Hess D A, Sisson M E, Suria H, Wijsman J, Puvanesasingham R, Madrenas J, Rieder M J
Department of Pharmacology and Toxicology, University of Western Ontario, London, Ontario, Canada.
FASEB J. 1999 Oct;13(13):1688-98. doi: 10.1096/fasebj.13.13.1688.
Treatment with sulfonamide antibiotics in HIV-infected patients is associated with a high incidence (> 40%) of adverse drug events, including severe hypersensitivity reactions. Sulfonamide reactive metabolites have been implicated in the pathogenesis of these adverse reactions. Sulfamethoxazole hydroxylamine (SMX-HA) induces lymphocyte toxicity and suppression of proliferation in vitro; the mechanism(s) of these immunomodulatory effects remain unknown. We investigated the cytotoxicity of SMX-HA via apoptosis on human peripheral blood mononuclear cells and purified cell subpopulations in vitro. CD19(+), CD4(+), and CD8(+) cells were isolated from human peripheral blood by positive selection of cell surface molecules by magnetic bead separation. SMX-HA induced significant CD8(+) cell death (67 +/- 7%) at 100 microM SMX-HA, with only minimal CD4(+) cell death (8 +/- 4%). No significant subpopulation toxicity was shown when incubated with parent drug (SMX). Flow cytometry measuring phosphatidylserine externalization 24 h after treatment with 100 microM and 400 microM SMX-HA revealed 14.1 +/- 0.7% and 25. 6 +/- 4.2% annexin-positive cells, respectively, compared to 3.7 +/- 1.2% in control PBMCs treated with 400 microM SMX. Internucleosomal DNA fragmentation was observed in quiescent and stimulated PBMCs 48 h after incubation with SMX-HA. Our data show that CD8(+) cells are highly susceptible to the toxic effects of SMX-HA through enhanced cell death by apoptosis.
在感染HIV的患者中，使用磺胺类抗生素治疗会导致药物不良事件的高发生率（>40%），包括严重的过敏反应。磺胺类反应性代谢产物被认为与这些不良反应的发病机制有关。磺胺甲恶唑羟胺（SMX-HA）在体外可诱导淋巴细胞毒性并抑制其增殖；这些免疫调节作用的机制尚不清楚。我们在体外研究了SMX-HA通过凋亡对人外周血单个核细胞和纯化的细胞亚群的细胞毒性。通过磁珠分离阳性选择细胞表面分子，从人外周血中分离出CD19(+)、CD4(+)和CD8(+)细胞。在100 microM SMX-HA时，SMX-HA诱导显著的CD8(+)细胞死亡（67±7%），而CD4(+)细胞死亡极少（8±4%）。与母体药物（SMX）孵育时未显示明显的亚群毒性。用100 microM和400 microM SMX-HA处理24小时后，通过流式细胞术检测磷脂酰丝氨酸外化，发现分别有14.1±0.7%和25.6±4.2%的膜联蛋白阳性细胞，而用400 microM SMX处理的对照PBMC中为3.7±1.2%。与SMX-HA孵育48小时后，在静止和受刺激的PBMC中观察到核小体间DNA片段化。我们的数据表明，CD8(+)细胞通过凋亡增强细胞死亡，对SMX-HA的毒性作用高度敏感。
