Semiquantitative analysis of residual disease in patients treated for adult T-cell leukaemia/lymphoma (ATLL).

International audienceMany adult T-cell leukaemia/lymphoma (ATLL) patients who respond to induction treatment, then relapse. Knowing the clonality pattern of residual tumourous clones during treatment could help understand disease evolution and aid therapeutic decisions. We developed a sensitive and semi-quantitative molecular analysis of these clones in ATLL patients. DNA samples from PBMCs derived from eight ATLL patients were studied over time by quadruplicate linker mediated PCR (LMPCR) amplification of HTLV-1 integration sites. Patients were treated with combination chemotherapy, zidovudine-interferon-alpha and/or by peripheral stem cell transplantation or allogeneic bone marrow transplantation. Persistence of tumourous clones at a high frequency (>1/300 PBMCs) was frequently observed, even in complete responders, and was invariably correlated with relapse and/or poor outcome. Fluctuation in the frequency of some tumourous clones was observed with evidence for clonal change under treatment in one patient, indicating that treatment of ATLL can result in the selection of resistant clones. Finally, allogeneic bone marrow transplantation (BMT) using an HTLV-1 infected sibling as donor was found to be associated with long-lasting disappearance of tumourous clones and a possible cure of the disease. Long-term persistent clonal expansion of circulating HTLV-1 bearing T cells which derived from the donor bone marrow was evidenced in this patient. In conclusion, variable success in treatment of ATLL is probably due to the clonal heterogeneity which results in the selection of resistant clones. Semi-quantitative assessment of residual disease (RD) through LMPCR may predict treatment failure. Accordingly, additional therapy may be tailored to the clonality pattern observed after first-line therapy

Solutions for Extended Split PON.

C

Reduction of Abeta amyloid pathology in APPPS1 transgenic mice in the absence of gut microbiota

Alzheimer's disease is the most common form of dementia in the western world, however there is no cure available for this devastating neurodegenerative disorder. Despite clinical and experimental evidence implicating the intestinal microbiota in a number of brain disorders, its impact on Alzheimer's disease is not known. To this end we sequenced bacterial 16S rRNA from fecal samples of Aβ precursor protein (APP) transgenic mouse model and found a remarkable shift in the gut microbiota as compared to non-transgenic wild-type mice. Subsequently we generated germ-free APP transgenic mice and found a drastic reduction of cerebral Aβ amyloid pathology when compared to control mice with intestinal microbiota. Importantly, colonization of germ-free APP transgenic mice with microbiota from conventionally-raised APP transgenic mice increased cerebral Aβ pathology, while colonization with microbiota from wild-type mice was less effective in increasing cerebral Aβ levels. Our results indicate a microbial involvement in the development of Abeta amyloid pathology, and suggest that microbiota may contribute to the development of neurodegenerative diseases