IL6 and Bone marrow hypocellularity: Although IL-6 is generally elevated in infected patients, we still hope to elucidate the expression of cytokines in pulmonary bacterial or/and fungal infections of AA patients, which may provide clues for clinical practice in AA.The most urgent task for us as clinicians is to detect the presence of infection as early as possible and to intervene as soon as possible, especially in bone marrow failure diseases such as AA.