highly significant decrease (median Alutard SQ v median placebo (95% confidence interval for difference between medians] in total symptom scores (p=0.001) in the Alutard SQ treated group (360 v 928 (238 to 825]. Significant differences were also found in total drug use (p=0.002, 129 v 627 (178 to 574]. Visual analogue symptom scores were also reduced in the active group (p=0.02, 2.2 v 5.5 (-4.8 to -0.5]. The postseasonal assessment, by either the doctor or the patients, showed a large improvement (p less than 0.001) in favour of Alutard SQ. Provocation tests showed a greater than 10-fold reduction for the active group in immediate conjunctival allergen sensitivity (p=0.001), a 40% decrease in early phase response (p=0.02), and a 57% decrease in the late phase (p=0.001) cutaneous response after intradermal allergen. A total of 523 active injections were given. There was one systemic reaction at 10 minutes after injection, which was rapidly reversed with intramuscular adrenaline. There was one mild delayed urticarial reaction at 2 1/2 hours. CONCLUSION: Immunotherapy is effective in patients with severe summer hay fever, but immediate anaphylactic reactions limit its use to specialised centres. Patient selection is extremely important, and chronic perennial asthma should be specifically excluded. As serious reactions occur within minutes a two hour wait for all patients after each injection seems unnecessary.

Adult↗

PubMed1991

Immunotherapy and allergic inflammation.

A double-blind placebo-controlled trial of allergen injection immunotherapy in adult patients with severe summer hayfever. We used a partially purified biologically standardised grass pollen depot preparation (Alutard SQ, ALK Denmark Ltd.). Immunotherapy was extremely effective in reducing symptoms and medication requirements. Clinical improvement was accompanied by a decrease in both a target organ (conjunctival) and skin sensitivity. The injections were well-tolerated with minimal side effects. The results suggest that 30 minutes rather than 2 hours is an acceptable post-injection observation period. Successful immunotherapy was accompanied by suppression of the late cutaneous response to allergen. Specific immunostaining of skin biopsies revealed inhibition of the characteristic CD4+ T cell and EG2+ activated eosinophil cellular infiltrate during the late response. There was a significant relationship between CD4+ T cell and eosinophil counts after immunotherapy, i.e. the lower the number of infiltrating CD4+ cells, the lower the eosinophil counts. An unexpected finding was a prominent CD25+ (interleukin-2 receptor positive) cellular infiltrate which was only observed following Alutard SQ. Further studies involving double immunostaining methods should identify the phenotype of these activated, IL-2R+ cells. Based on murine studies Mosmann and colleagues have classified T cell responses into two types according to their profile of lymphokine production [11]. TH1 cells produce predominantly the IL-4 family of cytokines (IL-3, IL-4, IL-5) whereas TH2 cells produce predominantly interleukin-2 and interferon gamma. Insofar as the Mosmann classification may possibly be relevant to human T cell responses, the above findings would support a switch from a "TH2-" to a "TH1-" lymphocyte response following immunotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Immunohistology of human allergic late-phase skin reactions.

Human late-phase allergic skin reactions (LPSR) are characterised histologically by a mixed infiltrate of granulocytes and mononuclear cells. Quantitative immunohistology reveals a correlation between the numbers of CD4+ T-cells and the number of activated eosinophils at LPSR sites. These CD4+ T-cells are predominantly CD45RO+ and belong to the 'memory' T-cell subset. Immunofluorescence studies indicate that type III (immune complex) mechanisms make no significant contribution to the LPSR. On the other hand, the LPSR and classical delayed-type hypersensitivity (DHT) both have a marked CD4+ T-cell component. T-cell infiltration is a more diffuse process in DTH than in the LPSR; between 24 and 48 h, DTH sites show a further increase in T-cell numbers with the appearance of CD8+ T-cells and an influx of monocytes. Activated eosinophils are present in the early stages of both LPSR and DTH, but are more prominent in the LPSR. These different patterns of cellular infiltration and activation are probably due to differences in the cytokine secretion pattern of the infiltrating T-cells. Detailed analysis of this hypothesis will require the use of in situ hybridization techniques.

Eosinophils↗

PubMed1990

Alveolar partial pressures of carbon dioxide and oxygen measured by a helium washout technique.

A non-invasive technique was developed for measuring alveolar carbon dioxide and oxygen tension during tidal breathing. This was achieved by solving the Bohr equations for mean alveolar carbon dioxide and oxygen tensions (PACO2, PAO2) from known values of the dead-space:tidal volume ratio measured by helium washout, and from the mixed expired partial pressure of carbon dioxide and oxygen. The derived values of wPACO2 and wPAO2 were compared with PaCO2 obtained from arterial gas analysis and PAO2 calculated from the ideal air equation. Four normal subjects and 58 patients were studied. Calculated and measured PCO2 values agreed closely with a difference in mean values (wPACO2 - PaCO2) of 0.01 kPa; the SD of the differences was 0.7 kPa. The difference in mean values between wPAO2 and PAO2 was 0.02 kPa; the SD of the differences was 0.93 kPa. The method is simple and not time consuming, and requires no special cooperation from the patients. It can be applied in the laboratory or at the bedside to any subject breathing tidally. Physiological deadspace:tidal volume ratio, PAO2 and PACO2, static lung volumes, respiratory exchange ratio, carbon dioxide production, oxygen uptake, tidal volume, and total ventilation can be measured with acceptable accuracy and reproducibility in one test. An arterial blood sample is needed initially to provide an independent measure of PaCO2 and for measurement of the alveolar-arterial PO2 difference. Subsequently, PaCO2 can be estimated from wPACO2 sufficiently well for clinical purposes and PaO2 or SaO2 can be monitored by non-invasive methods.

Adult↗

PubMedDate not supplied

Tuberculous effusion: ADA activity correlates with CD4+ cell numbers in the fluid and the pleura.

BACKGROUND: Adenosine deaminase (ADA) is a commonly used marker in the diagnosis of tuberculous effusion and there is evidence that its production is linked to T cells and monocytes. Data on the correlation between ADA and T cells or macrophages in tuberculous effusions are conflicting. Furthermore, no studies have examined a possible correlation between pleural tissue infiltration and ADA. OBJECTIVES: We undertook this study to examine cell subsets in the fluid and the pleura in tuberculous effusion and their correlation to ADA. The use of cell subsets as a marker in the differential diagnosis was also examined. METHODS: Pleural fluid from 36 patients with tuberculous and 34 patients with malignant effusion as well as pleural tissue biopsies from 16 patients with tuberculous pleurisy were examined. The APAAP and the avidin-biotin complex immunocytochemical methods were used to examine CD4+ T cells and macrophages (CD68+), while ADA activity was measured by the Giusti colorimetric method. RESULTS: Our results showed that, in pleural fluid, CD4+ cells and ADA were significantly higher in tuberculous compared to malignant effusion (p<0.001 for all measurements). In pleural tissue biopsies, macrophages were the predominant cells but CD4+ T cells were also abundant. A significant correlation was found between ADA and CD4+ numbers in pleural fluid and tissue (r=0.45, p<0.01; r=0.75, p<0.001, respectively). ADA had high sensitivity and specificity for differential diagnosis while cell subsets did not. CONCLUSIONS: These results indicate that ADA activity correlates to CD4+ T cell infiltration in the pleura and the fluid. Moreover, ADA but no cell subsets may be used as markers of tuberculous effusion.

Adenosine Deaminase↗

PubMedDate not supplied

A single-blind crossover study of two different slow release theophylline preparations.

In a single-blind crossover study, two slow release theophylline preparations were evaluated in 18 patients with chronic bronchitis or asthma without cardiac, renal or liver disease. After randomization into two groups, patients were treated, in a crossover study design, with 600 mg choline theophyllinate or 300 mg anhydrous theophylline administered orally every 12 h for 7 days. A 2-day washout period separated the two periods of treatment evaluation. Blood samples in which plasma theophylline concentration was to be measured were taken at 7.30 a.m., 2.00 p.m. and 7.30 p.m. during the last 5 days of therapy with each drug. The mean fluctuation in plasma theophylline concentration was less than or equal to 40% in all 18 patients taking choline theophyllinate yet in only 15 (83%) patients administered anhydrous theophylline. Salbutamol inhaler was more frequently required for the relief of bronchospasm when taking anhydrous theophylline than when taking choline theophyllinate (total of 41 vs 25 puffs, respectively, over 7 days). Drug-related adverse reactions occurred in four patients while taking anhydrous theophylline and in one patient while taking choline theophyllinate.

Asthma↗