Abstract: The present invention relates to a method of profiling the energetic metabolism of a single cells. The inventors designed a method that rapidly and efficiently measures the protein synthesis level in single cells upon inhibition of the different energy producing pathways. The method developed by the inventors permits to acquire energetic metabolism profiles with single cell resolution in non-abundant cells ex-vivo and permits to decrease to a minimum manipulation time, incubations and cost of sample preparation. The method is particularly suitable for determining activation state of a cell, diagnosing inflammatory diseases, or predicting the response of a subject to immunotherapy treatment. In particular, the present invention relates to a method of profiling the energetic metabolism in single cells comprising measuring the protein synthesis level of the cells and contacting the cell with different inhibitors of metabolic pathways.