We will enroll adults admitted to RPCI for chemotherapy or allogeneic hematopoietic stem cell transplantation (HSCT). All of these patients will have indwelling central lines as part of routine care. Blood will be drawn from central lines by nursing staff, and collected in heparinized green-top tubes. We will obtain baseline plasma (pre-treatment), and follow-up plasma samples will be obtained weekly on a fixed schedule. Additional blood collections may be ordered to coincide with clinical events, such as neutropenic fever, diagnosed infection, or other complications of chemotherapy. A maximum of 3 blood collections per week, with no more than 10 ml of blood per collection, will be obtained. The duration of blood collection will be a maximum of 6 weeks (or until the patient is discharged). This period of time will encompass a pre-treatment baseline, the period of chemotherapy-induced marrow suppression and mucotoxicity, and myeloid recovery.Study endpoints will be as follows: (i) plasma mitochondrial DAMP levels assessed by q-PCR of mitochondrial DNA; (ii) plasma cytokine levels; (iii) evaluation of bacterial DNA by PCR using bacterial-specific primers. We will in an exploratory fashion correlate these results with clinical data (e.g., neutropenic fever and culture results). All of these studies will be performed on de-identified batched plasma samples, and will have no impact on clinical treatment decisions.