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Biomedical subjects

A Padial

Publications and source records attributed to A Padial.

5 recordsLinked to original sources
PubMed2005

Nonimmediate reactions to systemic corticosteroids suggest an immunological mechanism.

BACKGROUND: Administration of corticosteroids (CS) by different routes may cause varying types of allergic reactions, thereby hampering their further use in affected patients. In order to verify an immunological involvement we evaluated a group of patients with symptoms compatible with nonimmediate allergic reactions to CS. METHODS: Studies included patch and intradermal tests, immunohistochemical studies and controlled administration to reproduce the response. The cytokines interleukin (IL)-4, interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha were quantified in peripheral blood during the response. RESULTS: Of 32 subjects evaluated presenting nonimmediate urticaria or exanthema, 21 were finally considered positive after re-exposure. The drugs most frequently involved were betamethasone and dexamethasone. Fewer than half the patients responded to prednisolone whilst some responded to three or more CS. Hydrocortisone and deflazacort were well tolerated by all the patients. Subjects with a positive intradermal or patch test had a perivascular mononuclear cell infiltrate with the presence of CD4 and CD8 lymphocytes positive for CD45RO+ (memory) and CD69 (activation marker) cells. Monitoring peripheral blood during the acute response showed expression of IFN-gamma and TNF-alpha, with downregulation of IL-4. CONCLUSION: Adverse systemic responses to different CS are suggestive of a nonimmediate reaction. The symptoms elicited together with the immunlogical studies suggest a T-cell mediated response. The response to closely related CS was especially marked between betamethasone and dexamethasone, whereas hydrocortisone and deflazacort were well tolerated.

Adolescent↗
PubMed2004

Skin test evaluation in nonimmediate allergic reactions to penicillins.

BACKGROUND: Nonimmediate reactions (NIR) to aminopenicillins (AP) are frequent. Although patch testing (PT) and intradermal testing (IT) are used for diagnosis, comparative results have never been adequately performed. We compared PT and IT in subjects with NIR to AP. METHODS: Twenty-one subjects with NIR to AP and positive IT were re-evaluated. Skin tests were performed with amoxicillin (AX) and ampicillin (AM) at different concentrations in petrolatum, 50, 25, and 5% w/w, for PT and in saline, 20, 2, and 0.2 mg/ml for both PT and IT. Skin biopsies from the site of the positive response were studied with haematoxylin-eosin and immunohistochemistry. RESULTS: In the re-evaluation, one case was IT and PT negative and was excluded; 20 were IT positive and 18 PT positive for both AX and AM. Decreasing concentrations of AP induced a reduction in positivity in both methods when diluted in saline, but not when mixed in petrolatum (PT only). With both PT and IT, immunohistochemical studies showed a perivascular mononuclear infiltrate with CD4 and CD8 memory cells expressing perforin and granzyme B. CONCLUSIONS: Both tests appear valuable for the diagnosis of NIR to AP. However, IT diagnosed more patients than PT. The vehicle (saline or petrolatum) had no influence on the response, although in the former the concentration was critical. The immunohistochemical analysis showed skin infiltrates compatible with a T-cell drug reaction.

Adult↗
PubMed2004

The diagnostic interpretation of basophil activation test in immediate allergic reactions to betalactams.

BACKGROUND: Basophil activation by allergens, including drugs, has been used to determine sensitivity and to study IgE recognition and cross-reactivity. OBJECTIVE: We sought to determine the sensitivity and specificity of a basophil activation test (Basotest) in patients with immediate allergic reactions to betalactams, with a later comparison between patients who were selective (those recognizing the culprit drug excluding benzylpenicillin (BP)) and cross-reactors (those recognizing several penicillin determinants including BP). METHODS: Basotest to different haptens was performed in 70 patients with immediate allergic reactions to betalactams, classified into three groups: (A) skin test positive independently of CAP/RAST immunoassay value, (B) skin test negative and CAP/RAST positive, and (C) skin test and CAP/RAST negative but drug provocation test positive. Basotest was carried out by flow cytometry following the manufacturer's instructions using different betalactam determinants and results expressed as a stimulation index. RESULTS: Of the 70 patients, 34 (48.6%) were positive to Basotest (sensitivity: 48.6%), 31 (44.3%) to CAP/RAST and 46 (65.7%) to either one or the other. Considering the different groups, Basotest was positive in 50.9% of patients in Group A, 60% in Group B and 14.3% in Group C. The specificity was 91.3%. Positivity to the haptens was 28.6% to amoxicillin (AX), 21.7% to BP, 20% to benzylpenicilloyl-poly-l-lysine, 12.5% to ampicillin and 2.2% to minor determinant mixture. In patients with cephalosporin reactions, Basotest to the culprit cephalosporin was positive in 77.7%. There were differences between the two reactor groups in the sensitivity of Basotest (selective to AX=50%, cross-reactors=28.6%; chi(2)=10.809, P=0.004) and in the CAP/RAST (selective to AX=28.6%, cross-reactors=61.9%; chi(2)=8.944, P=0.011). CONCLUSIONS: The sensitivity of Basotest is similar to immunoassays (CAP/RAST). Sensitivity is improved when used in combination. Although further studies are required, Basotest results for cephalosporin allergy seem very promising. This technique does not help differentiate between selective reactors and cross-reactors.

Adult↗