Acquired Downregulation of Donor-Specific Antibody Production After ABO-Incompatible Kidney Transplantation.

The mechanism of long-term B cell immunity against donor blood group antigens in recipients who undergo ABO-incompatible (ABOi) living-donor kidney transplantation (LKTx) is unknown. To address this question, we evaluated serial anti-A and anti-B antibody titers in 50 adult recipients. Donor-specific antibody titers remained low (≤1:4) in 42 recipients (84%). However, antibodies against nondonor blood group antigens were continuously produced in recipients with blood type O. We stimulated recipients' peripheral blood mononuclear cells in vitro to investigate whether B cells produced antibodies against donor blood group antigens in the absence of graft adsorption in vivo. Antibodies in cell culture supernatant were measured using specific enzyme-linked immunosorbent assays (ELISAs). Thirty-five healthy volunteers and 57 recipients who underwent ABO-compatible LKTx served as controls. Antibody production in vitro against donor blood group antigens by cells from ABOi LKTx patients was lower than in the control groups. Immunoglobulin deposits were undetectable in biopsies of grafts of eight recipients with low antibody titers (≤1:4) after ABOi LKTx. One patient with blood type A1 who received a second ABOi LKTx from a type B donor did not produce B-specific antibodies. These findings suggest diminished donor-specific antibody production function in the setting of adult ABOi LKTx.

Tolerance of Vascularized Islet-Kidney Transplants in Rhesus Monkeys.

We previously reported that transplantation (Tx) of prevascularized donor islets as composite islet-kidneys (IK) reversed diabetic hyperglycemia in both miniature swine and baboons. In order to enhance this strategy's potential clinical applicability, we have now combined this approach with hematopoietic stem cell (HSC) Tx in an attempt to induce tolerance in nonhuman primates. IKs were prepared by isolating islets from 70% partial pancreatectomies and injecting them beneath the autologous renal capsule of five rhesus monkey donors at least 3 months before allogeneic IK Tx. HSC Tx was performed after mobilization and leukapheresis of the donors and conditioning of the recipients with total body irradiation, T cell depletion, and cyclosporine. One IK was harvested for histologic analysis and four were transplanted into diabetic recipients. IK Tx was performed either 20-22 (n = 3) or 208 (n = 1) days after HSC Tx. All animals accepted IKs without rejection. All recipients required >20 U/day insulin before IK Tx to maintain <200 mg/dL, whereas after IK Tx, three animals required minimal doses of insulin (1-3 U/day) and one animal was insulin free. These results constitute a proof-of-principle that this IK tolerance strategy may provide a cure for both end-stage renal disease and diabetes without the need for immunosuppression.

Adoptive Transfer of Renal Allograft Tolerance in a Large Animal Model.

Our recent studies in an inbred swine model demonstrated that both peripheral and intra-graft regulatory cells were required for the adoptive transfer of tolerance to a second, naïve donor-matched kidney. Here, we have asked whether both peripheral and intra-graft regulatory elements are required for adoptive transfer of tolerance when only a long-term tolerant (LTT) kidney is transplanted. Nine highly-inbred swine underwent a tolerance-inducing regimen to prepare LTT kidney grafts which were then transplanted to histocompatible recipients, with or without the peripheral cell populations required for adoptive transfer of tolerance to a naïve kidney. In contrast to our previous studies, tolerance of the LTT kidney transplants alone was achieved without transfer of additional peripheral cells and without strategies to increase the number/potency of regulatory T cells in the donor. This tolerance was systemic, since most subsequent, donor-matched challenge kidney grafts were accepted. These results confirm the presence of a potent tolerance-inducing and/or tolerance-maintaining cell population within LTT renal allografts. They suggest further that additional peripheral tolerance mechanisms, required for adoptive transfer of tolerance to a naïve donor-matched kidney, depend on peripheral cells that, if not transferred with the LTT kidney, require time to develop in the adoptive host.

Role of Bone Marrow Maturity, Insulin-Like Growth Factor 1 Receptor, and Forkhead Box Protein N1 in Thymic Involution and Rejuvenation.

Thymic involution is associated with age-related changes of the immune system. Utilizing our innovative technique of transplantation of a thymus as an isolated vascularized graft in MHC-inbred miniature swine, we have previously demonstrated that aged thymi are rejuvenated after transplantation into juvenile swine. Here we have studied the role of insulin-like growth factor (IGF) and forkhead-box protein-N1 (FOXN1) as well as bone marrow (BM) in thymic rejuvenation and involution. We examined thymic rejuvenation and involution by means of histology and flow cytometry. Thymic function was assessed by the ability to induce tolerance of allogeneic kidneys. Aged thymi were rejuvenated in a juvenile environment, and successfully induced organ tolerance, while juvenile thymi in aged recipients involuted and had a limited ability to induce tolerance. However, juvenile BM inhibited the involution process of juvenile thymi in aged recipients. An elevated expression of both FOXN1 and IGF1 receptors (IGF-1R) was observed in juvenile thymi and rejuvenated thymi. Juvenile BM plays a role in promoting the local thymic milieu as indicated by its ability to inhibit thymic involution in aged animals. The expression of FOXN1 and IGF-1R was noted to increase under conditions that stimulated rejuvenation, suggesting that these factors are involved in thymic recovery.

High incidence of xenogenic bone marrow engraftment in pig-to-baboon intra-bone bone marrow transplantation.

Previous attempts of α-1,3-galactocyltransferase knockout (GalTKO) pig bone marrow (BM) transplantation (Tx) into baboons have demonstrated a loss of macro-chimerism within 24 h in most cases. In order to achieve improved engraftment with persistence of peripheral chimerism, we have developed a new strategy of intra-bone BM (IBBM) Tx. Six baboons received GalTKO BM cells, with one-half of the cells transplanted into the bilateral tibiae directly and the remaining cells injected intravenously (IBBM/BM-Tx) with a conditioning immunosuppressive regimen. In order to assess immune responses induced by the combined IBBM/BM-Tx, three recipients received donor SLA-matched GalTKO kidneys in the peri-operative period of IBBM/BM-Tx (Group 1), and the others received kidneys 2 months after IBBM/BM-Tx (Group 2). Peripheral macro-chimerism was continuously detectable for up to 13 days (mean 7.7 days; range 3-13) post-IBBM/BM-Tx and in three animals, macro-chimerism reappeared at days 10, 14 and 21. Pig CFUs, indicating porcine progenitor cell engraftment, were detected in the host BM in four of six recipients on days 14, 15, 19 and 28. In addition, anti-pig unresponsiveness was observed by in vitro assays. GalTKO/pCMV-kidneys survived for extended periods (47 and 60 days). This strategy may provide a potent adjunct for inducing xenogeneic tolerance through BM-Tx.

The induction of tolerance of renal allografts by adoptive transfer in miniature swine.

Our previous in vitro data have demonstrated that regulatory mechanisms are involved in tolerance of class I-mismatched renal allografts in miniature swine treated with 12 days of high dose Cyclsporin A. In this study, we attempted to induce tolerance of class I-mismatched kidneys by adoptive transfer of cells and/or kidneys from long-term tolerant animals. Fifteen SLA(dd) miniature swine received 1.5 Gy whole body irradiation and class I-mismatched (SLA(gg) ) kidneys from naïve pigs with or without cotransplanted kidneys and/or adoptively transferred cells from long-term tolerant (LTT) SLA(dd) recipients of SLA(gg) grafts. In addition, three SLA(dd) miniature swine received class I mismatched kidney with adoptively transferred cells from LTT SLA(dd) recipients. Naïve kidneys transplanted without a LTT kidney were rejected within 9 days. All recipients of naive kidneys along with cells and kidney grafts from LTT animals showed markedly prolonged survival of the naive renal grafts (day 28, >150 and >150 days). These studies suggest that (1) tolerated kidneys have potent regulatory effects and (2) cells from LTT animals infused in conjunction with kidney grafts augment these regulatory effects. To our knowledge, these studies represent the first demonstration of successful adoptive transfer of tolerance in large animals.

Induction of cardiac allograft tolerance across a full MHC barrier in miniature swine by donor kidney cotransplantation.

We have previously shown that tolerance of kidney allografts across a full major histocompatibility complex (MHC) barrier can be induced in miniature swine by a 12-day course of high-dose tacrolimus. However, that treatment did not prolong survival of heart allografts across the same barrier. We have now tested the effect of cotransplanting an allogeneic heart and kidney from the same MHC-mismatched donor using the same treatment regimen. Heart allografts (n = 3) or heart plus kidney allografts (n = 5) were transplanted into MHC-mismatched recipients treated with high-dose tacrolimus for 12 days. As expected, all isolated heart allografts rejected by postoperative day 40. In contrast, heart and kidney allografts survived for >200 days with no evidence of rejection on serial cardiac biopsies. Heart/kidney recipients lost donor-specific responsiveness in cell-mediated lympholysis and mixed-lymphocyte reaction assays, were free of alloantibody and exhibited prolonged survival of donor, but not third-party skin grafts. Late (>100 days) removal of the kidney allografts did not cause acute rejection of the heart allografts (n = 2) and did not abrogate donor-specific unresponsiveness in vitro. While kidney-induced cardiac allograft tolerance (KICAT) has previously been demonstrated across a Class I disparity, these data demonstrate that this phenomenon can also be observed across the more clinically relevant full MHC mismatch. Elucidating the renal element(s) responsible for KICAT could provide mechanistic information relevant to the induction of tolerance in recipients of isolated heart allografts as well as other tolerance-resistant organs.

ALKBH3, a human AlkB homologue, contributes to cell survival in human non-small-cell lung cancer.

BACKGROUND: We have demonstrated for the first time that a novel human AlkB homologue, ALKBH3, contributes to prostate cancer development, but its clinical and biological roles in lung cancer remain unclear. METHODS: Expression of both mRNA and protein of PCA-1 was examined by RT-PCR and western blotting. We also assessed association with senescence and in vivo ALKBH3 treatment on orthotopic tumour cell inoculation, and analysed it clinicopathologically. RESULTS: We have since found novel biological roles for ALKBH3 in human lung cancers, particularly in adenocarcinoma. Our immunohistochemical analysis of human adenocarcinomas and squamous cell carcinomas of the lung not only showed overexpression of ALKBH3 in these tumours but the percentage of cells positive for ALKBH3 also correlated statistically to recurrence-free survival in adenocarcinoma. Knockdown of ALKBH3 by siRNA transfection induced expression of p21(WAF1/Cip1) and p27(Kip1) in the human lung adenocarcinoma cell line A549, resulting in cell cycle arrest, senescence and strong suppression of cell growth in vitro. In vivo, peritoneal tumour growth and dissemination was inhibited in nude mice, previously inoculated with the A549 cell line, by intraperitoneal injection of ALKBH3 siRNA + atelocollagen, as demonstrated by the reduction in both number and diameter of tumours developing in the peritoneum. CONCLUSION: We suggest that ALKBH3 contributes significantly to cancer cell survival and may be a therapeutic target for human adenocarcinoma of the lung.

Correlation between the pharmacological efficacy of cyclosporine and tacrolimus as evaluated by the lymphocyte immunosuppressant sensitivity test (LIST) and the MTT assay procedure in patients before and after renal transplantation.

OBJECTIVES: Cyclosporine and tacrolimus are calcineurin inhibitors that are used to prevent acute rejection in renal transplant recipients. The lymphocyte immunosuppressant sensitivity test (LIST) can predict the pharmacological efficacy of these immunosuppressive agents for renal transplant recipients. There is a correlation between cyclosporine and tacrolimus pharmacological efficacy as evaluated by LIST by the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay procedure prior to renal transplantation. However, the LIST can also evaluate patients before and after the transplantation. MATERIALS AND METHODS: The present study examined the relationship between cyclosporine and tacrolimus pharmacological efficacy by LIST using the MTT assay in 16 renal transplant recipients at 1, 3 and 12 months after transplantation, as well as before the operation. RESULTS: The relationship of cyclosporine and tacrolimus pharmacological efficacy gave a significant Kendall and Spearman's coefficient correlation in these transplant recipients by the LIST using the MTT assay procedure immediately prior to renal transplantation (rk = 0.711, rs = 0.877, p < 0.01). Furthermore, correlations between the cyclosporine and tacrolimus IC50 values were also observed with a significant Kendall and Spearman's coefficient correlation at 1 and 12 months after transplantation (rk1month = 0.65, rs1month = 0.829, p < 0.01, and k12month = 0.433, rs12month = 0.603, p < 0.01, respectively). However, no statistically significant relationship was observed between the pharmacological efficacies of the calcineurin inhibitors at 3 months after transplantation (rk3month = 0.117, rs3month = 0.1, p > 0.05). CONCLUSIONS: Both cyclosporine and tacrolimus exhibit pharmacological efficacy by the inhibition of calcineurin. However, the correlation between cyclosporine and tacrolimus pharmacological efficacies may be altered, due to immunosuppressive therapy or clinical events at 3 months after renal transplantation.

Cyclosporine pharmacological efficacy estimated by lymphocyte immunosuppressant sensitivity test before and after renal transplantation.

OBJECTIVE: Lymphocyte immunosuppressant sensitivity test (LIST) is useful for predicting the pharmacological efficacy of immunosuppressive agents. In this study, the pharmacological efficacy of cyclosporine was estimated by LIST before and after renal transplantation. METHODS: Lymphocyte immunosuppressant sensitivity test was performed by the 3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide (MTT) assay before and at 1, 3, and 12 months after transplantation in 19 consecutive renal transplant recipients. RESULTS: There was wide intersubject variability in cyclosporine IC50 before transplantation [Mean (SD) of 593.9 (1067.6) ng/mL]. This variability worsened 1 month after transplantation [525.7 (1532.7) ng/mL] but decreased at 3 months (193.5 (347.9) ng/mL) and 12 months (75.4 (95.4) ng/mL). In this small study, observed differences in IC50 values for the individual subjects at various time intervals was not associated with the occurrence of rejection, graft loss, and infection episodes. CONCLUSION: Lymphocyte sensitivity to cyclosporine assessed by the LIST assay showed a high level of inter-subject variability particularly before and 1 month after transplantation. The observed difference in IC50 values was not associated with clinical outcome in this small study.

Low-Dose-Rate and High-Dose-Rate Brachytherapy for Localized Prostate Cancer in ABO-Incompatible Renal Transplant Recipients.

BACKGROUND: Brachytherapy is one of the standard treatments for localized prostate cancer (CaP). However, the feasibility of brachytherapy for renal transplant recipients (RTRs) is still uncertain. MATERIALS AND METHODS: Between August 2007 and March 2018, all patients who had undergone low-dose-rate (LDR) brachytherapy or high-dose-rate (HDR) brachytherapy for clinically localized CaP at our institution were retrospectively identified (n = 394). Of these patients, 3 had a history of renal transplantation. We reviewed all available clinical data retrospectively. RESULTS: All of the RTRs received ABO-incompatible renal grafts from their spouses and had stable renal graft function before the diagnosis of CaP. The median age at diagnosis of CaP was 65 years (range, 60-67 years). The median time between transplantation and brachytherapy was 7 years (range, 4-10 years). In all of the patients, clinical stage was cT1cN0M0. Two patients received 125I LDR-brachytherapy (dose, 145 Gy) and 1 patient was treated by 192Ir HDR brachytherapy (dose, 19 Gy in 2 fractions) combined with external beam radiation therapy of 39 Gy in 13 fractions. The median follow-up period after brachytherapy was 44 months (range, 34-50 months). During the follow-up period, none of the patients developed disease progression including biochemical recurrence or clinically significant adverse events associated with radiation therapy. CONCLUSIONS: LDR brachytherapy and HDR brachytherapy are safe and technically feasible in RTRs with CaP, and oncological outcomes in RTRs do not appear to be inferior to those of patients who did not receive renal transplant.

Safety assessment of ellagic acid, a food additive, in a subchronic toxicity study using F344 rats.

Ellagic acid is a phenolic acid compound, used as a food additive for its antioxidative properties. Because of its chemical characteristics, use is also to be expected in cosmetics. The present 90-day subchronic toxicity study was performed in F344 rats at dose levels of 0, 1.25, 2.5 and 5% in powdered basal diet, with actual doses of 9.4, 19.1, 39.1 g/kg b.w., respectively, in males, and 10.1, 20.1, 42.3 g/kg b.w. in females. No mortality or treatment-related clinical signs were observed throughout the experimental period. Body weight gain was significantly reduced from weeks 3 (5% group), 6 (2.5% group) and 7 (1.25% group) to the end of the experiment (except week 8 in the lowest group) in the treated females, the final body weights being decreased in the 5% (92.5%), 2.5% (94.2%) and 1.25% (94.8%) treated groups as compared to the control. Changes in MCV and serum AST, ALP, Ca, Cl and P were sporadically observed, but these were not considered to be treatment-related alterations. There were no obvious histopathological changes in any of the groups. The no-observed-effect level (NOEL) was estimated to be 5% (3011 mg/kg b.w./day) for males and the no-observed-adverse-effect level (NOAEL) and NOEL in females were estimated to be 5% (3254 mg/kg b.w./day) and <1.25% (778 mg/kg b.w./day), respectively.

Safety assessment of dietary administered paprika color in combined chronic toxicity and carcinogenicity studies using F344 rats.

Combined chronic toxicity and carcinogenicity studies of paprika color, used as a food additive in various countries, were performed in male and female F344 rats. Dietary concentrations of 0%, 0.62%, 1.25%, 2.5% and 5% were applied in a 52-week toxicity study and 0%, 2.5% and 5% in a 104-week carcinogenicity study. Treatment with paprika color caused a significant increase in incidence of hepatocellular vacuolation in 5% males, but no toxicological effects were found with reference to survival rates, body weights, hematological or serum biochemical parameters and organ weights at any dose level in either sex in the chronic toxicity study. Also, paprika color did not induce specific tumors nor did it exert significant influence on the development of spontaneous tumors in any of the organs examined in the carcinogenicity study. In conclusion, based on slight histopathological changes observed in 5% male livers, the no-observed-effect level (NOEL) was estimated to be 2.5% in the diet (1,253 mg/kg bw/day) and the no-observed-adverse-effect level (NOAEL) was determined to be 5% in the diet (2,388 mg/kg bw/day) for male rats, and for females, the NOEL was concluded to be 5% in the diet (2,826 mg/kg bw/day). Additionally, paprika color was not carcinogenic to male and female F344 rats under the present experimental conditions.

Management of Juvenile Idiopathic Arthritis in ABO-incompatible Kidney Transplantation: A Case Report.

Biologic agents are a beneficial therapy for juvenile idiopathic arthritis (JIA). However, there is a lack of evidence with regard to management of these agents for JIA patients who undergo kidney transplantation (KTx). A 36-year-old woman with JIA who was treated with tocilizumab targeting interleukin-6 (IL-6) receptor underwent ABO-incompatible kidney transplantation (ABOi KTx). To prevent over-immunosuppression, tocilizumab was discontinued before ABOi KTx. Rituximab, tacrolimus, mycophenolate mofetil, everolimus, and methylprednisolone were used for immunosuppression. Clinical remission of joint pain was maintained for over 3 years despite complete discontinuation of tocilizumab. Both serum IL-6 and soluble IL-6 receptor levels were markedly decreased, suggesting that multitargeted immunosuppression for ABOi KTx induced long-term clinical remission of JIA through inhibition of the IL-6 pathway. However, levels of C-reactive protein (CRP) and matrix metalloproteinase-3 (MMP-3) gradually increased thereafter and abatacept was initiated to prevent joint deterioration. These levels decreased without any adverse events. The patient's renal graft function was well maintained.

Ombitasvir-Paritaprevir-Ritonavir Therapy in a Kidney Transplant Recipient With Chronic Hepatitis C Virus Genotype 1 Infection: A Case Report on the Importance of Considering Drug-Drug Interactions and Monitoring Cyclosporine Levels.

A 74-year-old Japanese man with a history of chronic hepatitis C and kidney transplant (KT) was administered pegylated-interferon plus ribavirin therapy. However, this therapy was ineffective. The patient was then hospitalized to receive ombitasvir (OBV) plus paritaprevir (PTV) plus ritonavir (r) antiviral combination therapy. He tested negative for the virus after 4 weeks, and completed 12 weeks of treatment. The patient ultimately achieved a sustained virological response after the 12 weeks of treatment. Cyclosporine (CyA) trough levels, during the OBV-PTV-r therapy, reached a peak within 5 days of initiating therapy, and increases in serum creatinine and total bilirubin were also observed. However, onset of irreversible nephropathy and hepatopathy were avoided by reducing the CyA dosage. The OBV-PTV-r therapy demonstrated a sufficient antiviral effect and could be safely administered postoperatively to patients having undergone KT. When a combination therapy with interferon-free, direct-acting antivirals is used in patients post-transplantation, consideration of drug-drug interactions with and monitoring CyA are of vital importance.

Re-evaluating Cut-off Points for the Expansion of Deceased Donor Criteria for Kidney Transplantation in Japan.

BACKGROUND: A shortage of donors poses a serious problem for organ transplantation around the world. In response, the concept of the expanded criteria donor (ECD) has been defined to include donors with traditionally less favorable characteristics. That definition has now been accepted and is being applied in kidney transplantation in the United States and Europe. However, the ECD has not yet been defined for deceased donor kidney transplantation in Japan. PATIENTS AND METHODS: We analyzed data on graft survival and relevant risk factors in patients who received deceased donor kidney transplants through the East Japan Branch of the Japan Organ Transplant network (n = 1051). Recipients were divided into two groups: the standard-function group (estimated glomerular filtration rate [eGFR] ≥20 mL/min/1.73 m2; n = 906) and the poor-function group (eGFR <20 mL/min/1.73 m2; n = 145; Cox proportional hazards regression analysis; P < .0001). RESULTS: The 10-year survival rate was significantly lower in the poor-function group than in the standard-function group (85.5% vs 22.5%; P < .0001). The two groups differed significantly in recipient and donor risk for graft failure. Recipient risk factors were length of time on dialysis before renal transplantation and incidence of acute rejection after transplantation. Donor risk factors were donor category (heart death), age, history of hypertension, presence of cerebrovascular disease, mean urine output, and donor creatinine level immediately before donor nephrectomy, total ischemic time, and warm ischemic time. CONCLUSION: Data from deceased donor transplantation should be analyzed in depth to determine which factors influence renal function after transplantation. In addition, ECD standards should be reconsidered for use in a Japanese context.

Successful Second Allogeneic Stem Cell Transplantation From a Sibling Donor for Relapse of Myelodysplastic Syndrome in a Recipient of a Renal Transplant From His Mother: Case Report.

There have been few reports on allogeneic stem cell transplantation in patients who have previously undergone solid organ transplantation. The clinical course of such patients is not yet well recognized. Therefore, appropriate immunosuppressive prophylaxis for the rejection of a solid organ graft or for graft-versus-host disease has not yet been established. We present the case of a successful allogeneic stem cell transplantation in a patient who relapsed after a first allogeneic stem cell transplantation for myelodysplastic syndrome and who had previously undergone renal transplantation. The prophylaxis in this case for graft-versus-host disease and rejection of the transplanted kidney was mycophenolate mofetil and tacrolimus. No hyperacute rejection of the transplanted kidney was observed. However, the patient's renal function deteriorated after the cessation of the mycophenolate mofetil and the reduction of the tacrolimus. This deterioration seemed to be due to rejection with humoral immunity of donor lymphocytes, and we were able to control it by resuming the mycophenolate mofetil and local graft irradiation.

Plasma progesterone profiles and embryo quality in superovulated Japanese Black cattle.

The relationship between plasma progesterone (P(4)) levels before and after superovulation treatment and embryo yield and quality was examined in Japanese Black cattle. It is concluded that a plasma P(4) level at the start of follicle stimulating hormone (FSH) injections is related to embryo quality. The P(4) level of over 3.0 ng/ml appears to be useful in preselection of donors when we want to get more than 8 normal (transferable) embryos on the average.

Endocrine profiles and embryo quality in superovulated Japanese Black cattle.

The relationships between plasma concentrations of progesterone (P4), estradiol-17beta (E2) and lutenizing hormone (LH) and embryo yield and quality were examined in 40 superovulated Japanese Black cattle. The results indicated that the ovarian function, especially the function of corpus luteum on the first treatment day, is an important factor for reliable superovulation in cattle. The levels of plasma E2 and LH at estrus were related to embryo yield and quality.

Analyses of serum copper and zinc levels and copper/zinc ratios in skin diseases.

With the objective of comprehending abnormal metabolisms of the essential metals of zinc (Zn) and copper (Cu) in three groups of skin diseases, skin cancer, inflammatory diseases, and non-inflammatory disease, we measured serum levels of Zn and Cu in 151 cases of various cutaneous manifestations and estimated the significance of the ratios between the two metals (Cu/Zn). The serum level of Zn was significantly decreased in cases of bullous pemphigoid, decubitus ulcer, and alopecia areata. The serum level of Cu was elevated in cases of psoriasis, decubitus ulcer, and skin cancer. We observed no elevation of serum Zn level or abnormally depressed serum Cu level. The Cu/Zn ratio showed significantly different values among these three groups of the diseases, suggesting the utility of measuring Cu/Zn ratios for differential diagnosis over that of determining the serum level of Zn or Cu alone. It was also demonstrated that, in each skin disease, the Cu/Zn ratio clearly reflects the severity of the progress.