Katja Rombaut

IL-4 deficiency prevents eosinophilic rejection and uncovers a role for neutrophils in the rejection of MHC class II disparate skin grafts.

Background. Acute rejection of MHC class II-disparate bm12 skin grafts by C57BL/6 recipient mice is characterized by massive graft infiltration by eosinophils, together with increased intragraft amounts of IL-4 and IL-5 mRNA. IL-5 blockade prevents the intragraft eosinophil infiltration and prolongs the survival of skin allografts. As the differentiation of T cell precursors into Th2 cells is largely driven by IL-4, we investigated the role of IL-4 in MHC class II-disparate allograft rejection. Methods. We performed skin grafts from MHC class II incompatible bm12 mice into wild-type C57BL/6 mice (IL-4+/+) or C57BL/6 IL-4 deficient mice (IL-4−/−). Graft survival, in vitro T cell reactivity, and histology were compared. Results. We observed that 50% of IL-4−/− mice rapidly rejected their bm12 allograft, whereas the other 50% retained their graft 60 days after transplantation. Histological examination of bm12 allografts retained by IL-4−/− mice showed a normal appearance with no inflammatory infiltrate and no eosinophils. Among IL-4−/− mice that acutely rejected their bm12 skin graft, we observed a dense polymorphonuclear infiltrate. The depletion of neutrophils significantly prolonged bm12 graft survival. Conclusions. Eosinophil infiltrates, typical of MHC class II disparate acute skin graft rejection, are critically dependent on the availability of IL-4. IL-4−/− mice reject MHC class II disparate skin grafts by a pathway of rejection where neutrophils play a direct causal role.

Assessment of nuclear size, nuclear DNA content and proliferation index in stereotaxic biopsies from brain tumours

In this paper we study the feasibility of measuring the diverse biological parameters in stereotaxic biopsies from human brain lesions. These biological parameters are the nuclear area (NA), the proliferation index (PI) and the ploidy level, the latter of which was evaluated by means of the DNA index (DI) and histogram type (DHT). These parameters were assessed by means of the digital cell image analysis of Feulgen‐stained nuclei. This analysis was performed on 124 samples from 22 computed tomography (CT)‐guided stereotaxic biopsies. The data show that the methodology used here enables the above parameters to be assessed on small samples without limiting the classical anatomopathological diagnosis. The data also reveal that the DHT corresponded more accurately to the ploidy level in the sample analysed than the DI. Lastly, it appears that supratentorial astrocytic tumours of the adult, which constituted the majority of the cases analysed here, are strongly heterogeneous at a biological level.

Lectin histochemistry, ploidy level and proliferation indices in meningioma subtypes

I. Salmon, I. Camby, M. Remmelinck, K. Rombaut, J.‐L. Pasteels, J. Brotchi, R. Kiss and A. Danguy (1996) Neuropathology and Applied Neurobiology 22, 68–76

How Could Static Telepathology Improve Diagnosis in Neuropathology

The present paper reports our experience with, and our opinion of static telepathology as applied to neuropathology by means of the PHAROS acquisition system and conventional telephone data transmission (modem). The classical procedure of expert consultation based on surface mailing of histological slides is routinely performed, especially in highly specialized fields of pathology. Telepathology is an easy means of sharing scientific expertise at international level and could thus improve diagnosis particularly in neuropathology, where certain tumor types are very rare and complex to diagnose. Dynamic telepathology allows the referring pathologist to capture by himself images supporting their diagnosis. Using static telepathology the pathologist could be limited in diagnosis by problems in fields selection. We devoted a whole year to collecting all the technical parameters characterizing the use of digitized neuropathological data files in order to investigate the feasibility of telepathology and the extent to which its use could improve diagnoses. Our results on a series of 38 histological brain examinations illustrate how we successfully established an international connection between two departments of pathology in Belgium and the USA. The referring pathologists gave diagnoses in 35 cases and deferred only 3. Despite a time‐consuming procedure for the telepathology session of a few cases, this tool provides easy access to expert diagnosis and real‐time discussion, both of which are of considerable interest and offer significant improvements in neuropathology.

Lectin histochemistry, ploidy level, and proliferative activity in rhabdomyosarcoma subtypes.

The glycohistochemical expression of binding sites for eight lectins is characterized in a series of 8 embryonal, 4 alveolar and 4 pleomorphic rhabdomyosarcomas. The correlation between lectin staining and either the proliferation index or the ploidy level was also investigated. The data show that rhabdomyosarcomas exhibit heterogeneous lectin binding expressions. A comparable level of lectin labeling is observed in euploid and aneuploid tumours. In contrast to other neoplasms, lectin staining has proved to be of doubtful value in distinguishing between different RMS subtypes. The data also reveal that a significantly lower level of proliferative activity was observed in the pleomorphic group as compared to the alveolar one.