Dear Editor,

We read with interest the article, “Pretransplant nutritional habits and clinical outcome in children undergoing hematopoietic stem cell transplant” by Tavil and associates.¹ This study investigated the effects of pretransplant energy and nutrient contents, nutritional habit (probiotic and prebiotic intake), and the nutritional status on clinical outcomes and deleted complications of hematopoietic stem cell transplant that may affect the transplant.

High-dose chemotherapy and radiation therapy may be required before a transplant can cause frequent and severe gastrointestinal adverse effects, leading to poor oral intake and requiring assistance to maintain adequate nutrition. Ensuring adequate nutrition is important, and a nutritional replacement is necessary.²

Bloodstream infections, mainly during pre-engraftment neutropenia, represent a significant cause of morbidity in patients undergoing a hematopoietic stem cell transplant.³ Risk factors are associated with this complication, but presence of granulocytopenia, central venous catheters, and acute graft-versus-host disease (aGVHD) represent the leading predisposing conditions.⁴

Bacterial lipopolysaccharide is significant in developing aGVHD.⁵ Some authors report that the proinflammatory potency of bacterial lipopo­ly­saccharide varies from bacterial species to species.⁶

The gastrointestinal tract holds a collection of microorganisms that form an individual microbiota that this typical for each person.⁷ Chronic inflammatory bowel disease appears to be the result of a genetically determined unbalanced immune response to ubiquitous luminal bacterial antigens.⁸

Probiotic microorganisms recently have received much attention owing to reports of beneficial effects in treating various chronic intestinal inflammatory conditions.⁹ The definition of probiotics has evolved from a live active culture that improves the balance of the gut microbiota composition to specific effects; particularly, the immunomodulatory potential of clearly defined strains.¹⁰ Bacteria strains with beneficial properties, potential sources of probiotics, frequently belong to the such genera Bifidobacterium and Lactobacillus, some of which exhibit powerful anti-inflammatory properties.7 Indeed, probiotic therapy has attracted research interest in human infectious, inflammatory, and allergic diseases. Current interest in nutrition is directed toward developing dietary compounds, such as probiotic bacteria.¹¹

We agree with authors who write that we should evaluate the nutrient contents and nutritional habits of patients, because they may influence transplant outcomes. However, precise information regarding the strain used in the yogurt is needed to estimate the negative correlation that these authors claim.

The joint FAO/WHO Expert Communication recommended that strains be named according to the International Code of Nomenclature.¹² Indeed, the biology of a probiotic strain cannot be extrapolated to another strain, even within the same species.¹³ The properties of a specific strain may be of significant importance when studying the biological and clinical effects of probiotic bacteria.

Furthermore, there is increasing evidence that probiotic therapy can effectively treat inflammatory bowel disease.⁶ To address the effect that modulation of the bowel flora has on aGVHD, some authors have used a well-described murine transplant model in which aGVHD is induced across a haploidentical major histocompatibility complex mismatch. The model is characterized by severe damage of the bowel mucosa, high-serum bacterial lipopolysaccharide levels after transplant, and strong release of proinflammatory cytokines.^14,15 Gerbitz and associates6 showed that oral administration of Lactobacillus rhamnosus GG, before and after a transplant, results in improved survival and a reduced incidence of aGVHD.

Also, probiotics intended to control H. pylori have attracted attention. Lactobacillus gasseri OLL2716 has proved effective in suppressing H. pylori colonization of the stomach and reducing gastric mucosal inflammation, and it has been reported that an L. gasseri OLL2716 strain contained in a yogurt drink may colonize the gastric mucosal layer in infected patients. But the mechanisms by which these bacteria mediate their effects remain unclear.¹⁶

Therefore, the use of probiotics should be considered relevant if selecting microorganism strains to achieve specific health targets. This may reveal the full effect of its therapeutic potential. Further studies are necessary to explore and confirm any beneficial effects of probiotics in hematopoietic stem cell transplants.

References:

1. Tavil B, Koksal E, Yalcin SS, Uckan D. Pretransplant nutritional habits and clinical outcome in children undergoing hematopoietic stem cell transplant. Exp Clin Transplant. 2012;10(1):55-61.
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2. Rodgers C, Young A, Hockenberry M, Binder B, Symes L. The meaning of adolescents' eating experiences during bone marrow transplant recovery. J Pediatr Oncol Nurs. 2010;27(2):65-72. doi: 10.1177/1043454209355984.
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3. Sarashina T, Yoshida M, Iguchi A, et al. Risk factor analysis of bloodstream infection in pediatric patients after hematopoietic stem cell transplantation. J Pediatr Hematol Oncol. 2013;35(1):76-80. doi: 10.1097/MPH.0b013e3182677f35.
   CrossRef - PubMed
4. Mikulska M, Del Bono V, Bruzzi P, et al. Mortality after bloodstream infections in allogeneic haematopoietic stem cell transplant (HSCT) recipients. Infection. 2012;40(3):271-278. doi: 10.1007/s15010-011-0229-y.
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5. Cooke KR, Olkiewicz K, Erickson N, Ferrara JL. The role of endotoxin and the innate immune response in the pathophysiology of acute graft versus host disease. J Endotoxin Res. 2002;8(6):441-448.
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6. Gerbitz A, Schultz M, Wilke A, et al. Probiotic effects on experimental graft-versus-host disease: let them eat yogurt. Blood. 2004;103(11):4365-4367.
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7. Isolauri E, Salminen S, Ouwehand AC. Microbial-gut interactions in health and disease. Probiotics. Best Pract Res Clin Gastroenterol. 2004;18(2):299-313.
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8. Hogan SP, Waddell A, Fulkerson PC. Eosinophils in infection and intestinal immunity. Curr Opin Gastroenterol. 2013;29(1):7-14. doi: 10.1097/MOG.0b013e32835ab29a.
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9. Schultz M, Schölmerich J, Rath HC. Rationale for probiotic and antibiotic treatment strategies in inflammatory bowel diseases. Dig Dis. 2003;21(2):105-128.
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10. Hedin CR, Mullard M, Sharratt E, et al. Probiotic and prebiotic use in patients with inflammatory bowel disease: a case-control study. Inflamm Bowel Dis. 2010;16(12):2099-2108. doi: 10.1002/ibd.21286.
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11. Saad N, Delattre C, Urdaci MC, Schmitter JM, Bressollier, P. An overview of the last advances in probiotic and prebiotic field. LWT — Food Sci Technol. 2013;50(1):1-16.
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12. Health and Nutritional Properties of Probiotics in Food Including Powder Milk with Live Lactic Acid Bacteria: Report of a Joint FAO WHO Expert Consultation on Evaluation of Health and Nutritional Properties of Probiotics in Food Including Powder Milk with Live Lactic Acid Bacteria, American Córdoba Park Hotel, Córdoba, Argentina, October 1-4, 2001
13. Azaïs-Braesco V, Bresson JL, Guarner F, Corthier G. Not all lactic acid bacteria are probiotics, ...but some are. Br J Nutr. 2010;103(7):1079-1081. doi: 10.1017/S0007114510000723.
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14. Hill GR, Cooke KR, Teshima T, et al. Interleukin-11 promotes T cell polarization and prevents acute graft-versus-host disease after allogeneic bone marrow transplantation. J Clin Invest. 1998;102(1):115-123.
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15. Hill GR, Crawford JM, Cooke KR, Brinson YS, Pan L, Ferrara JL. Total body irradiation and acute graft-versus-host disease: the role of gastrointestinal damage and inflammatory cytokines. Blood. 1997;90(8):3204-3213.
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16. Fujimura S, Watanabe A, Kimura K, Kaji M. Probiotic mechanism of Lactobacillus gasseri OLL2716 strain against Helicobacter pylori. J Clin Microbiol. 2012;50(3):1134-1166. doi: 10.1128/JCM.06262-11.
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