Anti-CD5 monoclonal antibody, clone DE6-65-G7

B cells possess various immuno regulatory functions. However, research about their participation in tolerance induction toward the fetus is just emerging. Accumulating evidence supports the idea that B cells can play seemingly conflicting roles during pregnancy, either protecting or harming the fetus. Previous findings indicated the presence of two different peritoneal B cell subsets, defined by the expression of the plasma cell alloantigen 1 (PC1) and with distinct immune modulatory functions. Here, we aimed to study the participation of these two B cell subsets, on pregnancy outcome in a murine model of disturbed fetal tolerance. The frequencies and cell numbers of peritoneal and splenic CD19(+) IL-10(+) and CD19(+) CD5(+) IL-10(+) PC1(+) cells were assessed in virgin as well as normal pregnant (NP) and abortion-prone (AP) females during the course of gestation. Peritoneal PC1(low) or PC1(high) B1a B cells were sorted, analyzed for their ability to secrete IL-10 and adoptively transferred into NP or AP females. On gestation day (gd) 12, the abortion rate as well as the frequencies and cell numbers of regulatory T cells, TH1 and TH17 cells were determined in spleens and decidua. In addition, mRNA expression of IL-10, TGF-beta, IFN-gamma, and TNF-alpha was analyzed in decidual tissue. Peritoneal CD19(+)IL-10(+) and CD19(+) CD5(+) IL-10(+) PC1(+) frequencies fluctuated during the progression of normal pregnancies while no significant changes were observed in spleen. AP females showed significantly reduced frequencies of both B cell populations and exhibited an altered peritoneal PC1(high)/PC1(low) ratio at gd10. Adoptive transfers of PC1(low) B1a B cells into NP females increased the abortion rate in association with a reduced splenic regulatory T/TH17 ratio. By contrast, the transfer of PC1high B1a B cells into AP females significantly diminished the fetal rejection rate and significantly reduced the numbers of splenic TH17 cells. Our results suggest that the peritoneum harbors two distinct B1a B cell subsets that can be distinguished by their PC1 expression. Whereas PC1(high) B1a B cells seem to support fetal survival, PC1(low) cells B1a B cells may compromise fetal well-being.

T-cell large granular lymphocytic leukemia (T-LGLL) is an uncommon but probably underdiagnosed disease caused by clonal proliferation of large granular lymphocytes. Diagnosis is typically based on the high number of morphologically characteristic lymphoid cells and finding of an abnormal immunophenotype by flow cytometry. Because of its relatively indolent clinical behavior, observation is often an appropriate therapy. Here we present a case of a 53-year-old male admitted to the hospital because of abdominal pain. Blood examination revealed mild mycrocitic anemia and multiplied lactate dehydrogenase level. Abdominal ultrasound showed splenomegaly of 16 cm, with no lymphadenopathy. Fine needle aspiration of bone marrow revealed hypocellular marrow with 50% of atypical lymphoid cells. There were 81% of atypical medium sized granular lymphocytes with irregularly shaped nuclei in peripheral blood, so the cytologic diagnosis was lymphoproliferative process. Bone marrow biopsy showed nodular and interstitial proliferation of small, partially atypical T lymphocytic cells positive for CD2, CD3, CD5, CD8, granzyme and TIA, and negative for hairy cell markers, CD10, MUM 1, bcl 1, CD4 and CD56. The finding was consistent with T-LGLL. Due to splenomegaly, the patient was treated with cyclosporine and gradually reduced dose of corticosteroids, leading to regression of splenomegaly and normalization of lactate dehydrogenase level.