SDS & Science Snapshots (2022-03-13)

In this issue: New report this week about COVID and COVID-vaccine tolerance in SDS patients; Plus, what is HLA and a Haplo-transplant, inspired by a case report of a Haplo-transplant in Japan

Welcome to our weekly updates on all things SDS and Science. We bring you a digest of recent scientific publications, conferences, and other newsworthy content - all relevant to SDS - with links to more details and learning opportunities. Are you interested in anything specific? Did we miss something? Let us know. Email or message us on Facebook! This is all for you!

New report published last week about COVID and COVID-vaccine tolerance in SDS patients

The COVID-19 poses a significant risk to patients with various chronic medical conditions. It has been a big question since the beginning of the pandemic to what extent SDS patients are at risk, in particular as SDS can cause patients to be immunocompromised due to malignancy or bone marrow failure (BMF). Because patients with SDS can experience neutropenia due to BMF, they carry a higher risk for serious infections - at least bacterial origin - compared with the general population. In this new report, the authors investigate the incidence and severity of COVID-19 in the population of patients with SDS.

Participants in the North American SDS Registry received a survey in the summer of 2021. 73 participants responded. Answers were anonymous.

  • 10 participants experienced COVID-19 All participants who developed COVID-19 were symptomatic of infection, with the most common symptoms being respiratory, such as congestion or cough (70%), and fever (60%). The median duration of symptoms was 4.5 days. One of 10 patients required hospitalization, but did not require supplemental oxygen. Most reported having a short duration of symptoms that did not require hospitalization or result in serious virus-related complications.

  • 18 participants received a COVID-19 vaccine, and actually all of them received two mRNA vaccine doses. Arm pain was the most common side effect (66.7%), followed by fatigue (50%), fever and/or chills (38.9%), and muscle aches (33.3%). Five of the 18 recipients (27.8%) reported experiencing no side effects.

The authors conclude: "Most patients reported a short clinical course with few requiring COVID-19–directed therapy, and only one requiring hospitalization; none experienced significant complications or severe cytopenias. However, these results cannot be generalized to patients with more severe comorbidities, and the relatively small number of patients described limits our ability to comment on risk of developing serious COVID-19 compared with the general population"

Coronavirus disease 2019 and vaccination in patients with Shwachman-Diamond syndrome.

Galletta TJ, Loveless SK, Malsch MM, Shimamura A, Myers KC. Pediatr Blood Cancer. 2022 Mar 6:e29647. doi: 10.1002/pbc.29647. Online ahead of print. PMID: 35253346

What is HLA? What is a Haplo-transplant?

Bone marrow or stem cell transplants are always on the mind of the SDS community, as SDS can make it necessary either due to causing bone marrow failure or MDS/leukemia. If it comes to that, many patients rely on the generosity of stem cell donors who sign up with special registries and volunteer to donate stem cells if a patient in need matches with their HLA type. However, many patients can't find a match.

More information about the need and donation process is available on our website, here.

HLA stands for human leukocyte antigens. HLA are proteins—or markers—on most cells in the body. Our immune system uses HLA to see which cells belong in our body and which do not. These markers are critical for stem cell transplants. The closer the donor's and recipient's HLA type match (are the same), the more likely it is for the recipient to accept the new cells and the new cells not to cause complications (such as Graft versus Host Disease (GvHD)) in the recipient's body. That's why in preparation for a bone marrow transplant, the medical team performs a very thorough search and analysis of potential donors.

Unfortunately, many patients in need of a stem cell transplant don't have a suitable donor - a donor who's HLA type matches with theirs nearly identically - in their family or in the general population/ stem cell registries. The chances of this happening are particularly high in populations of ethnic minorities and mixed race patients.

This is where haploidentical matches/transplants are coming in. A haploidentical transplant is a type of allogeneic transplant. It uses healthy, blood-forming cells from a half- matched donor to replace the unhealthy ones. This is a type of allogeneic transplant where the donor matches exactly half of your HLA. A haploidentical, or half-matched, donor is usually the recipient's mom, dad, or child. Parents are always a half-match for their children. Siblings (brothers or sisters) have a 50% (1 out of 2) chance of being a half-match for each other. It’s very unlikely that other family members (like cousins, aunts or uncles) would be a half-match.

While haploidentical transplant is a newer type of transplant and carries a higher risk of complications such as GvHD or graft failure, it also has some advantages. In particular, because donors are usually a close family members, they are usually very willing to donate and can travel to the medical center where the recipient is, ensuring very fresh stem cells and reducing the chance of delays during transport. They can also be available to donated additional stem cells during recovery, if needed. In many countries, haplo-transplants are preferred due to much higher costs associated with unrelated donors. There are medical centers that specialize in haplo-transplants, and there are many active clinical trials ongoing to improve outcomes.

Another alternative are cord blood stem cells. We will cover that in another post.

This video covers both options in great detail.

New case report of a haplo-transplant in an adult SDS patient

In the SDS community, we have only been aware of one successful haplo-transplant. But last week, a new case report from Japan has been published.

The authors describe their experience treating a 21-year-old male patient with SDS, diagnosed with SDS genetically, as an adult. He developed acute myeloid leukemia (AML) and received a hematopoietic stem cell transplantation from his father, who is human-leukocytic-antigen-haploidentical. The patient received standard conditioning chemotherapy, total body irradiation, and Graft-versus-host disease prophylaxis. Unfortunately, although the patient achieved a complete remission initially, AML relapsed a year later. He passed away of sepsis.

[Haploidentical stem cell transplantation for acute myeloid leukemia associated with adult-onset Shwachman-Diamond syndrome].Uemura Y, Hirakawa T, Matsunawa M, Kozuki K, Saiki Y, Takimoto M, Sano F, Watanabe K, Inoue Y, Arai A. Rinsho Ketsueki. 2022;63(2):94-98. doi: 10.11406/rinketsu.63.94. PMID: 35264508 Japanese.

This report highlights the importance of focusing our research on the prevention of AML and our advocacy efforts on early and wide reaching SDS diagnosis of patients.

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