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Individual donor strains show no association between fecal microbiota transplantation and successful melanoma immunotherapy

30% and average depth> 3.5). Credit: DOI: 10.1186 / s12866-021-02312-0″ width =”800″ height =”530″/>

WSS score from FMT using a single donor / recipient pair. Davar et al. The WSS score was determined by comparing the donor sample with the sample of all available pairs of recipients using the data from. The number of samples before and after FMT from each recipient varies, and all the samples used in the analysis are listed in Table S1. The WSS scores for each donor / recipient pair were grouped into different color boxes (see the diagram keys in the diagram for more information). This figure contains the major species found in the faeces sample and the common species observed in the two different datasets used in this study (Baruch et al. And Davaret al.). The remaining species found in this dataset are summarized in Figure S2 and the WSS scores for all pairwise comparisons are shown in Table S3. White boxes indicate microbial strains for which association could not be reliably determined due to a pair of samples that did not meet the WSS analysis criteria (minimum coverage> 30% and average depth> 3.5). Credit: DOI: 10.1186 / s12866-021-02312-0

A mixture of microorganisms in the intestine can shape a person’s immune response. For example, in melanoma immunotherapy, the composition of the gut microbiota correlates with the effectiveness of anti-PD-1 therapy in animal models and cancer patients.

One clinical trial published this year of Chemistry Put Fecal transplant From patients with successful anti-PD-1 therapy for melanoma to the colon of patients with melanoma who are resistant to anti-PD-1 therapy. The recipient then received anti-PD-1 therapy. Researchers found rapid and durable microbiota perturbations in recipients, and 6 out of 15 patients benefited from compound therapy. Researchers have concluded that fecal microbiota transplantation can overcome resistance to anti-PD-1 therapy.

Marnix E, University of Alabama at Birmingham. Heersink School of Medicine researchers use the fecal metagenomic DNA sequencing dataset from that study and the DNA sequencing dataset from two other studies to determine if a particular donor strain has been established. Did. Whether in recipient patients and their donor strains were correlated with successful treatment outcomes.

Researchers Dr. Hyunmin Koo and Dr. Casey Morrow can use the microbiota “fingerprint” method developed at UAB to identify a particular single strain of a bacterial species. This method uses powerful genomic tools and supercomputers to analyze large amounts of genetic data from metagenomic sequences in fecal samples.

This new bioinformatics technology, among other studies, has emerged as a new microbial strain after obesity surgery and inhibitory antibiotics, as well as donor microbial strains 2 years after fecal microbiota transplantation to treat recurrent Clostridium difficile. Previously demonstrated stable sustainability. Infection.

Now, BMC Microbiology, Koo and Morrow report that individual differences between melanoma patients did not correlate with response to anti-PD-1 therapy for fecal-dominant donor microbes in recipient patients after fecal microbiota transplantation.

In detail, they are Baruch et al. We analyzed the metagenomic sequence dataset published by.of Chemistry In 2021, we discovered that the presence of symbiotic donor microbes in the feces of recipient patients after transplantation of the fecal microflora did not correlate with the patient’s response to immunotherapy.

They also analyzed the metagenomic sequences published by Davar et al.of Chemistry “From the Davaretal. Dataset, four patients who responded to immunotherapy had donor-related strains after fecal microbiota transplantation, but two patients who did not respond to immunotherapy also had donor strains after fecal microbiota transplantation. I had it, “Morrow said. “Importantly, no donor microbes were identified in the feces of one recipient, post-fecal microbiota transplant, who responded to immunotherapy.”

View vertical sequence data set From Davar et al. Analyzing fecal samples up to 18 months after transplantation, two patients who responded to immunotherapy revealed both donor and recipient strains at different times after fecal microbiota transplantation. This ongoing competition for fecal dominance over time between donor and recipient strains further supports the inconsistent association between donor microbes in the recipient’s faeces and their response to immunotherapy. Morrow says.

Koo and Morrow also analyzed metagenomics datasets from a study by James et al.of Nature immunology This study analyzed the microbial flora associated with the mucosa of the intestinal epithelium of the normal human cecum, transverse colon, and sigmoid colon to gain insight into the interaction of microorganisms with the human immune system.

UAB analysis showed significant strain sharing between the transverse cecal colon and the sigmoid colon of the cecum for the two bacterial species. The cecum is at the beginning of the colon, where it connects to the small intestine. The transverse colon is in the center of the colon and the sigmoid colon is at the end near the rectum.

“Therefore, these results indicate that strain sharing occurs for symbiotic strains of the intestinal epithelium over the entire length of the normal colon,” Morrow said. “This suggests a large community structure that extends throughout. colon It interacts with the immune system and may affect the ability of donor microorganisms to derive from fecal microbiota transplants and promote a response to immunotherapy. These niches may help recipients resist colonization of donor microorganisms. stock..

“The results of our strain tracking analysis are Transplant Invasion of donor microorganisms into existing microbial communities does not guarantee comprehensive replacement of recipient microorganisms. donor Microorganisms, And this provides new insights to explain the inter-individual variation of fecal microbiota transplantation, Immunotherapy“Morrow said.


Obesity surgery leads to the emergence of new microbial strains in the human fecal community


For more information:
Hyunmin Koo et al, Mismatch between dominant symbiotic donor microorganisms in recipient feces after fecal transplantation and response to anti-PD-1 immunotherapy, BMC Microbiology (2021). DOI: 10.1186 / s12866-021-02312-0

Quote: Individual donor strains obtained from https://medicalxpress.com/news/2021-10-individual-donor-strains-link-fecal on October 7, 2021 for successful fecal microbiota transplantation and melanoma immunotherapy Not shown to be related to (October 7, 2021) .html

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Individual donor strains show no association between fecal microbiota transplantation and successful melanoma immunotherapy

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