Lack of skin test reactivity to common mycobacterial antigens in human immunodeficiency virus infected individuals with high CD4 counts.

BACKGROUND: T cell response to mycobacterial antigens may be directed against those antigens common to all mycobacteria (group i), those restricted to slow (group ii) or fast growers (group iii), or those which are species- or subspecies-specific (group iv). These responses were assessed by skin testing patients infected with the human immunodeficiency virus (HIV) and healthy controls with reagents derived from different strains of mycobacteria. METHODS: Skin test responses to new tuberculins prepared from Mycobacterium tuberculosis, M avium serotypes 4 and 8, and either M intracellulare or M flavescens antigens were evaluated prospectively in 51 HIV infected patients and 67 healthy controls. RESULTS: Assessment of induration at 72 hours showed absence of skin test response to common mycobacterial antigens in all 27 HIV positive patients with CD4 counts of > or = 400/mm3 (range 400-1594, median 540) compared with 27% reactivity in controls; complete anergy was demonstrated in 24 patients with CD4 counts of < 400/mm3. By contrast, no difference in species or subspecies-specific responses was found between healthy controls and HIV positive patients with CD4 counts of > or = 400/mm3. CONCLUSIONS: Subsets of CD4+ T helper cells are instrumental in determining the balance between cell-mediated and humoral immunity. One T helper subset (TH1) produces cytokines that increase cellular immunity and is stimulated by group i common mycobacterial antigens. Lack of this response, but preservation of responses to species-specific antigens while CD4 counts are near normal, may indicate an early failing of TH1 immunity and explain the increased susceptibility of HIV positive patients to mycobacterial infection early on in the evolution of their HIV infection.

背景：T细胞对分枝杆菌抗原的反应可能针对所有分枝杆菌共有的抗原（第Ⅰ组）、仅限于缓慢生长（第Ⅱ组）或快速生长（第Ⅲ组）的分枝杆菌的抗原，或者是种属或亚种特异性的抗原（第Ⅳ组）。通过对感染人类免疫缺陷病毒（HIV）的患者以及健康对照者使用源自不同分枝杆菌菌株的试剂进行皮肤试验，来评估这些反应。 方法：对51例HIV感染患者和67例健康对照者前瞻性地评估其对由结核分枝杆菌、鸟分枝杆菌血清型4和8以及胞内分枝杆菌或微黄分枝杆菌抗原制备的新型结核菌素的皮肤试验反应。 结果：在72小时时对硬结的评估显示，在所有27例CD4计数≥400/mm³（范围400 - 1594，中位数540）的HIV阳性患者中，对常见分枝杆菌抗原无皮肤试验反应，而在对照者中有27%的反应性；在24例CD4计数＜400/mm³的患者中表现出完全无反应性。相比之下，在健康对照者和CD4计数≥400/mm³的HIV阳性患者之间，未发现种属或亚种特异性反应的差异。 结论：CD4⁺T辅助细胞亚群在决定细胞介导免疫和体液免疫之间的平衡方面起重要作用。一种T辅助细胞亚群（TH1）产生细胞因子，可增强细胞免疫，并受第Ⅰ组常见分枝杆菌抗原刺激。在CD4计数接近正常时缺乏这种反应，但对种属特异性抗原的反应保留，这可能表明TH1免疫早期失效，并解释了HIV阳性患者在其HIV感染进展早期对分枝杆菌感染易感性增加的原因。