Plasma Levels of Soluble CD30 in Kidney Graft Recipients as Predictors of Acute Allograft Rejection K. Ayed, T.B. Abdallah, R. Bardi, E. Abderrahim, and A. Kheder ABSTRACT In renal transplant recipients elevated soluble serum CD30 levels are associated with increased rejection and graft loss. We sought to determine the sCD30 plasma levels before and after kidney transplantation and to assess whether sCD30 was a predictive factor of immunological risk. sCD30 plasma levels were determined by an enzyme-linked immunosorbent assay assay in 52 kidney graft recipients before as well as 7, 15, and 21 days after transplantation. Eighteen patients developed acute allograft rejection (group I) and 34 patients showed uneventful courses (group II). Before transplantation sCD30 plasma levels were elevated in both groups (mean: 162.6 ⫾ 89.5 U/mL). After transplantation, group I recipients with acute rejection showed higher relative levels of plasma sCD30 on days 7 and 15 (120.8 ⫾ 74.6 U/mL and 210.6 ⫾ 108.7 U/mL respectively) compared with group II patients without rejection (95 ⫾ 45 U/mL and 59.4 ⫾ 31.6 U/mL), a difference that was significant for group I (P ⫽ .0003) and not significant for group II (P ⫽ .09). On day 21, sCD30 decreased in the two groups but remained higher among group I patients (120.6 ⫾ 92.7 U/mL). HLA antibodies were positive in 18 patients (34.6%) with 9 (50%) experiencing at last one episode of acute rejection. Among 34 patients negative for anti-HLA antibodies, nine displayed acute rejection only (26.4%), a difference that was not significant (P ⬎ .05). If we consider 100 U/mL as the minimum predictive level for allograft rejection, our results suggested that levels of sCD30 should be taken into consideration with the presence of HLA-antibodies detectable before and after transplantation, especially in patients with more than three HLA mismatches [RR ⫽ 3.20 (0.94 ⬍ RR ⬍ 10.91)]. These data suggested that measurement of plasma sCD30 is a useful procedure for the recognition of rejection in its earliest stages.
CUTE REJECTION is a frequent complication of renal transplantation and a predictor of late transplant failure. Acute rejection episodes (ARE) typically develop soon after transplantation and are believed to be secondary to T cell–mediated immune responses involving hypersensitivity and cytotoxicity. The diagnosis of ARE in its earliest phase may significantly help to prevent irreversible damage. A few biologic assays that may be potentially useful for monitoring the immune status of renal graft recipients have been reported.1 The determination of the sensitization level in renal transplant candidates is critical in a pretransplant evaluation. The presence of allogeneic antibodies in patient serum, panel of reactive antibodies (PRA), substantially affects graft outcomes. Recent studies have suggested that high pre- and posttransplant serum levels of soluble CD30 (sCD30) may be a risk factor for acute rejection episodes and for graft loss.1,2 The measure-
ment of serum levels of sCD30 in renal allograft recipients has gained momentum as a predictive factor for ARE.2,3 CD30 is a member of the tumor necrosis factor receptor superfamily. It is normally expressed by a subset of T cells after activation by a variety of stimuli. Mainly CD30 is also expressed in various lymphomas as well as circulating CD4⫹ and CD8⫹ T cells, which produce Th2 cytokines in immunoreactive conditions. sCD30 is released into serum after activation of CD30⫹ T cells.4,5 Using an immunoassay we investigated the plasma levels of sCD30 before and after kidney transplantation to define From the Departments of Immunology (K.A., R.B.) and Nephrology (T.B.A., E.A., A.K.), Charles Nicolle Hospital, Tunis, Tunisia. Address reprint requests to Dr Khaled Ayed, Immunology-Lab, CH Nicolle Hospital, 1006 Tunis, Tunisia. E-mail: [email protected]
0041-1345/06/$–see front matter doi:10.1016/j.transproceed.2006.07.002
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Transplantation Proceedings, 38, 2300 –2302 (2006)
PLASMA LEVELS OF SOLUBLE CD30
the possible relationship of this molecule to PRA and to prediction of acute rejection.
Table 2. Incidence of Acute Rejection (AR) in Patients with sCD30 >100 by Pretransplant AR⫹
MATERIALS AND METHODS Patients
Fifty-two renal transplant recipients (32 men and 20 women) of overall mean age of 29 ⫾ 10.6 years received first grafts between January 2003 and December 2004. The grafts came from living donors in 38 cases (31 related and seven unrelated), whereas 14 received a deceased donor graft. ARE was clinically suspected when the serum creatinine increased above 250 mol/L and urine excretion declined. A renal biopsy was performed in some cases when ARE was clinically suspected with kidney pathology classified using the Banff classification.6
Methods CD30 levels were determined by an enzyme-linked immunosorbent assay (ELISA) (Bender Medsystems, Vienna, Austria). Plasma concentrations of sCD30 were determined before as well as 7, 15, and 21 days following transplantation. Sera from 30 healthy blood donors served as controls. Their mean CD30 value was 16.95 ⫾ 13 U/mL. HLA antibodies were detected by complement dependent cytotoxicity or ELISA assay (LATM kits). HLA typing was performed using molecular analysis kits obtained from One Lambda Inc (Canoga Park, Calif). The statistical analysis was performed with chi-square test. Contingency analysis used Fisher exact and Wolff’s approximation to determine the 95% confidence interval.
Among 38 patients grafted from living donors, 31 were related including 10 who shared two haplotypes and 21 who shared one haplotype. In contrast seven patients received an organ from an unrelated individual and 14 patients received deceased donor grafts. HLA mismatch in the unrelated living donors and cadaveric donors group was three to six and three to four, respectively. The mean patient follow-up was 28 ⫾ 11 months. Within the first 6 months postransplantation, 18 patients (34.6%) developed an ARE (group I) and 34 patients displayed normal graft function during the first 6 months following kidney transplantation (group II). The pre- and posttransplant profile of anti-HLA antibodies was analyzed in 52 transplant recipients by CDC or Table 1. Plasma Levels of Soluble CD30 in Kidney Graft Recipients n
All patients Controls Posttransplant AR⫹ (day 7) AR⫺ (day 7) AR⫹ (day 15) AR⫺ (day 15)
18 34 18 34
188.15** 171.6** 210.25*** 59.37***
44.56 81.69 66.56 39.06
AR, acute rejection. *P ⬍ .001; **P ⫽ .025; ***P ⫽ .03.
6 (40%)* 3 (12.5%)†
*P ⬍ .05, RR: 4.69 [0.77 ⬍ OR ⬍ 31.23]; Pc 0.056; †P ⬍ .001
ELISA (LAT-M). Pretransplantation 4 of 52 patients had HLA antibodies by CDC (7.6%) and three experienced an ARE. With LAT-M, 18 of the 52 (34.6%) tested sera were positive; among them eight recipients displayed ARE and 10 did not have ARE. Posttransplantation, 15 of the 52 (28.8%) sera tested by CDC were positive with seven of them showing graft rejection (46.6%) compared with 21.6% (n ⫽ 8) among the 37 HLA antibody-negative subjects. With LAT-M, 18 of the 52 (34.6%) sera tested were positive, with seven subjects displaying graft rejection (38.8%) versus 11 (32.3%) of the 34 LAT-M negative. The graft rejection rate was higher among PRA-positive than PRA-negative patients, although the difference was not statistically significant. The mean sCD30 serum levels (Table 1) were significantly higher in all patients before transplantation than in healthy blood donors (162 ⫾ 89.5 U/mL vs 16.95 ⫾ 13.08 U/mL; P ⫽ .001) with similar sCD30 concentrations in group I and group II patients (188.15 U/mL vs 171.6 U/mL, respectively). If we consider 100 U/mL as the minimum predictive level for rejection, we notice that group I includes more patients with a higher risk of rejection (level ⬎ 100 U/mL) than group II; RR ⫽ 4.67 (0.77 ⬍ RR ⬍ 31.23). A relative decrease in sCD30 levels occurred in the two groups on day 7 after transplantation. However, on day 15 group I subjects showed a significant increase in sCD30 plasma levels (210.25 U/mL) compared with those in group II (59.37 U/mL; P ⬍ .001). This difference remained significant for the 18 patients who developed acute rejection on day 21 (120.6 U/mL vs 66.7 U/mL; P ⬍ .04). Pretransplant PRA (CDC/LAT-M) were positive in 18 (34.6%) recipients, whereas sCD30 was ⬎100 U/mL in 39 (75%). Fifteen (28.8%) recipients displayed both PRA and sCD30 ⬎ 100 U/mL; whereas 10 (19.2%) were PRAnegative and sCD30 ⬍ 100 U/mL. Among the 18 PRApositive patients, 6 (40%) displayed ARE, whereas 3 (12.5%) patients with sCD30 ⬎ 100 U/mL developed ARE (P ⬍ .05; pc ⫽ .056; Table 2). Patients with rejection in the PRA-positive group showed a trend toward higher levels of sCD30 posttransplant (P ⬎ .001). Moreover, HLA matching influenced the predictive value of sCD30 levels for ARE. Rejecting patients with three or more than three mismatches of HLA class I and class II displayed significantly higher concentrations of sCD30 than did nonrejecting recipients (P ⬎ .001). DISCUSSION
Several reports from the Collaborative Transplant Study (CTS) have suggested that high soluble sCD30 levels in graft recipients before or after transplantation were associated with
increased ARE and graft loss.1,2 Our results confirmed the higher sCD30 levels in recipients with rejection. However, in contrast to the CTS study, the sCD30 concentration was also high in both groups of patients before transplantation.3 Thereafter the levels of sCD30 decreased during the first 3 to 5 posttransplant days, increasing significantly between 5 and 15 days following transplantation among recipients who developed ARE. Our results agree with those reported by Slavcev et al,7 suggesting the benefit of repetitive measurements of sCD30 levels. Production of anti-HLA antibodies following transplantation has been shown to be involved in the incidence and severity of AREs.8 Multifactorial analysis revealed that high serum levels of sCD30 and the presence of HLA class I antibodies after transplantation represented risk factors for the occurrence of ARE.3,8 Our results suggested that sCD30 levels should be taken into consideration with the presence of HLA antibodies detectable after transplantation, especially among patients with more than three HLA mismatches. In conclusion, posttransplantation sCD30 levels were found to be independent, highly predictive factors of immunological risk. Moreover, the effects of sCD30 and anti-HLA antibodies seemed to be additive.
AYED, ABDALLAH, BARDI ET AL
REFERENCES 1. Sûsal C, Pelzl S, Simon T, et al: Advances in pre- and posttransplant immunologic testing in kidney transplantation. Transplant Proc 36:29, 2004 2. Sûsal C, Pelzl S, Opelz G: Strong human leukocyte antigen matching effect in nonsensitized kidney recipients with high pretransplant soluble CD30. Transplantation 76:1231, 2003 3. Sûsal C, Pelzl S, Dôhler B, et al: Identification of highly responsive kidney transplant recipients using pretransplant soluble CD30. J Am Soc Nephrol 13:1650, 2002 4. Chiarle R, Podda A, Prolla G: CD30 in normal and neoplastic cells. Clin Immunol 90:157, 1999 5. Del Prete G, De Carli M, Almerigogna F, et al: Preferential expression of CD30 by human CD4⫹ T cells producing Th2-type cytokines. FASEB J 9:81, 1995 6. Racusen LC, Solez K, Colvin RB, et al: The Banff97 working classification of renal allograft pathology. Kidney Int 55:713, 1999 7. Slavcev A, La’cha J, Honsova E, et al: Soluble CD30 and HLA antibodies as potential risk factors for kidney transplant rejection. Transpl Immunol 14:117, 2005 8. Kaufman A, Faria L, Queiroz Marques M, et al: Analysis of AHG-PRA and ELISA-PRA in kidney transplant patients with acute rejection episodes. Transpl immunol 11:175, 2003