--- title: "Dr. Jianyun Liao: Why Is DSA Desensitization Needed Before Stem Cell Transplantation? Is Strong DSA Positivity a Contraindication?" url: "https://www.yyhmedical.com/en/news/dsa-clearance-before-stem-cell-transplantation" type: Article inLanguage: en-US category: Expert Insights datePublished: 2026-01-09 --- # Dr. Jianyun Liao: Why Is DSA Desensitization Needed Before Stem Cell Transplantation? Is Strong DSA Positivity a Contraindication? > Dr. Jianyun LIAO of GoBroad Chunfu Institute of Hematology & Oncology explains how donor-specific antibodies (DSAs) can affect transplantation, why DSA positivity is not an absolute contraindication, and how appropriate desensitization may help improve transplant success. Summary: Dr. Jianyun LIAO of GoBroad Chunfu Institute of Hematology & Oncology discusses donor-specific antibodies (DSAs) before hematopoietic stem cell transplantation in patients with transfusion-dependent severe thalassemia. She explains how DSAs develop, how their strength is assessed using mean fluorescence intensity (MFI), and how they may contribute to graft failure or poor hematopoietic recovery. The article also reviews desensitization strategies including rituximab, bortezomib, plasma exchange, and combination approaches, emphasizing early screening and individualized intervention to reduce transplant-related risk and help patients reach transplantation at the right time.  ![47444833-0fac-4174-ad90-b0dec264e78b.png](https://gaobo-byh-h5.oss-accelerate.aliyuncs.com/images/20260913/59922df01d8c7ed1e6b7f7e98a2399e4_20260913225739.png "59922df01d8c7ed1e6b7f7e98a2399e4_20260913225739.png") For people with transfusion-dependent thalassemia, hematopoietic stem cell transplantation can be thought of as rebuilding the body's blood-forming and immune systems. The goal is for healthy donor stem cells to engraft and establish new, functioning hematopoiesis and immunity. As people with thalassemia grow older, the burden of ongoing transfusions and iron chelation often increases. In patients who have received many transfusions over time, another challenge may emerge: donor-specific antibodies (DSAs). These antibodies can recognize and attack donor cells, potentially interfering with engraftment and increasing the risk of transplant failure. Dr. Jianyun LIAO of GoBroad Chunfu Institute of Hematology & Oncology explains where DSAs come from, how they are assessed, and how DSA levels may be reduced before transplant to help lower transplant-related risk. **What Are Donor-Specific Antibodies, and Where Do They Come From?** When a transplant recipient has previously been exposed to another person's human leukocyte antigens (HLA) through blood transfusions, a prior transplant, pregnancy, or other circumstances, the immune system may develop immunologic memory and produce antibodies. If those antibodies specifically recognize HLA antigens carried by the intended donor, they are called donor-specific antibodies, or DSAs. For patients with thalassemia, repeated red blood cell transfusions can expose the immune system to residual leukocytes and soluble HLA antigens. Over time, this may stimulate antibody formation, and the risk generally increases with a greater number of transfusions. **How Is DSA Strength Assessed, and Why Does It Matter?** DSA strength is commonly assessed using mean fluorescence intensity (MFI). In general, higher MFI values are associated with a greater risk of transplant failure: • MFI 1,000-5,000: low to intermediate risk • MFI 5,000-10,000 or C1q positive: high risk • MFI >10,000: very high risk • MFI >20,000: often associated with a very high risk of transplant failure **1\. Graft Failure or Delayed Engraftment** Patients with moderate or higher DSA levels (MFI >5,000) are more likely to experience primary graft failure. DSAs can attack donor hematopoietic stem cells through complement-mediated mechanisms or antibody-dependent cellular cytotoxicity, preventing the donor cells from successfully engrafting in the recipient. **2\. Poor Hematopoietic Recovery** Even when DSA levels are not high enough to cause immediate and complete graft failure, they may still interfere with donor stem cell expansion after transplantation. This can lead to delayed neutrophil and platelet recovery, persistent cytopenias, and prolonged transfusion dependence. This condition is often referred to as poor graft function. Data presented at meetings of the European Society for Blood and Marrow Transplantation (EBMT) have reported poor graft function rates of 28%-42% among DSA-positive patients. Poor graft function can significantly affect quality of life and may increase the risk of serious complications such as infection and bleeding. **3\. Higher Risk of Other Complications** More intensive immunosuppressive treatment may be needed to overcome the effects of DSAs, which can in turn increase risks such as infection and drug-related toxicity. **How Can the Impact of DSAs Be Reduced?** DSA positivity is not an absolute contraindication to transplantation. With appropriate screening, desensitization, and an individualized transplant strategy, DSA levels can often be reduced, helping lower transplant-related risk and improve the likelihood of successful engraftment. - Before transplant, treatments such as rituximab and bortezomib may be used to reduce antibody production. High-dose intravenous immunoglobulin (IVIG) may also be given as part of a desensitization strategy to help reduce the impact of circulating antibodies. - Plasma exchange or immunoadsorption: these approaches remove antibody-containing plasma from the patient's blood and return the blood cells together with replacement plasma or fluid, allowing DSA levels to be reduced more rapidly. - Donor platelet or buffy coat infusion before transplant may also be used to help neutralize antibodies. For very high-risk patients with DSA MFI >10,000 or C1q positivity, a combination desensitization approach is often used to lower antibody levels as much as possible before transplantation and improve the chance of successful engraftment. *Important Considerations* *• DSA desensitization should be individualized. Before treatment, the medical team needs to assess antibody strength, including MFI level, complement-binding status such as C1q positivity, and the patient's overall condition.* *• During desensitization, DSA levels, hematopoietic function, and infection risk should be monitored closely. In some patients, antibody levels may rebound.* *• When feasible, choosing a donor against whom the patient does not have DSAs can help avoid this additional source of transplant risk.* Hematopoietic stem cell transplantation is an important treatment option for people with thalassemia. As patients grow older, the cumulative burden of transfusion and iron chelation may increase, and the likelihood of developing DSAs may also rise. For DSA-positive patients, identifying and addressing these antibodies before transplantation can help improve the chance of engraftment, reduce transplant-related complications, and support better quality of life. If a patient meets transplant indications, has a suitable donor, and is medically fit for transplantation, the timing of transplant should be discussed carefully with the treating team. Please note: This article is for general educational purposes only. Because every patient's situation is different, please discuss your individual circumstances with your treating physician, who can provide recommendations based on a full clinical assessment. --- Original (HTML):https://www.yyhmedical.com/en/news/dsa-clearance-before-stem-cell-transplantation This is a clean Markdown mirror for large language models; the original page is authoritative.