Level of Soluble CD30 After Kidney Transplantation Correlates With Acute Rejection Episodes J.L. Yang, H.J. Hao, B. Zhang, Y.X. Liu, S. Chen, and Y.Q. Na ABSTRACT Measurement of soluble CD30 (sCD30) levels may predict acute rejection episodes (ARE). To explore the value of sCD30 after transplantation, we tested serum sCD30 levels in 58 kidney transplant cases at 1 day before and 7 and 28 days after transplantation by enzyme-linked immunosorbent assay (ELISA). The incidences of ARE after kidney transplantation were recorded simultaneously. Meanwhile, 31 healthy individuals were selected as a control group. The results showed a relationship between sCD30 level in serum before kidney transplantation and the incidence of ARE. However, the relationship was more significant between serum sCD30 levels at day 7 after kidney transplantation and the incidence of ARE. There was no obvious relationship between serum sCD30 levels at day 28 after kidney transplantation and the incidence of ARE. These results suggested that the level of sCD30 at day 7 posttransplantation provides valuable data to predict ARE.
N ACUTE REJECTION EPISODE (ARE) is a frequent complication of renal transplantation as well as a predictor of late transplant failure. Irreversible damage caused by rejection could be relieved and even avoided by early diagnosis and treatment. Thus, it is important to find a sensitive, specific noninvasive method to predict ARE following renal transplantation. Panel-reactive antibodies (PRA) are generally accepted as indicators of immunological status of renal graft candidates and predictors of renal graft outcome.1 However, one major drawback to PRA is that patients with negative assays or low levels cannot be allocated to the high- or low-risk class to estimate immunological risk.2 Recent studies have suggested that high preand posttransplantation serum levels of soluble CD30 (sCD30) may be a risk indicator for ARE and graft loss.3,4 CD30, a member of the tumor necrosis factor receptor family, is a large 120-kDa transmembrane glycoprotein that was originally identified on the surface of Hodgkin’s and Reed-Sternberg cells.5 sCD30 is released into the bloodstream after activation of CD30⫹ T cells. sCD30 can be detected in the serum of most normal individuals. However, elevated serum sCD30 levels have been detected in patients with CD30⫹ hematopoietic malignancies, certain viral infections, and several autoimmune disorders.6 To provide more information to support sCD30 as a sensitive indicator of ARE after kidney transplantation, we detected serum sCD30 levels in renal graft candidates pre- and posttransplantation, and analyzed the relationship between sCD30 levels and ARE occurrence.
MATERIALS AND METHODS Fifty-eight patients who received renal transplantations from March 2001 to January 2004 were enrolled in this study. Among them, 28 were male and 30 female with an overall average age of 45.2 ⫾ 8.3 years. All patients were administered cyclosporine/ Prograf, mycophenolate mofefil/azathioprine, and prednisone, and showed PRA values ⱕ10%. Human leukocyte antigens of donors and recipients showed an incorrect matching rate of ⱕ3. Healthy blood donors (14 males and 17 females) were selected as controls with an average age of 40.3 ⫾ 4.2 years. Blood samples of patients were obtained at day 1 before transplantation and days 7 and 28 after transplantation. Separated serum was stored at ⫺70°C until being tested. ARE was diagnosed if the following symptoms occurred: sudden enuresis, increased blood pressure, pain in transplanted kidney and fever in clinic, with increased blood creatinine. sCD30 levels were detected by enzyme-linked immunosorbent assay (ELISA) using a kit from Bender Medsystems (Vienna, Austria) according to the manufacturer’s instructions. A value of sCD30 ⬎20 U/mL was considered positive according to our pilot study, which showed that the sCD30 level in healthy individuals was 14.84 ⫾ 4.58 U/mL. SPSS software package was used for analysis with values of P ⬍ .05 considered significant.
From the Department of Urology, Beijing Tongen Hospital, Affiliate of Capital University of Medical Sciences, Beijing, China. Address reprint requests to Jianlin Yang, MD, Beijing Tongen Hospital, Affiliate of Capital University of Medical Sciences, No. 1 Dongjiaominxiang St, Beijing 100730, China.
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0041-1345/08/$–see front matter doi:10.1016/j.transproceed.2008.06.093
Transplantation Proceedings, 40, 3381–3383 (2008)
YANG, HAO, ZHANG ET AL
Blood samples were collected from all transplant recipients at day 1 before as well as days 7 and 28 after transplantation. Separated were sera subjected to sCD30 level detection. As shown in Figure 1, sCD30 level in patients before transplantation was similar to that of healthy controls (14.46 ⫾ 4.46 vs 14.84 ⫾ 4.58 U/mL; P ⬎ .05). However, sCD30 level increased significantly at day 7 after transplantation (70.29 ⫾ 67.49 U/mL); the value was still significantly higher at day 28 after transplantation (22.52 ⫾ 3.73 U/mL) than that in pretransplant patients, indicating that sCD30 level increased significantly following kidney transplantation, although the patients had low sCD30 levels pretransplantation. Among 58 cases of kidney transplantation, 20 suffered ARE within 1 month after transplantation, and all ARE occurred 7 days after transplantation. Among them, 4 cases occurred on day 8, 3 on day 9, 3 on day 10, 3 on day 11, 3 on day 12, and 4 on day 13. As shown in Figure 2, the sCD30 level in 20 ARE cases was 17.48 ⫾ 6.35 U/mL at 1 day before transplantation, which was significantly higher than that of 38 non-ARE cases (14.29 ⫾ 4.87 U/mL; P ⬍ .05). However, the difference in sCD30 between ARE and non-ARE cases at day 7 posttransplantation was much more significant (106.99 ⫾ 68.08 vs 23.01 ⫾ 20.58 U/mL; P ⬍ .01), whereas there was no significant difference at day 28 posttransplantation (28.16 ⫾ 25.5 vs 13.5 ⫾ 2.12 U/mL; P ⬎ .05). These results suggested that sCD30 levels at day 7 posttransplantation were more valuable to predict ARE. If we consider sCD30 ⱖ 20 U/mL as positive, 18 of 33 cases (54.5%) with a positive sCD30 level at 7 day posttransplantation developed ARE, whereas only 2 of 25 cases (8.0%) with a negative sCD30 level developed ARE (Fig 3).
Fig 1. sCD30 levels in healthy controls (HC) and in transplant recipients at day 1 before as well as days 7 and 28 after kidney transplantation (KT). **P ⬍ .01.
Fig 2. sCD30 levels in 20 ARE vs 38 non-ARE cases at 1 day before as well as 7 and 28 days after kidney transplantation. *P ⬍ .05; **P ⬍ .01.
Statistical analysis revealed that sCD30 level significantly correlated with ARE (P ⬍ .01), indicating that about at least half of the cases with ARE could be predicted using sCD30 levels at day 7 posttransplantation. DISCUSSION
Prediction of rejection following kidney transplantation may help to choose the proper immune inhibitor. A highly effective inhibitor can decrease the risk for transplanted kidney failure in highly sensitive recipients, whereas a
Fig 3. Positive sCD30 level (ⱖ20 U/mL) at day 7 posttransplantation significantly correlated with ARE. *P ⬍ .01.
sCD30 PREDICTS ACUTE REJECTION
high-dose inhibitor may increase drug side effects, such as toxicity, infection, or malignant tumor, in low immune responders. Süsal et al3 reported that an sCD30 test before transplantation predicted highly sensitive recipients of kidney transplantation. Pelzl et al7 further proved that sCD30 determination before transplantation was a powerful index to forecast rejection episodes in a series of studies involving 3900 cases. This index can be applied to both presensitized and nonsensitized cases. Recipients with high levels of PRA and sCD30 before transplantation show poorer transplantation outcomes. Clinical studies have revealed that ARE can occur at 1 week after transplantation, while the clinical diagnosis mainly relies on blood creatinine detection and pathological biopsy. Although symptoms such as sudden enuresis, increased blood pressure, transplanted kidney discomfort, and fever occur, a clinically effective inhibitor hides some of these clinical expressions. Once an increased blood creatinine is detected, obvious immune pathological damage has already been triggered. Therefore, early diagnosis of ARE enables one to take effective measures to avoid pathological damage in the early period. Puncture biopsy of the kidney can help to detect subclinical rejection,8 but it hurts the transplanted kidney to some extent, thus few patients accept this examination. Therefore, the sCD30 test provides a rapid, convenient, and easy procedure with reliable results. A high level of sCD30 before transplantation suggests that the patient is in a highly sensitive state and has a higher risk for an ARE. We chose 58 low sensitivity recipients, thus their sCD30 level was low before transplantation. Most cases did not experience steroid-resistant rejection; 20 ARE cases were effectively controlled, indicating that patients with low sCD30 levels have better outcomes after transplantation, which is consistent with the study by Süsal et al.3 We compared sCD30 contents between ARE and nonARE cases, showing a significant correlation between sCD30 level at 1 day before kidney transplantation and ARE occurrence. Tests for sCD30 content before transplantation can predict the occurrence of ARE after operation and reflect the immune state before transplantation, consistent with the studies of Pelzl et al.7 Besides the detection of sCD30 at 1 day before transplantation, we also conducted dynamic tests of sCD30 following transplantation. We observed high sCD30 levels at day 7 posttransplantation which correlated with the ARE. It is worthy to note that all ARE cases occurred 7
days after transplantation, indicating that sCD30 level at day 7 has a predictive role. Although sCD30 level at day 28 posttransplantation was higher than pretransplantation, there was no significant correlation between this high sCD30 level and an ARE, indicating that this high sCD30 level was induced by large dosages of inhibitors after the operation. The group with a high level of sCD30 before transplantation (compared with the average value of the healthy group) witnessed a notable increase in the number of AREs after transplantation. Therefore, recipients in the group with a high level of sCD30 should be provided with good HLA matches to decrease the occurrence and strength of ARE. Highly effective inhibitors posttransplantation can prevent the occurrence of rejection. A decrease in recent ARE or subclinical rejection may prevent the occurrence of chronic disease thereby increasing the life cycle of the transplanted kidney. Besides the PRA test, recipients with a high level of sCD30 can also undergo kidney transplantation after a manipulation to decrease the sCD30 level. In conclusion, this study further showed that sCD30 levels acted as simple and effective indices of rejection. sCD30 after transplantation was significant for early discovery of rejection among kidney transplant recipients. REFERENCES 1. Gebel HM, Bray RA, Nickerson P: Pre-transplant assessment of donor-reactive, HLA-specific antibodies in renal transplantation: contraindication vs. risk. Am J Transplant 3:1488, 2003 2. Cinti P, Pretagostini R, Arpino A, et al: Evaluation of pretransplant immunologic status in kidney-transplant recipients by panel reactive antibody and soluble CD30 determinations. Transplantation 79:1154, 2005 3. Süsal C, Pelzl S, Simon T, et al: Advances in pre- and posttransplant immunologic testing in kidney transplantation. Transplant Proc 36:29, 2004 4. Süsal C, Pelzl S, Opelz G: Strong human leukocyte antigen matching effect in nonsensitized kidney recipients with high pretransplant soluble CD30. Transplantation 76:1231, 2003 5. Dürkop H, Latza U, Hummel M, et al: Molecular cloning and expression of a new member of the nerve growth factor receptor family that is characteristic for Hodgkin’s disease. Cell 68:421, 1992 6. Kennedy MK, Willis CR, Armitage RJ: Deciphering CD30 ligand biology and its role in humoral immunity. Immunology 118:143, 2006 7. Pelzl S, Opelz G, Wiesel M, et al: Soluble CD30 as a predictor of kidney graft outcome. Transplantation 73:3, 2002 8. Rush DN, Nickerson P, Jeffery JR, et al: Protocol biopsies in renal transplantation: research tool or clinically useful? Curr Opin Nephrol Hypertens 7:691, 1998