Escape of pathogens from the host immune response by mutations and mimicry. Possible means to improve vaccine performance.

The ability of certain pathogens, such as human immunodeficiency, hepatitis C, herpes simplex, influenza viruses, Plasmodium falciparum, etc., to escape from host immune response is generally ascribed to high mutation rate of their genome. We challenge this assumption and propose that molecular mimicry of host antigens by these pathogens could also participate to this resistance. Several studies show that there is no correlation between the mutation rate value of a pathogen and the possibility to develop an effective vaccine. On the other hand, pathogens which do not respond to vaccine are usually reported to display host protein mimicry. We propose to suppress in the thymus the epitopes of the self which are in common with the pathogen. This could be achieved by intrathymic injection of antibodies against this microorganism. These antibodies would be obtained by vaccination of a foreign animal species. It is expected that the negative selection of the CD4(+) and CD8(+) T lymphocytes specific for these epitopes would be prevented, that the number of epitopes recognized as foreign to the host would be increased and that the immune response diversity would be enhanced.

Expression of galectin-3 in gonads and gonadal sex cord stromal and germ cell tumors.

Galectin-3, a beta-galactoside-binding lectin, has been implicated in many human malignancies, but has seldom been studied in human gonads and gonadal tumors. The aim of our study was to investigate galectin-3 mRNA and protein expression in normal ovaries and testes as well as in a variety of 51 gonadal sex cord stromal and germ cell tumors, and two testicular seminomatous and non-seminomatous cell lines, using either real-time PCR or immunohistochemistry. In human testes, galectin-3 is specifically expressed in mature Sertoli cells and Leydig cells, and is absent from fetal and pre-pubertal testes, suggesting a hormone-dependence of this gene. In human ovaries, galectin-3 is absent from granulosa cells, as well as from granulosa cell and Sertoli-Leydig cell tumors, and is not a useful marker in distinguishing granulosa cell from Sertoli-Leydig cell tumors. In testicular tumorigenesis, galectin-3 has a dual function according to the histological type of tumors and their hormone dependency. In malignant testicular Sertoli cell tumors, the expression of galectin-3 is down-regulated while, in benign Leydig cell tumors, this expression is maintained, indicating the possible implication of this gene in the development of more aggressive testicular sex cord stromal tumors. In contrast to sex cord stromal tumors, galectin-3 expression is up-regulated in testicular germ cell tumors. By real-time PCR, we demonstrated a significant elevation of the galectin-3 mRNA level in non-seminomatous testicular germ cell tumors and cell line as compared to normal testes and seminomas (p=0.0432 and p=0.0247, respectively), indicating the possible role of this gene in the non-seminomatous differentiation of germ cell tumors.

[Infiltrating lobular carcinoma of the breast with histiocytoid features: three cases]. / Variant histiocytoïde du carcinome lobulaire infiltrant du sein. A propos de trois cas.

Histiocytoid carcinoma of the breast, a cellular variant of invasive breast cancer, is mainly found among infiltrating lobular carcinomas (ILC). It can be easily confused with benign conditions or other mammary tumors also composed of cells with a pink granular to foamy cytoplasm and an eccentric nucleus. We report 3 cases of histiocytoid ILC. Our aim is to discuss recent immunocytochemical data that could suggest a special type of apocrine differentiation of tumor cells, including a diffuse immunoreactivity for GCDFP-15 (Gross Cystic Disease Fluid Protein 15) and a predominant expression of androgen receptor, and to describe the features useful for the differential diagnosis.

[Placental site trophoblastic tumor of the uterus after in vitro fertilization. A case report with initial vaginal metastasis]. / Tumeur trophoblastique du site placentaire de l'utérus après fécondation in vitro. A propos d'un cas avec métastase vaginale initiale.

We report the first case of placental site trophoblastic tumor following in vitro fertilization. A 32-year-old woman presented with a vaginal polyp diagnosed 11 months after a successful fertilization, resulting in the delivery of a term male baby, but followed by persistent amenorrhea. The diagnosis of PSTT was done on examination of the vaginal polyp and the curettage specimen and was confirmed after hysterectomy. The patient was well 30 months later. The value of initial metastases limited to the pelvis and the role of in vitro fertilization in the pathogenesis of the tumor are discussed.

[Carcinomatous transformation of an atypical polypoid adenomyofibroma of the uterus]. / Transformation carcinomateuse d'un adénomyofibrome polypoïde atypique de l'utérus.

We report a case of an atypical polypoid adenomyofibroma (APA) with carcinomatous transformation that occurred in a nulliparous 32 year-old woman treated with estroprogestatives. The well-differentiated mucinous adenocarcinoma was in continuity with the APA, showed a deep myoinvasion and extended to the upper part of the cervix. No hormonal receptor was expressed by tumor cells. Because of the risk of carcinomatous transformation, complete excision of APA(s) is warranted.