Our data indicate that -- on the level of TH lymphocytes -- SIT induces tolerance to the allergen and a modulation of the cytokine pattern produced in response to allergen stimulation.

Among peripheral T-cell lymphomas (PTCL), the heterogeneous category of unspecified PTCL represents the most common subtype. Nevertheless, recurrent chromosomal translocations are unknown in this aggressive type of lymphoma. Here we describe a novel t(5;9)(q33;q22) in unspecified PTCL. Molecular analyses delineated the breakpoints to ITK and SYK resulting in a previously undescribed expression of the Syk tyrosine kinase by Itk. ITK-SYK transcripts were detected in five of 30 (17%) unspecified PTCL, but not in cases of angioimmunoblastic T-cell lymphoma (n ¼ 9) and anaplastic lymphoma kinasenegative anaplastic large-cell lymphoma (n ¼ 7). In all five translocation-positive cases, the breakpoints were identical fusing the N-terminal pleckstrin homology domain and prolinerich region of ITK to the tyrosine kinase domain of SYK. Three of the five t(5;9)(q33;q22) þ unspecified PTCL shared a very similar histological pattern with predominant involvement of lymphoid follicles and the same CD3 þ CD5 þ CD4 þ bcl-6 þ CD10 þ immunophenotype. These results demonstrate the presence of a recurrent t(5;9)(q33;q22) in a subset of unspecified PTCL, which may represent a novel distinct subgroup of PTCL.

SUMMARYMast cells (MC), blood basophils (Ba) and moncoytes (Mo) are of haemopoietic origin. Lineagerelationships and transdifferentiation between MC and Mo, or MC and Ba, have been considered, based on common expression of antigens. In this study, comparative phenotypic analyses on MC, Ba and Mo and on respective cell lines were performed using monoclonal antibodies (mAb) to previously defined and novel CD antigens (CD1-130). By cluster analysis, the overall (all 130 CD) phenotypic relationships (given as similarity indices, SI), between primary cells (MC, Ba and Mo) and corresponding cell lines (HMC-1, KU-812, U937) were 0 . 716, 0 . 779 and 0 . 757, respectively. When primary cells were compared, lower SI values were found (MC versus Ba, 0 . 509; MC versus Mo, 0 . 625; Mo versus Ba, 0 . 698). More distant relationships were found between MC versus Ba and MC versus Mo, compared with Ba versus Mo, for adhesion receptor (R)-, complement R-and cytokine R profiles. Analysis of cytokine R revealed most significant dissimilarities between MC versus Ba and MC versus Mo (SI < 0 . 2). Moreover, in contrast to other CD subgroups and other lineages, MC and HMC-1 differed from each other in cytokine R expression (SI 0 . 286). Cytokine R detectable on HMC-1 but not MC were granulocyte-macrophage colony-stimulating factor (GM-CSFR)a(CD116), CD40, Apo-1/ FAS(CD95) and gp130(CD130). Cytokine R detectable on Ba but not MC, were interleukin-3 (IL-3)Ra(CD123), IL-1RII(CD121b), IL-2Ra(CD25) and CD40. In summary, MC, Ba and Mo display a unique CD profile with MC being the most distantly related cell. The most significant mismatch within a given lineage is the loss of cytokine R on mature MC as compared with normal myeloid progenitors and HMC-1 cells.

Twenty-five T cell clones specific for Bet v I were established from the peripheral blood of two birch pollen-allergic patients. The T cell epitopes of these clones were mapped using dodecapeptides overlapping for 2 amino acids (neighbors share 10 residues) spanning the whole amino acid sequence of the protein (159 amino acids). In total, 7 epitopes could be detected. One donor displayed 6 distinct T cell specificities for the Bet v I molecule in 14 T cell clones; for the other donor, 4 stimulating peptides for 11 clones could be identified. Two T cell epitopes were recognized by both subjects. One of these might represent an immunodominant epitope located at amino acid position 77-92 of the Bet v I molecule, as in 13/25 T cell clones activation could be induced by this amino acid sequence. One T cell clone reacted with purified pollen-derived Bet v I, but neither with any peptide synthesized according to a Bet v I-encoding cDNA nor with the respective recombinant protein. Upon stimulation with allergen, the majority of the clones (21/24) revealed the TH0 or TH2 type of cytokine production (interleukin-4 production), indicating their importance in the pathogenesis of the allergic disease.