Methods and compositions for detecting immune system activation

A method of determining immune system activation in a subject, the method comprising one or more of the following steps:

• (a) measuring the amount of 13CO2 in a test sample obtained from a subject that received 13C-labeled palmitate;
• and comparing (i) the amount of 13CO2 in the test sample to (ii) a control, wherein a greater amount of 13CO2 in the test sample than the control indicates immune system activation in the subject;
• and
• (b) measuring the molar percent enrichment in [4,5-13C2]-L-glutamate in a test sample obtained from a subject that received 13C-labeled palmitate;
• and comparing (i) the molar percent enrichment in [4,5-13C2]-L-glutamate in the test sample to (ii) a control, wherein greater molar percent enrichment in [4,5-13C2]-L-glutamate in the test sample compared to the control indicates immune system activation in the subject.

A method of determining whether a subject has a medical condition featuring immune system activation, the method comprising one or more of the following steps:

• (a) measuring the amount of 13CO2 in a test sample obtained from a subject that received 13C-labeled glutamine;
• and comparing (i) the amount of 13CO2 in the test sample to (ii) a control, wherein a greater amount of 13CO2 in the test sample than the control indicates that the subject has the medical condition;
• (b) measuring the amount of 13C-labeled ribose in a population of cells selected from the group consisting of lymphocytes and immune cells, wherein said population of cells is obtained from a subject that received 13C-labeled glutamine;
• and comparing (i) the amount of 13C-labeled ribose in said population of cells to (ii) a control, wherein a greater amount of 13C-labeled ribose in said population of cells than the control indicates that the subject has the medical condition;
• (c) measuring the amount of 13C-labeled glutamine in a test sample obtained from a subject that received 13C-labeled glutamine;
• and comparing (i) the amount of 13C-labeled glutamine in the test sample to (ii) a control, wherein a greater amount of 13C-labeled glutamine in the test sample than the control indicates that the subject has the medical condition;
• and
• (d) measuring the amount of total glutamine in a test sample obtained from a subject that received glutamine;
• and comparing (i) the amount of total glutamine in the test sample to (ii) a control, wherein less total glutamine in the test sample than the control indicates that the subject has the medical condition.

A method of determining whether a subject has a medical condition featuring immune system activation, the method comprising one or more of the following steps:

• (a) measuring the amount of 13CO2 in a test sample obtained from a subject that received 13C-labeled palmitate;
• and comparing (i) the amount of 13CO2 in the test sample to (ii) a control, wherein a greater amount of 13CO2 in the test sample than the control indicates that the subject has the medical condition;
• and
• (b) measuring the molar percent enrichment in [4,5-13C2]-L-glutamate in a test sample obtained from a subject that received 13C-labeled palmitate;
• and comparing (i) the molar percent enrichment in [4,5-13C2]-L-glutamate in the test sample to (ii) a control, wherein greater molar percent enrichment in [4,5-13C2]-L-glutamate in the test sample compared to the control indicates that the subject has the medical condition.

A method of determining whether a subject has an immune disorder selected from the group consisting of graft-versus-host disease, acute graft-versus-host disease, rheumatoid arthritis, psoriasis, Crohn's disease, inflammatory bowel disease, multiple sclerosis, Celiac Sprue, idiopathic thrombocytopenic thrombotic purpura, myasthenia gravis, Sjogren's syndrome, scleroderma, ulcerative colitis, asthma, uveitis, epidermal hyperplasia, cartilage inflammation, bone degradation, arthritis, juvenile arthritis, juvenile rheumatoid arthritis, pauciarticular juvenile rheumatoid arthritis, polyarticular juvenile rheumatoid arthritis, systemic onset juvenile rheumatoid arthritis, juvenile ankylosing spondylitis, juvenile enteropathic arthritis, juvenile reactive arthritis, juvenile Reter's Syndrome, SEA Syndrome, juvenile dermatomyositis, juvenile psoriatic arthritis, juvenile scleroderma, juvenile vasculitis, pauciarticular rheumatoid arthritis, polyarticular rheumatoid arthritis, systemic onset rheumatoid arthritis, ankylosing spondylitis, enteropathic arthritis, reactive arthritis, Reter's Syndrome, dermatomyositis, psoriatic arthritis, vasculitis, myolitis, polymyolitis, dermatomyolitis, osteoarthritis, polyarteritis nodossa, Wegener's granulomatosis, arteritis, polymyalgia rheumatica, sarcoidosis, sclerosis, primary biliary sclerosis, sclerosing cholangitis, dermatitis, atopic dermatitis, atherosclerosis, Still's disease, chronic obstructive pulmonary disease, Guillain-Barre disease, Type I diabetes mellitus, Graves' disease, Addison's disease, Raynaud's phenomenon, glomerular nephritis, or autoimmune hepatitis, the method comprising the steps of:

• (a) measuring the amount of 13CO2 in a test sample obtained from a subject that received 13C-labeled glucose;
• and
• (b) comparing (i) the amount of 13CO2 in the test sample to (ii) a control, wherein a greater amount of 13CO2 in the test sample than the control indicates that the subject has said immune disorder.