Epstein-Barr virus load in transplant patients: Early detection of post-transplant lymphoproliferative disorders

High levels of circulating EBV load are used as a marker of post-transplant lymphoproliferative disorders (PTLD). There is no consensus regarding the threshold level indicative of an increase in peripheral EBV DNA. The aim of the study was to clinically validate a developed EBV quantification assay for early PTLD detection. Transversal study: paired peripheral blood mononuclear cells (PBMC), plasma and oropharyngeal lymphoid tissue (OLT) from children undergoing a solid organ transplant with (n=58) and without (n=47) PTLD. Retrospective follow-up: 71 paired PBMC and plasma from recipients with (n=6) and without (n=6) PTLD history. EBV load was determined by real-time PCR. The diagnostic ability to detect all PTLD (categories 1-4), advanced PTLD (categories 2-4) or neoplastic PTLD (categories 3 and 4) was estimated by analyzing the test performance at different cut-off values or with a load variation greater than 0.5log units. The higher diagnostic performance for identifying all, advanced or neoplastic PTLD, was achieved with cut-off values of 1.08; 1.60 and 2.47log EBVgEq/10(5) PBMC or 2.30; 2.60; 4.47loggEq/10(5) OLT cells, respectively. EBV DNA detection in plasma showed high specificity but low (all categories) or high (advanced/neoplastic categories) sensitivity for PTLD identification. Diagnostic performance was greater when: (1) a load variation in PBMC or plasma was identified; (2) combining the measure of EBV load in PBMC and plasma. The best diagnostic ability to identify early PTLD stages was achieved by monitoring EBV load in PBMC and plasma simultaneously; an algorithm was proposed.

Epstein-Barr virus-specific CD8(+) T lymphocytes from diffuse large B cell lymphoma patients are functionally impaired

Epstein-Barr virus (EBV) is a persistent virus with oncogenic capacity that has been implicated in the development of aggressive B cell lymphomas, primarily in immunosuppressed individuals, although it can be present in immunocompetent individuals. Changes in the function and clonal diversity of T lymphocytes might be implied by viral persistence and lymphoma development. The aim of the present study was to evaluate the frequency, phenotype, function and clonotypical distribution of EBV-specific T cells after peripheral blood stimulation with a virus lysate in newly diagnosed patients with diffuse large B cell lymphoma (DLBCL) aged more than 50 years without prior histories of clinical immunosuppression compared with healthy controls. Our results showed impaired EBV-specific immune responses among DLBCL patients that were associated primarily with decreased numbers of central and effector memory CD8(+) T lymphocytes. In contrast to healthy controls, only a minority of the patients showed CD4(+)/tumour necrosis factor (TNF)-α(+) T cells expressing T cell receptor (TCR)-Vβ17 and CD8(+)/TNF-α(+) T cells with TCR-Vβ5·2, Vβ9 and Vβ18 in response to EBV. Notably, the production of TNF-α was undetectable among TCR-Vβ5·3(+), Vβ11(+), Vβ12(+), Vβ16(+) and Vβ23(+) CD8(+) T cells. In addition, we observed decreased numbers of CD4(+)/TNF-α(+) and CD8(+)/TNF-α(+), CD8(+)/interleukin (IL)-2(+) and CD8(+)/TNF-α(+)/IL-2(+) T lymphocytes in the absence of T cells capable of producing TNF-α, IL-2 and IFN-γ after EBV stimulation simultaneously. Moreover, DLBCL patients displayed higher IL-10 levels both under baseline conditions and after EBV stimulation. These findings were also observed in patients with positive EBV viral loads. Prospective studies including a large number of patients are needed to confirm these findings.

Tumor Microenvironment Remodeling by 4-Methylumbelliferone Boosts the Antitumor Effect of Combined Immunotherapy in Murine Colorectal Carcinoma

We have previously demonstrated that a low dose of cyclophosphamide (Cy) combined with gene therapy of interleukin-12 (AdIL-12) has a synergistic, although limited, antitumoral effect in mice with colorectal carcinoma. The main mechanism involved in the efficacy of Cy+AdIL-12 was the induction of a specific immune response mediated by cytotoxic T lymphocytes. Our current aims were to evaluate the effects of 4-methylumbelliferone (4Mu), a selective inhibitor of hyaluronan (HA) synthesis, on tumor microenvironment (TME) and to investigate how 4Mu affects the therapeutic efficacy of Cy+AdIL-12. The results showed that 4Mu significantly reduced the amount of tumoral HA leading to a significant decrease in tumor interstitial pressure (TIP). As a consequence, tumor perfusion was improved allowing an increased adenoviral transgene expression. In addition, treatment with 4Mu boosted the number of cytotoxic T lymphocytes that reach the tumor after adoptive transfer resulting in a potent inhibition of tumor growth. Importantly, we observed complete tumor regression in 75% of mice when 4Mu was administrated in combination with Cy+AdIL-12. The triple combination 4Mu+Cy+AdIL-12 also induced a shift toward antiangiogenic factors production in tumor milieu. Our results showed that TME remodeling is an interesting strategy to increase the efficacy of anticancer immunotherapies based on gene and/or cell therapy.

Molecular identification and genetic studies in Peruvian Phragmipediums

Peru has inherited one of the greatest biodiversities of the planet. The orchid genus Phragmipedium has several representatives in the country. They are listed in Appendix 1 of CITES, restricted from international trade. 

Tissue integration and inflammatory reaction in full-thickness abdominal wall repair using an innovative composite mesh

PURPOSE

When composite meshes are used in abdominal wall repair, seroma formation may persist and delay the desired integration leading to recurrence. This study compares tissue integration and inflammatory response in abdominal wall repair with composites with different absorbable synthetic barriers.

METHODS

Full-thickness defects created in the abdominal wall of rabbits were repaired using polypropylene prosthesis or the following composites: Physiomesh™ (Phy); Ventralight™ (Vent) and "new composite mesh" (Ncm) not yet used clinically in humans. The collected seroma was evaluated for IFN-γ/IL-4 by ELISA. Tissue integration, anti- (IL-13/TGFβ-1/IL-10/IL-4) and pro-inflammatory (TNF-α/IL-6/IFN-γ/VEGF) cytokine mRNA expression and TGFβ/VEGF immunolabeling were evaluated at 14 and 90 days post-implant.

RESULTS

Seroma was observed in 10 of 12 Phy/Vent and 4 of 12 Ncm. Wound fluid IFN-γ showed a time-dependent significant increase in Vent and tendency to decrease in Ncm, while all composites exhibited IL-4 upward trend. Prostheses were fully infiltrated by an organized connective tissue at end time although the area had shown prior seroma. A stable mesothelium was developed, except in adhesion areas. Vent/Phy displayed a significant increase in TNF-α/IFN-γ-mRNA over time. Significant decrease in VEGF mRNA was observed in Phy/Ncm, while a significant increase of TGFβ-1 mRNA was evident in all composites over time. Ncm exhibited the highest TGFβ protein expression area at short term and the greatest percentage of VEGF positive vessels at end time.

CONCLUSION

Ncm could be an appropriate candidate to improve clinical outcome showing the lower development of seroma and optimal tissue integration with minimal pro-inflammatory cytokine response over time and consistent pro-wound healing cytokine expression.

Bacterial adhesion to biological versus polymer prosthetic materials used in abdominal wall defect repair: do these meshes show any differences in vitro?

PURPOSE

Although clinical data suggest the similar performance of collagen-based biological prosthetic materials to some polymer materials, the use of a biomesh for abdominal hernia repair in a setting of infection is controversial. This in vitro study compares the adhesion of two Staphylococcus strains to polymer and biological meshes.

METHODS

Sterile fragments of Optilene(®) (Op), Surgipro™ (Surg), Preclude(®) (Precl), TIGR(®) (TIGR), Bio-A(®) (BioA), Permacol™ (Perm), Surgisis(®) (SIS), and Tutomesh(®) (Tuto) were inoculated with 10(6) CFU of S. aureus (Sa) or S. epidermidis (Se) (n = 18 per strain per mesh). The first five meshes are polymer materials while Perm, SIS and Tuto are biomeshes. After 24/48 h of incubation, bacterial adhesion was examined by sonication, scanning electron microscopy (SEM) and light microscopy.

RESULTS

Sa and Se showed a high affinity for the absorbable meshes (TIGR, BioA, Perm, SIS, Tuto) (p < 0.001). Precl yielded the lowest bacterial loads (p < 0.001). Surg, Precl and BioA underwent no substantial change over time, while Op (p < 0.001) and TIGR (p < 0.05) showed decreasing bacterial loads during incubation. The Sa-contaminated biomeshes behaved similarly while biomeshes inoculated with Se returned higher bacterial yields at 48 h, especially SIS (p < 0.001). SEM and light microscopy observations revealed planktonic bacteria and biofilms on the polymer surface and bacterial niches in biomesh pores.

CONCLUSIONS

Within 48 h of contamination, the absorbable polymer and biological meshes exhibited high bacterial loads. Given their lower affinity for both bacterial strains, the conventional non-absorbable polymer materials could be better candidates for use in contaminated surgical fields.

Action of anti-M₃muscarinic acetylcholine receptor IgG of primary Sjögren's syndrome on the enzymatic antioxidant system in rat submandibular gland

BACKGROUND

We demonstrate that serum immunoglobulin G (IgG) directed against glandular M3 muscarinic acetylcholine receptors (M₃mAChR) and pilocarpine triggers the increment of superoxide dismutase (SOD) and catalase (CAT) and the production of nitric oxide (NO) and prostaglandin E₂(PGE₂).

METHODS

Enzyme-linked immunosorbent assay (ELISA) was performed in the presence of the human M₂mAChR synthetic peptide as antigen to detect in serum of pSS patients the autoantibodies. Further, SOD and CAT specific activity and NO were determined chemically in the presence of anti-M₃mAChR IgG and pilocarpine. The level of PGE₂generation in the presence of autoantibody and pilocarpine was determined by ELISA.

RESULTS

An association between anti-M₂mAChR autoantibodies and pilocarpine given the increment of the specific activity of SOD and CAT in the serum of pSS patients and in the rat submandibular gland was observed. As a result of this action, M₃synthetic peptide and atropine abrogated the stimulatory action. The L-type calcium channel, calcium/calmodulin complex and COX-2 inhibitors selectively blocked the increment of the specific activity of SOD and CAT in the rat submandibular gland. An increased production of NO and PGE₂by the cholinergic autoantibody and pilocarpine was also detected.

CONCLUSION

On the basis of these results, the increment of the specific activity of SOD and CAT in pSS patients as compared to control healthy individuals may be seen as a defensive reaction to the increment of the amount of ROS, which becoming uncontrollable, leads to irreversible cellular and tissue damage.

91 SILDENAFIL CITRATE MODIFIES FETOPLACENTAL DEVELOPMENT IN A RABBIT MODEL OF INTRAUTERINE GROWTH RESTRICTION

The failure of fetuses to achieve their full growth potential is known as intrauterine growth restriction (IUGR). Sildenafil citrate (SC) is a phosphodiesterase 5 (PDE-5) inhibitor, which enhances nitric oxide (NO)-dependent vasodilatation, and it may have a potential therapeutic role in the treatment of IUGR. The aim of this study was to evaluate the effect of SC on placental and fetal development in a diet-induced rabbit model of IUGR. A total of 24 rabbits does weighing 4.3 ± 0.49 kg on average were used. At Day 9 of pregnancy, females were randomly allocated into 3 experimental groups: one group was fed ad libitum during pregnancy (Group C; n = 8); the rest of the does had 50% restricted daily intake and were treated or not with 20 mg of SC daily from Day 22 of pregnancy until parturition (Groups SC and R, respectively, n = 8 for both). At Day 28 of pregnancy, half of the pregnant does from each group were euthanised to study fetoplacental development, while the remaining does were allowed to deliver. At Day 28, weight, length, and thickness of fetal and maternal placentas, and fetal weight and size [crown-rump length (CRL), and transversal thoracic diameter (TD)] were assessed. A fetus was considered IUGR when it weighted less than the 10th percentile for its normal gestational weight. Statistical analysis was performed using the PROC GLM procedure. Nutritional restriction induced a higher rate of fetuses IUGR than control group (31.0% v. 15.1%; P < 0.05). The percentage of fetuses with IUGR was 23% in SC group (no significant differences with groups C and R). However, SC increased the thickness of maternal and fetal placentas compared to group R (0.4 ± 0.02 v. 0.2 ± 0.02 cm; 0.6 ± 0.02 v. 0.3 ± 0.02 cm; P < 0.05 respectively), being similar to group C (0.4 ± 0.02 and 0.5 ± 0.03 cm). Maternal placental weight in group C showed higher values (1.5 ± 0.08 g; P < 0.05) than both restricted groups (1.2 ± 0.07 g). CRL in group SC was larger than in group R (10.5 ± 0.12 v. 10.0 ± 0.12 cm; P < 0.05) and similar to that in group C (10.5 ± 0.15 cm). The neonates in group SC showed higher values for CRL (10.9 ± 0.15 cm) than those from groups R and C (10.5 ± 0.11, 10.2 ± 0.20 cm; P = 0.05). Regarding TD, fetuses in group SC showed higher values than group R (2.3 ± 0.04 v. 2.1 ± 0.03 cm; P < 0.05) and equaled that of group C (2.3 ± 0.03 cm). In conclusion, maternal malnutrition prejudices fetoplacental development, causing IUGR. Treatment with SC in the last third of gestation counteracts fetal growth retardation by favouring placental development and function and, thus, fetal growth. These results confirm that administration of SC may have a potential benefit in pregnancies complicated by placental insufficiency and IUGR.We acknowledge CM, FSE, and AGL2011-23822 for funding.