Identification of a zinc finger protein that inhibits IL-2 gene expression.

Transient activation of the interleukin-2 (IL-2) gene after antigen recognition by T lymphocytes is crucial for subsequent T cell proliferation and differentiation. Several IL-2 gene regulatory elements and binding factors necessary for activation of the IL-2 gene have been defined. However, little is known about negative regulation of IL-2 expression, which is likely to be important in the rapid shut-off of IL-2 transcription. A nucleotide sequence element (NRE-A) that negatively regulates IL-2 expression has been identified within the IL-2 gene. T cell nuclear extracts contained an NRE-A binding activity. A complementary DNA was isolated that encodes a zinc finger-containing protein that suppressed IL-2 gene expression. The observation of negative regulation of the immunoglobulin heavy chain gene enhancer by an element similar to NRE-A suggests that related proteins may regulate multiple immune response genes.

Esophageal intramural pseudodiverticulosis: a reevaluation.

Esophageal intramural pseudodiverticulosis is an unusual condition manifested by tiny flask-shaped outpouchings in the wall of the esophagus. The condition was diagnosed in 21 (0.15%) of 14,350 patients undergoing radiologic examinations of the esophagus at our hospitals. The pseudodiverticula were detected only by single-contrast technique in five of 18 patients (28%) who underwent both single- and double-contrast examinations. Thus, thin, low-density barium seems to enter these structures more readily than the high-density barium used for double-contrast esophagography. While most patients reported in the literature have diffuse or segmental pseudodiverticulosis associated with high esophageal strictures, the majority of our patients (11 [52%] of 21) had isolated involvement of the distal esophagus with 10 or fewer pseudodiverticula in the region of a peptic stricture. Other associated conditions included Candida esophagitis, herpes esophagitis, and squamous cell carcinoma of the esophagus. Our experience suggests that pseudodiverticulosis usually represents a sequela of reflux esophagitis, although the reason that so few patients with esophagitis develop this condition is unclear.

High deferral rate for maternal-neonatal donor pairs for an allogeneic umbilical cord blood bank.

BACKGROUND: To fully evaluate the safety and efficacy of umbilical cord blood (UCB) as a source of hematopoietic progenitor cells, UCB banks are being established worldwide to provide a readily accessible resource of stem and progenitor cells for allogeneic transplantation. Guidelines for UCB donor criteria have been proposed to minimize the possibility of disease transmission to UCB recipients. STUDY DESIGN AND METHODS: In preparation for the establishment of an allogeneic UCB bank, 285 maternal-neonatal donor pairs were evaluated in our tertiary-care hospital, which was chosen because of the high percentage of African Americans among the maternal population. Maternal, neonatal, and family histories were obtained by confidential interview and medical record review to determine the number of eligible donor pairs on the basis of a conservative interpretation of proposed donor criteria. RESULTS: Only 44 percent of donor pairs were considered eligible. The most common deferral factors were maternal, and they included fever at delivery, history of chronic disease, and history of sexually transmitted disease. In most cases, more than one deferral factor was identified. CONCLUSIONS: High-risk maternal populations, which may provide access to ethnic minorities targeted for some UCB banks, may contain low percentages of eligible donors. Further refinement of donor criteria will be important in the evolution of UCB banking and transplantation.

CD28-stimulated IL-2 gene expression in Jurkat T cells occurs in part transcriptionally and is cyclosporine-A sensitive.

CD28 is a glycoprotein expressed as a homodimer on the surface of a major subset of human T cells. Previous studies have shown that proliferation of peripheral blood T cells involving the CD28 pathway is associated with cyclosporine A (CsA) resistant IL-2 gene expression. This pathway was shown to specifically regulate the stability of mRNA for several lymphokines including IL-2. We have investigated the expression of the IL-2 gene in the Jurkat cell line, J32 clone, induced by CD28 stimulation. Cross-linked anti-CD28 mAb alone was sufficient to induce the release of small amounts of IL-2 (256 U/ml). The CD28-mediated IL-2 release was enhanced with simultaneous engagement of CD28 and CD2 or CD28 and CD3 molecules. Hybrid constructs in which the human IL-2 gene 5' flanking region drives luciferase expression (pIL-2-Luc) were used to help delineate whether the CD28 pathway activates the IL-2 gene transcriptionally. Costimulation of cells with CD28 mAb and either PHA or CD2 mAb induced a 20- to 90-fold increase in the expression of pIL-2-Luc as well as IL-2 release. Costimulation with CD28 mAb plus PMA gave only five- to sevenfold increase in enhancer activity. In contrast, no enhancer activity was detected after stimulation with CD28 or CD2 mAb alone. Both IL-2 release and pIL-2-Luc activity were inhibited by CsA in J32 cells. The degree of CsA inhibition was concentration dependent and was similar in cells stimulated with either CD28 mAb or CD3 mAb. Maximum inhibition was achieved with 1 microgram/ml of CsA. Studies with internal deletion mutations of the IL-2 gene 5' flanking sequence revealed that as with stimulation through the TCR pathway, the CD28 pathway requires 5' flanking sequences located within 500 bp of the transcription start site. These results are the first direct evidence that the triggering of CD28 molecule is sufficient to induce IL-2 release in J32 cells. Furthermore these studies strongly indicate that IL-2 gene expression induced by CD28 stimulation occurs, in part, transcriptionally and is CsA sensitive in these cells.