Transplantation immunology

Clinical outcomes of endodontic microsurgery in complicated cases with large or through-and-through lesions: a retrospective longitudinal study

OBJECTIVES

To investigate the clinical outcomes of endodontic microsurgery in complicated cases presenting with large or through-and-through lesions.

MATERIALS AND METHODS

We retrospectively collected and analyzed preoperative, intraoperative, and follow-up data from 143 complicated cases that underwent endodontic microsurgery. Clinical outcomes were assessed in terms of tooth survival and surgery success. Cox regression analysis was used to evaluate the survival rate and identify associated risk factors. Additionally, the success rate was compared across different postoperative periods, and potential factors contributing to surgical failure were identified through binary logistic regression.

RESULTS

The overall survival and success rates were 93.0% and 91.7%, respectively. The Cox regression model identified four risk factors affecting tooth survival, including apicoectomy of four teeth (HR = 35.488; P = 0.0002), an open apex observed on preoperative radiographs (HR = 6.300; P = 0.025), the performance of guided tissue regeneration technique (HR = 8.846; P = 0.028), and a palatal surgical approach (HR = 8.685; P = 0.030). The success rate demonstrated an initial increase in the early postoperative period (from 0.5 to 2 years; P = 5.8124e-30), followed by stabilization (from 2 to 9 years; P = 0.298). Surgery success rate significantly declined when apicoectomy involved four teeth (OR = 109.412; P = 0.002).

CONCLUSIONS

Endodontic microsurgery demonstrates satisfactory outcomes in complicated cases, maintaining a stable success rate after two years. However, tooth survival and surgery success are significantly compromised when apicoectomy involves four teeth. Factors such as guided tissue regeneration, an open apex, and the palatal surgical approach are associated with an increased risk of tooth extraction.

CLINICAL RELEVANCE

Despite achieving acceptable outcomes in complicated cases, endodontic microsurgery is adversely affected by the apicoectomy of four teeth.

Immunosuppression armamentarium in 2010: mechanistic and clinical considerations

Effective immunosuppression is the key to successful organ transplantation, with success being defined as minimal rejection risk with concomitant minimal drug toxicities. Despite the general recognition of this fact, a paucity of appropriate clinical trials in children has contributed to lack of standardization of clinical management regimens, resulting in an extensive diversity of favored approaches. Nonetheless, although consensus has not been reached on the ideal approach to immunosuppression in pediatric transplantation, new drug therapies have contributed to a continuing improvement in graft and patient survival. Future clinical research must focus on diminishing the extensive burden of toxicities of these therapeutic agents in children.

The effect of skin transplantation on tumor growth in mice

BACKGROUND

Skin allograft is an immunostimulant. Skin allograft activates effector arms of the immune system including the cytotoxic T lymphocytes, activated macrophages, and natural killer cells. These cells may be involved in the destruction of tumor cells.

METHODS

Balb/c mice were divided into the study (n = 10) and control (n = 10) groups. Alloskin grafts 1 cm in diameter from the backs of Swiss albino mice were placed on the backs of balb/c mice (study group). The same size autoskin grafts from the backs of other balb/c mice were used for the control group. Fourteen days after grafting, we inoculated 1,000 Ehrlich ascites tumor cells intraperitoneally into both groups. Two days after tumor inoculation, we used secondary allografts and autografts (which were about 2 to 3 mm in diameter) for the same groups. We followed up graft survival and animal survival in both groups.

RESULTS

All 10 of the autografted mice died between the 18th and 25th days owing to malignancy. In the allografted group, 2 mice died (1 on day 17 and the other on day 23). Allograft rejection had not occurred in these 2 mice at the time of their death. The other 8 mice in the same group rejected allograft, on average within 9 days (9+/-3, median 8). These 8 mice were alive and without apparent health problems during the 4 months of follow-up.

CONCLUSION

Allo-skin graft rejection may help rejection of tumor cells and may be of use in immunotherapy of cancer.

Muromonab-CD3 and antithymocyte globulin in renal transplantation

OBJECTIVE

To review the recently published medical literature for the practical and efficient use of muromonab-CD3 (OKT-3) and antithymocyte globulin (ATG) in renal transplantation.

DATA SOURCES

MEDLINE and EMBASE were searched (1985-February 1996). Key words used were antithymocyte globulin (ATG, Atgam), muromonab-CD3 (OKT-3, Orthoclone), and kidney transplantation. Thereafter, the search was restricted to English-language articles, clinical trials, and human studies.

STUDY SELECTION AND DATA EXTRACTION

The search was reviewed for articles of interest, and pertinent references from these articles were further reviewed to supplement the initial search. The review focused on antibody therapy as induction and/or rejection therapy in renal transplantation.

DATA SYNTHESIS

Although ATG and OKT-3 are effective in delaying and reducing the occurrence of acute rejection, their impact on long-term graft survival has not been established. Improved graft survival has, however, been demonstrated in patients at high risk for rejection. These risks are described in the review. As first-line or steroid-resistant rejection therapy, ATG and OKT-3 have proven efficacious. Some studies have shown improved graft survival with OKT-3. Although serious infections may occur, OKT-3 has been shown to be effective in reversing rejections resistant to both steroids and ATG. Therefore, reserving OKT-3 for steroid- or ATG-resistant rejections may be preferred over the first-line use of OKT-3, which is limited by the development of antimurine antibodies with subsequent uses. However, the benefits of first-line antibody therapy may outweigh the risks of developing these antibodies in patients for whom high-dose steroids may not be the most appropriate treatment. Other factors that need to be considered are adverse effects, which appear to be lower with ATG, cost, and total hospital charges. The accuracy of treatment outcomes analysis among these studies is limited by variations in the immunosuppressive regimens of the study centers, doses of concomitant therapies, use of prophylactic antibiotics, and time to follow-up.

CONCLUSIONS

While important benefits are realized from using antibody therapies in renal transplantation, their use is often associated with excess immunosuppression and increased treatment costs. Despite encouraging results from published trials, questions regarding the extent of their prophylactic use and impact on long-term outcomes need to be answered. The current literature contains no prospective, controlled, randomized comparisons of OKT-3 and ATG with standardized regimens of conventional immunosuppressive agents and antirejection protocols. The majority of studies use OKT-3 as part of the treatment protocol. Well-designed studies using ATG are lacking. Further research is needed to refine treatment protocols for ATG and OKT-3 to determine the optimal timing and dosing for these agents.

Acute pulmonary allograft rejection. Mechanisms, diagnosis, and management

Rejection is a common complication following lung transplantation, and can lead to considerable short- and long-term morbidity. As numbers and survival rates of lung transplant recipients increase, it is apparent that acute rejection can occur months or years after transplantation, and may be resistant to standard therapies. Mechanisms of acute rejection have been well studied in other solid organ transplant recipients, and are beginning to be addressed in the lung recipient. This article addresses some of the common issues of diagnosis and management of acute rejection which arise frequently during the care of lung transplant recipients.

Muromonab CD3: a reappraisal of its pharmacology and use as prophylaxis of solid organ transplant rejection

The murine monoclonal antibody muromonab CD3 (OKT3) is directed against the CD3 antigen on peripheral human T cells and effectively blocks all T cell function. Prophylaxis with muromonab CD3 (5mg intravenously once daily for 10 to 14 days) as induction therapy together with corticosteroids, azathioprine and delayed cyclosporin (sequential therapy) optimises early graft function by delaying the potentially nephrotoxic and hepatotoxic effects of cyclosporin until graft function is established. Although clinical data are limited (by inconsistencies in trial design and trial size), prophylactic muromonab CD3-based sequential therapy is significantly more effective than standard triple therapy in the prophylaxis of allograft rejection in renal and hepatic, but not cardiac, transplant recipients. Benefits are particularly notable in patients with delayed graft function. No significant between-treatment differences in patient survival have been observed. The overall efficacy of muromonab CD3- and polyclonal-based prophylactic regimens appears to be similar, although results vary between investigators and confirmation is needed. An anti-interleukin-2 monoclonal antibody-based prophylactic regimen improved graft and patient survival compared with muromonab CD3-based prophylaxis in hepatic transplant recipients. Antimuromonab CD3 antibodies may develop; however, muromonab CD3 may be successfully reused in patients with low titres. Preliminary pharmacoeconomic data suggest that mean drug costs are greater with quadruple immunosuppressive regimens containing muromonab CD3, antithymocyte globulin (ATG) or antilymphocyte globulin (ALG) than with triple therapy. Drug costs with prophylactic muromonab CD3-based regimens were similar or greater than those with polyclonal-based protocols. The first doses of muromonab CD3 are associated with the 'cytokine-release syndrome'. More severe first-dose events include aseptic meningitis, intragraft thromboses, seizures and potentially fatal pulmonary oedema. The incidence and/or severity of cytomegalovirus infection with prophylactic muromonab CD3 based immunosuppression is similar to or greater than that with triple therapy and ATG- or ALG-based regimens. However, the risk of infection and also the observed increase in lymphoproliferative disorders appears to be related to the degree of immunosuppression rather than to the drug itself Thus, sequential muromonab CD3-based therapy is more effective than standard triple therapy (in renal and hepatic transplant recipients) and appears to be similar to that of polyclonal-based regimens in the prophylaxis of transplant rejection. Although the routine use of prophylactic muromonab CD3 in low-risk patients with primary graft function does not appear to be justified, prophylactic muromonab CD3-based therapy has a role in patients at high risk of rejection.