Biomedical subjects

Jean-Claude Brouet

Publications and source records attributed to Jean-Claude Brouet.

7 recordsLinked to original sources

PubMed2006

[Waldenström's macroglobulinemia].

Waldenström's macroglobulinemia associates a serum monoclonal IgM and a lymphoplasmacytic infiltration of bone marrow, spleen, lymph nodes and various organs. Clinical symptoms are related either to the lymphoid disorder or to the physico-chemical characteristics or antibody activity of the monoclonal IgM. Visceral infiltration may target stomach small bowel, lungs, exocrine glands or skin. Major complications include bone marrow failure, auto-immune cytopenia, occurrence of large cell lymphoma and infections (related either to the humoral immunodeficiency or to chemotherapy). Asymptomatic macroglobulinemia does not deserve any treatment. Otherwise, alkylating agents or nucleoside analogues are first line agents. The benefit of monoclonal antibodies, high dose chemotherapy followed by auto or allogenic stem cell graft is currently assessed.

Age Factors↗

PubMed2004

Comparison of sequential cytomegalovirus isolates in a patient with lymphoma and failing antiviral therapy.

BACKGROUND: Long-term anti-cytomegalovirus (CMV) treatments in immunocompromised patients are hampered by resistance to antiviral drugs. Longitudinal changes in the resistance genotype may depend on changes in selective pressure and the complexity of CMV isolates. OBJECTIVE: To evaluate longitudinal changes in the CMV resistance genotype and phenotype along with strain-specific variability in a patient with non-Hodgkin's lymphoma in whom successive anti-CMV treatments failed. STUDY DESIGN: The resistance phenotype and genotype of seven CMV isolates collected from one patient during a 2-year follow-up period were retrospectively analysed. In parallel, we used glycoprotein B (gB) genotyping, and a- and UL10-13-sequence analysis to study CMV interstrain variability. RESULTS: The patient was infected by at least three CMV strains plus variants of the parental strains. Resistance to ganciclovir, cidofovir and foscarnet was successively detected during the follow-up period. UL97 protein kinase changes responsible for resistance to ganciclovir were initially detected at residues 591 and 592, and then at position 594. Decreased sensitivity to foscarnet coincided with the appearance of amino acid substitution N495K in DNA polymerase, whereas cross-resistance to ganciclovir and cidofovir was due to the L501I substitution. CONCLUSIONS: The CMV isolates obtained from our patient were complex mixtures of strains. Changes in resistance genotypes depended on resistance selective pressure and were not linked to interstrain variation.

Aged↗

PubMed2004

Arsenic trioxide is effective in the treatment of multiple myeloma in SCID mice.

OBJECTIVES: Pharmacological concentrations of arsenic trioxide (ATO) and organic arsenic melarsoprol induce apoptosis in malignant plasma cells. In an attempt to further document the interest of the arsenic in vivo, we treated severe combined immunodeficient (SCID) mice transplanted with human myeloma cells by ATO or melarsoprol. METHODS: Fifty-two SCID mice were irradiated before intraperitoneal (i.p.) injection of plasma cells from five myeloma patients. Engraftment was assessed by serial measurement of the human monoclonal immunoglobulin G (HuMIgG) concentration in mouse serum. Treatment with ATO (10 microg/g i.p. 5 d a week), melarsoprol (30 microg/g i.p. 5 d a week) or phosphate buffer saline was started when a sustained growth of the tumor cells was demonstrated. RESULTS: Seventeen mice developed the human tumor. A significant decrease in HuMIgG amounts was observed in three of five mice of the ATO group, including two that achieved an apparent complete remission persisting up to 5 months after ATO discontinuation. In these mice, no human plasma cells were detected in tissue samples collected postmortem. Soluble human interleukin-6 receptor amount, measured in mice sera as a surrogate marker of the plasma cell proliferation, varied in parallel with HuMIgG concentration. A significant difference in survival was observed between control and ATO treated mice (113 and 158 d, respectively; P = 0.01) whereas no difference could be evidenced in control and melarsoprol groups. CONCLUSION: Present study confirms in vivo the in vitro effects of ATO on myeloma cells. Delayed relapses were observed suggesting that prolonged or maintenance therapy has to be considered in future clinical trials. Whether or not this will translate into clinically relevant effect of the drug in myeloma patients deserves further consideration.

Animals↗

PubMed2004

High dose chemotherapy in light chain or light and heavy chain deposition disease.

BACKGROUND: Conventional chemotherapy for myeloma yield unsatisfactory results in light and/or heavy chain deposition disease [(H)CDD] Because of the well-established dose-response effect of high dose melphalan in multiple myeloma, aiming to dramatically reduce the pathogenic monoclonal immunoglobulin (MIg) level, high dose therapy is a tempting alternative approach. METHODS: We treated 11 young patients with L(H)CDD by high dose therapy with the support of autologous blood stem cell transplantation. All had renal symptoms, including four who required dialysis and seven who had various, mainly cardiac, extrarenal manifestations. RESULTS: No toxic deaths occurred. A decrease in the MIg level was observed in eight patients, with complete disappearance from serum and urine in six cases. Improvement in manifestations related to MIg deposits were observed in six patients, including renal, cardiac, and hepatic responses in 4/11, 4/4, and 2/2 cases, respectively. Histologic regression of MIg deposits was documented in cardiac, hepatic, and skin biopsies. In contrast, examination of the kidney still showed light chain deposits in one patient who had renal transplantation 3 years after high dose therapy, at a time when he was in persisting remission. Within a median follow-up of 51 months, three patients were retreated because of multiple myeloma relapse, of whom one died and one required hemodialysis, and renal function secondarily deteriorated in a patient who had resistant multiple myeloma. Otherwise, no manifestations related to MIg deposits occurred or recurred in any patient. CONCLUSION: Present results of this retrospective study argue in favor of a benefit of high dose therapy with stem cell support in young patients with L(H)CDD.

Adult↗

PubMed2002

Evidence for naive T-cell repopulation despite thymus irradiation after autologous transplantation in adults with multiple myeloma: role of ex vivo CD34+ selection and age.

Immunodeficiency following autologous CD34+-purified peripheral blood stem cell (PBSC) transplantation could be related to T-cell depletion of the graft or impaired T-cell reconstitution due to thymus irradiation. Aiming to assess the role of irradiated thymus in T-cell repopulation, we studied 32 adults with multiple myeloma, randomly assigned to receive high-dose therapy including total body irradiation (TBI) followed by autologous transplantation with either unselected or CD34+-selected PBSCs. The median number of reinfused CD3+ cells was lower in the selected group (0.03 versus 14 x 10(6)/kg; P =.002). Lymphocyte subset counts were evaluated from month 3 to 24 after grafting. Naive CD4+ T cells were characterized both by phenotype and by quantification of T-cell receptor rearrangement excision circles (TRECs). The reconstitution of CD3+ and CD4+ T cells was significantly delayed in the CD34+-selected group, but eventually led to counts similar to those found in the unselected group after month 12. Mechanism of reconstitution differed, however, between both groups. Indeed, a marked increase in the naive CD62L+CD45RA+CD4+ subset was observed in the selected group, but not in the unselected group in which half of the CD45RA+CD4+ T cells appear to be CD62L-. Age was identified as an independent adverse factor for CD4+ and CD62L+CD45RA+CD4+ T-cell reconstitution. Our results provide evidence that infusing PBSCs depleted of T cells after TBI in adults delays T-cell reconstitution but accelerates thymic regeneration.

Adult↗

PubMed2002

High-dose therapy and autologous blood stem cell transplantation in POEMS syndrome.

We treated 5 patients with polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome and multifocal bone lesions or diffuse bone marrow plasmacytic infiltration with high-dose therapy (HDT) and autologous blood stem cell transplantation. In all cases, the treatment produced remission of plasma cell proliferation associated with marked improvement in the patients' performance status, neurologic symptoms, and other manifestations of the syndrome. HDT with stem cell support should be investigated further as a therapeutic option in patients with POEMS syndrome and disseminated plasma cell dyscrasia.

Adult↗

PubMed2002

Prevalence of monoclonal gammopathy in patients with primary hyperparathyroidism: a prospective study.

BACKGROUND: The association between primary hyperparathyroidism (PHPT) and monoclonal gammopathy has been reported, but whether it is fortuitous remains unsettled. We conducted a prospective study to determine the prevalence of monoclonal gammopathies in patients with surgically proved PHPT. METHODS: In 101 consecutive patients with PHPT, serum immunoglobulins were systematically studied using agarose gel electrophoresis and immunofixation before and, when appropriate, after parathyroid surgery. The PHPT population was compared with a control series of patients with other diseases requiring surgery and with a group of patients with benign disease of the thyroid gland matched for age and sex to the PHPT population. RESULTS: Monoclonal immunoglobulin was detected in 10 (10%) of 101 patients with PHPT (including 2 with multiple myeloma) compared with 2 (2%) of 127 patients who underwent other surgery (P =.005) and 3 (3%) of 101 patients with benign thyroid diseases (P =.04). CONCLUSIONS: The prevalence of monoclonal gammopathies is high in patients with PHPT. At minimum, sensitive serum protein electrophoresis should be performed routinely in all patients with PHPT. Conversely, in patients with monoclonal gammopathy who have hypercalcemia but no other symptoms of progressive disease, clinicians must seek PHPT.

Adult↗