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Anti-TJa alloimmunization is an extremely rare condition which can cause miscarriages during the first and second terms of pregnancy. At 20-year-old female patient, an anti-TJa carrier, was given plasma transfusions in the course of her first two pregnancies. The cordocentesis, which was the main follow-up test during the first pregnancy, could not be carried out during the second pregnancy due to the presence of a huge subchorionic hematoma. Both pregnancies were characterized by fetal growth retardation, which was particularly considerable in one. Due to chronic fetal distress, both infants were delivered prematurely by cesarean section. The immunohematological data concerning anti-TJa alloimmunization and the different palliative treatments available to date are reviewed.

MALDI direct analysis of tissues and imaging has shown to be a very powerful tool, it still require new developments. In peculiar, the search for new matrices that would be more adapted to direct tissue analysis was looked for. Ionic matrices were found to be especially well suited for such purpose. In peculiar, two matrices gave very good results for tissue analysis looking in term of crystallization, signal intensity, resolution, sensitivity and number of detected compounds compared to classical MALDI matrices. Moreover, in order to work on tissues kept in hospital libraries, FFPE tissues were studied. Fixation raises many problems for mass spectrometry analysis especially for long stored tissues. For older samples, no signal can be obtained directly from the tissues and a new strategy has to be developed. Thus, protocols of in situ tissue enzymatic digestion were developed. Using such a strategy in combination with automatic micro-spotting MALDI imaging of old tissues became possible. In addition, to increase the field of application of MALDI imaging, by giving access to other biomolecules than peptides/proteins, such as mRNA, or to lowly abundant, high mass or membrane proteins, a new concept of specific MALDI imaging was developed.. Using tagged oligonucleotide or antibody probes in combination with respectively In Situ Hybridization (ISH) or ImmunoCytoChemistry (ICC) will allow to performed molecular images of the repartition of specific mRNA or proteins by MALDI. All these new developments will be presented.

International audience; MALDI direct analysis and MALDI imaging of tissues have shown to be a very powerful tool by localizing molecules in tissue and by avoiding extraction, pre-purification, separation. Nevertheless, this new method requires new developments to increase sensitivity and specificity. We propose here a new concept and evolutions of each step of MALDI Imaging analysis. New matrices called Ionic matrices were synthesized to be especially well adapted for a good crystallization, sensitivity and resolution compared to the classical matrices. Moreover, for tissue kept in hospital libraries, FFPE tissues we developed a new strategy of in situ tissue enzymatic digestion was developed in combination with automatic microspotting MALDI Imaging. In order to add a dimension of specificity to imaging by MS, we have developed specific imaging using designed probes directed against specific targets with mass spectrometry detection. This strategy has been developed for different class of biomolecules with a specific highlight, to mRNA and peptides/proteins. This concept is based of indirect detection of specific targeted molecule using a photocleavable tagged probe. The introduction of the specific imaging give another dimension by targeting specific disease-marker-gene RNA transcripts, following their expression within tissues and then confirming their translation by targeting their specific proteinproducts or metabolites

International audience; La protéomique connaît un essor considérable depuis ces dernières années comme le démontre les nombreux travaux réalisés dans le domaine. Elle a permis de conduire à l'identification de nombreuses protéines. Cependant, malgré la puissance de cette stratégie, l'information concernant la localisation des composés au sein des tissus ne peut être conservée. En revanche, le développement de méthodologies nouvelles, comme l'analyse directe de tissus par spectrométrie de masse permet d'obtenir cette information. Dans le cadre de l'analyse des biomolécules sous leur forme intacte, les sources MALDI sont bien adaptées. Ainsi, il est possible de réaliser l'analyse directe de composés au sein des tissus de biomolécules en MALDI. L'automatisation de cette méthode ouvre vers l'imagerie par spectrométrie de masse MALDI au travers de cartes de répartition moléculaires dans le tissu. Néanmoins, cette méthodologie nécessite encore de nombreux développements afin d'améliorer les qualités d'analyse et la résolution des images. Nous nous sommes plus intéressés à développer différents aspects de cette technologie. Ces développements ont été appliqués à l'étude du cancer de l'ovaire et la recherche de nouveaux biomarqueurs de cette pathologie. L'analyse directe différentielle de biopsies de patientes présentant une tumeur et de patientes témoins (descente d'organe) a conduit à la mise en évidence de plusieurs biomarqueurs potentiels.