Inherited human TNF deficiency undermines macrophages respiratory burst and underlies recurrent pulmonary tuberculosis

Severe inherited defects of human IFN-gamma immunity confer a predisposition to both BCG disease and tuberculosis, whereas milder defects confer a predisposition only to tuberculosis. We report two adults with recurrent pulmonary tuberculosis homozygous for the same private loss-of-function TNF variant. Neither displays other clinical phenotypes, including BCG disease; both patients mount normal clinical and biological inflammatory responses. Their leukocytes, including blood monocytes and monocyte-derived macrophages (MDMs), do not produce TNF. The development of their blood myeloid and lymphoid leukocyte subsets is normal, as is their TNFR1 and TNFR2 expression. However, an impairment of the respiratory burst was observed in vitro in GM-CSF-matured MDMs and alveolar macrophage-like cells (AMLs) from the TNF-deficient patients, TNF- or TNFR1-deficient gene-edited iPSC-derived GM-CSF-matured macrophages, in healthy control MDMs and AMLs differentiated with TNF blockers, as well as ex vivo in lung macrophages treated with TNF blockers. These findings contrast with those for patients with an inherited deficit of the respiratory burst across all types of phagocytes, including neutrophils and monocytes, who are prone to both BCG disease and tuberculosis. The priming of TNF-deficient iPSC-derived macrophages with TNF rescued the respiratory burst. TNF deficiency did not impair IFN-gamma production by lymphocytes or the response to IFN-gamma in macrophages. Human TNF is, thus, required for respiratory burst-dependent IFN-gamma-independent immunity to Mycobacterium tuberculosis in macrophages, but is surprisingly redundant otherwise, including for inflammation and immunity to weakly virulent mycobacteria and other infectious agents.

人类干扰素γ（Interferon-gamma, IFN-γ）免疫的严重遗传性缺陷，会使人同时易患卡介苗（Bacillus Calmette-Guérin, BCG）病与结核病；而较轻的缺陷仅会使人易患结核病。我们报道了2例复发性肺结核成年患者，二者均为同一特有功能丧失型肿瘤坏死因子（Tumor Necrosis Factor, TNF）变异的纯合子。二人均未表现出包括卡介苗病在内的其他临床表型；两名患者的临床与生物学炎症应答均正常。他们的白细胞，包括血液单核细胞与单核细胞衍生巨噬细胞（monocyte-derived macrophages, MDMs），均无法产生TNF。其血液髓系与淋巴系白细胞亚群发育正常，肿瘤坏死因子受体1（Tumor Necrosis Factor Receptor 1, TNFR1）与肿瘤坏死因子受体2（Tumor Necrosis Factor Receptor 2, TNFR2）的表达亦无异常。然而，体外实验中我们观察到：TNF缺陷患者经粒细胞-巨噬细胞集落刺激因子（Granulocyte-Macrophage Colony-Stimulating Factor, GM-CSF）诱导成熟的MDMs与肺泡巨噬细胞样细胞（alveolar macrophage-like cells, AMLs）、经基因编辑敲除TNF或TNFR1的诱导多能干细胞（induced pluripotent stem cells, iPSC）衍生的GM-CSF成熟巨噬细胞、经TNF阻滞剂诱导分化的健康对照MDMs与AMLs，以及经TNF阻滞剂处理的离体肺巨噬细胞，均存在呼吸爆发功能受损。上述发现与一类患者的表型形成鲜明对比：这类患者的所有吞噬细胞（包括中性粒细胞与单核细胞）均存在遗传性呼吸爆发缺陷，因此同时易患卡介苗病与结核病。用TNF预处理TNF缺陷的iPSC衍生巨噬细胞，可恢复其呼吸爆发功能。TNF缺陷并不会损伤淋巴细胞的IFN-γ产生能力，亦不会影响巨噬细胞对IFN-γ的应答。由此可见，人类TNF是巨噬细胞中依赖呼吸爆发、不依赖IFN-γ的结核分枝杆菌（Mycobacterium tuberculosis）免疫所必需的，但在其他场景下却出人意料地冗余，包括炎症反应以及针对弱毒分枝杆菌与其他病原体的免疫防御。