The authors found specific features by increased serum ferritin and/or lymphopenia, acute urticarial skin lesions and/or anaphylactic-type reactions, and characteristic thoracic CT lesions (thickening of the alveolar septa, ground-glass opacities, etc.)secondary to the treatment with tocilizumab (TCZ), an IL-6 inhibitor. This evidence concerns the gene IL6 and lymphopenia.