Anne-Marie Christensen

Soluble Mediators in Platelet Concentrates Modulate Dendritic Cell Inflammatory Responses in an Experimental Model of Transfusion.

The transfusion of platelet concentrates (PCs) is widely used to treat thrombocytopenia and severe trauma. Ex vivo storage of PCs is associated with a storage lesion characterized by partial platelet activation and the release of soluble mediators, such as soluble CD40 ligand (sCD40L), RANTES, and interleukin (IL)-8. An in vitro whole blood culture transfusion model was employed to assess whether mediators present in PC supernatants (PC-SNs) modulated dendritic cell (DC)-specific inflammatory responses (intracellular staining) and the overall inflammatory response (cytometric bead array). Lipopolysaccharide (LPS) was included in parallel cultures to model the impact of PC-SNs on cell responses following toll-like receptor-mediated pathogen recognition. The impact of both the PC dose (10%, 25%) and ex vivo storage period was investigated [day 2 (D2), day 5 (D5), day 7 (D7)]. PC-SNs alone had minimal impact on DC-specific inflammatory responses and the overall inflammatory response. However, in the presence of LPS, exposure to PC-SNs resulted in a significant dose-associated suppression of the production of DC IL-12, IL-6, IL-1α, tumor necrosis factor-α (TNF-α), and macrophage inflammatory protein (MIP)-1β and storage-associated suppression of the production of DC IL-10, TNF-α, and IL-8. For the overall inflammatory response, IL-6, TNF-α, MIP-1α, MIP-1β, and inflammatory protein (IP)-10 were significantly suppressed and IL-8, IL-10, and IL-1β significantly increased following exposure to PC-SNs in the presence of LPS. These data suggest that soluble mediators present in PCs significantly suppress DC function and modulate the overall inflammatory response, particularly in the presence of an infectious stimulus. Given the central role of DCs in the initiation and regulation of the immune response, these results suggest that modulation of the DC inflammatory profile is a probable mechanism contributing to transfusion-related complications.

Are there better Bcr-Abl kinase inhibitors for chronic myeloid leukaemia than imatinib?

The Bcr-Abl kinase inhibitor imatinib is the standard treatment for chronic myeloid leukaemia (CML). Some subjects with CML do not respond to, or are intolerant of, imatinib. Nilotinib and dasatinib were initially developed to treat these subjects, and were shown to be effective. They are now being trialled as initial ‘inib’ treatment for CML. The objective was to evaluate the recent Phase III clinical trials comparing nilotinib or dasatinib with imatinib in newly diagnosed CML. Nilotinib and dasatinib were shown to give a higher rate of complete cytogenic and major molecular responses than imatinib over 1 year. They should be considered as first choice in the treatment of subjects who develop CML. However, there are still major limitations to the populations with which these ‘inib’ drugs can be used, and how they can be used.

Does the p38 MAP kinase inhibitor pamapimod have potential for the treatment of rheumatoid arthritis

Methotrexate alone or in combination with other agents is the standard treatment for moderate-to-severe rheumatoid arthritis. As biological agents are expensive, they are not usually used until methotrexate has failed to give a good response. Thus, there is scope for the development of cheaper drugs that can be used instead of methotrexate or in addition to methotrexate. Pamapimod is a p38α inhibitor being developed for use in the treatment of rheumatoid arthritis. The objective of this review was to evaluate the recent clinical trials of pamapimod in subjects with rheumatoid arthritis. There is no clear-cut evidence that pamapimod alone or in the presence of methotrexate is efficacious in subjects with rheumatoid arthritis but it does cause adverse effects. It is unlikely that pamapimod will be useful in the treatment of rheumatoid arthritis.