Bacterial stimulation plays an important role in modulating the allergic immune response. The aim of this study was to investigate the effects of inactivated probiotic Lactobacillus acidophilus and non-pathogenic Escherichia coli strain Nissle on the phenotype and function of T- and B-cells. Peripheral blood mononuclear cells from patients with grass-pollen allergy (n=10) and non-allergic patients (n=19) were co-stimulated with inactivated bacteria and grass-pollen allergen. Expression of CD23, CD80, CD86 and CD69 were analysed, and the intracellular production of interleukin-4 and interferon-gamma was measured by direct ex vivo flow cytometry after stimulation. Both bacteria induced a significant up-regulation of CD69 expression on T-lymphocytes (p=0.001). CD23 expression was significantly increased following stimulation with allergen (p=0.008), but reduced after stimulation with Lactobacillus and significantly reduced with E. coli plus allergen (p=0.029). CD80 expression was reduced after stimulation with Lactobacillus in the allergic group only (p=0.021). By contrast, CD86 expression was significantly increased after stimulation with Lactobacillus (p=0.049) and distinctly increased with E. coli in both groups (p=0.001). The cytokine patterns of CD69-positive T-lymphocytes from allergic patients showed a TH2-dominated response after allergen stimulation (interferon-gamma/interleukin-4-ratio 0.2), directed into a T-helper1-like response by stimulation with both types of bacteria (interferon-gamma/interleukin-4-ratios 1.5-2.0 in both groups). These data show that both types of bacteria modulate the allergic immune response by the alteration of CD23 and co-stimulatory molecule expression. Regarding cytokine production, the data suggest a differential response to both bacteria depending on the atopic state, but a clear promotion of T-helper1-dominated response in allergic donors.

Cellular inflammation of the nasal mucosa demonstrates a local immune response which plays an important role in allergic rhinitis. The aim of the present study was to characterize nasal mucosal lymphocytes regarding their activation and differentiation state by direct ex vivo flowcytometric analysis. Lymphocytes from the inferior turbinates were isolated by a mechanical method of preparation and, for comparison, from peripheral blood by Ficoll gradient centrifugation. Patients suffering from rhinitis or difficulty in nasal breathing were divided into an allergic (pollen-allergy, n = 13) and non-allergic group (n = 24). Expression of different T- and B-cell markers was determined by flowcytometric analysis. CD4+ T-cells from the nasal mucosa exhibited a memory phenotype (CD45RO+, 97%), were highly activated (CD69+, 43-73%), and showed low expression of the cutaneous lymphocyte antigen (CLA+, 5%). Nasal CD20+ B-lymphocytes expressed significantly higher levels of mIgE and lower levels of CD23 and CD80 than peripheral B-cells. Subsets of CD80+ (4%) and CD86+ (6%) CD20+ B-lymphocytes were identified in the nasal mucosa. No significant differences between allergic and non-allergic individuals were determined. As expected, the data show profound phenotypical differences between circulating peripheral blood and nasal mucosal lymphocytes. Activated memory lymphocytes are present in the nasal mucosa from allergic, but also non-allergic patients and may indicate to a significant role of a local inflammatory state without systemic criteria for allergy. In our study, we show that direct ex vivo isolation of lymphocytes is practicable method and offers a new technique to examine the local nasal allergic immune response using a multiparametric phenotypical analysis.