Introduction

Stem cells, are produced by the bone marrow, have the ability to become specific blood cells, and can be transplanted to treat many diseases. This is known as a stem cell transplant and involves replacing damaged blood cells with healthy ones. There are different types of stem cell transplants depending on where the stem cells are sourced from, with varying advantages and disadvantages. Although stem cell transplants can be used to treat severe conditions such as leukaemia, side effects that can arise from this treatment. Side effects can occur during treatment, immediately after treatment and a longer time after treatment. It is important to understand these side effects so that patients understand the potential downfalls of undertaking stem cell transplants. Understanding them in greater depth could also lead to further research into stem cell transplant methods, which could reduce some of these effects, improving the treatment for patients. This would help improve the quality of life of the patients as well as aid with their treatment.

What can a stem cell transplant be used for?

Stem cell transplants can be used to help treat many diseases such as:¹

• Acute lymphoblastic leukaemia
• Acute myeloid leukaemia
• Inherited bone marrow failure syndromes
• Inherited immune deficiency syndrome
• Metabolic disorders
• Myelodysplastic syndromes
• Myeloproliferative neoplasms
• Potential future use in autoimmune diseases
• Severe aplastic anaemia
• Sickle cell disease
• Solid tumours
• Transfusion-dependent thalassemia

Types of stem cell transplant

Stem cell transplant refers to the general act of transplanting stem cells to replace blood cells in a patient via a needle but there are more specific types.  Peripheral blood stem cell transplant is when the stem cells are collected from the blood, whilst bone marrow transplant refers to the collection from bone marrow. A cord blood transplant can also occur when the cells are collected from the umbilical cord blood. In all the treatments, the stem cells replace cells destroyed via the bloodstream. Stem cell transplants can be split up depending on who donates the stem cells. Here are the 3 main types:

• Autologous stem cell transplant means the stem cells are collected from the patient. There is a lower risk of immune rejection with this method but a higher risk of relapse for the patient
• Allogenic stem cell transplant involves the stem cells being collected from someone who is not the patient. This could be a blood relative or not depending on how close the cells match is to the patient. There is a higher risk of complications with this method with the potential of graft-versus-host disease (GVHD).² To prevent this, patients are treated with immunosuppressive drugs, allowing the patient’s immune system to gradually tolerate the donor cells²
• Syngeneic stem cell transplant means that the patient’s identical twin provides the stem cells. This has the lowest risk of rejection and GVHD compared to normal allogeneic transplants

Immediate side effects

The first side effect that can occur when undergoing a stem cell transplant is during the pre-engraftment period, the time between the infusion of stem cells and the point at which the transplanted stem cells begin to produce new, healthy blood cells. During this time, the immune system is severely weakened, making the patient vulnerable. The toxicities of the regimen used can cause the patient to experience gastrointestinal toxicities, infections as well as organ dysfunction during this period.¹ Neutropenia, a lack of white blood cells, occurs during this period and could lead to infections such as: candidiasis; gram-positive and gram-negative bacteria; herpes simplex virus; and invasive aspergillosis.¹

Sometimes, organ failure can occur, as well as fatality so it is important to monitor patients carefully and provide anti-infectives and general care where necessary.¹ It is not straightforward to know what side effects will occur and how to prevent them. This is because the stem cell transplant type, the disease being treated and the patient’s comorbidities all cause varied risks.¹ As well as the severe side effects in the post-engraftment period, stem cell transplant can cause more general symptoms such as nausea and vomiting. It is important to understand all symptoms and monitor them appropriately in order to provide patients with adequate care and maintain a good quality of life for them.

Short-term side effects

Early on in the post-engraftment period, GVHD can occur for allogenic transplants only. This is because it is caused by the transplanted immune cells identifying the host as foreign and therefore causing an immune reaction.¹ Acute  GVHD can cause many symptoms:

• Anorexia
• Cholestatic jaundice
• Liver dysfunction
• Persistent nausea/ vomiting
• Rash
• Watery diarrhoea

The main treatment used for this is systemic corticosteroids but severe cases of acute GVHD lower survival chances for the individual. Although patients have now recovered from neutropenia experienced pre-engraftment, they are still vulnerable to infections due to lowered cellular and humoral immunity.¹ Patients are also more vulnerable to respiratory viruses like Influenza during this period. It is important to monitor patients post-engraftment due to them being immunosuppressed and susceptible to more infections. Monitoring allows any infections or side effects to be treated rapidly, thus reducing their severity.

Long-term side effects

After a longer period of time post-engraftment, it is possible to be susceptible to chronic GVHD, which can affect multiple organs. Chronic GVHD majorly affects the skin causing lesions as well as affecting lung function. Suffering from chronic GVHD can lead to an individual being more susceptible to opportunistic infections. Similar to short-term effects, patients need to be careful and hygienic as well as be monitored due to their vulnerability to infections. Avoiding large crowds is suggested to reduce the chance of picking up an infection. Chronic GVHD  can be treated with corticosteroids as well as calcineurin inhibitors. Between 6 to 12 months after the transplant, it is imperative for patients to receive their primary immunisations again.¹ After receiving a transplant, there is always the risk of the original disease relapsing, which is the main cause of death. After undergoing the transplant, patients have a higher risk of long-term diseases such as dyslipidaemia, diabetes and cardiovascular disease.¹ Consequently, it is vital that patients are monitored and screened regularly after transplant. This allows comorbidities or relapses to be identified early and treated with a higher chance of survival.  Quality of life has been found to be lower post-transplant, especially if the patient has suffered from chronic GVHD. Patients must be treated with care and supported after the transplant to try and maintain a high quality of life.

Psychological and emotional side effects

Psychological distress is very prevalent in patients who have undergone a stem cell transplant. This can cause recovery, function and mortality outcomes to be impaired so the psychological and emotional side effects of the treatment must be fully understood. Assessing these symptoms correctly can help lead to management of them, ultimately leading to more successful treatment outcomes.³ All patients should be screened for common psychiatric symptoms prior to undergoing a stem cell transplant. This will allow the patient to receive recommendations for managing and mitigating potential symptoms they may experience. For example, psychotherapy could be put in place for an individual before the transplant if they suffer from depression. Psychiatric symptoms often experienced in stem cell transplant patients:³

• Adjustment reactions
• Anxiety
• Delirium
• Demoralisation
• Depression
• Neurocognitive dysfunction
• Post-traumatic stress reactions
• Sleep disruption

Although patients may suffer from psychiatric symptoms due to undergoing a stem cell transplant there are strategies that can be put in place to alleviate these symptoms and increase their quality of life. Pharmacological interventions such as psychiatric medications may be used when necessary. There are also non-pharmacological strategies such as cognitive behavioural therapy which can be used to help the individual. Spiritual care services and social work support can also be used to help patients throughout the process and afterwards.³ It is vital that patients receive support officially from healthcare as well as have a strong support network of family and friends to help them with undergoing a transplant. Having support will increase the patient’s quality of life and allow them to manage their symptoms and changes effectively.

Summary

Stem cell transplants, used to treat diseases like leukaemia and inherited disorders, offer hope but come with significant side effects. These vary depending on the source of the stem cells—whether from the patient, a donor, or an identical twin. Immediate risks include infections and organ dysfunction during the pre-engraftment period, particularly due to weakened immunity. Short-term effects like graft-versus-host disease (GVHD) and infections can arise post-engraftment. Long-term complications may include chronic GVHD, a higher risk of relapse, cardiovascular issues, and psychological distress. To ensure better outcomes, careful monitoring, psychological support, and preventive care are essential for transplant patients.