Glucocorticoid-resistant asthma. T-lymphocyte defects

In vitro steroid resistance correlates with outcome in severe alcoholic hepatitis

Steroids improve the outcome in alcoholic hepatitis (AH), but up to 40% of patients fail to respond adequately. Interleukin-2 (IL-2) exacerbates steroid resistance in vitro. We performed a prospective study to determine if intrinsic steroid sensitivity correlates with response to steroids in individuals with severe AH and if IL-2 receptor blockade can reverse this. Peripheral blood mononuclear cells (PBMCs) were isolated from 20 patients with AH and a Maddrey's score >32. Patients were treated with oral prednisolone plus full supportive measures. Clinical resistance to oral steroid treatment was defined as a drop in serum bilirubin of <25% within 7 days or death within 6 months. In vitro steroid resistance was measured in PBMC using the dexamethasone suppression of lymphocyte proliferation assay and repeated after the addition of the anti-IL-2 receptor (anti-CD25) monoclonal antibody, basiliximab. Suppression of lymphocyte proliferation <60% was considered to indicate steroid resistance. In all, 82% (9/11) of in vitro steroid-resistant patients were dead at 6 months as compared to 21% (2/9) of steroid-sensitive patients (P = 0.03). Similarly, 91% (10/11) of in vitro steroid-resistant patients failed to show a significant fall in bilirubin at day 7 as compared to 44% (4/9) of steroid-sensitive patients (P < 0.05). Basiliximab improved the maximal proliferation count in 91% (10/11) of in vitro steroid-resistant patients (P = 0.003).

CONCLUSION

Clinical outcome of steroid therapy in this patient cohort correlated with in vitro steroid resistance. IL-2 blockade improved in vitro steroid sensitivity. This suggests that intrinsic lack of steroid sensitivity may contribute to poor clinical response to steroids in severe AH. IL-2 receptor blockade represents a possible mechanism to overcome this.

Interleukin-6 and the development of social disruption-induced glucocorticoid resistance

Following social disruption (SDR) stress in male mice, corticosterone resistance of splenocytes was accompanied by enhanced LPS-stimulated interleukin (IL)-6 secretion. The present study examined the role of IL-6 in the development of corticosterone resistance. Addition of IL-6 to control splenocyte cultures did not induce corticosterone resistance. SDR also elevated IL-6 in plasma and liver, but not in spleen. IL-6 deficient mice that were exposed to SDR developed glucocorticoid resistance despite the absence of systemic IL-6. These findings suggest that although SDR enhanced IL-6 responses, IL-6 was not essential for the development of stress-induced splenocyte corticosterone resistance.

Social stress induces glucocorticoid resistance in macrophages

Stress-induced levels of plasma glucocorticoid hormones are known to modulate leukocyte function. These experiments examined the effects of a social stressor on the responsiveness of peripheral immune cells. Male mice experienced six evening cycles of social disruption (SDR), in which an aggressive male intruder was placed into their home cage for 2 h. Although circulating corticosterone was elevated in SDR mice, they had enlarged spleens and increased numbers of splenic leukocytes. Splenocytes from SDR and control mice were cultured with lipopolysaccharide and corticosterone. Cells from SDR mice exhibited decreased sensitivity to the antiproliferative effects of corticosterone, suggesting that the peripheral immune cells were resistant to glucocorticoids. In addition, SDR cells produced more interleukin (IL)-6. To determine which cell population was affected, we used antibody-labeled magnetic beads to deplete splenocyte suspensions of B cells or macrophages. Depletion of macrophages from SDR cultures, but not depletion of B cells, abolished both the corticosterone resistance and enhanced IL-6 secretion. These findings demonstrate that a psychosocial stressor induced glucocorticoid resistance in mouse splenic macrophages.

Pseudo-steroid resistant asthma

BACKGROUND

Steroid resistant asthma (SRA) represents a small subgroup of those patients who have asthma and who are difficult to manage. Two patients with apparent SRA are described, and 12 additional cases who were admitted to the same hospital are reviewed.

METHODS

The subjects were selected from a tertiary hospital setting by review of all asthma patients admitted over a two year period. Subjects were defined as those who failed to respond to high doses of bronchodilators and oral glucocorticosteroids, as judged by subjective assessment, audible wheeze on examination, and serial peak flow measurements.

RESULTS

In 11 of the 14 patients identified there was little to substantiate the diagnosis of severe or steroid resistant asthma apart from symptoms and upper respiratory wheeze. Useful tests to differentiate this group of patients from those with severe asthma appear to be: the inability to perform reproducible forced expiratory manoeuvres, normal airway resistance, and a concentration of histamine causing a 20% fall in the forced expiratory volume (FEV1) being within the range for normal subjects (PC20). Of the 14 subjects, four were health care staff and two reported childhood sexual abuse.

CONCLUSION

Such patients are important to identify as they require supportive treatment which should not consist of high doses of glucocorticosteroids and beta2 adrenergic agonists. Diagnoses other than asthma, such as gastro-oesophageal reflux, hyperventilation, vocal cord dysfunction and sleep apnoea, should be sought as these may be a cause of glucocorticosteroid treatment failure and pseudo-SRA, and may respond to alternative treatment.