Yang L, Lu Y P, Luo G H, Song J, Shi Y J, Li Y Ping
Transplantation Institute, West China Hospital, Chengdu, Sichuan, China.
Transplant Proc. 2008 Oct;40(8):2782-5. doi: 10.1016/j.transproceed.2008.07.124.
Deposition of C4d in peritubular capillaries (PTC) has been considered to be a marker of humoral immunity in renal transplant. This study is to investigate C4d deposition in rat renal allografts undergoing CAN and the effects of immunosuppressants on it.
Fisher 344 rat renal grafts were orthotopically transplanted into Lewis rats following the procedure of Kamada with our modification. All the recipients were given CsA 10 mg/kg(-1).d(-1) x 10 d and then divided into 5 groups (each n = 9); (1) Vehicle: vehicle orally, (2) CsA: 6 mg/kg(-1).d(-1), (3) RAPA: 0.8 mg/kg(-1).d(-1), (4) FK 506: 0.15 mg/kg(-1).d(-1), (5) MMF: 20 mg/ kg(-1).d(-1). At 4 weeks, 8 weeks, 12 weeks, the rats were sacrificed, renal allografts were harvested and sera were collected. The deposition of C4d was detected by immunofluorescence and analyzed by Integrated Optical Density (IOD). The pathological changes were accessed according to the Banff 97 criteria.
C4d deposition in PTC was found in all the allografts at 4 weeks, while there was no obvious manifestations of CAN in all the groups; the differences of Banff Score between all groups were not significant (P > .05). The values of IOD in RAPA and MMF group were lower than those in other 3 groups (P = .002, .006). The differences between RAPA and MMF, and between other 3 groups were not significant (P > .05). The intensity of C4d increased along with the progression of CAN, the heaviest C4d deposits in PTC were found at 12 weeks, and meanwhile the severest CAN was found. Comparing with Vehicle group, CsA and FK 506 had no effect on C4d deposition (P > .05), however, MMF and RAPA obviously decreased the C4d deposition (P = .000). The intensity of C4d deposition had a significant correlation with the severity of CAN (r = 0.894, P = .000).
Our study suggests that the deposition of C4d in allografts appears earlier than pathological changes of CAN and has a correlation with the progression of CAN. MMF and RAPA can attenuate CAN by inhibiting humoral immunity. In contrast, CsA and FK 506 have no effect on humoral immunity.
肾小管周围毛细血管（PTC）中C4d沉积被认为是肾移植中体液免疫的一个标志物。本研究旨在调查慢性移植肾肾病（CAN）大鼠同种异体肾移植中C4d的沉积情况以及免疫抑制剂对其的影响。
按照Kamada的方法并加以改进，将Fisher 344大鼠肾移植到Lewis大鼠体内。所有受体均给予环孢素A（CsA）10mg/kg⁻¹·d⁻¹×10天，然后分为5组（每组n = 9）；（1）溶剂对照组：口服溶剂，（2）CsA组：6mg/kg⁻¹·d⁻¹，（3）雷帕霉素（RAPA）组：0.8mg/kg⁻¹·d⁻¹，（4）他克莫司（FK 506）组：0.15mg/kg⁻¹·d⁻¹，（5）霉酚酸酯（MMF）组：20mg/kg⁻¹·d⁻¹。在4周、8周、12周时处死大鼠，摘取同种异体肾移植组织并收集血清。通过免疫荧光检测C4d沉积，并采用积分光密度（IOD）进行分析。根据Banff 97标准评估病理变化。
4周时所有同种异体移植肾均发现PTC中有C4d沉积，而此时所有组均无明显的CAN表现；各组间Banff评分差异无统计学意义（P > 0.05）。RAPA组和MMF组的IOD值低于其他3组（P = 0.002，0.006）。RAPA组与MMF组之间以及与其他3组之间的差异无统计学意义（P > 0.05）。C4d强度随CAN进展而增加，12周时PTC中C4d沉积最重，同时CAN也最严重。与溶剂对照组相比，CsA和FK 506对C4d沉积无影响（P > 0.05），然而，MMF和RAPA明显降低了C4d沉积（P = 0.000）。C4d沉积强度与CAN严重程度呈显著正相关（r = 0.894，P = 0.000）。
我们的研究表明，同种异体移植肾中C4d沉积比CAN的病理变化出现更早，且与CAN进展相关。MMF和RAPA可通过抑制体液免疫减轻CAN。相比之下，CsA和FK 506对体液免疫无影响。
