Immunotoxin Against a Donor MHC Class II Molecule Induces Indefinite Survival of Murine Kidney Allografts

Rejection of donor organs depends on the trafficking of donor passenger leukocytes to the secondary lymphoid organs of the recipient to elicit an immune response via the direct antigen presentation pathway. Therefore, the depletion of passenger leukocytes may be clinically applicable as a strategy to improve graft survival. Because major histocompatibility complex (MHC) class II(+) cells are most efficient at inducing immune responses, selective depletion of this population from donor grafts may dampen the alloimmune response and prolong graft survival. In a fully MHC mismatched mouse kidney allograft model, we describe the synthesis of an immunotoxin, consisting of the F(ab')2 fragment of a monoclonal antibody against the donor MHC class II molecule I-A(k) conjugated with the plant-derived ribosomal inactivating protein gelonin. This anti-I-A(k) gelonin immunotoxin depletes I-A(k) expressing cells specifically in vitro and in vivo. When given to recipients of kidney allografts, it resulted in indefinite graft survival with normal graft function, presence of Foxp3(+) cells within donor grafts, diminished donor-specific antibody formation, and delayed rejection of subsequent donor-type skin grafts. Strategies aimed at the donor arm of the immune system using agents such as immunotoxins may be a useful adjuvant to existing recipient-orientated immunosuppression.

A cross-sectional analysis of the relationships of FAM components and their effects on quality of life in Chinese patients with chronic musculoskeletal pain

Introduction

A body of evidence has accrued supporting the Fear-Avoidance Model (FAM) of chronic pain which postulated the mediating role of pain-related fear in the relationships between pain catastrophizing and pain anxiety in affecting pain-related outcomes. Yet, relatively little data points to the extent to which the FAM be extended to understand chronic pain in Chinese population and its impact on quality of life (QoL).

Objective

This study explored the relationships between FAM components and their effects on QoL in a Chinese sample.

Methods

A total of 401 Chinese patients with chronic musculoskeletal pain completed measures of three core FAM components (pain catastrophizing, pain-related fear, and pain anxiety) and QoL. Cross-sectional structural equation modeling (SEM) assessed the goodness of fit of the FAM for two QoL outcomes, Physical (Model 1) and Mental (Model 2). In both models, pain catastrophizing was hypothesized to underpin pain-related fear, thereby influencing pain anxiety and subsequently QoL outcomes.

Results

Results of SEM evidenced adequate data-model fit (CFI30.90) for the two models tested (Model 1: CFI = 0.93; Model 2: CFI = 0.94). Specifically, pain catastrophizing significantly predicted pain-related fear (Model 1: stdb = 0.90; Model 2: stdb = 0.91), which in turn significantly predicted pain anxiety (Model 1: stdb = 0.92; Model 2: stdb = 0.929) and QoL outcomes in a negative direction (Model 1: stdb = −0.391; Model 2: stdb = −0.651) (all P < 0.001) (Table 1, Fig. 1).

Conclusion

Our data substantiated the existing FAM literature and offered evidence for the cross-cultural validity of the FAM in the Chinese population with chronic pain.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

The net suppression effect of pain catastrophic cognition on anxiety sensitivity

Introduction

The existing literature on chronic pain points to the effects anxiety sensitivity, pain hypervigilance, and pain catastrophizing on pain-related fear; however, the nature of the relationships remains unclear. The three dispositional factors may affect one another in the prediction of pain adjustment outcomes. The addition of one disposition may increase the association between another disposition and outcomes, a consequence known as suppressor effects in statistical terms.

Objective

This study examined the possible statistical suppressor effects of anxiety sensitivity, pain hypervigilance and pain catastrophizing in predicting pain-related fear and adjustment outcomes (disability and depression).

Methods

Chinese patients with chronic musculoskeletal pain (n = 401) completed a battery of assessments on pain intensity, depression, anxiety sensitivity, pain vigilance, pain catastrophizing, and pain-related fear. Multiple regression analyses assessed the mediating/moderating role of pain hypervigilance. Structural equation modeling (SEM) was used to evaluate suppression effects.

Results

Our results evidenced pain hypervigilance mediated the effects of anxiety sensitivity (Model 1: Sobel z = 4.86) and pain catastrophizing (Model 3: Sobel z = 5.08) on pain-related fear. Net suppression effect of pain catastrophizing on anxiety sensitivity was found in SEM where both anxiety sensitivity and pain catastrophizing were included in the same full model to predict disability (Model 9: CFI = 0.95) and depression (Model 10: CFI = 0.93) (all P < 0.001) (see Figs. 3 and 4, Figs. 1 and 2).

Conclusions

Our findings evidenced that pain hypervigilance mediated the relationship of two dispositional factors, pain catastrophic cognition and anxiety sensitivity, with pain-related fear. The net suppression effects of pain catastrophizing suggest that anxiety sensitivity enhanced the effect of pain catastrophic cognition on pain hypervigilance.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

An Extraperitoneal Technique for Murine Heterotopic Cardiac Transplantation

The mouse heterotopic cardiac transplantation model has been used extensively by investigators in the field of organ transplantation to study the rejection process, test new antirejection treatments, tolerance induction protocols or to understand basic immunological principles. Due to its extensive use, any small refinement of the technique would have a major impact on replacement, reduction and refinement (commonly known as the 3Rs). Here, we describe a novel approach to refine this model. The donor aorta and pulmonary artery are anastomosed peripherally to the femoral artery and vein of the recipient, respectively. The technical success rate is comparable to the conventional abdominal site, but it avoids a laparotomy and handling of the bowels making it less invasive method. As a result, recipients recover faster and require less postoperative analgesia. It is a major refinement under one of the 3Rs and would represent an advance in animal welfare in scientific research.