Baker B S, Powles A, Garioch J J, Hardman C, Fry L
Department of Dermatology, St Mary's Hospital, London, U.K.
Br J Dermatol. 1997 Mar;136(3):319-25.
Pityrosporum yeasts have been implicated as a trigger for the initiation of scalp lesions in psoriasis. To determine whether Pityrosporum-reactive T cells are present in lesional psoriatic skin. T-cell lines (TCL) were cultured from the scalps of nine patients with psoriasis and seven with alopecia areata (disease controls), and from non-scalp lesions from six of the psoriatic patients. The psoriatic skin TCL were stained for CD3, CD4, CD8 and TCR alpha beta expression and tested in a proliferation assay with Candida albicans and purified protein derivative (PPD), and cytoplasmic and cell-wall extracts of P. ovale (oval) and P. orbiculare (round). The proliferative responses of corresponding peripheral blood mononuclear cells (PBMC) were also determined. All the PBMC samples responded to the Pityrosporum extracts to variable extents, but no significant difference in the response of the group to the two different forms of yeast was observed. The response was mediated by CD4+ T cells and inhibited by the addition of anti-HLA-DR antibody. In addition, all nine psoriatic scalp TCL, which were predominantly CD3+, CD4+ TCR alpha beta(+), responded to the cytoplasmic, and five of nine TCL to the cell-wall extract of P. orbiculare. In contrast, only three of the nine TCL proliferated to either extract of P. ovale. This difference was significant for both the cytoplasmic (P < 0.01) and cell wall (P = 0.01) extracts. Similarly, the TCL cultured from non-scalp psoriatic lesions also showed a more marked response to the P. orbiculare extracts (P = 0.05). Furthermore, four of seven and two of seven scalp TCL from lesions of alopecia areata responded to the P. orbiculare and P. ovale extracts, respectively; these responses did not differ significantly from those of the psoriatic scalp TCL. None of the skin TCL responded to either Candida albicans or PPD. These findings demonstrate that T cells with differential reactivity to the round and oval forms of Pityrosporum are present in, but are not specific for, psoriatic skin lesions. A role for these cells in the pathogenesis of psoriasis remains speculative.
马拉色菌酵母被认为是引发银屑病头皮病变的一个因素。为了确定在银屑病皮损中是否存在针对马拉色菌的反应性T细胞，从9例银屑病患者和7例斑秃患者（疾病对照）的头皮，以及6例银屑病患者的非头皮皮损中培养T细胞系（TCL）。对银屑病皮肤TCL进行CD3、CD4、CD8和TCRαβ表达染色，并在增殖试验中用白色念珠菌、纯化蛋白衍生物（PPD）以及卵形马拉色菌（oval）和圆形马拉色菌（round）的细胞质和细胞壁提取物进行检测。同时也测定了相应外周血单个核细胞（PBMC）的增殖反应。所有PBMC样本对马拉色菌提取物均有不同程度的反应，但该组对两种不同形态酵母的反应未观察到显著差异。该反应由CD4+T细胞介导，并被抗HLA - DR抗体的添加所抑制。此外，所有9个主要为CD3+、CD4+、TCRαβ(+)的银屑病头皮TCL对圆形马拉色菌的细胞质提取物有反应，9个TCL中有5个对其细胞壁提取物有反应。相比之下，9个TCL中只有3个对卵形马拉色菌的任何一种提取物有增殖反应。这种差异在细胞质提取物（P < 0.01）和细胞壁提取物（P = 0.01）中均具有显著性。同样，从非头皮银屑病皮损中培养的TCL对圆形马拉色菌提取物也表现出更明显的反应（P = 0.05）。此外，7个斑秃皮损的头皮TCL中有4个和2个分别对圆形马拉色菌和卵形马拉色菌提取物有反应；这些反应与银屑病头皮TCL的反应无显著差异。皮肤TCL对白色念珠菌或PPD均无反应。这些发现表明，对圆形和卵形马拉色菌具有不同反应性的T细胞存在于银屑病皮肤病变中，但并非银屑病皮肤病变所特有。这些细胞在银屑病发病机制中的作用仍具有推测性。
