BLOG: Nomenclature in GVHD — words matter
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Editor's note: This article is part of the ASTCT Update blog. To read more from this blog, click here.
For years now, transplant physicians have spoken different languages when referring to a matter of utmost relevance — graft-versus-host disease.
Here is a practical example: If a patient with lower gastrointestinal acute GVHD with a volume of stools of 900 ml per day with bloody stools — without another explanatory cause — is scored according to the original Glucksberg criteria, it would be a grade 2 lower GI. However, when graded according to Mount Sinai Acute GVHD International Consortium (MAGIC) criteria, the same patient would fall under grade 4.
This difference impacts both treatment and prognosis, so one can see where the confounding begins.
This issue has not gone unnoticed. Several attempts have been made throughout the decades to standardize criteria.
The latest and most cited is the EBMT-NIH-CIBMTR Task Force position statement on standardized terminology and guidance for GVHD assessment.
In this position statement — which only addresses definitions, not treatment — acute GVHD refers to an inflammatory response in exclusively skin, liver or GI tract (upper and/or lower). The diagnosis must occur in the absence of chronic GVHD and should ideally — but not necessarily — be supported by histological findings.
The proposed criteria to grade acute GVHD is MAGIC.
On the other hand, chronic GVHD diagnosis relies on either specific or distinctive signs accompanied by additional confirmation (eg, biopsy) in at least one target organ (eg, skin and appendages, mouth, eyes, genitalia, esophagus, lungs, muscles or fascia).
The proposed criteria to grade chronic GVHD is 2014 NIH Consensus on Chronic GVHD.
“Overlap chronic GVHD subtype” was defined by the diagnosis of chronic GVHD together with acute GVHD manifestations of the skin, liver or gut.
Other causes must be ruled out before GVHD is diagnosed, and this complicates things further.
For example, a patient with diarrhea could be judged to be affected by GVHD until biopsy shows gut compromise by cytomegalovirus. If antiviral treatment is started and diarrhea stops, the diagnosis of GVHD must be struck out of the patient's diagnosis.
It is worth mentioning that none of the scores have an adjusting method if more than one cause is present for a sign/symptom.
For example, bilirubin elevation due to GVHD and drug-induced liver injury both might be present in the same patient, but scoring is done as if GVHD is the only agent (though we know that is not the case). In this scenario, both diagnoses remain.
As we learn more about the pathophysiology of GVHD, it is imperative that we get together and use the same terminology so our tower may be built upon education, not confusion.
References:
Schoemans HM, et al. Bone Marrow Transplant. 2018;doi:10.1038/s41409-018-0204-7.
Schoemans HM. Bone Marrow Transplant. 2018;doi:10.1038/s41409-017-0017-0.