Factors Associated with the Platelet Graft in Hematopoietic Precursor Cell Transplant Patients in a Third Level Hospital in Mexico
Authors: Pelayo Mena Cynthia , Valero Saldaña Luis Manuel , Acosta-Maldonado Brenda Lizeth , Perez Camargo Dana , Urbalejo Ceniceros Victor Itaí 
Published: November 2020

Factors associated with the platelet graft in hematopoietic precursor cell transplant patients in a third level hospital in Mexico
Introduction
The success of TCPH is affected by various factors such as graft versus host disease (GVHD), relapse, treatment-related toxicity, and infection, leading to increased morbidity and mortality. Thrombocytopenia is almost universal in the pre-graft period in patients sometimes on TCPH, delayed platelet recovery beyond the expected time occurs in 5% to 37% of patients sometimes on TCPH.
Various studies have described a relationship between platelet graft delay and CD34 + cell dose, pre-transplant disease status, source of the graft, blood group, and even the development of platelet refractoriness. Male receptor gender and elevated serum hepcidin level have also been associated as risk factors for delayed platelet graft.
Aims
To assess the factors associated with late platelet grafting in the post-transplant patient of hematopoietic precursor cells.
Methods
Retrospective, cross-sectional, observational and descriptive study. From January 2018 to December 2019.
Results
101 patients were included, 59.4% men and 40.6% women. The mean age was 37 years. Patients diagnosed with MM were 24.8%, ALL 22.8%, NHL 19.8%, HL 15.8%, AML 14.9%, CML 1%. 73.3% of the patients had a CR prior to transplantation and 26.7% had a PR.
BUCY was used as a conditioning scheme in 27.7%, PEAM 27.7%, FLUBUCY 16.8%, BORMEL 11.9%, BUMEL 9.9%.
55.4% of the patients underwent autologous transplantation and 44.6% underwent allogeneic. During the peritransplantation period, 32.7% had some type of infection, 21.8% developed GVHD, and 12.9% had a relapse of the disease. Of the 101 patients, 85.1% were alive at the time of this study; 3 of these patients did not achieve a platelet graft, 2 of them required a thrombopoietic receptor agonist, 2 had a diagnosis of ALL and one had MM, the 3 patients died before the +100 day due to infectious complications. The mean platelet apheresis transfusion was 1.80. The mean recovery time for neutrophils was 11 days and for platelets 13 days.
The mean follow-up was 25 months. The overall one-year survival is 70% in allogeneic post-transplant patients and 95% in autologous post-transplant patients
Of the factors evaluated using the KM method to relate them to overall survival, statistical significance was found: relapse (p = 0.0001), GVHD (p = 0.002) and more than 5 x 106CD34 infused (p = 0.047).
The recovery time for the platelet and neutrophil graft was not statistically significant, p=0.288 and p = 0.421 respectively.
GVHD was the only factor associated with relapse-free survival.
When performing a bivariate analysis, the factors with statistical significance (p= &lt;0.05) related to the platelet graft were: allogeneic transplantation, the amount of CD34 infused, infections and GVHD.
Discussion
The mean time for neutrophil and platelet grafting was 11 and 13 days, respectively. According to the bivariate analysis performed, allogeneic transplantation confers 6.7 times more risk for the platelet graft to be greater than 13 days p= 0.0001.
Begeman et al. have reported that there is an inverse relationship between the amount of CD34 infused and the time of platelet grafting. This observation was not reproducible in our population since we found that an amount greater than 5 x 106 CD34 conferred a 4.4-fold risk for the platelet graft to be greater than 13 days, with a p= 0.0001. This could suggest that it is probable that an amount greater than 5 x 106 could have an opposite effect and prolong the grafting time; this will have to be taken with reserve since in our multivariate a significant result was not confirmed.
Overall survival and relapse-free survival were not affected by neutrophil or platelet graft time as described in some studies; probably due to the size of our sample and that in other series the follow-up time has been comparable. The median of relapse-free survival was reached at 5 months and it should be noted that relapse was the only factor that had a negative impact on the survival of our population, and was observed only in patients undergoing allogeneic transplantation; therefore, those patients who present a relapse of the disease have a poor prognosis, whose median was reached at 25 months, so perhaps it would be worthwhile to search for available rescue therapies in these patients.

Disclosures
No relevant conflicts of interest to declare.