Assessment and reduction of risk of graft-versus-host disease

A method of assessing risk, of a candidate human transplant donor, of inducing graft versus host disease (GVHD) in a human transplant recipient, said method comprising:

• (a) comparing a candidate gene expression profile derived from a CD4+ and/or CD8+ T cell sample from said candidate human transplant donor to a corresponding reference gene expression profile, wherein said candidate gene expression profile comprises a candidate expression value for a TCIRG1 nucleic acid;
• wherein said reference gene expression profile comprises a reference expression value for a TCIRG1 nucleic acid, said reference gene expression profile being derived from a comparison of:
• (i) a GVHD+ expression profile comprising a GVHD+ expression value for a TCIRG1 nucleic acid derived from a CD4+ and/or CD8+ T cell sample obtained from a human transplant donor known to have induced GVHD in a human transplant recipient with (ii) a GVHD− expression profile comprising a GVHD− expression value for a TCIRG1 nucleic acid derived from a CD4+ and/or CD8+ T cell sample obtained from a human transplant donor known to have not induced GVHD in a human transplant recipient, whereby said reference expression value is determined as being (A) the level of expression midway between said GVHD+ expression value and said GVHD− expression value whereby the midway level separates a GVHD+ class comprising said GVHD+ expression value from a GVHD− class comprising said GVHD− expression value;
• (B) the level of expression between said GVHD+ expression value and said GVHD− expression value defined as separating expression values into GVHD+ and GVHD− classes on the basis of discriminatory analysis;
• or (C) both (A) and (B);
• and
• (b) assessing risk of said candidate human transplant donor of inducing GVHD in a human transplant recipient in accordance with said comparing step of said candidate gene expression profile with said reference gene expression profile,
• wherein said candidate expression value and said reference expression value are obtained by determining the level of expression of said TCIRG1 nucleic acid.