Central Venous Catheter Consideration in Pediatric Oncology: A Systematic Review and Meta-analysis From the American Pediatric Surgical Association Cancer Committee

BACKGROUND

Tunneled central venous catheters (CVCs) are the cornerstone of modern oncologic practice. Establishing best practices for catheter management in children with cancer is essential to optimize care, but few guidelines exist to guide placement and management.

OBJECTIVES

To address four questions: 1) Does catheter composition influence the incidence of complications; 2) Is there a platelet count below which catheter placement poses an increased risk of complications; 3) Is there an absolute neutrophil count (ANC) below which catheter placement poses an increased risk of complications; and 4) Are there best practices for the management of a central line associated bloodstream infection (CLABSI)?

METHODS

Data Sources: English language articles in Ovid Medline, PubMed, Embase, Web of Science, and Cochrane Databases.

STUDY SELECTION

Independently performed by 2 reviewers, disagreements resolved by a third reviewer.

DATA EXTRACTION

Performed by 4 reviewers on forms designed by consensus, quality assessed by GRADE methodology.

RESULTS

Data were extracted from 110 manuscripts. There was no significant difference in fracture rate, venous thrombosis, catheter occlusion or infection by catheter composition. Thrombocytopenia with minimum thresholds of 30,000-50,000 platelets/mcl was not associated with major hematoma. Limited evidence suggests a platelet count <30,000/mcL was associated with small increased risk of hematoma. While few studies found a significant increase in CLABSI in CVCs placed in neutropenic patients with ANC<500Kcells/dl, meta-analysis suggests a small increase in this population. Catheter removal remains recommended in complicated or persistent infections. Limited evidence supports antibiotic, ethanol, or hydrochloric lock therapy in definitive catheter salvage. No high-quality data were available to answer any of the proposed questions.

CONCLUSIONS

Although over 15,000 tunneled catheters are placed annually in North America into children with cancer, there is a paucity of evidence to guide practice, suggesting multiple opportunities to improve care.

LEVEL OF EVIDENCE

III. This study was registered as PROSPERO 2019 CRD42019124077.

Postoperative respiratory complications in SARS-CoV-2 positive pediatric patients across 20 United States hospitals: A Cohort Study

INTRODUCTION

Data examining rates of postoperative complications among SARS-CoV-2 positive children are limited. The purpose of this study was to evaluate the impact of symptomatic and asymptomatic SARS-CoV-2 positive status on postoperative respiratory outcomes for children.

METHODS

This retrospective cohort study included SARS-CoV-2 positive pediatric patients across 20 hospitals who underwent general anesthesia from March to October 2020. The primary outcome was frequency of postoperative respiratory complications, including: high-flow nasal cannula/non invasive ventilation, reintubation, pneumonia, Extracorporeal Membrane Oxygenation (ECMO), and 30-day respiratory-related readmissions or emergency department (ED) visits. Univariate analyses were used to evaluate associations between patient and procedure characteristics and stratified analyses by symptoms were performed examining incidence of complications.

RESULTS

Of 266 SARS-CoV-2 positive patients, 163 (61.7%) were male, and the median age was 10 years (interquartile range 4-14). The majority of procedures were emergent or urgent (n = 214, 80.5%). The most common procedures were appendectomies (n = 78, 29.3%) and fracture repairs (n = 40,15.0%). 13 patients (4.9%) had preoperative symptoms including cough or dyspnea. 26 patients (9.8%) had postoperative respiratory complications, including 15 requiring high-flow oxygen, 8 with pneumonia, 4 requiring non invasive ventilation, 3 respiratory ED visits, and 2 respiratory readmissions. Respiratory complications were more common among symptomatic patients than asymptomatic patients (30.8% vs. 8.7%, p = 0.01). Higher ASA class and comorbidities were also associated with postoperative respiratory complications.

CONCLUSIONS

Postoperative respiratory complications are less common in asymptomatic versus symptomatic SARS-COV-2 positive children. Relaxation of COVID-19-related restrictions for time-sensitive, non urgent procedures in selected asymptomatic patients may be reasonably considered. Additionally, further research is needed to evaluate the costs and benefits of routine testing for asymptomatic patients.

LEVEL OF EVIDENCE

Iii, Respiratory complications.

A novel founder MSH2 deletion in Ethiopian Jews is mainly associated with early-onset colorectal cancer

Lynch syndrome is an inherited cancer predisposition syndrome caused by germline defects in any of the mismatch repair (MMR) genes. Diagnosis of carriers makes precision prevention, early detection, and tailored treatment possible. Herein we report a novel founder deletion of 18,758 bp, mediated by Alu repeats on both sides, detected in Ethiopian Jews. The deletion, which encompasses exon 9-10 of the MSH2 coding sequence, is associated mainly with early-onset MSH2/MSH6-deficient colorectal cancer (CRC) and liposarcoma. Testing of 35 members of 5 seemingly unrelated families of Ethiopian origin yielded 10/21 (48%) carriers, of whom 9 had CRC. Age at first tumor diagnosis ranged from 16 to 89 years. Carriers from the oldest generations were diagnosed after age 45 years (mean 57), and carriers from the younger generation were diagnosed before age 45 years (mean 30). Awareness of this founder deletion is important to improve patient diagnosis, institute surveillance from an early age, and refer patients for genetic counseling addressing the risk of bi-allelic constitutional MMR deficiency syndrome.

Plasma cells are not necessary for regulatory B cells and preventing their differentiation markedly prolongs allograft survival

Plasma Cells produce Abs. Recently, PCs were reported to be the major source of B-cell IL-10, and absence of PCs worsened EAE, implying that PCs underlie “Breg” activity. To test the hypothesis in transplantation, we transplanted Bc islets into chemically diabetic B6 Blimp-1fl/flCD19-Cre+/− (PCKO) mice. Surprisingly, allograft survival (GS) was prolonged by ~42% in untreated PCKO vs. Cre-neg Ctl recipients (Mean GS: 27 vs. 19d; p&lt;0.05). This prompted us to re-examine the EAE model where the regulatory role of PCs was first identified. Surprisingly, in our hands, the severity of EAE (MOG35–55 induced) was dramatically reduced in PCKO vs. Ctl mice (p&lt;0.05). These unexpected results suggested that PCs are not essential for Breg activity, but might actually promote EAE and allograft rejection. These improved results do not appear to be mediated simply by loss of Ab production, since EAE is worse in the complete absence of B cells. To investigate the differences between our own and published results, we examined B cells from PCKO mice and found a 1.4-fold ↑ in IL-10+and &gt;2-fold ↓ in IL-17+ B cells vs. Ctl mice (intracellular staining; flow cytometry). Moreover, CD4+T cells from PCKO mice exhibited a ~2.5× ↑ in IL-10 and ~2× ↓ in IL-17.

Therefore, we examined cytokine expression by splenic PCs in alloimmunized Blimp-1-YFP reporter mice. While PCs are enriched for IL-10 expression (42±3%), they are also highly enriched for IL-17 (50 ±9%).

Thus, PCs are not essential for Breg activity in either auto- or allo- immunity. We hypothesize preventing newly induced PCs may reduce immune responsiveness through the loss of potentially proinflammatory PCs. To further address these questions, we are now developing novel mice with PC-specific deletion of IL-10 or IL-17.

Outstanding questions in transplantation: B cells, alloantibodies, and humoral rejection

Over the past three decades, improved immunosuppression has significantly reduced T cell-mediated acute rejection rates, but long-term graft survival rates have seen only marginal improvement. The cause of late graft loss has been under intense investigation, and chronic antibody-mediated rejection (AMR) has been identified as one of the leading causes, thus providing a strong rationale for basic science investigation into donor-specific B cells and antibodies in transplantation and ways to mitigate their pathogenicity. In 2018, the American Society of Transplantation launched a community-wide online discussion of Outstanding Questions in Transplantation, and the topic of B cell biology and donor-specific antibody prevention emerged as a major area of interest to the community, leading to a highly engaged dialogue, with comments from basic and translational scientists as well as physicians (http://community.myast.org/communities/community-home/digestviewer). We have summarized this discussion from a bedside to bench perspective and have organized this review into outstanding questions within the paradigm that AMR is a leading cause of graft loss in the clinic, and points of view that challenge aspects of this paradigm. We also highlight opportunities for basic and translational scientists to contribute to the resolution of these questions, mapping important future directions for the transplant research field.

Guidelines and checklists for short-term missions in global pediatric surgery: Recommendations from the American Academy of Pediatrics Delivery of Surgical Care Global Health Subcommittee, American Pediatric Surgical Association Global Pediatric Surgery Committee, Society for Pediatric Anesthesia Committee on International Education and Service, and American Pediatric Surgical Nurses Association, Inc. Global Health Special Interest Group

Pediatric surgeons, anesthesia providers, and nurses from North America and other high-income countries are increasingly engaged in resource-limited areas, with short-term missions as the most common form of involvement. However, consensus recommendations currently do not exist for short-term missions in pediatric general surgery and associated perioperative care. The American Academy of Pediatrics (AAP) Delivery of Surgical Care Subcommittee and American Pediatric Surgical Association (APSA) Global Pediatric Surgery Committee, with the American Pediatric Surgical Nurses Association, Inc. (APSNA) Global Health Special Interest Group, and the Society for Pediatric Anesthesia (SPA) Committee on International Education and Service generated consensus recommendations for short-term missions based on extensive experience with short-term missions. Three distinct, but related areas were identified: (i) Broad goals of surgical partnerships between high-income countries and low- and middle-income countries. A previous set of guidelines published by the Global Paediatric Surgery Network Collaborative (GPSN) was endorsed by all groups; (ii) Guidelines for the conduct of short-term missions were developed, including planning, in-country perioperative patient care, post-trip follow-up, and sustainability; and (iii) travel and safety considerations critical to short-term mission success were enumerated. A diverse group of stakeholders developed these guidelines for short-term missions in low- and middle-income countries. These guidelines may be a useful tool to ensure safe, responsible, and ethical short-term missions given increasing engagement of high-income country providers in this work.

CD45 ligation reduces Tregs’ motility and enhances recognition of activating signals in vitro

Regulatory T cells (Tregs) play a pivotal role in modulating immune response hence supporting immune tolerance. Recently, CD45 ligation with anti-CD45RB mAb MB23G2 (anti-CD45RB) was reported to enhance graft-survival; evidence shows it was by homeostatic Treg proliferation in vivo. While many in vivo data support the notion that anti-CD45RB supports Tregs expansion, it is still unclear if the ligation ex vivo is sufficient to enhance Tregs’ avidity for activation and further promote their expansion and function. Here, we were to see if anti-CD45RB ligation can enhance Treg’s sensitivity to perceive activating signals in varying strength in vitro. To test this hypothesis, mouse CD4+ T cells (Foxp3-GFP linked B6 mouse, both Foxp3+ and Foxp3−, or Tregs and Tconvs, respectively) were seeded onto surfaces micropatterned with an antibody targeting the CD3 on T cell (anti-CD3) with and without the presence of anti-CD45RB. These surfaces were created by first microcontact printing of 2-μm diameter features of anti-CD3 at various concentrations (i.e., 1, 5, and 20 μg/mL) on glass coverslips and back-filled with ICAM-1. The effect of anti-CD45RB on Treg and Tconv activation was compared by the ratios of phosphorylation of Lck at Tyr 394 to 505 sites, cell registration on anti-CD3 dot array, and motility of each cell type on varying concentration of activation signals. Overall results show that anti-CD45RB specifically slow-down Treg motility and, therefore, enhance the probability to contact to activating signals (cell registration) and improve T cell activation indicated by ratios of phospho-Lck at active over inactive sites. This study assures the importance of further investigation on the role of anti-CD45RB in Treg activation mechanism.

Guidelines and checklists for short-term missions in global pediatric surgery: Recommendations from the American Academy of Pediatrics Delivery of Surgical Care Global Health Subcommittee, American Pediatric Surgical Association Global Pediatric Surgery Committee, Society for Pediatric Anesthesia Committee on International Education and Service, and American Pediatric Surgical Nurses Association, Inc. Global Health Special Interest Group

INTRODUCTION

Pediatric surgeons, anesthesia providers, and nurses from North America and other high-income countries (HICs) are increasingly engaged in resource-limited areas, with short-term missions (STMs) as the most common form of involvement. However, consensus recommendations currently do not exist for STMs in pediatric general surgery and associated perioperative care.

METHODS

The American Academy of Pediatrics (AAP) Delivery of Surgical Care Subcommittee and American Pediatric Surgical Association (APSA) Global Pediatric Surgery Committee, with the American Pediatric Surgical Nurses Association, Inc. (APSNA) Global Health Special Interest Group, and the Society for Pediatric Anesthesia (SPA) Committee on International Education and Service generated consensus recommendations for STMs based on extensive experience with STMs.

RESULTS

Three distinct, but related areas were identified: 1) Broad goals of surgical partnerships between HICs- and low and middle-income countries (LMICs). A previous set of guidelines published by the Global Paediatric Surgery Network Collaborative (GPSN), was endorsed by all groups; 2) Guidelines for the conduct of STMs were developed, including planning, in-country perioperative patient care, post-trip follow-up, and sustainability; 3) travel and safety considerations critical to STM success were enumerated.

CONCLUSION

A diverse group of stakeholders developed these guidelines for STMs in LMICs. These guidelines may be a useful tool to ensure safe, responsible, and ethical STMs given increasing engagement of HIC providers in this work.

LEVEL OF EVIDENCE

5.

Small molecule drug inhibition of PD-1 transcription is as effective as anti-PD-1 biologic blockade in cancer therapy

Despite the importance of the co-receptor PD-1 in T cell immunity, the upstream signaling pathway(s) that regulate PD-1 expression has not been defined. Glycogen synthase kinase 3 (GSK-3, isoform α and β) is a serine-threonine kinase implicated in cellular processes. We have shown that GSK-3 is a key upstream kinase that regulates PD-1 expression in CD8+ T cells. GSK-3 inactivation increased Tbx21 transcription for enhanced Tbet expression, and its suppression of Pdcd1 transcription in CD8+ cytolytic T-cells (CTLs) (Taylor et al 2016 Immunity 44, 274–86). Here, we show that GSK-3 inhibitor blockade of pcdc1 (PD-1) transcription with a small molecule inhibitor (i.e. SB415286) is as effective as anti-PD-1 and PDL-1 blocking antibodies in the control of pulmonary metastasis of B16 melanoma, intra-dermally injected B16 and EL4 lymphoma solid tumors, and in the ex vivo pre-treatment of T-cells before adoptive transfer into mice carrying tumors. In an analysis of knock out mice, GSK-3α/β−/− mice, which had greatly reduced PD-1 expression on T-cells, showed the same reduction in B16 pulmonary metastasis as Pdcd1−/− mice. Further, the ex vivo treatment of T-cells with SB415286, anti-PD-1, or in combination followed by adoptive transfer, had identical effects in inhibiting EL4 lymphoma growth. In all tumor models, GSK-3 inactivation markedly inhibited Pdcd1 transcription and PD-1 expression on tumor infiltrating T-cells (TILs), while increasing Tbx21 (Tbet) transcription and the presence of CD8+ TILs expressing CD107a+ (LAMP1) and granzyme B (GZMB). Our findings define for the first time that a next generation approach using small molecule inhibition of PD-1 expression is as effective as anti-PD-1/PL1 biologics in cancer therapy.

Foxp3+ regulatory T cell expression of IL-10 is required for IL-33-mediated expansion of regulatory B cells

BACKGROUND

FoxP3+ regulatory T cells (Tregs) are crucial to self- and antigen-specific tolerance. IL-33 drives expansion of Tregs expressing the IL-33 receptor, ST2, and secreting high levels of IL-10. Regulatory B cells (Bregs) are recently identified negative regulators of the immune system and depend on IL-10 to suppress effector T cell responses. In new data, we find that IL-33 also expands Bregs, however, the relationship between ST2+ Treg and Bregs cells remains unknown. Herein we elucidated if a directional relationship exists between IL-33-expanded Bregs and Tregs.

METHODS

B6 eGFP-FoxP3-Diptheria Toxin (DT) receptor mice were used to establish whether IL-33-expanded Treg were needed for IL-33-aided increases of TIM-1+ IL-10+ Bregs. B6 Foxp3-Cre X IL-10fl/fl mice were used to determine the need for IL-10 expression by Tregs for IL-33-mediated expansion of Bregs.

RESULTS

Assessment of splenocytes for Tregs and Bregs by flow cytometry showed that IL-33 administration led to a 3–5-fold increase in ST2+ Tregs. IL-33 also led to a 3-fold increase in the frequency of IL-10+ Breg, most of which expressed ST2. A lack of Tregs hindered the ability of IL-33 to increase Bregs. While Treg expression IL-10 was not required for ST2+ Treg expansion by IL-33, IL-10 expression by Tregs is crucial for Breg expansion by IL-33.

CONCLUSIONS

We have uncovered a relationship between Tregs and Bregs in response to IL-33. Specifically, while we show that Bregs express ST2, our data suggest that IL-33 expansion of Bregs is indirectly mediated by Treg IL-10 production.

Concomitant fundoplication increases morbidity of gastrostomy tube placement

BACKGROUND

Fundoplication is often performed in conjunction with gastrostomy tube (GT) placement in children, but there is a great deal of variation in rates of and indications for this procedure. Little is known about the impact of fundoplication on peri-operative outcomes. This study examines a national cohort of pediatric patients to compare risk-adjusted surgical outcomes in patients undergoing GT placement with or without concomitant fundoplication.

METHODS

We identified all patients undergoing GT placement in the 2012 National Surgical Quality Improvement Program - Pediatric. We evaluated demographics, comorbidities, complications, and length of stay for GT with fundoplication versus GT alone. We defined composite morbidity as a dichotomous variable for the presence of any complication. Logistic regression was performed to identify predictors of morbidity after adjusting for covariates.

RESULTS

1289 GT patients were identified, and 148 (11.5%) underwent concurrent fundoplication. The fundoplication patients were more likely to be younger, have cardiac risk factors, and be on respiratory support. They also had higher rates of surgical site infection (7.4% vs 3.7%, p=0.03) and composite morbidity (16.9% vs 8.7%, p=0.001), and longer LOS (median 5 vs 3 days, p=<0.0001) compared to GT only. After adjusting for covariates, fundoplication was a predictor of composite morbidity and increased LOS.

CONCLUSION

Concomitant fundoplication is an independent risk factor for 30-day post-operative morbidity in patients undergoing GT placement. These findings do not negate the value of fundoplication but underscore the importance of careful patient selection, and should be taken into consideration when discussing risks and benefits with families.

Treg suppressor function in inflamed peripheral tissue and lymphoid tissue occurs through distinct mechanisms (IRC11P.426)

The mechanisms by which Treg (CD4+Foxp3+) affect DC function and modulate immunity in inflamed non-lymphoid tissues remain poorly understood. Here, we used 2-photon intravital microscopy to visualize how Treg suppressor function operates within allografts. To restrain the immune reaction to the transplant site, we adoptively transferred effector T cells (Teff), wt Treg, or both (2-3x106 each) to B6 mice lacking 2° lymphoid organs (SLO; splenectomized LTβR-/-) 3-4 days after transplantation of BALB/c islets. Teff alone induced acute allograft rejection. However, the co-transfer of Teff + wt Treg led to long-term allograft survival in ~50% of recipients. Intravital microscopy of transplanted islets on day 2 showed that wt Treg infiltrated the peri-islet region, where they predominantly made contacts with DCs. Wt Treg restrained the motility parameters of Teff in the peri-islet region, reduced Teff-DC contacts, and decreased Teff intra-islet infiltration (insulitis), compared to Teff alone. Treg constitutively express the ecto-nucleotidase CD73, which generates anti-inflammatory adenosine from AMP. CD73-/- mice do not develop autoimmunity, and CD73-/- Treg are potent suppressors in vitro. In contrast, CD73-/- Tregs were unable to prevent allograft rejection by Teff, despite their presence at the graft site. These results indicate that Treg function does not require priming in SLO and that their mechanisms of action may differ from those used in SLO.

The spleen is the primary site for Breg induction and is required for anti-TIM-1 mediated tolerance (TRAN2P.963)

IL-10+ B cells (Bregs) have potent regulatory activity and can transfer tolerance in auto/allo immune models. We showed that: TIM-1 (T1) is an inclusive Breg marker; T1+ B cells transfer allograft tolerance; and anti-T1 induces IL-10+ T1+ Bregs. However, little is known about where Bregs are induced or act in vivo. We found that most Bregs reside in the spleen (85%) vs LN (1%) or marrow (15%), and few are found in islet allografts. Anti-T1 increased Bregs in the spleen from 2% to 7% of B cells, but had no effect in LN (0.5%) or marrow (1%). In splenectomized (spl-X) mice, anti-T1 did not increase Bregs in LN or marrow. Apoptotic cells (ACs) can induce Bregs in vivo. ACs increased Bregs from 2% to 5% in spleen and from 0.5% to 2% in LN. However, after spl-X, ACs did not increase Bregs in LN. Hence, Bregs are induced in the spleen, but then may migrate. Next, we examined the importance of the spleen for Breg-mediated allograft survival (GS). Anti-T1 was unable to induce long-term GS in spl-X islet recipients vs. controls (MST 24d vs. 100d; p=0.002). To confirm that anti-T1 acts through Bregs, we used inducible hCD20ERT2-CreXIL-10fl/fl mice. In such “B cell-IL-10KO” mice, anti-T1 was unable to prolong GS compared to controls (MST 20d vs. &gt;50d). Moreover, LTβR-KO mice (lack LNs) that received alloreactive T cells, exhibited longer islet GS (MST 18d) vs spl-X LTβR-KO recipients (MST 7d p=0.02). Thus, our data elucidate a vital role for the spleen in Breg induction and function.

Anti-TIM-4 mediates long-term engraftment of islet allografts by promoting IL-10 expression by TIM-1+ Bregs and inhibiting IFNγ expression by proinflammatory “Be1” B cells (IRC3P.464)

We previously defined TIM-1 as an inclusive marker for IL-10+ regulatory B cells (Bregs). Moreover, α-TIM-1 mAb prolongs islet allograft survival (GS) through induction of TIM-1+ Bregs. We recently noted that TIM-4, a TIM-1 ligand, identifies B cells enriched for IFNγ (Be1). We therefore hypothesized that TIM-4 blockade should also prolong GS and that this may involve B cells. In fact, α-TIM-4 (RMT4-53) treatment resulted in long-term GS in BALB/c recipients of B6 islets (MST &gt;100d). Moreover, α-TIM-4 increases Th2 cytokines (IL-4, IL-10) and Foxp3+Tregs, while reducing both Th1 cytokines (IFNγ) and CD4 proliferation. However, these α-TIM-4-mediated changes and long-term GS were B cell dependent, and did not occur in either B cell deficient (JHD) or depleted (α-CD20) recipients. To address whether α-TIM-4 directly targets (TIM-4+) Be1 cells, we showed that adoptive transfer of WT, but not TIM-4-/- B cells, into μMT recipients, reconstitutes long-term GS mediated by α-TIM-4. We also found that α-TIM-4 inhibits IFNγ expression by TIM-4+ B cells by 40%. Bregs were also required for α-TIM-4 induced transplant tolerance. Transfer of B cells from TIM-1Δmucin (mucin domain deletion) mice, which exhibit a defect in Bregs, is unable to prolong GS in B deficient mice. In wt mice, α-TIM-4 increases TIM-1+ IL-10+ Bregs by ~100%. Taken together, our data reveal that targeting TIM-4 enhances IL-10 expressing Bregs and also reduces inflammatory Be1 B cells to promote allograft tolerance.

TIM-4 expression by B cells identifies an inflammatory B effector 1 subset that promotes allograft rejection and inhibits tumor metastases (IRC3P.471)

B cells, like T cells, give rise to polarized subsets, termed Be1, Be2 and Breg that produce IFNγ, IL-4 and IL-10, respectively. We previously reported that TIM-1 is an inclusive marker for Be2 cells and Breg that can transfer allograft tolerance. We now show that TIM-4, a TIM-1 ligand, is expressed by a distinct subpopulation (~6-10%) of B cells. TIM-4 B cells are enriched for IFNγ (2.5%) and express relatively less IL-4 (1%) and IL-10 (4%) while TIM-1 B cells are enriched for IL-4 (6.5%) and IL-10 (14%) and express less IFNγ (1%). Accordingly, transfer of TIM-4 B cells to B cell deficient (JhD) islet allograft recipients accelerated rejection (MST 11d) vs. controls (no B cells; MST 15d) or TIM-1 B cell transfer (MST 70d), p&lt;0.05. TIM-4 B cell-mediated rejection required IFNγ as transfer of IFNγ-/- TIM-4 B cells modestly prolonged MST (15d to 25d, p&lt;0.05). In this model, transfer of TIM-4 B cells enhanced IFN-γ+ T cells (1.5X) while decreasing IL-4+, IL-10+ and Foxp3+ T cells (1.2-1.8X) whereas TIM-1 B cells increased IL-4+, IL-10+ and Foxp3+ T cells (1.2-1.7X) while decreasing IFNγ+ T cells (1.4X) vs. no B cell controls (p&lt;0.05 for each). Moreover, transfer of TIM-4 B cells into μMT mice decreased B16 melanoma lung metastases ~ 2-fold, while TIM-1 B cells increased lung metastases ~2-fold vs. controls (p &lt; 0.0001). Thus, we provide strong evidence that TIM-4 expression by B cells identifies a distinct Be1 inflammatory subset that can directly impact T cells responses.

Mechanisms of effector T cell suppression by CD4+Foxp3+ Treg in inflamed peripheral tissue (IRC4P.482)

In secondary lymphoid organs (SLO), CD4+Foxp3+ regulatory T cells (Treg) control immunity by preventing prolonged T cell-DC interactions. Whether Treg suppressor function in inflamed non-lymphoid tissues differs from SLO remains unclear. Thus, we used 2-photon intravital microscopy to dissect how Treg prevent allograft rejection by effector T cells (Teff) in transplanted islets. To restrain the immune reaction to the transplant site, we adoptively transferred Teff, Treg, or both (2-3x106 each) to B6 mice lacking SLO (splenectomized LTβR-/- mice) 3-4 days after transplantation of BALB/c islets. Teff alone induced acute allograft rejection. However, the co-transfer of Teff + Treg led to long-term allograft survival in ~50% of recipients. Analysis of adoptively transferred CFSE-labeled Teff recovered from the graft on day 3 and 5 revealed that Treg did not affect either Teff migration or proliferation at that site (compared to Teff alone), despite the presence of Treg in significant numbers. Intravital microscopy of transplanted islets on day 2 showed that Treg were found in the peri-islet region, where they made brief (&lt;1 min) contacts with DCs. Interestingly, Treg restrained the motility parameters of Teff in the peri-islet region, and significantly reduced Teff intra-islet infiltration, compared to Teff alone. These results indicate that Treg can function directly in inflamed non-lymphoid tissues, but that their mechanisms of action may differ from those used in SLO.

The role of Foxp3 in Treg homeostatic proliferation: Necessary for nTregs, but insufficient for iTregs. (LYM3P.734)

NTregs exhibit higher homeostatic proliferation (HP) than Tconv which may provide a competitive advantage during Treg adoptive immunotherapy. Increased Treg HP could be 2° to a self-reactive TCR repertoire and/or Foxp3-mediated increase in survival/fitness. To address this, CFSE-labeled CD4 populations from Foxp3-reporter mice, were compared 10d after transfer into wt mice. We generated Foxp3+ iTregs by activating Tconv and adding TGFβ, or transducing with Foxp3-retrovirus (RV). iTregs did not increase HP over Tconv controls (no TGFβ; RV-vector). Thus, Foxp3 itself is not sufficient to augment HP. To determine the role of Foxp3, we examined GFP+ nTreg from Filig mice (F-nTreg; Foxp3 ~10% wt levels due to unstable mRNA). F-nTreg exhibited reduced HP (10%) vs. wt nTregs (50%). Foxp3-RV transduction increased HP of F-nTregs, while RV-control had no effect (40 vs. 12%). Thus, Foxp3 is necessary for high HP by nTreg. We also examined role of Foxp3 during thymic ontogeny, irradiated Thy1.1 hosts received Filig (Thy1.2) bone marrow that was transduced with Foxp3-RV vs. RV-control. Surprisingly, in this setting, Tconv cells (no endogenous Foxp3) constitutively expressing Foxp3, exhibited increased HP vs. Foxp3- RV-controls (32 vs. 12%). Thus, Foxp3 increases HP in nTreg and when expressed during thymic ontogeny but not in mature Tconv. Our findings provide new insight into the role of Foxp3 expression in Treg homeostasis and highlight additional distinctions between iTreg and nTreg.

Innate recognition of allogeneic non-self by monocytes initiates the rejection of transplanted organs (P2128)

It is generally assumed that inflammation or ‘danger’ at the time of transplantation triggers rejection. Here we tested the alternate hypothesis that the innate immune system distinguishes between self and allogeneic non-self, causing DC maturation and initiation of adaptive immunity. B6 Rag-/-γc-/- CX3CR1-GFP+/- reporter mice, which lack T, B, and NK cells, received syngeneic (B6) or allogeneic (Balb/c) vascularized heart grafts. &gt;90% of DCs present in the grafts by d.1 after Tx were derived from host monocytes. Mono-DC (GFP+lineage-Ly-6G-CD45+CD11b+CD11c+F4/80lo) were observed in greater numbers in allo than syn grafts at early time points and persisted at later time points (&gt;21d) only in allografts. Mono-DC in allografts were mature (MHCII+CD80+), expressed IL-12p40, and presented endotoxin-free OVA to CD4+ (OT-II) and CD8+ (OT-I) cells, causing proliferation and IFNγ production. Mono-DC from syn grafts were less mature, did not express IL-12p40, and failed to induce IFNγ production. In vivo exposure of monocytes to allogeneic non-self precipitated T cell-mediated rejection of single minor Ag-mismatched grafts that are otherwise accepted by the host. Transient depletion of host CD11b+ cells in WT mice abrogated T cell accumulation and IFNγ production in heart allografts and prevented acute rejection. Therefore, sensing allogeneic non-self by monocytes is a key, and previously unrecognized, innate pathway by which alloimmune responses are initiated.

CD45RB ligation ameliorates experimental colitis by inducing Tregs and inhibiting inflammatory Teff cells (P4206)

In wt mice, α-CD45RB (MB23G2) treatment expands Tregs by both inducing iTregs and by enhancing homeostatic proliferation of nTregs. We examined the effect of α-CD45RB in a cell transfer model of colitis. Transfer of 3X105 CD4+Foxp3-CD45RBHi (Tconv) cells from Foxp3-reporter mice into Rag-/- mice resulted in severe colitis with 20% wt loss by 8 wks. α-CD45RB treatment (100ug; d0, 1) had no effect on number of Tconv but increased iTreg ≥ 2X in mesenteric LN (MLN), spleen, and colonic tissue. This completely prevented wt loss and decreased colitis score (at 8 wks) by 25% vs. Tconv cells alone (p&lt;.05). While transfer of subtherapeutic (104) nTreg had no effect on colitis induced by Tconv, adding a-CD45RB prevented wt loss, further cut the colitis score by 50%, and increased Treg ~2.5X. To confirm the role of Tregs, Tconv were transferred from Foxp3-DTR mice and iTregs eliminated with diphtheria toxin. In this setting α-CD45RB still delayed onset of colitis, although all mice began losing wt by 3 wks (and there was no survival benefit). In this setting, delayed colitis by α-CD45RB was associated with a 2X decrease in IFNγ expression by Teff in MLN, whereas IL-17 was unchanged. These data demonstrate that α-CD45RB can uniquely ameliorate colitis by inducing iTreg or by expanding nTregs, and also inhibits colonic inflammation by Teff cells, possibly by inhibiting IFNγ.

The role of Foxp3 in augmented homeostatic proliferation of Treg (P1187)

Natural CD4+Foxp3+ Tregs (nTreg) exhibit a high rate of constitutive homeostatic proliferation (HP) compared to CD4+Foxp3- conventional T (Tconv) cells (~50% vs. &lt;10% proliferate over 10d, respectively, as determined by transfer of CFSE-labeled CD4 subsets into replete recipients). nTreg from Filig mutant mice (~10% wt Foxp3 level), exhibited low HP (&lt;10%). Transducing Filig nTreg with Foxp3 retrovirus (rv), restored high HP (40%) vs. vector control (12% HP). However, when Foxp3 rv was expressed in Tconv cells, the resulting induced Tregs (iTregs) exhibited similar HP to Tconv cells transduced with vector control (17% vs. 16%, respectively). Thus, Foxp3 is necessary but not sufficient for high HP. Next, we examined the role of Foxp3 in HP of endogenously selected T cells (using EdU labeling). Filig bone marrow transduced with Foxp3 rv vs. control rv was transplanted into irradiated congenic hosts. Surprisingly, in this setting, Tconv cells transduced to constitutively express Foxp3 (iTregs), underwent high HP (32%) compared to control rv (or nontransduced) Foxp3- counterparts (12% HP). Thus, forced Foxp3 expression during thymic ontogeny augments HP capacity, not seen when Foxp3 is acquired by mature Tconv in the periphery. These findings provide new insight into the regulation of HP in Treg, the role of Foxp3 expression in Treg homeostasis, and highlight additional distinctions between induced and natural Treg.

Enhancing alloreactivity does not restore GVHD induction but augments skin graft rejection by CD4⁺ effector memory T cells

Graft-versus-host disease (GVHD) caused by donor T cells attacking recipient tissues is a major cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation (alloSCT). Studies have shown that effector memory T (T(EM) ) cells do not cause GVHD but are capable of immune functions post-transplant, including graft-versus-leukemia (GVL) effects, but the reasons for this are unclear. In mice, the T(EM) pool may have a less diverse T-cell receptor (TCR) repertoire than naive T (T(N) ) cells with fewer alloreactive clones. We therefore tested whether enhancing the alloreactivity of T(EM) cells would restore their ability to cause GVHD. In an MHC-matched system, alloreactive T(EM) cells were created by transferring GVHD effector cells into syngeneic recipients and allowing conversion to T(EM) cells. Upon retransfer to freshly transplanted recipients, these cells caused only mild GVHD. Similarly, in an MHC-mismatched system, T(EM) cells with a proven increased precursor frequency of alloreactive clones only caused limited GVHD. Nonetheless, these same cells mounted strong in vitro alloresponses and caused rapid skin graft rejection. T(EM) cells created from CD4(+) T cells that had undergone lymphopenia-induced proliferation (LIP) also caused only mild GVHD. Our findings establish that conversion to T(EM) cells significantly reduces GVHD potency, even in cells with a substantially enhanced alloreactive repertoire.

Maintenance and homeostatic proliferation of regulatory CD4 T cells occur independent of the thymus and of secondary lymphoid organs (104.7)

In vivo manipulations that influence regulatory Foxp3+CD4+ T cells (Treg) homeostasis represent a valuable therapeutic mean for balancing immunity and regulation. However, the signals and the anatomical sites of Treg homeostasis are not completely defined. Therefore, we investigated the role of the thymus, and of secondary lymphoid organs (SLO) on Treg homeostasis in steady state. The absolute numbers of conventional CD4 T cells (Tconv) and Treg in spleen, peripheral lymph nodes, bone marrow, blood, liver, and lungs were determined by flow cytometry in euthymic or thymectomized adult wt B6 mice and in mice lacking SLO (splenectomized Lymphotoxin receptor β knockout). Proliferation was measured by EdU incorporation over a period of 3 days prior to analysis. We found that, in wt B6 mice, Treg exhibited a much higher rate of homeostatic proliferation (HP) than Tconv in both lymphoid and non-lymphoid compartments. Thymectomy of adult B6 mice reduced Tconv numbers in all compartments by 30-60%, while Treg numbers remained primarily unaffected (d30 and d60). In absence of SLO or both thymus and SLO, Treg accumulated in non-lymphoid organs, in blood, and in bone marrow in higher numbers and displayed similar rates of HP compared to wt mice. Our data show that Treg homeostasis occurs independently of thymic production and of SLO, suggesting an intrinsic Treg ability to respond to antigens in non-lymphoid tissues.

Graft-versus-host disease is independent of innate signaling pathways triggered by pathogens in host hematopoietic cells

Graft-versus-host disease (GVHD) is initiated by APCs that prime alloreactive donor T cells. In antipathogen responses, Ag-bearing APCs receive signals through pattern-recognition receptors, including TLRs, which induce the expression of costimulatory molecules and production of inflammatory cytokines, which in turn mold the adaptive T cell response. However, in allogeneic hematopoietic stem cell transplantation (alloSCT), there is no specific pathogen, alloantigen is ubiquitous, and signals that induce APC maturation are undefined. To investigate APC activation in GVHD, we used recipient mice with hematopoietic cells genetically deficient in pathways critical for APC maturation in models in which host APCs are absolutely required. Strikingly, CD8-mediated and CD4-mediated GVHD were similar whether host APCs were wild-type or deficient in MyD88, TRIF, or MyD88 and TRIF, which excludes essential roles for TLRs and IL-1β, the key product of inflammasome activation. Th1 differentiation was if anything augmented when APCs were MyD88/TRIF(-/-), and T cell production of IFN-γ did not require host IL-12. GVHD was also intact when APCs lacked the type I IFNR, which amplifies APC activation pathways that induce type I IFNs. Thus in GVHD, alloreactive T cells can be activated when pathways critical for antipathogen T cell responses are impaired.

Quantifying terrestrial ecosystem carbon dynamics in the Jinsha watershed, upper Yangtze, China from 1975 to 2000

Quantifying the spatial and temporal dynamics of carbon stocks in terrestrial ecosystems and carbon fluxes between the terrestrial biosphere and the atmosphere is critical to our understanding of regional patterns of carbon budgets. Here we use the General Ensemble biogeochemical Modeling System to simulate the terrestrial ecosystem carbon dynamics in the Jinsha watershed of China's upper Yangtze basin from 1975 to 2000, based on unique combinations of spatial and temporal dynamics of major driving forces, such as climate, soil properties, nitrogen deposition, and land use and land cover changes. Our analysis demonstrates that the Jinsha watershed ecosystems acted as a carbon sink during the period of 1975-2000, with an average rate of 0.36 Mg/ha/yr, primarily resulting from regional climate variation and local land use and land cover change. Vegetation biomass accumulation accounted for 90.6% of the sink, while soil organic carbon loss before 1992 led to a lower net gain of carbon in the watershed, and after that soils became a small sink. Ecosystem carbon sink/source patterns showed a high degree of spatial heterogeneity. Carbon sinks were associated with forest areas without disturbances, whereas carbon sources were primarily caused by stand-replacing disturbances. It is critical to adequately represent the detailed fast-changing dynamics of land use activities in regional biogeochemical models to determine the spatial and temporal evolution of regional carbon sink/source patterns.

[Chronic pain management]

Pain is one of the major complaints leading to doctor visits. Therefore basic knowledge of frequent pain diagnoses and possible treatment approaches is essential. Numerous medical and interventional therapeutic options are available for causal or symptomatic treatment of pain. The treatment of neuropathic pain is often difficult and demands special knowledge. Antidepressants like amitriptyline and anticonvulsive drugs are the first choice in these cases. Also interventional approaches are useful, such as spinal cord stimulation for angina pectoris. For the treatment of complex regional pain syndrome and phantom pain the use of mirror feed-back is a new effective method for pain relief. The only way to prevent from development of chronic pain is the early and effective treatment of acute pain.

Efficacy of superoxide dismutase mimetic M40403 in attenuating radiation-induced oral mucositis in hamsters

PURPOSE

M40403 is a small-molecule superoxide dismutase mimetic that has shown efficacy in animal model disease states in which superoxide anions are thought to play a key role. Radiation treatment and chemotherapy for cancer generate free oxygen radicals that are hypothesized to trigger unwanted side effects in healthy tissue. For some patients undergoing these antineoplastic treatments, one of the most prevalent side effects is oral mucositis, which is a painful, often dose-limiting condition. Preclinical and clinical studies of this condition have shown the positive effect of treatment with compounds that decrease free oxygen radicals. This study investigated the efficacy M40403 in a clinically relevant hamster model of acute, radiation-induced oral mucositis.

METHODS

Oral mucositis was induced in hamsters by irradiation of the cheek pouch. The ability of i.p. administered M40403 to decrease the duration and severity of oral mucositis was assessed after treatment at different doses and dosing schedules. Oral mucositis was scored using the WHO grading scale.

RESULTS

Compared with placebo-treated animals, those irradiated on day 0 and treated twice daily with 30 mg/kg M40403 had significantly less severe and shorter duration mucositis over a range of treatment schedules, including from days -1 to 3, day 0 to 3, and day 0 alone. Similar efficacy was achieved at doses of 10 and 3 mg/kg twice daily on days -1 to 3.

CONCLUSIONS

These results implicate free oxygen radicals in the onset of oral mucositis and also provide the basis for further development of M40403 in the prevention of this condition in at-risk cancer patients.

Induction of tolerance across fully mismatched barriers by a nonmyeloablative treatment excluding antibodies or irradiation use

A mixed-chimerism approach is a major goal to circumvent sustained immunosuppression, but most of the proposed protocols need antibody treatment or host irradiation. Another promising experience involves busulfan combined with cyclophosphamide treatment. Additionally, recent publications demonstrated that, differing from busulfan, treosulfan administration does not present severe organ or hemato toxicities. Currently, Duchenne muscular dystrophy (DMD) patients are treated with chronic immunosuppression for muscle precursor cell transplantation (MT). We have developed a safe tolerance approach within this cellular allotransplantation therapy background. Thus, we have conditioned, prior to a donor BALB/c MT, the dystrophic mouse model C57Bl10J mdx/mdx, with our treatment based on a donor-specific transfusion, then a treosulfan treatment combined with single cyclophosphamide dose, and finally a donor bone marrow transplantation (TTCB). A first MT was performed in all mixed chimeric mice resulting from the TTCB treatment in the left tibialis anterior (TA) muscles. A second MT from the same donor strain was performed 100 days later in the right TA without any additional therapy. Results show that all treated mice developed permanent mixed chimerism. Long-lasting donor-positive fibers were present in both TAs of the mice, which received MT after the TTCB treatment. Only a basal level of infiltration was observed around donor fibers and mixed chimeric mice rejected third-party haplotype skin grafts. Thus, mixed chimerism development with this TTCB conditioning regimen promotes donor-specific stable tolerance, avoiding costimulatory blockade antibodies or irradiation use and side effects of sustained immunosuppressive treatments. This protocol could be eventually applied for MT to DMD patients or others tissue transplantations.

Chronischer Schmerz im ärztlichen Alltag

Acute or chronic pain are the most frequent reasons to seek medical help. Primarily acute pain is a symptom and warning sign. However, insufficient treatment of acute pain may induce a change to a chronic long lasting pain illness. Therefore a consequent immediate treatment is essential. Chronic pain is a bio-psycho-social illness. In this situation pharmacotherapy or any other monotherapy alone is no longer effective. Interdisciplinary treatment is needed. Effective treatment of acute pain to prevent from long lasting pain episodes is an essential and the only way to prevent from enormous financial consequences of chronic pain.

Rifalazil treats and prevents relapse of clostridium difficile-associated diarrhea in hamsters

Although vancomycin and metronidazole effectively treat Clostridium difficile-associated diarrhea and colitis (CDAD), their use is associated with a high incidence of relapsing C. difficile infection. Rifalazil is a new benzoxazinorifamycin that possesses activity against Mycobacterium tuberculosis and gram-positive bacteria. Here we compared rifalazil and vancomycin for effectiveness in preventing or treating clindamycin-induced cecitis in a hamster model of CDAD. Golden Syrian hamsters were injected subcutaneously with clindamycin phosphate (10 mg/kg), followed 24 h later by C. difficile gavage. Hamsters received by gavage for 5 days vehicle, vancomycin (50 mg/kg), or rifalazil (20 mg/kg) either simultaneously with (prophylactic protocol) or 24 h after C. difficile administration (treatment protocol). While all vehicle-administered animals became moribund within 48 h of C. difficile administration, no rifalazil- or vancomycin-treated animals in either protocol showed signs of morbidity after 7 days. Ceca of rifalazil-treated animals showed absence of epithelial cell damage, significantly reduced congestion and edema, and less, but not statistically significantly less, neutrophil infiltration compared to those of vehicle-treated animals. In contrast, vancomycin-treated animals demonstrated severe epithelial cell damage and mildly reduced congestion and edema. Moreover, hamsters relapsed and tested C. difficile toxin positive (by enzyme-linked immunosorbent assay) 10 to 15 days after discontinuation of vancomycin treatment. None of the rifalazil-treated hamsters showed signs of disease or presence of toxins in their feces 30 days after discontinuation of treatment. Our results indicate that once daily rifalazil may be superior to vancomycin for curative treatment of CDAD.

Antimicrobial activity of silver nitrate against periodontal pathogens

Metal ions were evaluated as potential antimicrobial agents suitable for local delivery in the oral cavity for the treatment of periodontitis. Silver nitrate, copper chloride, and zinc chloride were tested for antimicrobial activity in in vitro killing assays conducted in phosphate buffered saline with a series of oral bacteria including gram-negative periodontal pathogens and gram-positive streptococci. Copper and zinc salts failed to exhibit strong and consistent activity against periodontal pathogens. In contrast, silver at a concentration of 0.5 microg/mL produced a 3 log10 reduction in colony forming units (CFU)/mL or greater against all periodontal pathogens tested including Porphyromonas gingivalis, Prevotella intermedia, Prevotella denticola, Bacteroides forsythus, Fusobacterium nucleatum vincentii, Campylobacter gracilis, Campylobacter rectus, Eikenella corrodens, and Actinobacillus actinomycetemcomitans. In comparison, substantially higher concentrations of silver nitrate failed to kill oral streptococci. A silver nitrate concentration of 25 microg/mL produced log10 reductions in CFU/mL of 3.5-5 in killing assays performed in human serum against P. gingivalis, demonstrating the ability of silver to retain activity in a biological medium similar to that encountered in vivo in the periodontal pocket. These results identify silver nitrate, an antimicrobial that may possess advantages over traditional antibiotics, as a potential agent for controlled release local delivery in the oral cavity for the treatment of periodontitis.

Identification and analysis of bacterial protein secretion inhibitors utilizing a SecA-LacZ reporter fusion system

Protein secretion is an essential process for bacterial growth, yet there are few if any antimicrobial agents which inhibit secretion. An in vivo, high-throughput screen to detect secretion inhibitors was developed based on the translational autoregulation of one of the central protein components, SecA. The assay makes use of a SecA-LacZ fusion reporter construct in Escherichia coli which is induced when secretion is perturbed. Several compounds, including two natural product extracts, which had the ability to induce the reporter fusion were identified and the MICs of these compounds for Staphylococcus aureus strain MN8 were found to be < or =128 microg/ml. Enzyme-linked immunosorbent assay, Western blotting, and immunoprecipitation techniques were used to analyze the affects of these compounds on protein secretion. Six representative compounds presented here appear to be bona fide secretion inhibitors but were found to have deleterious effects on membranes. It was concluded that, while the method described here for identifying inhibitors of secretion is valid, screens such as this, which are directed against the membrane-bound portion of a pathway, may preferentially identify compounds which affect membrane integrity.

[A survey of physicians' knowledge about pain therapy with strong opioid analgesics]

INTRODUCTION

The WHO analgesic ladder, including the use of strong opioid analgesics for the treatment of cancer pain, is widely accepted. However, the use of opioids for the treatment of non-cancer pain is still controversial. This study investigates doctors' medical knowledge about basic aspects of pain management. Additionally, we determined whether the deficiencies in the treatment of patients suffering from pain are based on the rigorous national narcotic control system in Germany.

METHODS

We investigated the juridical and technical knowledge of physicians specializing in pain therapy by a questionnaire. During a postgraduate course the knowledge about pain therapy according to the WHO analgesic ladder and the beliefs concerning the narcotic regulations in Germany were evaluated. The survey participants were asked to rate their attitudes on a 10-point analogue scale (1=disagreement, 10=full agreement). The participants were also asked to indicate occupational criteria such as specialty, clinical practice area, and postgraduate years of practice. Descriptive statistics for the mean values were used.

RESULTS

One hundred and forty-three questionnaires were completed. The majority of participants worked at departments of anaesthesiology. Some 51.1% of the participants had no specific multiple-copy prescriptions for opioid analgesics. Only 72% of the physicians knew from which governmental institution they could order multiple-copy prescriptions. In general, more doctors would prescribe opioids by the use of normal forms. The controlled substance laws were seen as an impediment by the majority of participants, without relevant differences as to their years of practice. The regulations were regarded as ineffective protection against illegal use of opioids. Treatment of pain with strong opioid analgesics was seen as beneficial for the patients. The use of strong opioids for long-term treatment was recommended, and psychological addiction was regarded as non-existent.

CONCLUSION

Therapy with strong opioids is accepted practice, but significant deficits of legal and technical knowledge uphold the undertreatment of patients suffering from cancer and non-cancer pain. Patients with a legitimate need for pain relief by strong opioids are the unintended victims of tight narcotic regulations and deficits in medical education. An ease of regulatory conditions is mandatory to reduce the reluctance for prescribing opioids. On the other hand intensified continuous medical education is mandatory to reduce the undertreatment of patients with severe pain conditions.

Neovascularization in hyperplastic, metaplastic and potentially preneoplastic lesions of the bronchial mucosa

Angiogenesis is important in a large number of normal and pathological processes including tumour growth and development, inflammation and in wound healing. We investigated whether neovascularization exists in hyperplastic, metaplastic and potentially preneoplastic lesions of the bronchial mucosa as prestages for lung cancer. Biopsy specimens from 86 patients were investigated light microscopically. Formalin-fixed and paraffin-embedded specimens of regular bronchial mucosa including epithelium, basement membrane zone and tunica propria (n = 12) without inflammation were compared with specimens with inflammatory reaction (n = 9), basal cell- and goblet cell hyperplasia (n = 24), squamous cell metaplasia (n = 9), squamous cell metaplasia with different degrees of dysplasia (n = 11), specimens of micropapillomatosis (n = 9) and 13 cases with carcinoma in situ. The grade of neovascularization was assessed by the microvessel density, which was obtained by an immunohistochemical staining of endothelial cells using factor VIII-related antigen and determined by an automatic image-analysing-system. Microvessels were counted in selected areas of highest neovascularization on a x 100 field 0.4 mm underneath the basement membrane zone in the tunica propria. Microvessel count, minimal and maximal diameter of the vessels were chosen as morphological variables. A significantly increased microvessel count with 33 vessels/0.6 mm2 was found in specimens with inflammation of the tunica mucosa (regular bronchial mucosa: 20 vessels/0.6 mm2). Microvessel diameter (surface of cut section) increased in specimens of bronchial mucosa with inflammation to 11.3 x 10(-4) mm2 (regular bronchial mucosa: 9.04 x 10(-4) mm2). Microvessel count increased in cases of squamous cell metaplasia (33 vessels/0.6 mm2) squamous cell metaplasia with different degrees of dysplasia (50 vessels/0.6 mm2) and carcinoma in situ with 61 vessels/0.6 mm2. With increasing dysplasia, increasing neo-vascularization was found in close vicinity to the basement membrane zone. Simultaneously, interepithelial sprouts of endothelial cells were seen. Qualitative and quantitative differences were thus found in potentially preneoplastic lesions.

The same epitope on CD22 of B lymphocytes mediates the adhesion of erythrocytes, T and B lymphocytes, neutrophils, and monocytes

CD22 is a B lineage-restricted member of the Ig superfamily that serves as an adhesion receptor expressed by mature B lymphocytes. In this study, the ability of different cell types to attach to COS cells transiently transfected with a full-length CD22 cDNA (COS-CD22) was examined to determine the cellular distribution of the ligand for CD22. T and B lymphocytes, monocytes, erythrocytes, and neutrophils formed specific rosettes with COS-CD22 cells at 4 degrees C. A panel of 33 new mAb directed against CD22 were developed to examine the regions of CD22 that mediate adhesion. Four of these mAb, HB22-7, -22, -23, and -33 (at 1 to 5 micrograms/ml) specifically blocked adhesion (75 to 95%) of all cell types to COS-CD22 cells. Each of these mAb cross-blocked each other's binding, suggesting that ligand binding occurs through a single region of CD22. These mAb also identify a region of CD22 distinct from those defined by previously described CD22 mAb. CD22-mediated adhesion of cell lines to COS-CD22 cells was independent of CD45RO and CDw75 expression, and it was not inhibited by mAb against known integrins. Although alpha-2,6-linked sialic acid expressed on the surface of COS cells did not serve as a ligand for CD22, the CD22 ligand may contain a critical sialic acid determinant, as neuraminidase treatment of all target cells eliminated CD22-mediated adhesion. CD22-mediated adhesion was Ca2+/Mg2+ independent, again suggesting that integrins were not involved. An inhibitory substance for CD22-mediated adhesion was found to be present in FCS and some ascites fluid. Analysis of CD22 mRNA and protein revealed that although multiple mRNA splice variants of CD22 mRNA can be detected, only a single protein isoform was detected on the cell surface. Therefore, although the identity of the CD22 ligands remains incompletely characterized, it is possible that a single major ligand is expressed by RBC and leukocytes, which binds to a single region of CD22.

The same epitope on CD22 of B lymphocytes mediates the adhesion of erythrocytes, T and B lymphocytes, neutrophils, and monocytes

CD22 is a B lineage-restricted member of the Ig superfamily that serves as an adhesion receptor expressed by mature B lymphocytes. In this study, the ability of different cell types to attach to COS cells transiently transfected with a full-length CD22 cDNA (COS-CD22) was examined to determine the cellular distribution of the ligand for CD22. T and B lymphocytes, monocytes, erythrocytes, and neutrophils formed specific rosettes with COS-CD22 cells at 4 degrees C. A panel of 33 new mAb directed against CD22 were developed to examine the regions of CD22 that mediate adhesion. Four of these mAb, HB22-7, -22, -23, and -33 (at 1 to 5 micrograms/ml) specifically blocked adhesion (75 to 95%) of all cell types to COS-CD22 cells. Each of these mAb cross-blocked each other's binding, suggesting that ligand binding occurs through a single region of CD22. These mAb also identify a region of CD22 distinct from those defined by previously described CD22 mAb. CD22-mediated adhesion of cell lines to COS-CD22 cells was independent of CD45RO and CDw75 expression, and it was not inhibited by mAb against known integrins. Although alpha-2,6-linked sialic acid expressed on the surface of COS cells did not serve as a ligand for CD22, the CD22 ligand may contain a critical sialic acid determinant, as neuraminidase treatment of all target cells eliminated CD22-mediated adhesion. CD22-mediated adhesion was Ca2+/Mg2+ independent, again suggesting that integrins were not involved. An inhibitory substance for CD22-mediated adhesion was found to be present in FCS and some ascites fluid. Analysis of CD22 mRNA and protein revealed that although multiple mRNA splice variants of CD22 mRNA can be detected, only a single protein isoform was detected on the cell surface. Therefore, although the identity of the CD22 ligands remains incompletely characterized, it is possible that a single major ligand is expressed by RBC and leukocytes, which binds to a single region of CD22.

Human antigen-specific memory T cells express the homing receptor (LAM-1) necessary for lymphocyte recirculation

Lymphocytes must circulate from blood into lymphoid tissues and sites of infection and inflammation to function efficiently in vivo. This process of "homing" is in part directed by the expression of the leukocyte adhesion molecule (LAM-1, also known as TQ1 and Leu-8) in humans and the homologous MEL-14 antigen in mice. In this report, we demonstrate that the LAM-1 molecule is a 74-kDa protein and that only half of the CD4+ T cells in humans which have a memory phenotype (CD45RA -CD29hi) express the LAM-1 molecule. Functionally, these two phenotypically distinct subpopulations of memory cells were quite different. The LAM-1+ memory cells proliferated better to recall antigen and induced three to seven times higher levels of B cell immunoglobulin secretion than their LAM-1- counterparts. Thus, antigen-specific memory T cells within the helper lineage express the homing receptor appropriate for regulating their migration to secondary lymphoid tissues and sites of inflammation.