Organizer and regulatory role of colonic isolated lymphoid follicles in inflammation.

Gut-associated lymphoid tissue (GALT) is supposed to play an integral role in the organization of colonic repair mechanisms. Majority of the GALT is composed of isolated and aggregated lymphoid follicles distributed throughout the intestines. These lymphoid follicles, including Peyer's patches of the small, and isolated lymphoid follicles (ILFs) of both the small and large intestines, are composed of a specialised follicle associated epithelium overlying a subepithelial dome containing numerous dendritic cells, macrophages, T and B cells. Within inflammatory conditions the number, the diameter and the density of ILFs are increasing. Follicles are involved not just in immune surveillance, but their presence is also indispensable for normal colonic mucosal regeneration. Regarding mucosal repair the relation of ILFs to bone marrow derived stem cells, follicular dendritic cells, subepithelial myofibroblasts and crypt formations, and the putative organizer role of ILFs have not been clarified yet.

Is the efficacy of successful infliximab induction therapy maintained for one year lasting without retreatment in different behavior types of Crohn's disease?

UNLABELLED: The high cost of infliximab inhibits the regular retreatment of all patients in Hungary with Crohn's disease (CD) after beneficial induction therapy. This study is set out to evaluate the medium-term efficacy of induction therapy with infliximab without retreatment in CD patients with chronic activity and/or fistulae refractory to conventional therapy. METHODS: A retrospective 1-year review was undertaken of all CD patients with successfully induced remission or fistula closure with 3 infusions of infliximab. Infliximab was administered in a dose of 5 mg/kg 3 times, in weeks 0, 2 and 6. Clinical remission was defined as symptom resolution and an estimated Crohn's Disease Activity Index (CDAI) <150 and complete fistula closure. We evaluated the clinical response, the estimated CDAI, the number of draining fistulae, the dosages of steroid and immunosuppressive drugs at 6 and 12 months after the last infusion, and the needs for hospitalization and surgical intervention during this period. Breslow (Generalized Wilcoxon) test was used as the statistical method. RESULTS: The data of the 50 patients (19 luminal, 31 fistulizing disease; average age 29. 3 [13-59] years, disease localization: 23 colon, 13 ileum, 13 ileocolon, 1 duodenum) were suitable for analysis. Infliximab induction therapy without retreatment resulted in a beneficial effect lasting for at least 1 year in 22 of the 50 patients (44%). 11 of the 19 patients (57.9%) with luminal disease remained in steroid-free complete remission, while the fistulae persisted closed in only 11 of the 31 patients (35.5%) (p<0.05). CONCLUSION: Infliximab induction therapy alone may result in sustained remission mainly in patients with luminal disease. These results suggest the need for maintenance therapy with infliximab after successful therapy induction in patients with fistulae, while luminal CD patients could possibly participate in regular retreatment only if needed. If these data are confirmed, this modification of the therapeutic procedure could well increase the cost-effectiveness of infliximab.

The insulin-like growth factor system: IGFs, IGF-binding proteins and IGFBP-proteases.

Insulin-like growth factors (IGF-I/-II) are not only the endocrine mediators of growth hormone-induced metabolic and anabolic actions but also polypeptides that act in a paracrine and autocrine manner to regulate cell growth, differentiation, apoptosis and transformation. The IGF system is a complex network comprised of two growth factors (IGF-I and -II), cell surface receptors (IGF-IR and -IIR), six specific high affinity binding proteins (IGFBP-I to IGFBP-6), IGFBP proteases as well as several other IGFBP-interacting molecules, which regulate and propagate IGF actions in several tissues. Besides their broad-spectrum physiological and pathophysiological functions, recent evidence suggests even a link between IGFs and different malignancies.