A foodborne outbreak of group A streptococcal disease at a birthday party.

A severe foodborne outbreak of group A streptococcal disease (T28) affected 122/169 people (72%) who attended a church party or ate leftovers from the party. The median incubation time was 42 h. Muscular pain or weakness and fatigue usually preceded pharyngeal symptoms. Complications included otitis media with perforation, peritonsillitis requiring tonsillectomy, arthritis and pericarditis. A 45-year-old man died 36 h after he developed an influenza-like illness, and at necropsy there were histological signs of early streptococcal septicaemia. The strain produced erythrogenic exotoxins B and C. Streptococci were probably transmitted by sliced eggs on sandwiches. Laboratory experiments showed that there was an increment in viable count of streptococci with 6 logs after incubation in egg yolk for 24 h at room temperature. The unusually warm climate and flaws in food handling routines contributed to this large foodborne epidemic.     

Plasma Concentrations of Mycophenolic Acid Acyl Glucuronide Are Not Associated with Diarrhea in Renal Transplant Recipients

The aim of this study was to determine whether plasma concentrations of the acyl (AcMPAG) and phenolic (MPAG) glucuronide metabolites of mycophenolic acid (MPA) were related to diarrhoea in renal transplant patients on mycophenolate mofetil (MMF) with cyclosporine (CsA) or tacrolimus (TCL). Blood samples (0, 30, 120 min) were taken at days 3, 10, week 4, months 3, 6 and 12 for determination of MPA, MPAG and AcMPAG. MPA-AUC was estimated using validated algorithms. Two hour AUCs were calculated for MPAG and AcMPAG. Immunosuppressive therapy consisted of CsA/MMF (n= 110) and of TCL/MMF (n= 180). In 70/290 (24%) patients 86 episodes of diarrhoea were recorded during 12 months. Significantly more patients on TCL (31.1%) suffered from diarrhea compared to CsA (12.7%). MMF dose, MPA-AUC and the 2 h AUCs of MPAG and AcMPAG did not differ between patients with and without diarrhoea. Plasma AcMPAG and MPAG concentrations were substantially higher in patients on CsA compared with TCL, while MPA-AUC was lower in the former group. These data support the concept that CsA inhibits the biliary excretion of MPAG and AcMPAG, thereby potentially reducing the risk of intestinal injury through enterohepatic recycling of MPA and its metabolites.     

CD4+ T regulatory cells from the colonic lamina propria of normal mice inhibit proliferation of enterobacteria-reactive,disease-inducing Th1-cells from scid mice with colitis

Adoptive transfer of CD4+ T cells into scid mice leads to a chronic colitis in the recipients. The transferred CD4+ T cells accumulate in the intestinal lamina propria (LP), express an activated Th1 phenotype and proliferate vigorously when exposed ex vivo to enteric bacterial antigens. As LP CD4+ T cells from normal BALB/c mice do not respond to enteric bacterial antigens, we have investigated whether colonic LP-derived CD4+ T cells from normal mice suppress the antibacterial response of CD4+ T cells from scid mice with colitis. LP-derived CD4+ T cells cocultured with bone marrow-derived dendritic cells effectively suppress the antibacterial proliferative response of CD4+ T cells from scid mice with colitis. The majority of these LP T-reg cells display a nonactivated phenotype and suppression is independent of antigen exposure, is partly mediated by soluble factor(s) different from IL-10 and TGF-beta, and is not prevented by the addition of high doses of IL-2 to the assay culture. Functionally and phenotypically the T-reg cells of the present study differ from previously described subsets of T-reg cells. The presence of T cells with a regulatory potential in the normal colonic mucosa suggests a role for these cells in the maintenance of local immune homeostasis of the gut.     

T-cell activation. I. Evidence for a functional linkage between class I MHC antigens and the Tc-Ti complex

This paper examines the possibility of a functional linkage between class I MHC molecules and the T-cell receptor complex for antigen (T3-Ti). A newly developed anti-CD3 antibody (500A2) was used as an activation signal for EL4 lymphoma cells and allospecific cytotoxic T-cell clones (CTL), and the production of IL-2/IL-2 receptor in EL4 cells and serine esterase in CTL was determined. Anti-CD3 antibody-induced activation of both EL4 and CTL cells was enhanced in the presence of immunologically cross-linked and immobilized anti-H-2 (class I) antibody reactive against the H-2 haplotype of the responding T cells. A number of H-2-negative and H-2-positive EL4 subclones were generated and tested for anti-CD3 antibody-induced IL-2/IL-2 receptor production. Although both H-2-positive and -negative subclones expressed CD3 antigen and produced IL-2 after activation with the phorbol ester TPA, only the H-2-positive cell clones produced IL-2 and expressed IL-2 receptor after anti-CD3 antibody induction. Our results are compatible with the existence of a functional linkage between the class I and the CD3 molecules on the surface of T cells.     

Comparison of ultrasonographic findings in spontaneous abortions with normal and abnormal karyotypes

To determine whether ultrasonographic findings can predict the karyotype of spontaneous abortions, 137 pregnancies (54 spontaneous, 83 assisted ovulatory cycles) that subsequently aborted and had chromosome analysis performed on the products of conception were studied ultrasonographically. Transvaginal ultrasound was performed using an Acuson 128XP/10 with 7.5 MHz probe. The numbers of empty gestational sacs, small and normal for gestational size, embryonic poles and embryos with documented cardiac activity were calculated. The frequency of each of these findings in pregnancies with normal and abnormal karyotypes was compared. Of the 137 spontaneous abortions, 51 had normal chromosome analyses and 86 had abnormal karyotypes (68 aneuploidies and 18 polyploidies). Ultrasonographic findings in the 51 karyotypically normal pregnancies included 16 (31%) with empty gestational sacs, and 35 (69%) with embryonic poles, of which 24 (69%) were at least 1 week smaller than expected for gestational age and 11 (31%) were the expected size. Embryonic cardiac activity was documented in 22 (63%) of the 35 embryonic poles. Amongst 86 pregnancies with abnormal karyotypes, similar frequencies of ultrasound findings were found: 23 (27%) with empty gestational sacs, 42 (67%) with embryonic poles smaller than expected for gestational age, and 50 (79%) embryos lost after documentation of embryonic cardiac activity. No differences in the frequency of ultrasonographic findings of empty gestational sacs, small embryonic pole and embryonic cardiac activity were observed between karyotypically normal and abnormal spontaneous abortions. Ultrasonographic findings cannot predict the karyotype of spontaneous abortions.      

C1-esterase inhibitor blocks T lymphocyte proliferation and cytotoxic T lymphocyte generation in vitro

We have previously shown that activated C1s complement and activated T cells cleave beta2-microglobulin (beta2m) in vitro leading to the formation of desLys58 beta2m. This process can specifically be inhibited by C1-esterase inhibitor (C1-inh). Furthermore we showed that exogenously added desLys58 beta2m in nanomolar amounts to a one-way allogenic mixed lymphocyte culture (MLC) increased the endogenous production of IL-2 and the generation of allo-specific cytotoxic T lymphocytes. C1-inh was purified from fresh human plasma and added to human or murine MLC and mitogen-stimulated lymphocyte cultures grown in the presence of complement-inactivated serum. Read-outs were cell proliferation, lymphokine production and development of T cell-mediated cytotoxicity. We found that addition of C1-inh to MLC and mitogen- exposed murine and human lymphocyte cultures inhibited proliferation, the development of allospecific cytotoxic activity, and changed the endogenous production of IL-2, IL-4, IL-10, IL-12 and IFN-gamma. These data clearly demonstrate a regulatory function of C1-inh on T cell- mediated immune functions.