In vitro release of interferon-gamma and macrophage migration inhibition factor in drug-induced urticaria and angioedema

In vitro release of interferon-gamma from peripheral blood lymphocytes in cutaneous adverse drug reactions

BACKGROUND

Cutaneous drug reactions are common but diagnostically challenging due to phenotypic heterogeneity and simultaneous exposure to multiple drugs. These limitations prompted the development of diagnostic tests.

AIMS

To evaluate the performance of an in vitro assay measuring interferon-gamma release from patients' lymphocytes in the presence of causative drugs for the diagnosis of drug reactions.

METHODS

Mononuclear cells derived from patients were incubated with and without suspected drugs, and increment of interferon-gamma levels was measured by ELISA. We performed a telephonic survey to evaluate the effect of stopping the drugs incriminated by the assay on cutaneous manifestations.

RESULTS

We assessed 272 patients who used 1035 medications. When assessed against the questionnaire data collected at least 6 months after stopping the causative drug, sensitivity was found to be 83.61% and specificity 92.67%. Likelihood ratio for a positive test is 11.40 and for a negative test 0.18. Positive predictive value is 75.37% and negative predictive value is 95.47%. The test was found to perform significantly better in females and in older patients.

CONCLUSIONS

Interferon-gamma release test is a useful adjunct tool in the diagnosis of cutaneous drug reactions.

In vitro detection and characterization of drug hypersensitivity using flow cytometry

BACKGROUND

The lymphocyte transformation test (LTT) is the only in vitro test for detecting drug sensitization at the cellular level irrespective of the reaction's phenotype. However, the LTT includes working with radioactive substances and is considered impracticable for routine laboratory investigation.

OBJECTIVE

The aim of this study was to assess drug-specific cytokine production by means of flow cytometry as an alternative nonradioactive approach which may be more appropriate for routine testing and may provide in addition more information about the pathophysiology of the reaction than proliferation-based assays, like the LTT.

METHOD

Peripheral blood mononuclear cells of 19 patients were incubated with culprit drugs (n = 28) or irrelevant antigens (n = 10). Ten healthy persons served as controls for all different drugs (n = 15). Intracellular interleukin (IL)-5, interferon (IFN)-gamma and IL-10 production was investigated using flow cytometry. Accuracy of the flow cytometry test system was confirmed using different statistical tests, i.e. receiver operating characteristic curve and Mann-Whitney rank test. In addition, drug-specific secretion of IL-5, IL-2 and IFN-gamma were analysed using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Drug-specific cytokine production could be demonstrated in 75% of the patients using flow cytometry and in 79% using ELISA respectively. Combining ELISA and flow cytometry increased the sensitivity to 100%. Analysis of involved T-cell subsets [e.g. CD4(+) or CD8(+); T helper (TH) 1 or TH 2] allowed characterization of the in vitro lymphocyte reactivity pattern.

CONCLUSIONS

Analysis of drug-specific cytokine production by means of flow cytometry proved a useful and reliable approach for the in vitro detection and characterization of drug hypersensitivities.

Erythema multiforme and related disorders

Erythema multiforme (EM) and related disorders comprise a group of mucocutaneous disorders characterized by variable degrees of mucosal and cutaneous blistering and ulceration that occasionally can give rise to systemic upset and possibly compromise life. The clinical classification of these disorders has often been variable, thus making definitive diagnosis sometimes difficult. Despite being often caused by, or at least associated with, infection or drug therapy, the pathogenic mechanisms of these disorders remain unclear, and as a consequence, there are no evidence-based, reliably effective therapies. The present article reviews aspects of EM and related disorders of relevance to oral medicine clinical practice and highlights the associated potential etiologic agents, pathogenic mechanisms and therapies.

Use of in vitro release of interferon-gamma in the diagnosis of contact allergy to potassium dichromate - a controlled study

The use of in vitro release of interferon-gamma (IFN-gamma) in the diagnosis of contact allergy to potassium dichromate was studied in 20 patients who had positive patch tests to chromate and in 30 control subjects (10 patients with contact dermatitis, allergic to other allergens, 10 patients with other dermatologic diseases and 10 healthy subjects). The release of IFN-gamma in the supernatants of the peripheral blood lymphocytes was significantly higher in the patients with proven allergy to chromate (P = 0.001). Further studies are needed to determine if IFN-gamma release may serve as an additional diagnostic tool in contact dermatitis.

Acute generalized exanthematous pustulosis associated with polysensitivity to paracetamol and bromhexine: the diagnostic role of in vitro interferon-gamma release test

We report a patient with acute generalized exanthematous pustulosis (AGEP), which occurred 3 days after ingesting paracetamol and bromhexine. Both were immediately stopped and the rash resolved rapidly. To determine the offending drug responsible for AGEP, an in vitro drug-induced interferon (IFN)-gamma release test was performed using an ELISA technique. Increased IFN-gamma release was observed following in vitro challenge of the patient's lymphocytes with paracetamol or bromhexine (110% and 157% increase, respectively). In vitro challenge with paracetamol or bromhexine in a control patient, treated with paracetamol and bromhexine, did not induce an increase in IFN-gamma. These findings suggest that the patient with AGEP may have polysensitivity to both drugs. The ELISA assessment also demonstrates the relevance of in vitro cytokine release tests in the investigation of such dermatoses.

Evidence for a role of macrophage migration inhibitory factor in psoriatic skin disease

Macrophage migration inhibitory factor (MIF) was originally described as a T-cell-derived lymphokine with the potential to inhibit the random migration of macrophages. However, recent reports have shown a much broader tissue distribution, including the skin. Functionally, MIF appears to act as an antagonist of anti-inflammatory glucocorticoid action. To elucidate the role of MIF in inflammatory skin diseases, we investigated the production and localization of this cytokine in human skin of patients with psoriasis by means of reverse transcription-polymerase chain reaction, immunohistochemistry and Western blot analysis. In normal skin, our results showed a moderate but homogeneous MIF immunoreactivity in all epidermal layers. Endothelial cells and the outer root sheath of hair follicles were also positive for MIF. In lesional psoriatic human skin, a significant increase in MIF immunoreactivity was visible in suprabasal keratinocytes, especially of the spinous layer. In addition, endothelial cells also showed increased immunolabelling for MIF in psoriatic lesions, indicating a cell-specific upregulation of this mediator in untreated psoriasis. Western blot analysis also revealed a clear increase in MIF in homogenates of lesional skin from psoriasis patients. These results suggest a role for MIF in the inflammatory skin disease psoriasis.

The diagnostic role of the in vitro drug-induced interferon-gamma release test in Stevens-Johnson syndrome

BACKGROUND

Drug-related T-cell activity in cutaneous drug reactions may be assessed by in vitro cytokine release tests. The diagnostic role of in vitro drug-induced interferon-gamma (IFN-gamma) release was evaluated in a patient with Stevens-Johnson syndrome.

CASE REPORT

Stevens-Johnson syndrome was diagnosed in a 58-year-old man, treated with colchicine (1 mg daily for 39 days) and allopurinol (300 mg daily for 13 days). Based on a clinical-epidemiologic score, allopurinol was more likely to be the causative agent. In vitro drug-induced IFN-gamma release test was conducted on this patient and on two controls, using an enzyme-linked immunoabsorbent assay (ELISA) technique. Increased IFN-gamma release was observed following an in vitro challenge of the patient's lymphocytes with allopurinol, but not following in vitro challenge with colchicine. An in vitro challenge with allopurinol in two control patients, treated with allopurinol without adverse drug reactions, did not induce a significant increase in IFN-gamma release.

CONCLUSIONS

The role of allopurinol as the drug responsible for the induction of Stevens-Johnson syndrome in our patient was confirmed by in vitro allopurinol-induced IFN-gamma release, which may indicate a drug-specific immune response.