Anaemia management in patients with inflammatory bowel disease: routine practice across nine European countries.

BACKGROUND AND OBJECTIVES: Anaemia and iron deficiency (ID) are common complications in inflammatory bowel disease (IBD). In patients undergoing iron therapy, intravenous iron supplementation is recommended in preference to oral therapy. This study evaluated routine practice in the management of IBD-associated anaemia and ID to verify implementation of international treatment guidelines. MATERIALS AND METHODS: Gastroenterologists from nine European countries (n=344) were surveyed about their last five IBD patients treated for anaemia (n=1404). Collected information included tests performed at anaemia diagnosis, haemoglobin (Hb) levels and iron status parameters, the anaemia treatment given and, if applicable, the iron administration route. RESULTS: Selection of diagnostic tests and treatment for IBD-associated anaemia varied considerably across Europe. Anaemia and iron status were mainly assessed by Hb (88%) and serum ferritin (75%). Transferrin saturation was only tested in 25% of patients. At diagnosis of anaemia, 56% presented with at least moderate anaemia (Hb<10 g/dl) and 15% with severe anaemia (Hb<8 g/dl). ID (ferritin<30 ng/ml) was detected in 76%. Almost all patients (92%) received iron supplementation; however, only 28% received intravenous iron and 67% oral iron. Management practice was similar in 2009 and 2011. CONCLUSION: In clinical practice, most IBD patients received oral iron even though this administration route may aggravate the disease, and despite international guidelines recommending intravenous administration as the preferred route. The high frequency of ID suggests insufficient monitoring of iron status in IBD patients. There is a need to increase awareness and implementation of international guidelines on iron supplementation in patients with IBD.

Mycobacteria induce IFN-gamma production in human dendritic cells via triggering of TLR2.

IFN-gamma is of central importance for the induction of robust cell-mediated immunity and for the activation of APC. Recent studies using experimental murine systems have now suggested a fundamental role for APC-derived IFN-gamma during infection with intracellular pathogens. It is currently unknown whether human dendritic cells (DC) can respond to bacterial stimulation with production of IFN-gamma. To test this question, we used human monocyte-derived DC stimulated by Mycobacterium bovis bacillus Calmette-Guérin as a model system. We demonstrate production of IFN-gamma mRNA and protein on the single cell level. IFN-gamma in DC cultures was not simply produced by contaminating lymphocytes because production of DC-IFN-gamma could also be demonstrated in highly purified DC cultures containing virtually no T, B, and NK cells. TLR2 was identified as a key receptor involved in triggering production of DC-IFN-gamma. Interestingly, DC-IFN-gamma seems to participate in an autocrine DC activation loop, and production of DC-IFN-gamma could be enhanced by costimulation of DC with IL-12/IL-15/IL-18. In conclusion, we have demonstrated production of IFN-gamma by human DC on the single cell level, identified TLR2 as a pattern recognition receptor involved in this process, and elucidated some of the functional consequences of autocrine IFN-gamma production by human DC.

Platelet factor 4 in conjunction with IL-4 directs differentiation of human monocytes into specialized antigen-presenting cells.

Recent evidence suggests that platelets are not only involved in haemostatic processes but also modulate immune responses. As antigen-presenting cells (APC) are of crucial importance for the regulation of immunity, in this study we wanted to define the role of platelet factor 4 (PF-4) as one of the major platelet-derived chemokines on the transition of monocytes into APCs. Our experiments show that within 3 days PF-4 in conjunction with IL-4 induces a rapid differentiation of monocytes into APC. These PFAPC (PF-4/IL-4 differentiated APC) display unique phenotypical and functional characteristics setting them apart from macrophages and conventional dendritic cells. Functional studies revealed that PFAPC preferentially stimulated proliferation of lymphocytes and lytic NK activity while they induced only moderate cytokine responses. Beyond day 3 of differentiation, PFAPC became less immunostimulatory and maintained their capacity to phagocytose particulate material even after LPS-induced maturation. These experiments uncover a previously unknown role for the platelet-derived CXC-chemokine PF-4 in differentiation of human APC. Our data further support the newly discovered function of platelets in immunomodulation and provide new evidence for a rapid transition of monocytes into APC under the influence of inflammatory stimuli.