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Determining the Prevalence, Incidence, and Risk for Thrombotic Microangiopathy After Hematopoietic Stem Cell Transplantation

October 20, 2021

A retrospective study published in May in the Journal of Personalized Medicine analyzed data on hematopoietic stem cell transplant (HSCT) from 42 institutions that are part of the Pediatric Health Information System network between the years 2000-2012 to better understand the prevalence, incidence, and risk factors for developing the post-transplant complication thrombotic microangiopathy.

Leading the study were UPMC Children’s Hospital of Pittsburgh Division of Pediatric Hematology/Oncology fellow and first author Archana Ramgopal, DO, and director of pediatric sickle cell research, Ramasubramanian Kalpatthi, MD (senior author). Joining Drs. Ramgopal and Kalpatthi were Shiva Sridar, and Jignesh Dalal, MD, from Case Western Reserve Rainbow Babies Children’s Hospital.

Thrombotic microangiopathy is a severe complication experienced by some patients after HCST. However, there is uncertainty surrounding the prevalence and incidence of the disorder, who may be most at risk for developing the condition, and which patient cohorts have an increased chance of mortality. Coupled with the current lack of consensus on diagnostic criteria, there is an incomplete understanding of the molecular and cellular mechanisms driving the formation and severity of thrombotic microangiopathy in HSCT patients.

Study Highlights

Dr. Ramgopal and Kalpatthi’s study examined data from 12,369 cases of HSCT in children, adolescents, and young adults under the age of 21 at the time of transplantation. They identified 93 cases of thrombotic microangiopathy (TMA), representing 0.8% of the total cohort. Within the cluster of TMA cases, they observed a mortality rate of 30%.

In their analysis, TMA was more often associated with allogeneic HSCT and peripheral blood stem cell transplant cases. Additionally, those individuals with diagnosed cases of cytomegalovirus infection, herpesvirus 6, graft-versus-host disease, and fungal infections also had a higher association with TMA.

Of these associative factors for TMA, only herpesvirus 6 was found to be both a risk factor for acquiring TMA and a risk for higher rates of mortality.

Other associated complications identified in the patient cohort include hypertension and renal failure.

An important contribution to the understanding of TMA from this study is the association of various infections to increased rates of the disorder, a component not fully appreciated prior to this analysis.

Dr. Ramgopal and Kalpatthi’s analysis identifies additional risk scenarios for the disease that clinicians and transplantation protocols should be cognizant of, and it sets the stage for further analysis and follow-up investigations to better understand the risks for developing TMA and potential therapeutic interventions.

Learn more about the study and its findings and implications for clinical practice at the link below.


Ramgopal A, Sridar S, Dalal J, Kalpatthi R. Thrombotic Microangiopathy: Multi-Institutional Review of Pediatric Patients Who Underwent HSCT. J Pers Med. 2021 May 25; 11(6): 467.