High expression of latent membrane protein 1 of Epstein-Barr virus and BCL-2 oncoprotein in acquired immunodeficiency syndrome-related primary brain lymphomas

Nearly all primary brain lymphomas in acquired immunodeficiency syndrome (AIDS) patients are associated withEpstein-Barr virus (EBV). The role of EBV in lymphomagenesis is not totally elucidated. One possible mechanism is the overexpression of the BCL-2 oncoprotein, because the latent membrane protein 1 (LMP1) has been reported to transactivate the bcl-2 gene in vitro. To study the interrelationship beetween LMP1 and BCL-2 in vivo, we have analyzed and compared their expression in 11 AIDS-related primary brain lymphomas and 57 AIDS- related systemic lymphomas by immunoperoxidase technique on frozen sections. In AIDS-related primary brain lymphoma, LMP1 and BCL-2 were expressed in all cases but 1. All positive cases exhibited morphologic immunoblastic features. In contrast, the only negative case was histologically close to Burkitt's lymphoma. In systemic lymphomas, LMP1 was expressed in 21 cases, whereas BCL-2 was positive in only 3 cases, all of which were extranodal. These results indicate that, in addition to the histologic type, the role of EBV genes and BCL-2 expression in lymphomatous cells differ as a function of their localization. In AIDS- related primary brain lymphomas, this correlation between LMP1 and BCL- 2 overexpression may have a major implication in lymphomagenesis.     

Deletion variants within the NF-kappa B activation domain of the LMP1 oncogene prevail in acquired immunodeficiency syndrome-related large cell lymphomas and human immunodeficiency virus-negative atypical lymphoproliferations

This sequencing study of 17 acquired immunodeficiency syndrome-related lymphomas (9 primary brain, 8 systemic) and 8 human immunodeficiency virus-negative atypical lymphoproliferations expressing large amounts of the latent membrane protein 1 (LMP1) of Epstein-Barr virus was performed to characterize the carboxy terminal NF-kappa B activation domain of LMP1 at the molecular level in an immunocompromised host. In- frame deletions within the NF-kappa B activation domain were identified in all but 2 primary brain lymphomas, 4 systemic lymphomas, and 4 atypical lymphoproliferations, ie, in 60% of cases. In addition, non silent point mutations (range 1 to 5, mean 3.3) were detected in all cases. Although all changes occurred within the first 100 nucleotides of the carboxy terminal NF-kappa B activation domain--a critical sequence for the protein half-life--not a single point mutation was found in the remaining 62 nucleotides, necessary for malignant transformation. Such a clustering of nonrandom sequence variations, associated with a high oncoprotein expression in immunocompromised hosts, suggests that this part of the LMP1 oncogene behaves as a hypervariable region with natural selection of growth-promoting variants through prolongation of the protein half-life.     

Endobronchial sclerosing hemangioma: a rare presentation of a parenchymal tumor

Endobronchial localization of sclerosing hemangioma is extremely rare. Exact localization of lesion at preoperative work-up allows parenchymal-sparing procedures. We report a case of endobronchial sclerosing hemangioma diagnosed preoperatively and treated by lingular-sparing upper lobectomy with nodal dissection.     

Sprue tropicale chez un expatrié

Introduction

Tropical sprue is a postinfective malabsorption syndrome that occurs in some tropical endemic areas.

Case report

A 65-year-old Caucasian patient, with no significant past medical history, living in Cambodia for 10 years, presented with a 23 kg weight loss and chronic diarrhea. Clinical examination was unremarkable. Laboratory tests showed a moderate nutritional deficiency syndrome. The upper gastrointestinal endoscopy showed duodenal villous atrophy and histological analysis confirmed subtotal villous atrophy with important intraepithelial lymphocytosis. The diagnosis of tropical sprue was considered on the epidemiological, clinical and biological context, and the absence of other cause of villous atrophy. A three-month duration treatment with antibiotics, folic acid and vitamin B12 was initiated. The clinical course was favorable with disappearance of diarrhea in 15 days. One year later, the patient had resumed his usual weight, and laboratory tests and duodenal biopsies were normal.

Conclusion

The diagnosis of tropical sprue should be systematically discussed in any malabsorption syndrome with villous atrophy in a patient living or having lived in the tropics.