Definition of polymorphisms and haplotypes in the interleukin-12B gene: association with IL-12 production but not with Crohn's disease.

Interleukin-12 (IL-12) is a key cytokine for the induction of Th1 immune responses. Recently, functional polymorphisms in IL-12p40 (IL12B) were found to be associated with susceptibility to several autoimmune diseases. Similarly, variation in IL12B might be involved in susceptibility to Crohn's disease (CD), a chronic inflammatory bowel disorder associated with high IL-12 expression. We searched for additional polymorphism in IL12B and genotyped a large cohort of CD patients. Differential in vitro secretors of IL-12 were tested for polymorphism. Polymorphisms were analyzed using the intrafamilial transmission disequilibrium test (TDT) and by case-control analysis. A novel polymorphism was strongly associated with differential expression of IL-12. However, no association with susceptibility to CD was seen for this and other polymorphisms. The high level of conservation is consistent with the key regulatory role of IL-12. The lack of association with IL12B makes it unlikely that this gene is directly involved in the susceptibility to CD.

[The autoimmune lymphoproliferative syndrome: a disorder of programmed cell death]. / Het auto-immuun lymfoproliferatief syndroom: een stoornis in de geprogrammeerde celdood.

The autoimmune lymphoproliferative syndrome (ALPS) is a chronic, nonmalignant lymphoproliferative disorder caused by mutations in the genes that are involved in programmed cell death (apoptosis). The impaired apoptosis causes accumulation of lymphocytes, which underlies the clinical manifestations of lymphadenopathy, autoimmune phenomena and a markedly increased risk of malignant lymphomas. During the last few decades, great progress has been achieved in elucidating the aetiology of this syndrome. Several mutations have been found in the genes encoding proteins that are involved in the apoptotic cascade, which starts with the binding of the Fas ligand to the transmembranous Fas protein and which is followed by intracellular processes. ALPS is an autosomal dominant hereditary disease with variable penetrance. Unravelling the genetic abnormalities that cause ALPS has provided key insights into the clinical consequences of defective apoptosis.

IL12B and IRF1 gene polymorphisms and susceptibility to celiac disease.

Celiac disease (CD) is a common gastro-intestinal disorder resulting from permanent intolerance to wheat gliadins and related proteins in rye and barley. In addition to the strong genetic association with HLA-DQ2 and HLA-DQ8, a genetic region on chromosomes 5 (CELIAC2) has been identified that harbours a susceptibility gene for CD. The gene(s) responsible for this association, however, remains to be identified. In the present study we evaluated polymorphisms in the genes encoding interleukin-12 p40 (IL12B) and interferon regulatory factor 1 (IRF1). Both genes are located in the celiac2 region, and have key roles in inducing interferon (IFN)-gamma secreting T helper 1 (Th1) cells, one of the immunological hallmarks of CD. The frequencies of a TaqI gene polymorphism in the 3' UTR of IL12B and a HinfI gene polymorphism in the 3' UTR of IRF1 were studied in 258 Dutch CD patients and 237 ethnically matched healthy controls. The transmission of the polymorphic variants from parents to affected child was determined in 123 families with at least one affected child. The frequencies of the IL12B TaqI gene polymorphism and the IRF1 HinfI gene polymorphism did not differ significantly between patients and controls. In addition, in the family study, no deviation from the expected transmission from parents to affected child of any of the polymorphic variants was found. The IL12B TaqI and the IRF1 HinfI gene polymorphisms do not appear to be involved in susceptibility to CD. Further studies on the factors that drive the Th1 immunopathology in CD are required.

A TaqI polymorphism in the 3'UTR of the IL-12 p40 gene correlates with increased IL-12 secretion.

Interleukin-12 (IL-12) is a key cytokine for the induction of Th1 immune responses. We evaluated whether a TaqI polymorphism in the 3'UTR of the IL-12 p40 gene affects secretion of IL-12 in vitro, and whether this polymorphism is associated with susceptibility to Crohn's disease (CD). IL-12 p40 and p70 secretion by monocytes in relation to genotype was determined in 63 healthy donors. Genotype and allele frequencies of the TaqI polymorphism in 150 CD patients were compared with 145 ethnically matched healthy controls (HC). No significant association was found between genotype and IL-12 p40 secretion after stimulation of monocytes with SAC+IFNgamma. In contrast, increasing IL-12 p70 secretion was found across the categories of non-carriers, heterozygotes and homozygotes for the variant allele (median values+/-SEM: 147+/-27, 282+/-51 and 482+/-34 pg/ml, respectively; P<0.005). The allele and genotype frequencies of this polymorphism in patients with CD did not differ statistically significantly from HC. The presence of a TaqI polymorphism in the IL12 p40 3'UTR correlates with increased in vitro IL-12 p70, but not p40 secretion. While this polymorphism does not appear to be correlated with susceptibility to CD in the limited population of patients tested here, it could influence the occurrence of the disease in certain subsets of patients.

Review article: a critical approach to new forms of treatment of Crohn's disease and ulcerative colitis.

Most patients with inflammatory bowel disease can be managed with conventional immunosuppressive therapy. The choice of agents to prevent relapses of inflammatory bowel disease must be based on efficacy, toxicity and cost. Studies in animal models of inflammatory bowel disease indicate that chronic intestinal inflammation results from enhanced immune responses to bacteria that are present normally in the lumen. Loss of tolerance, an abnormal function or defective healing of the mucosal barrier may all give raise to chronic intestinal inflammation. This hypothesis is the basis of new therapies aimed at either decreasing the levels of luminal bacterial antigens and/or selectively blocking detrimental mucosal immune responses. Anti-TNF is an example of this novel approach that is very effective in Crohn's disease. The use of biological therapy is costly, however, and the long-term complications are not yet known. The recent increase of tuberculosis in patients treated with anti-TNF indicates that careful monitoring is necessary. It is clear that the new forms of treatment may play an important role in tailoring the appropriate drug to a specific group of patients. However, for the time being, fine-tuning in the use of conventional immunosuppression is necessary. New knowledge in the pharmacogenetics of these compounds allows improvements to be made in their use. It is to be hoped that a critical approach in the use of current and future drugs, taking into account the advances in the aetiopathogenesis of inflammatory bowel disease, will contribute to the quality of life of patients with inflammatory bowel disease.

The effect of TGF-beta1 on immune responses of naïve versus memory CD4+ Th1/Th2 T cells.

The role of TGF-beta1 in the regulation of T cell responses has been perplexing, possibly because it is dependent on the type of T cell being regulated and its cytokine microenvironment. In the present study, we demonstrate that TGF-beta1 has a profound inhibitory effect on naive CD4+ T cell undergoing differentiation under defined neutral, Th1 and Th2 priming conditions. In addition, we show that if CD4+ T cells are primed in the presence of TGF-beta1, they exhibit reduced secondary anti-CD3/anti-CD28-induced and antigen-specific immune responses (even when TGF-beta is absent during the secondary response), which is not due to reduced expression of co-stimulatory molecules or to inadequate IL-2 production. Finally, with respect to the effect of TGF-beta on fully differentiated antigen-specific memory CD4+ T cells, we demonstrate that while antigen-specific activation and cytokine secretion by memory Th1 T cells is inhibited by TGF-beta1, such inhibition is associated with partial down-regulation of IL-12 receptor beta2 chain expression. In contrast, memory Th2 T cells are not subject to TGF-beta1 -mediated suppression. In summary, these studies reveal that TGF-beta1 is a powerful negative regulator of the primary immune response of CD4+ T cells, but only Th1 T cells are subject to such regulation after the memory stage of T cell differentiation has been reached. Thus, these studies define the potential regulatory role of TGF-beta1 in Th1 and Th2 T cell-mediated autoimmunity.

Vidian neurectomy: neuroanatomical considerations and a report on a new surgical approach.

If conventional treatment fails, vidian neurectomy is a viable alternative for therapy of chronic rhinitis with recurrent polyposis of the nose and sinuses. From a neuroanatomical point of view beneficial and adverse effects of this surgical procedure are discussed. According to our own investigations and experiences, vidian neurectomy should be performed together with clearing out of the sinuses in every case. Beginning with this precondition a new surgical approach was developed: the vidian nerve is detected through a transethmoidal route in the pterygoid canal at the bottom of the sphenoid sinus and dissected using the operation microscope.

[The demonstration of HL-A antigens on thrombocytes under various conditions]. / Der Nachweis von HL-A-Antigenen an Thrombozyten unter verschiedenen Konditionen

Platelets of healthy test persons were gained according to the method of Aster (avital cells) and according to the procedure of BUBE and GMURZYNSKI (vital cells). Because of their tendency towards aggregation vital cells do bind any HL-A antibodies and whereas avital cells will fix antibodies and complement depending on the height of the titre. Thrombocytes stored in the own serum will respond less to the micro-C'-fixation test at + 4 degrees C as well as--196 degrees C, whereas storage in NaN3/NaCl and under the conditions of the own serum will reveal no differences up to--196 degrees C in each case.

[The effext of papain, neuraminidase and AET on the behavior of lymphocytes in cytotoxicity tests]. / Uber den Einflubeta von Papain, Neuraminidase und AET auf das Verhalten von Lymphozyten im zytotoxischen Test

The influence of papain, neuraminidase and AET to lymphocytes is reported. All three substances strengthen the lymphocytotoxic reaction in low concentrations or by short incubation time and lower it in higher concentrations or longer incubation since. Membrane changes by these three substances are reversible under defined conditions.