Feasibility of cryopreserved tracheal xenotransplants with the use of short-course immunosuppression.

OBJECTIVE: We evaluated the feasibility of discordant xenotransplantation of the cryopreserved trachea with intermittent immunosuppression to help solve the shortage of donor tracheas. METHODS: Two experiments were performed with heterotopic transplantation models in 14 guinea pigs and 85 rats. So that the minimal dose of FK506 for viable fresh xenografts could be determined, FK506 was given in escalating doses (0, 1.5, 2.5, and 3.5 mg/kg) for recipient animals after xenogeneic transplantation. With the goal of obtaining a long-term survival of the xenografts, the effect of cryopreservation on xenografts was assessed and thereafter different cycles of immunosuppression every third week were evaluated in fresh or cryopreserved xenografts in the second experiment. RESULTS: An FK506 dosage of more than 2.5 mg/kg per day was much more effective than smaller dosages, as demonstrated by morphologic assessment. A higher dosage of FK506 potentially delayed the rejection of xenografts and can thus maintain tracheal xenograft viability for less than 4 weeks in rat recipients. In experiment 2, the cryopreserved xenografts showed less histologic viability than fresh xenografts but greater patency of the lumen. The patency of cryopreserved xenografts was favorably maintained for a longer period than that of fresh xenografts with either the same number or more cycles of immunosuppression. CONCLUSIONS: We conclude that the synergistic effect of cryopreservation and adequate intermittent immunosuppression may enable tracheal xenografts to remain viable over longer periods.

Short-course immunosuppression using FK506 for rat tracheal allografts.

BACKGROUND: A minimizing immunosuppression after a tracheal allotransplantation is desirable. METHODS: We examined the usefulness of a short-course of immunosuppression after tracheal allotransplantation in rat. Each transplant consisting of a 5-ring segment was heterotopically implanted into the omentum. Four animals underwent a syngeneic transplantation and thus served as controls (Group A). Thirty animals underwent an allogeneic transplantation and were randomly classified into 4 groups as follows: No immunosuppression (Group B, n=6), treatment with 0.5 mg/kg of Tacrolims (FK506) (Group C, n=8), 1.0 mg/kg of FK506 (Group D, n=8), and 1.5 mg/kg of FK506 (Group E, n=8). Different doses of FK506 were administered intramuscularly for only three consecutive days after heterotopic tracheal allotransplantation. The serum levels of FK506 were then investigated 3, 7, 14, 21, and 28 days after transplantation in groups C, D, and E. All rats were killed 28 days after transplantation and then the implanted tracheae were harvested, and evaluated histologically. RESULTS: All animals survived for the protocol period. The graft morphology of Group E was significantly better than that of groups B, C, and D regarding both macro- and microscopy, and also showed the same findings as that of Group A, except for low-grade mononuclear cell infiltration. Only in Group E, the FK506 blood level was maintained at over 0.5 ng/ml, which is the lowest detectable limit in this assay, until 21 days after transplantation. CONCLUSIONS: We thus conclude that 1.5 mg/kg of FK506 which was administered for only three consecutive days after surgery may be used to maintain the morphology of tracheal allografts in rats for 28 days after transplantation.

Limit of warm ischemia time before cryopreservation in rat tracheal isografts.

BACKGROUND: The viability of cadaveric tracheal grafts undergoing cryopreservation is still unclear. We evaluated the limit of warm ischemia time before cryopreservation in rat tracheal isografts. METHODS: Each isograft was harvested from donor rats 0 to 48 hours (0, 6, 12, 18, 24, and 48 hours) after circulatory arrest, immersed in the preservative solution, and stored in a deep freezer until reaching -80 degrees C and then was kept in liquid nitrogen for 3 months. Heterotopic transplantation into the omentum was performed after the isografts were thawed. Graft morphology 3 months after transplantation was assessed. RESULTS: The stepwise increase of warm ischemia time significantly reduced graft survival. A prolonged period of warm ischemia had a degenerative effect on both the epithelium and cartilage. The morphology of the epithelium and cartilage in isografts undergoing warm ischemia for less than 18 hours was better preserved, whereas it deteriorated in isografts undergoing warm ischemia for more than 24 hours. CONCLUSIONS: We thus conclude that the permissible period of warm ischemia before 3-month cryopreservation to maintain tracheal isograft viability is 18 hours in rats.

Maximal period of cryopreservation with the Bicell biofreezing vessel for rat tracheal isografts.

OBJECTIVE: The maximal period of cryopreservation for the trachea is still unsolved. We assessed the maximal period of cryopreservation using the Bicell biofreezing vessel as an easy and cheap slow-freezing instrument for viable tracheal grafts in 95 rats. METHODS: Each isograft was harvested from 17 donor rats, immersed in the preservative solution, and stored in a Bicell device in a deep freezer at -80 degrees C. The tracheal isografts were then randomly assigned to 9 groups according to cryopreservation periods ranging from 0 to 12 months. Included in the 9 groups were 2 subgroups (n = 6 per subgroup) that were observed immediately after being thawed and 1 month after heterotopic transplantation into the omentum after being thawed. Four subgroups (n = 6 per subgroup) were added according to the cryopreservation period for 1, 3, 6, and 12 months to evaluate the graft morphology 3 months after being thawed and transplanted heterotopically. RESULTS: A prolonged period of cryopreservation had a degenerative effect on both the epithelium and cartilage. One month after transplantation, degeneration was more pronounced in the cartilage than in the epithelium, as characterized by the viable chondrocyte ratio and the epithelial score of isografts undergoing cryopreservation for more than 9 months. Three months after transplantation, the morphology of the epithelium and cartilage in isografts undergoing cryopreservation for less than 3 months was better preserved, whereas the morphology of both deteriorated in isografts undergoing cryopreservation for more than 6 months. CONCLUSIONS: We conclude that the permissible period of cryopreservation to maintain tracheal isograft viability in this simple system using a Bicell biofreezing vessel is 3 months.

Effect of coronary bypass grafting onto the site of old myocardial infarction and the recovery of cardiac function.

This study investigated whether or not revascularization to the site of old myocardial infarction can bring beneficial effects on postoperative cardiac function. Thirty-two patients without a history of old myocardial infarction and 71 with a history of old myocardial infarction were included. The mean number of grafts bypassed were 2.7 and 2.8, and the mean duration of aortic clamping was 99 min and 105 min in non-old myocardial infarction and old myocardial infarction patients, respectively. All the patients underwent simple coronary artery bypass grafting electively. The left ventricular stroke work index in non-old myocardial infarction and old myocardial infarction were 40.8 g-m/m2 and 38.9 g-m/m2 preoperatively, and this was recovered to 41.4 g-m/m2 and 38.7 g-m/m2, respectively, at 24 hours after reperfusion (NS). Subgroups of old myocardial infarctions had high ejection fractions of more than 50% (49) and low ejection fractions of less than 50% (22). The left ventricular stroke work index in high and low ejection fractions was 39.7 g-m/m2 and 36.7 g-m/m2 preoperatively (NS). Recovery rates in both high and low ejection fractions were reduced to 74.2% and 84.3% at 3 h after reperfusion (P < 0.001 and P < 0.05 versus preoperative value), but were increased in the low ejection fraction by up to 102.7% and 108.5% at 6 and 12 h after reperfusion, while still remaining reduced in the high ejection fraction at 88.8% and 88.2%, respectively (P < 0.01). At 24 h after reperfusion, left ventricular stroke work index in the low ejection fraction was improved to 44.3 g-m/m2 or 130% of the preoperative value, and the high ejection fraction was 37.5 g-m/m2 or 100% (NS). This showed that a chief cause of reduced cardiac function in the low ejection fraction was mainly reversible myocardial damage or hibernation. Preoperative mean left ventricular ejection fractions in non-old myocardial infarctions and old myocardial infarctions were 73.1% and 55.9%, and these returned to 73.7% (NS) and 61.8% (P < 0.001) at 1 month post-coronary artery bypass grafting. A similar trend towards a significant improvement was shown in both end-diastolic volume indices and end-systolic volume indices of patients with an old myocardial infarction (P < 0.001). Regional wall motion according to AHA classification in patients with old myocardial infarctions was estimated from biplane left ventriculogram as normal, reduced, none, dyskinetic and aneurysmal, and scored as 0, 1, 2, 3 and 4, respectively. Summated scores in old myocardial infarctions was improved from 5.2 to 4.1 after coronary artery bypass grafting (P < 0.05). There was a significant improvement of summated scores from 8.17 to 6.28 in the low ejection fraction (P < 0.05); however, this was not reflected in the high ejection fraction (3.76 to 3.0; NS). The regional wall motion in the old myocardial infarctions that were heart bypassed to the left anterior ascending artery (n = 67) or to the circumflex artery (n = 40) were significantly improved at regions 2 (P < 0.05), 3 (P < 0.05) and 7 (P < 0.05), and that bypassed to right coronary artery (n = 50) was also improved at regions 3 (P < 0.05), 5 (P < 0.05) and 7 (P < 0.001). This shows that augmentation of regional blood flow by coronary artery bypass grafting will contribute to awakening the hibernated myocardium even in the old myocardial infarction.

Can positive affect items be used to assess depressive disorders in the Japanese population?

BACKGROUND: The purpose of the present study was to examine the measurement properties of positive affect items among the Japanese population. METHODS: Responses to the Japanese version of the Center for Epidemiologic Studies Depression Scale and four additional negatively revised items of the original positive affect items were compared for 85 Japanese psychiatric out-patients with dysphoric-mood-related symptoms and 255 demographically matched controls. RESULTS: Responses to positive affect items were generally comparable between the two groups, whereas responses to negative symptom items were markedly different (P < 0.002 for all comparisons). The group difference was most marked for symptom persistence. Responses to the four negatively revised items of positive affect revealed a similar picture to that of the negative symptom items. The internal consistency of the scale significantly improved when the original positive affect items were replaced by the negatively revised items (P < 0.001 for both). CONCLUSIONS: Positive affect items with positive wording cannot be used to assess depressive disorders in the Japanese population adequately, but this can be done with the corresponding negatively revised items.

Fractionated dosing of cyclophosphamide for establishing long-lasting skin allograft survival, stable mixed chimerism, and intrathymic clonal deletion in mice primed with allogeneic spleen cells.

BACKGROUND: Injection of allo-spleen cells (SC) followed by a single dose of cyclophosphamide (CP) can induce tolerance of tumor and/or skin allografts in mice. To minimize the damage caused by CP, fractionation of CP that can establish long-lasting skin graft survival, stable mixed chimerism, and intrathymic clonal deletion in the host was investigated in the present study. METHODS: Allo-SC (10(8)) were given intravenously on day 0. CP at 200 mg/kg was given intraperitoneally on day 2 in a single dose (CP 200x1 group). CP at 100, 66, 50, 40, and 33 mg/kg was given daily from day 1 through days 2, 3, 4, 5 and 6, respectively, in the fractionated doses (CP 100x2, 66x3, 50x4, 40x5, and 33x6 groups; total dose=200 mg/kg). Allografting was performed on day 14. RESULTS: In a fully allogeneic combination of C57BL/6 (H2b)-->AKR (H2k, Mls-1a), an EL-4 tumor (H2b) was specifically accepted to kill the AKR mice in all of the SC+CP 200x1, 100x2, 66x3, 50x4, 40x5, and 33x6 groups (n=6), but C57BL/6 skin graft survival was not prolonged in any of the tumor-tolerant groups. In an H2-identical combination of AKR-->C3H (H2k, Mls-1b), AKR skin graft survival was prolonged remarkably (80-90 days) in the SC+CP 200x1, 100x2, and 66x3 groups (n=5-11), but was prolonged moderately (20-60 days) in the SC+CP 50x4 and 40x5 groups. In both of the SC+CP 200x1 and 66x3 groups in the AKR-->C3H combination, mixed chimerism was maintained for as long as 100 days after tolerance induction in both the spleen and thymus, associated with intrathymic clonal deletion of Vbeta6+ T cells. The decreases in leukocyte count, hemoglobin level, spleen weight, SC count, and body weight were significantly smaller in the SC+CP 66x3 group than in the SC+CP 200x1 group. CONCLUSIONS: Fractionated CP is effective in ameliorating the compromised state induced by a single dose of CP. To induce a long-lasting skin allograft survival associated with stable mixed chimerism and intrathymic clonal deletion in an H2-identical combination, 200 mg/kg of CP can be divided into three or fewer fractions.

Regulatory T cells in maintenance and reversal of peripheral tolerance in vivo.

Whether regulatory T cells could suppress the immune responses to an unrelated Ag and could induce tolerance to that Ag was investigated. In female B6 (I-Ab) mice tolerized to MHC class II I-Abm12 (bm12) alloantigen by cyclophosphamide-induced system, regulatory T cells specific for bm12 Ag were induced. These regulatory T cells suppressed in vivo immune responses to an unrelated Ag (male Ag) that was co-expressed with bm12 Ag on the same graft. However, the immune responses to male Ag suppressed by regulatory T cells were reverted by immunization with male Ag alone, indicating regulatory T cells suppressed the induction of immune responses to the unrelated Ag co-expressed with suppressogenic determinant, but did not inactivate T cells specific for that third Ag, such as clonal anergy or deletion. These results provided that minor Ag adjacent to major Ag, even if they were expressed on the professional APC, could be suppressed in the periphery, and the responses to those minor Ag could be activated when the suppression mechanism was abrogated or ineffective.

Cyclophosphamide-induced immunological tolerance: an overview.

A cyclophosphamide (CP)-induced tolerance system in mice that primarily consists of donor cell injection followed by CP-treatment was found useful for inducing a long-lasting allo- or xeno-tolerance to various solid organs. In the cells-followed-by-CP system, the sequential mechanisms of tolerance were clarified using the specific correlation between superantigens and certain T cell receptor (TCR) V beta segments. Those include the clonal destruction of antigen-stimulated mature T cells, the peripheral clonal deletion associated with peripheral chimerism, the intrathymic clonal deletion associated with intrathymic chimerism, and the clonal anergy. The generation of suppressor T cells was another important mechanism of tolerance in the late stage. Special care was taken to overcome the " hard" barriers of allo- or xeno-combinations by reducing the "split tolerance" produced through the clonal destruction mechanism. For this purpose, the tolerogen, antimitotic drugs, their doses, timing, route of administration, combined immunosuppressants, and supportive treatment were all crucial for successful induction of a long-lasting skin tolerance. This system may be applicable to human transplantation.

Thymus ontogeny and the development of TCR alpha beta intestinal intraepithelial lymphocytes.

Murine T cell receptor (TCR) alpha beta intestinal intraepithelial lymphocytes (IEL), which express the CD8 molecule as a homodimer (CD8 alpha alpha), can be divided into two subsets: those which are CD4+ (CD4+CD8+alpha alpha) and those which are CD4- (CD4-CD8+alpha alpha). Here, we demonstrate that most TCR alpha beta CD4+CD8+alpha alpha IEL and TCR alpha beta CD4-CD8+alpha alpha IEL subsets appear to be of thymus origin, as neonatal thymectomy of BALB/c mice on Day 3 nearly eliminated both subsets. To further support this hypothesis, we demonstrate by grafting the thymus of CBF1 (BALB/c x C57BL/6) mice into nude mice that the thymus is capable of generating both TCR alpha beta CD4-CD8+alpha alpha IEL and TCR alpha beta CD4+CD8+alpha alpha IEL. However, which of the two TCR alpha beta IEL subsets is generated depends largely on the age of the thymus. The thymus from fetal up to 2 weeks of age generates predominantly TCR alpha beta CD4-CD8+alpha alpha IEL, but very scant amounts CD4+CD8+alpha alpha IEL. In contrast, the thymus after 2 weeks of age generates very little TCR alpha beta CD4-CD8+alpha alpha IEL, but generates an abundant amount of TCR alpha beta CD4+CD8+alpha alpha IEL. These results are consistent with the observation in euthymic mice that TCR alpha beta CD4-CD8+alpha alpha IEL precede the appearance of TCR alpha beta CD4+CD8+alpha alpha IEL by several weeks, thus further suggesting that the thymus is the major source of both TCR alpha beta IEL subsets.

Sensitization of T-cell receptor-alpha beta+ T cells recovered from long-term T-cell receptor downmodulation.

Although the survival of fully allogeneic skin grafts was prominently prolonged by adult thymectomy in anti-T-cell receptor-alpha beta monoclonal antibody (TCR-alpha beta mAb)-treated mice compared with that of non-adult thymectomized (ATX) mice, the skin allografts were eventually rejected. In the anti-TCR-alpha beta mAb-treated ATX mice, as shown in the present study, most of TCR-alpha beta+ cells were promptly activated on day 2 and then rapidly disappeared by day 7, but some TCR-alpha beta- Thy-1+ cells remained at that time. These TCR-alpha beta- Thy-1+ cells which have downmodulated their TCR-alpha beta expression may be refractory to depletion events by the mAb treatment. Although these downmodulated T cells re-expressed their TCR-alpha beta on day 50, they could not respond to stimuli via TCR such as TCR cross-linking or alloantigens. However, they recovered the reactivity to donor antigens on day 85. These results indicate that the downmodulated T cells by anti-TCR-alpha beta mAb treatment are long-lived and re-express their TCR-alpha beta at a late stage to be sensitized to donor antigen, which suggests that additional regimens may be required to get permanent, or very long-term, graft acceptance.

Anti-CD4 monoclonal antibody reduces the dose of cyclophosphamide required to induce tolerance to H-2 haplotype identical skin allografts in mice.

Cyclophosphamide (CP)-induced tolerance which consists of a single i.p. injection of 200 mg/kg CP 2 days after priming with 1 x 10(8) donor spleen cells (SC), leads to long-lasting donor-specific skin allograft tolerance in H-2 compatible, multiminor antigen incompatible, murine strain combinations. In this system, the optimal dose of CP has been suggested to be 200 mg/kg, however, such a dose of CP causes strong myelosuppression. In the present study, we therefore attempted to reduce the dose of CP by administering anti-CD4 monoclonal antibody (mAb) before donor cell priming in this tolerance-inducing system. When C3H/He (C3H; H-2k, Mls-1b) mice were injected i.p. with 200 micrograms anti-CD4 mAb on day -3, 1 x 10(8) AKR/J (AKR; H-2k, Mls-1a) SC plus 3 x 10(7) bone marrow cells (BMC) i.v. on day -2 and then 100 mg/kg CP i.p. on day 0, a long-lasting donor-specific skin allograft tolerance was established; furthermore, the decreases in the number of leukocytes and the concentration of hemoglobin (Hb) in the peripheral blood were all less in the C3H mice treated with this new combined protocol than in the C3H mice injected with 200 mg/kg CP following the previous protocol. In the periphery of these tolerant mice, the number of donor-reactive V beta 6+CD4+ T cells decreased and mixed chimerism was observed on both days 14 and 80. On the other hand, in the mice injected with AKR SC, BMC plus 100 mg/kg CP without anti-CD4 mAb, the number of V beta 6+CD4+ T cells decreased on day 14, and then recovered by day 80 when the mixed chimerism disappeared. These results therefore suggest that the combined use of anti-CD4 mAb with CP can reduce the dose of CP without affecting the efficiency of inducing donor-specific tolerance, probably due to the enhancement of the destruction effect of donor-reactive T cells by CP.

Donor-specific prolongation of rat skin graft survival induced by rat-donor cells and cyclophosphamide under coadministration of monoclonal antibodies against T cell receptor alpha beta and natural killer cells in mice.

Because of the recent interest in human xenotransplantation, we investigated the possibility of inducing tolerance in a xenogeneic combination using cyclophosphamide (CP). Donor-specific prolongation of xenogeneic Fisher 344 (F344) rat skin graft survival for up to 60 days was induced in C57BL/6 (B6) mice by giving F344 bone marrow cells and spleen cells on day 0, CP on day 2, and monoclonal antibodies against murine TCR-alpha beta and NK1.1 on days--1 and 3. The inoculation of the xenogeneic cells brought accelerated repopulation of TCR-alpha beta+ T cells, even under the administration of anti-TCR-alpha beta mAb. The quick increase of the host TCR-alpha beta+ T cells caused by the xenogeneic cell injection was deeply suppressed by CP. Mixed lymphocyte reaction, CTL activity, and antibody production against donor F344 were profoundly suppressed for 50 days. Mixed xenogeneic chimerism was observed for 1 month after the inoculation of donor cells in the spleen and peripheral blood of the recipient B6 mice, but was never observed in the thymus. Moreover, when irradiated F344 cells were used in place of viable cells, chimerism was never detected and graft survival was only slightly prolonged. Clonal deletion of V beta 5- or V beta 11-bearing murine T cells was not observed on day 50 in the thymus or spleen of the recipient B6 mice. These results suggest that treatment with viable xenogeneic donor cells, CP, and mAbs against T and NK cells can induce a temporary peripheral mixed chimerism and donor-specific prolongation of xenogeneic skin graft survival. The destruction with CP of T and B cells that are xenoreactive and thus proliferating after antigen stimulation, followed by mechanism other than intrathymic clonal deletion, may be the mechanism of the hyporesponsiveness in the present system.

Development of TCR-gamma delta CD4-CD8+ alpha alpha but not TCR-alpha beta CD4-CD8+ alpha alpha i-IEL is resistant to cyclosporin A.

Present evidence suggests that cyclosporin A (CSA) inhibits the development of both alpha beta and gamma delta T cells in the thymus. However, whether CSA can inhibit the development of murine intestinal intraepithelial lymphocytes (i-IEL) is unknown as most i-IEL are clearly derived from a different lineage than the conventional thymus-derived T cells found in the periphery. Using the adult thymectomized, lethally irradiated bone-marrow reconstituted chimera (ATXBM mice) as a model for the development of extrathymically derived i-IEL and the fetal thymus-grafted (FTG) nude mice as a model for the development of thymically derived i-IEL, we demonstrate that CSA nearly completely inhibited the development of extrathymically, and possibly thymically, derived TCR-alpha beta i-IEL. Most of the TCR-alpha beta i-IEL whose development was inhibited by CSA belonged to the CD4-CD8+ alpha alpha subset. In contrast, the development of extrathymically and thymically derived TCR-gamma delta i-IEL was completely resistant to CSA. The phenotype of CSA-resistant TCR-gamma delta i-IEL in these models was not different from those in control mice, and the TCR-gamma delta i-IEL in CSA-treated mice appear to be mature and activated as most were large, granular, and CD69+. Lastly, we demonstrate that CSA does not affect the extrathymic positive selection of V delta 4 i-IEL in C3H hosts. These results suggest that despite their similarity, the intracellular activation cascade involved after TCR stimulation between TCR-alpha beta CD4-CD8+ alpha alpha and TCR-gamma delta CD4-CD8+ alpha alpha i-IEL are markedly different.

Prevention of anti-T-cell receptor alpha beta monoclonal antibody-induced side-effects by treatment with cyclosporin A without interference of monoclonal antibody-induced immunosuppression in mice.

Anti-T-cell receptor (TCR)alpha beta monoclonal antibody (mAb; H57-597) injection in mice caused cytokine (tumour necrosis factor and interferon-gamma) release and clinical side-effects such as piloerection and body weight loss similar to anti-CD3 mAb (145-2C11) injection. Treatment with cyclosporin A (CsA) for 3 days, from day -2 to day 0, prior to anti-TCR alpha beta mAb injection almost completely abolished the mAb-induced cytokine release, and completely inhibited the mAb-induced body weight loss. Furthermore, treatment with CsA from day -2 to day 0 did not inhibit the mAb-induced in vivo immunosuppressive effects, i.e. prolongation of skin allograft and T-cell depletion in the periphery. These results indicate that CsA treatment prior to mAb treatment could effectively inhibit the mAb-induced side-effects without interference of the mAb-induced in vivo immunosuppression. From these results, we propose that CsA treatment prior to injection of anti-TCR alpha beta mAb may be recommended to reduce mAb-induced side-effects.

Natural killer cells inhibit the development of autoantibody production in (C57BL/6 x DBA/2) F1 hybrid mice injected with DBA/2 spleen cells.

We investigated the role of natural killer (NK) cells in the development of autoantibody production in which (C57BL/6 x DBA/2) F1 (BDF1) hybrid mice were injected intravenously with spleen cells (SC) from parental DBA/2 mice (treated BDF1 mice). Treated BDF1 mice began to show an increase in serum anti-dsDNA antibody 2 weeks after injection, while the NK activity of their SC transiently increased initially in the first 1 to 2 weeks after injection, but subsequently decreased dramatically. Flow cytometric analysis suggested that this sequential change in NK activity correlated with the absolute number of host-derived NK1.1+ cells in SC from treated BDF1 mice. We demonstrated that the level of anti-dsDNA in serum is directly influenced by the level of NK activity in treated BDF1 mice. Depletion of NK cells by administration of anti-NK1.1 mAb accelerated the development of autoantibody production, whereas augmentation of NK activity by administration of poly-(I:C) inhibited the development of autoantibody production. This inhibitory effect of poly(I:C) was abolished by prior depletion of NK cells. Interestingly, suppression of autoantibody production was seen only when poly(I:C) was administrated within 1 week after injection of parental SC. Last, we demonstrate that adoptive transfer of interleukin-2 (IL-2)-activated NK cells had a protective effect against the development of autoantibody production. These findings imply that NK cells may have a protective role in lupus-like disease especially in its early stage. In addition, it opens up the possibility that adoptive immunotherapy with IL-2-activated NK cells can delay or even prevent the development of autoimmune disease.

Tolerance induction in a fully allogeneic combination using anti-T cell receptor-alpha beta monoclonal antibody, low dose irradiation, and donor bone marrow transfusion.

In a murine strain combination disparate in both H-2 antigens and minor histocompatibility antigens consisting of C57BL/6 (B6; H-2b, Mls-1b) mice as recipients and AKR/J (AKR; H-2k, Mls-1a) mice as donors, we reported that the administration of anti-TCR-alpha beta mAb nonspecifically suppresses the ability to reject allografts. However, such an effect was only temporary and all grafts were eventually rejected within 40 days in the anti-TCR-alpha beta mAb-treated mice. In this study, to induce donor-specific tolerance, the transfer of donor bone marrow cells was added to the administration of anti-TCR-alpha beta mAb but donor bone marrow cells were rejected and failed to cause donor-specific unresponsiveness. After donor bone marrow cell transfer in the anti-TCR-alpha beta mAb-treated mice, the B cells of the recipients were observed along with the production of antidonor antibody. To abolish the residual lymphocyte populations, low dose irradiation was also added. A long-lasting skin allograft tolerance can be achieved by the tolerance system, in which low dose irradiation was added to the combined treatment with anti-TCR-alpha beta mAb and transfer of donor bone marrow cells. Such a protocol also established central and peripheral chimerism, which suggests that hematopoietic chimerism is necessary to maintain the tolerance. B cells were completely abolished in recipients given this combined treatment and their antibody production against donor antigens after the transfer of donor bone marrow cells was also completely suppressed. A possible role of B cells in the rejection of donor bone marrow cells before the establishment of chimerism is discussed.

[Effects of open-heart surgery on renal function in patients with chronic renal failure--is hemodialysis during cardiopulmonary bypass really required?].

In 300 consecutive adult patients who underwent open-heart surgery in our department, 16 patients (ischemic heart disease in 8 patients, valvular heart disease in 7 and congenital heart disease in 1) were preoperatively complicated with chronic renal failure (CRF); creatinine clearance (Ccr) < 40 ml/min and serum creatinine (Scr) > 1.6 mg/dl. The effects of open-heart surgery on renal function were studied in these CRF patients who were divided into the following 3 groups according to their preoperative Ccr values: Group 1 (6 patients), 30 < Ccr < 40 ml/min; Group 2 (5 patients), 20 < Ccr < 30 ml/min; and Group 3 (5 patients, 4 of whom were on dialysis preoperatively), Ccr < 10 ml/min. In addition, Group C (38 patients, Ccr > 50 ml/min) was set up as normal controls. Instead of hemodialysis, the extracorporeal ultrafiltration method (ECUM) was employed for all patients during the cardiopulmonary bypass (CPB). The Ccr in Group 1 showed the lowest value of 24.2 +/- 12.0 ml/min on postoperative day (POD) 0 which then recovered to the preoperative level on POD 1. This quick recovery of the Ccr in Group 1 was similar to that in Group C. In contrast, the Ccr in Group 2 showed the lowest value of 13.0 +/- 6.0 ml/min on POD 1, followed by a delayed recovery that did not reach the preoperative level until POD 5. The Ccr in Group 3 was quite low (< 5 ml/min) throughout the test period.(ABSTRACT TRUNCATED AT 250 WORDS)