This study evaluates the factors that contribute to chronic graft-versus-host disease, which is a complication that can occur after allogeneic hematopoietic cell transplantation.

PRIMARY OBJECTIVE:

I. Characterize immune cells and their subsets in peripheral blood of patients who develop and do not develop chronic graft-versus-host disease (cGVHD).

OUTLINE: This is an observational study. Patients are assigned to 1 of 2 cohorts.

COHORT 1: Patients undergo blood, saliva/buccal, and stool sample collection for up to 2 years on study. Patients also have their medical records reviewed on study.

COHORT 2: Patients undergo a one-time blood, saliva/buccal, and stool sample collection and have their medical records reviewed on study.

Inclusion Criteria:

• * BOTH COHORTS:

  • Documented written informed consent of the participant and/or parent/guardian.

    • Assent from pediatric participants will be documented per institutional policies and practice.

  • Patients who have received allogeneic hematopoietic cell transplant (HCT) regardless of donor type, condition regimen, or GVHD prophylaxis.

  • Age: ≥ 18 years or ≥ 7 years if 30 kg and above

  • Willingness to:

    • Provide blood sample(s), stool, saliva, and buccal mucosa,

    • If applicable: Permit medical record/ clinical laboratory result review

      • COHORT 1:

  • Patients who have received allogeneic hematopoietic cell transplant (HCT) regardless of donor type, condition regimen, or GVHD prophylaxis.

    • COHORT 2:

  • Patients diagnosed with cGVHD at any time-point after allogeneic HCT regardless of donor type, condition regimen, or GVHD prophylaxis.

Exclusion Criteria:

• * Women of childbearing potential: Pregnant/nursing

  • Individuals with impaired decision-making capacity
  • An employee who is under the direct/ indirect supervision of the PI/ a co-investigator/ the study manager
  • A direct study team member

Patients who have received allogeneic hematopoietic cell transplant.