A role for antibodies to human leukocyte antigens, collagen-V, and K-α1-Tubulin in antibody-mediated rejection and cardiac allograft vasculopathy

Abstract

Background: We determined the role of donor-specific antibodies (DSA) and antibodies (Abs) to self-antigens, collagen-V (Col-V), and K-α1-Tubulin (KAT) in pathogenesis of acute antibody-mediated rejection (AMR) and cardiac allograft vasculopathy (CAV) after human heart transplantation (HTx).

Methods: One hundred thirty-seven HTx recipients, with 60 early period (≤ 12 months) and 77 late period (>12 months), were enrolled in this study. Circulating DSA was determined using LUMINEX. Abs against Col-I, II, IV, V, and KAT were measured using ELISA. Frequency of CD4+T helper cells (CD4+Th) secreting interferon (IFN)-γ, interleukin (IL)-5, -10, or -17 specific to self-antigens were determined using Enzyme Linked Immunosorbent Spot assay.

Results: A significant association between AMR and DSA was demonstrated. Development of DSA in AMR patients correlated well with the development of auto-Abs to Col-V (AMR[+]: 383 ± 72 μg/mL, AMR[-]: 172 ± 49 μg/mL, P=0.033) and KAT (AMR[+]: 252 ± 49 μg/mL, AMR[-]: 61 ± 21 μg/mL, P=0.014). Patients who developed AMR demonstrated increased frequencies of CD4+Th secreting IFN-γ and IL-5 with reduction in IL-10 specific for Col-V/KAT. Patients diagnosed with CAV also developed DSA and auto-Abs to Col-V (CAV[+]: 835 ± 142 μg/mL, CAV[-]: 242 ± 68 μg/mL, P=0.025) and KAT (CAV[+]: 768 ± 206 μg/mL, CAV[-]: 196 ± 72 μg/mL, P=0.001) with increased frequencies of CD4+Th secreting IL-17 with reduction in IL-10 specific for Col-V/KAT. CONCLUSIONS.: Development of Abs to human leukocyte antigens and self-antigens are associated with increases in CD4+Th secreting IFN-γ and IL-5 in AMR and IL-17 in CAV, with reduction in CD4+Th secreting IL-10 in both AMR and CAV.

Figure 1

AMR(+) (n=9) recipients develop increased Abs to Col-V and KAT compared to controls and AMR (−) (n=51) recipients. There is no significant difference in Abs to Col-I, II, IV between the controls, AMR(−), and AMR(+) recipients (data presented as mean± S.D).

Figure 2

Serial monitoring of DSA (every month), Abs to Col-V and KAT in 7 EP DSA(+)AMR(+) recipients indicated that DSA was detectable at 2.7±0.9 months, followed by Col-V at 6.0±1.2 months, KAT at 7.3±1.2months in patients diagnosed with AMR at 8.5±1.1months.

Figure 3

A: AMR(+) (n=9) recipients demonstrate increased frequencies of IL-5 and IFN-γ and decreased frequency of IL-10 secreting CD4+ T cells specific to Col-V compared to AMR(−) (n=51) recipients. There is no significant difference in the frequency of IL-17 secreting CD4+ T cells specific to Col-V between AMR(+) and AMR(−) recipients (data presented as mean± S.D). B: AMR(+) (n=9) recipients demonstrate increased frequencies of IL-5 and IFN-γ and decreased frequency of IL-10 secreting CD4+ T cells specific to KAT compared to AMR(−) (n=51) recipients. There is no significant difference in the frequency of IL-17 secreting CD4+ T cells specific to KAT between AMR(+) and AMR(−) recipients (data presented as mean± S.D).

Figure 4

CAV(+) (n=14) recipients develop increased Abs to Col-V and KAT compared to controls and CAV(−)(n=63) recipients. There is no significant difference in Abs to Col-I, II, IV between the controls, CAV(−), and CAV(+) recipients (data presented as mean± S.D).

Figure 5

A: CAV(+)(n=14) recipients demonstrate increased frequency of IL-17 and decreased frequency of IL-10 secreting CD4+ T cells specific to Col-V compared to CAV(−) (n=63) recipients. There is no significant difference in the frequencies of IFN-γ and IL-5 secreting CD4+ T cells specific to Col-V between CAV(+) and CAV(−) recipients (data presented as mean± S.D). B: CAV(+)(n=14) recipients demonstrate increased frequency of IL-17 and decreased frequency of IL-10 secreting CD4+ T cells specific to KAT compared to CAV(−)(n=63) recipients. There is no significant difference in the frequencies of IFN-γ and IL-5 secreting CD4+ T cells specific to KAT between CAV(+) and CAV(−) recipients (data presented as mean± S.D).