Autoimmune lymphoproliferative syndrome (ALPS) is a rare disease characterized among others things by chronic massive, nonmalignant lymphoadenopathy and splenomegaly. ALPS has been defined as a defect in the lymphocyte apoptotic pathway and is associate with inherited mutations in the FAS, Fas ligand and caspase 10 genes. However, 20-30% of the patients clinically diagnosed do not present any known mutations. We report here the case of a 10 years old girl with a probable diagnostic of ALPS. The patient meet the criteria of the disease nevertheless, the sequencing analysis of the genes involved did not present mutations. In order to go further in the knowledge of the ailment of this patient, we performed the study of the proteome of her peripheral blood mononuclear cells (PBMC) population. We compare the expression of proteins in the sample of the patient with a sample of a same years old healthy girl. The information achieved will provide us valuable elements to make a more integral diagnostic of ALPS and also, others autoimmune diseases.