Nicole Brousse

Activation-induced cytidine deaminase (AID) deficiency causes the autosomal recessive form of the Hyper-IgM syndrome (HIGM2).

The activation-induced cytidine deaminase (AID) gene, specifically expressed in germinal center B cells in mice, is a member of the cytidine deaminase family. We herein report mutations in the human counterpart of AID in patients with the autosomal recessive form of hyper-IgM syndrome (HIGM2). Three major abnormalities characterize AID deficiency: (1) the absence of immunoglobulin class switch recombination, (2) the lack of immunoglobulin somatic hypermutations, and (3) lymph node hyperplasia caused by the presence of giant germinal centers. The phenotype observed in HIGM2 patients (and in AID-/- mice) demonstrates the absolute requirement for AID in several crucial steps of B cell terminal differentiation necessary for efficient antibody responses.

Association between Staphylococcus aureus strains carrying gene for Panton-Valentine leukocidin and highly lethal necrotising pneumonia in young immunocompetent patients

BACKGROUND Between 1986 and 1998, eight cases of community-acquired pneumonia due to Staphylococcus aureus strains carrying the gene for the Panton-Valentine leukocidin (PVL) were recorded in France, six of which were fatal. We aimed to assess the clinical features of these eight cases, and those of other cases identified prospectively, and to compare them with the characteristics of patients with pneumonia caused by PVL-negative strains. METHODS We compared eight retrospective and eight prospective cases of PVL-positive S aureus pneumonia with 36 cases of PVL-negative S aureus pneumonia. For all patients, we recorded age, length of hospital stay, risk factors for infection, signs and symptoms, laboratory findings, antibiotic treatment, and serial radiological findings. FINDINGS Median age was 14.8 years (IQR 5.4-24.0) for the PVL-positive patients and 70.1 years (59.2-81.4) for the others (p=0.001). Influenza-like illness had occurred during the 2 days before admission in 12 of the 16 PVL-positive patients, but in only three of 33 PVL-negative patients (p<0.001). PVL-positive infections were more often marked by: temperature greater than 39 degrees C (p=0.01), heart rate above 140 beats per min (p=0.02), haemoptysis (p=0.005), onset of pleural effusion during hospital stay (p=0.004), and leucopenia (p=0.001). The survival rate 48 h after admission was 63% for the PVL-positive patients and 94% for PVL-negative individuals (p=0.007). Histopathological examination of lungs at necropsy from three cases of necrotising pneumonia associated with PVL-positive S aureus showed extensive necrotic ulcerations of the tracheal and bronchial mucosa and massive haemorrhagic necrosis of interalveolar septa. INTERPRETATION PVL-producing S aureus strains cause rapidly progressive, haemorrhagic, necrotising pneumonia, mainly in otherwise healthy children and young adults. The pneumonia is often preceded by influenza-like symptoms and has a high lethality rate.

Lymphoproliferative disorders in patients receiving thiopurines for inflammatory bowel disease: a prospective observational cohort study

BACKGROUND Reports of an increased risk of lymphoproliferative disorders in patients receiving thiopurines for inflammatory bowel disease are controversial. We assessed this risk in a prospective observational cohort study. METHODS 19,486 patients with inflammatory bowel disease, of whom 11,759 (60.3%) had Crohns disease and 7727 (39.7%) had ulcerative colitis or unclassified inflammatory bowel disease, were enrolled in a nationwide French cohort by 680 gastroenterologists, who reported details of immunosuppressive therapy during the observation period, cases of cancer, and deaths. The risk of lymphoproliferative disorder was assessed according to thiopurine exposure. Median follow-up was 35 months (IQR 29-40). FINDINGS At baseline, 5867 (30.1%) of patients were receiving, 2809 (14.4%) had discontinued, and 10,810 (55.5%) had never received thiopurines. 23 new cases of lymphoproliferative disorder were diagnosed, consisting of one case of Hodgkins lymphoma and 22 cases of non-Hodgkin lymphoproliferative disorder. The incidence rates of lymphoproliferative disorder were 0.90 per 1000 (95% CI 0.50-1.49) patient-years in those receiving, 0.20/1000 (0.02-0.72) patient-years in those who had discontinued, and 0.26/1000 (0.10-0.57) patient-years in those who had never received thiopurines (p=0.0054). The multivariate-adjusted hazard ratio of lymphoproliferative disorder between patients receiving thiopurines and those who had never received the drugs was 5.28 (2.01-13.9, p=0.0007). Most cases associated with thiopurine exposure matched the pathological range of post-transplant disease. INTERPRETATION Patients receiving thiopurines for inflammatory bowel disease have an increased risk of developing lymphoproliferative disorders. FUNDING Programme Hospitalier de Recherche Clinique National (AOM05157), Association François Aupetit, Délégation Inter-régionale de la Recherche clinique Ile de France-Assistance Publique Hôpitaux de Paris (AP-HP), Ligue contre le Cancer, and Fonds de Recherche de la Société Nationale Française de Gastro-entérologie.

Refractory sprue, coeliac disease, and enteropathy-associated T-cell lymphoma

BACKGROUND Adult refractory sprue is a poorly defined disorder. We did a multicentre national study of patients with refractory sprue to characterise their clinical and pathological profile and outcome, and to assess the frequency and prognostic significance of phenotypic and molecular abnormalities in the intraepithelial T-cell population. METHODS Patients with severe symptomatic villous atrophy mimicking coeliac disease but refractory to a strict gluten-free diet, and with no initial evidence of overt lymphoma, were diagnosed at gastrointestinal referral centres between 1974 and 1998. Fixed and/or frozen duodenojejunal biopsy samples were reanalysed and immunostained with CD3 and CD8 monoclonal antibodies to find out the phenotype of intraepithelial lymphocytes (IEL). TCRgamma gene rearrangements were assessed on frozen biopsy samples by multiplex fluorescent PCR. FINDINGS There were 21 patients with refractory sprue and 20 controls with coeliacs disease. 16 (84%) of 19 assessed patients had an aberrant intraepithelial lymphoid intestinal population expressing intracytoplasmic CD3 but not surface CD8. Clonal intestinal TCRgamma gene rearrangements were found in 13 (76%) of 17 patients assessed; four (out of 12 assessed) had clonal dissemination to the blood. The 16 patients with an aberrant phenotype all had uncontrolled malabsorption; three subsequently developed overt T-cell lymphoma, and eight died. The three (16%) patients without aberrant clonal IEL made a complete clinical and histological recovery with steroid therapy plus a gluten-free diet. INTERPRETATION An immunophenotypically aberrant clonal intraepithelial T-cell population (similar to that of most cases of enteropathy-associated T-cell lymphoma) can be found in up to 75% of patients with refractory coeliac sprue; its identification by simple diagnostic techniques represents a marker of poor outcome (including occurrence of overt T-cell lymphoma). We suggest that refractory sprue associated with an aberrant clonal IEL may be the missing link between coeliac disease and T-cell lymphoma and may be classified as cryptic enteropathy-associated T-cell lymphoma.

Interleukin 15: a key to disrupted intraepithelial lymphocyte homeostasis and lymphomagenesis in celiac disease

BACKGROUND & AIMS The mechanism of intraepithelial lymphocyte hyperplasia, a hallmark of celiac disease, is unknown. We have investigated the role of epithelium-derived interleukin (IL)-15 in the alterations of epithelial homeostasis in refractory celiac sprue, a privileged situation to study the first step of lymphoid transformation and the contribution of intraepithelial lymphocytes to villous atrophy in celiac disease. METHODS IL-15 expression was assessed in biopsy specimens and isolated enterocytes by combining immunohistochemistry, flow cytometry, and real-time quantitative polymerase chain reaction. The ability of IL-15 to induce growth and survival of clonal intraepithelial lymphocytes lacking surface CD3 and to induce their cytotoxicity and secretion of interferon gamma was tested using soluble IL-15 and coculture in the presence of epithelial cell lines expressing membrane IL-15. RESULTS IL-15 was massively overexpressed not only in lamina propria but also in the intestinal epithelium of patients with active celiac disease and refractory celiac sprue. IL-15 was not secreted but delivered at the surface of enterocytes. IL-15 specifically induced the expansion and survival of the clonal abnormal intraepithelial lymphocytes that characterize refractory celiac sprue and triggered their secretion of interferon gamma and their cytotoxicity against intestinal epithelial cells. Comparable activating signals could be delivered by IL-15 expressed at the membrane of the T84 enterocyte cell line. CONCLUSIONS These data provide strong evidence that uncontrolled overexpression of IL-15 in refractory celiac sprue perpetuates epithelial damage and promotes the emergence of T-cell clonal proliferations. Blocking IL-15 might prove useful to treat this severe complication of celiac disease.

Comparison in low-tumor-burden follicular lymphomas between an initial no-treatment policy, prednimustine, or interferon alfa: a randomized study from the Groupe d'Etude des Lymphomes Folliculaires. Groupe d'Etude des Lymphomes de l'Adulte.

PURPOSE To evaluate prospectively in patients with follicular lymphoma and a low tumor burden three therapeutic options: delay of any treatment until clinically meaningful progression, immediate treatment with an oral alkylating agent, or treatment with a biologic response modifier, interferon alfa-2b. PATIENTS AND METHODS Newly diagnosed follicular lymphoma patients with a low tumor burden (n = 193) were randomly assigned to one of three arms: arm 1, no initial treatment (n = 66); arm 2, prednimustine 200 mg/m2/d for 5 days per month for 18 months (n = 64); or arm 3, interferon alfa 5 MU/d for 3 months then 5 MU three times per week for 15 months (n = 63). Clinical characteristics were similar in the three arms. RESULTS Overall response rates with prednimustine and interferon alfa were 78% and 70%, respectively. The overall response to therapy, when deferred, was similar at 70%. With a median follow-up duration of 45 months after randomization, the median freedom-from-treatment (FFT) interval was 24 months in arm 1 and the interval of freedom from treatment failure (FFTF) was 40 months in arm 2 and 35 months in arm 3. The median overall survival time was not reached and the overall survival rate at 5 years was 78% in arm 1, 70% in arm 2, and 84% in arm 3. Therefore, deferred treatment does not adversely influence survival at 5 years. Patients who progressed within 1 year had a significantly shorter survival duration (median, 48 months). CONCLUSION Delayed treatment is feasible in patients with follicular lymphoma and a low tumor burden. For patients with early progression, more intensive therapy should be considered. For others, because delay of treatment until significant clinical progression does not seem to hamper the prognosis or subsequent response to treatment, the long-term toxicity of alkylating agents can be reduced.

High prevalence of BRAF V600E mutations in Erdheim-Chester disease but not in other non-Langerhans cell histiocytoses

Histiocytoses are rare disorders of unknown origin with highly heterogeneous prognosis. BRAF mutations have been observed in Langerhans cell histiocytosis (LCH). We investigated the frequency of BRAF mutations in several types of histiocytoses. Histology from 127 patients with histiocytoses were reviewed. Detection of BRAF(V600) mutations was performed by pyrosequencing of DNA extracted from paraffin embedded samples. Diagnoses of Erdheim-Chester disease (ECD), LCH, Rosai-Dorfman disease, juvenile xanthogranuloma, histiocytic sarcoma, xanthoma disseminatum, interdigitating dendritic cell sarcoma, and necrobiotic xanthogranuloma were performed in 46, 39, 23, 12, 3, 2, 1, and 1 patients, respectively. BRAF status was obtained in 93 cases. BRAF(V600E) mutations were detected in 13 of 24 (54%) ECD, 11 of 29 (38%) LCH, and none of the other histiocytoses. Four patients with ECD died of disease. The high frequency of BRAF(V600E) in LCH and ECD suggests a common origin of these diseases. Treatment with vemurafenib should be investigated in patients with malignant BRAF(V600E) histiocytosis.

Abnormal intestinal intraepithelial lymphocytes in refractory sprue

BACKGROUND & AIMS The etiology of refractory sprue is unclear. To gain insight into its pathogenesis, the phenotype and T-cell receptor (TCR) gene rearrangement status of intestinal lymphocytes were analyzed in a group of patients with clinical or biological features of celiac disease but either initially or subsequently refractory to a gluten-free diet. METHODS Intestinal biopsy specimens were obtained from 26 adults: 6 patients with refractory sprue, 7 patients with active celiac disease, and 13 normal controls. The phenotype of intestinal lymphocytes was studied by immunohistochemistry and, in 3 patients with refractory sprue, by cytometry of lymphocytes purified from intestinal biopsy specimens. TCR rearrangements were assessed by studying TCRgammaV-J junctional regions from DNA extracted from intestinal biopsy specimens and purified intestinal lymphocytes. RESULTS In the 6 patients with refractory sprue, but not in normal controls or patients with active celiac disease, the intestinal epithelium was massively infiltrated by small lymphocytes that lacked CD8, CD4, and TCR, contained intracytoplasmic but not surface CD3epsilon chains, and exhibited restricted TCRgamma gene rearrangements. CONCLUSIONS Refractory sprue is associated with an abnormal subset of intraepithelial lymphocytes containing CD3epsilon and restricted rearrangements of the TCRgamma chain but lacking surface expression of T-cell receptors.

LNH-84 regimen: a multicenter study of intensive chemotherapy in 737 patients with aggressive malignant lymphoma.

From July 1984 to September 1987, 737 patients with aggressive malignant lymphoma (ML) were treated by an intensive regimen (LNH-84) comprising three or four courses of doxorubicin, 75 mg/m2; cyclophosphamide, 1,200 mg/m2; vindesine, 2 mg/m2 x 2; bleomycin, 10 mg x 2; and prednisolone, 60 mg/m2 x 5 (ACVB), consolidation with high-dose methotrexate, ifosfamide, etoposide, asparaginase, and cytarabine, and a randomized late intensification with two courses of cytarabine, cyclophosphamide, teniposide, bleomycin, and prednisone (AraCVmB). Four hundred forty-two patients had intermediate-grade ML, 221 highgrade ML, and 74 unclassified ML. Most of the patients had advanced disease: stage IIE (23%), III (13%), or IV (47%); 38% disseminated nodes; 38% two or more extranodal sites; and 41% a tumoral mass greater than 10 cm. Five hundred fifty-three patients (75%) went into complete remission (CR), 63 (9%) into partial remission, 62 (8%) failed to respond, and 59 (8%) died during ACVB courses, 17 of them from progression of the disease. With a median follow-up of 23 months, the estimated 2-year overall survival time to failure (TTF), and time to relapse (TTR) survival are 67%, 56%, and 67%, respectively. Patients receiving a late intensification had the same relapse rate as the other patients. A persistent fibronecrotic mass was found in 150 patients (20%) and did not influence the relapse rate. Toxicity was mainly neutropenia and infection during the ACVB courses, with 40 patients (5%) dying from septic complications while responding to treatment. Fifty-three percent of the patients had a neutropenia less than 0.500 x 10(9)/L, 58% fever (6% grade 4), and 49% a documented infection (8% grade 4). These results obtained with the LNH-84 regimen demonstrate that this therapeutic scheme is an effective treatment for aggressive ML.

Recombinant Interferon Alfa-2b Combined with a Regimen Containing Doxorubicin in Patients with Advanced Follicular Lymphoma

BACKGROUND Interferon alfa and cytotoxic drugs have synergistic effects in patients with non-Hodgkins lymphoma. In 1986, we designed a clinical trial to evaluate the benefit of concomitant administration of recombinant interferon alfa with a regimen containing doxorubicin in patients with follicular non-Hodgkins lymphoma. METHODS The trial involved 242 patients with advanced low-grade follicular non-Hodgkins lymphoma selected on the basis of clinical, radiographic, and biologic criteria. All patients were treated with a regimen consisting of cyclophosphamide, doxorubicin, teniposide, and prednisone (CHVP), given monthly for six cycles and then every two months for one year. After randomization, 123 patients also received interferon alfa-2b at a dosage of 5 million units three times weekly for 18 months. The remaining 119 patients received chemotherapy alone. RESULTS As compared with the patients treated with CHVP only, the patients treated with CHVP plus interferon alfa had a higher overall rate of response (85 percent vs. 69 percent, P = 0.006), a longer median event-free survival (34 months vs. 19 months, P < 0.001), and a higher rate of survival at 3 years (86 percent vs. 69 percent, P = 0.02). Granulocyte toxicity was greater in the patients treated with CHVP plus interferon alfa than in those treated with CHVP alone. There were no treatment-related deaths. Interferon alfa had to be stopped because of toxic effects (fatigue and hepatitis) in 13 patients (11 percent). CONCLUSIONS The addition of interferon alfa to a regimen containing doxorubicin increased the rate of response, event-free survival, and overall survival in patients with advanced follicular non-Hodgkins lymphoma, without serious toxicity, although some patients were unable to tolerate the side effects.