Stem Cell Therapy

First bone marrow transplants

A 2019 historical review dates clinical bone marrow transplantation to 1957, when Donnall Thomas reported six patients given bone marrow to restore blood formation after it had been ablated by radiation or drug toxicity. Knowledge of tissue-matching genes and of immune responses to transplants was limited then, and all of those first patients died, although transient chimerism was recorded. The review says that by 2018 hundreds of thousands of hematopoietic transplants had been performed, using several cell sources and preparative regimens, and that graft-versus-host disease has remained the most challenging complication.

Widening donors and cell sources

The same review describes how donors and sources changed. Matched sibling donors lowered but did not remove the risk of graft-versus-host disease, unrelated matched donors raised it again, and haploidentical donors, who share one of two HLA haplotypes with the recipient, came into use in the 1990s. Cord blood is described as practical mainly for child recipients because a single donation rarely holds enough stem cells. The International Society for Stem Cell Research (ISSCR) guide adds that blood stem cells can be collected from bone marrow, circulating blood or umbilical cord blood, and that doctors have transferred healthy blood stem cells for more than 50 years.

Commercial clinics adopt the vocabulary

Alongside hospital transplantation, a separate set of commercial offerings has used the same vocabulary. A 2017 case series describes adipose tissue-derived 'stem cells' increasingly used by 'stem-cell clinics' in the United States and elsewhere, partly because the cells are easy to obtain and prepare. A 2020 orthopedic annotation voices concern about a growing number of centers worldwide making unwarranted claims or performing risky biological procedures, and a 2018 review analyzed the factors behind what it calls stem cell tourism. These sources describe the phenomenon; none of those reviewed here gives a start date for it.

Stem cells and stem cell treatments

The ISSCR guide defines stem cells by two properties: they can divide to make more of themselves, and they can generate specialized cell types such as skin, muscle or blood cells. It separates pluripotent stem cells, which include embryonic and induced pluripotent cells and can become any cell in the body, from tissue-specific or adult stem cells, which generate some or all of the cell types of their organ. A stem cell treatment, in the guide's wording, uses stem cells or the specialized cells derived from them to replace or repair a patient's damaged or absent cells or tissues, and the cells may come from the patient or from a donor.

Autologous, allogeneic and the marketing label

The National Cancer Institute (NCI) uses autologous for stem cells taken from the patient and allogeneic for cells from a donor, relative or unrelated, whose HLA type must match closely to limit immune rejection. In clinic marketing the label 'stem cell' is applied more loosely. The 2017 ophthalmology case series puts the term in quotation marks for the cell pellet made from liposuction fat by enzyme digestion and centrifugation, which it calls stromal vascular cells, and a 2026 knee meta-analysis treats this stromal vascular fraction as biologically distinct from cultured adipose-derived mesenchymal stromal cells.

The ISSCR guide sorts treatments into three groups: approved treatments backed by convincing evidence of efficacy and safety, investigational treatments being tested in clinical trials, and unproven treatments that have not gone through a rigorous multi-step trial process. It also says that many treatments sold by clinics have not been shown to contain stem cells, and an orthopedic annotation makes a similar point about preparations sold without sufficient data on their true content. This page follows the guide's three-way split.

Hospital transplantation

According to the NCI, a stem cell transplant restores blood stem cells in people whose own were destroyed by high-dose chemotherapy or radiation, so that the body can again make white blood cells, red blood cells and platelets. In an autologous transplant the cells are taken from the patient beforehand, and in an allogeneic transplant they come from a donor. Review authors describe conditioning regimens that have become milder since the late 1990s and the use of cyclophosphamide soon after infusion to reduce graft-versus-host disease.

A documented adipose-derived injection procedure

The 2017 case series reports the procedure as documented for three patients. Tumescent liposuction removed 60 ml of fat near the navel, 35 ml of blood was centrifuged to obtain platelet-rich plasma, and the washed fat was treated with enzyme for 12 minutes at 37 degrees Celsius. The resulting stromal vascular cell pellet was resuspended in 1 to 6 ml of platelet-rich plasma and injected into the vitreous of both eyes on the same day. The authors call bilateral same-day intravitreal injection atypical and say the procedure had never been studied in a clinical trial.

Other routes and products

Other reported routes include intrathecal injection by lumbar puncture, described in a 2023 report of two punctures during a four-day clinic visit for donor umbilical cord cells, and injection into a joint. A 2019 pair of case reports from US cash-based clinics involved umbilical cord blood-derived cellular products and morselized placental allograft tissue. A 2023 advertising analysis found businesses selling exosome products alongside stem cell interventions; the sources reviewed here do not describe how those products are made or dosed.

Uses described for hospital transplantation

The NCI lists leukemia, lymphoma and multiple myeloma as the cancers most often treated with stem cell transplants, and neuroblastoma, Ewing sarcoma, brain tumors and testicular cancer in some cases. The ISSCR guide names disorders of the blood and immune system, acquired loss of bone marrow function and inherited metabolic diseases, and notes that stem cells from skin and cornea also play a role in tissue transplants. A 2019 review adds hemoglobinopathies such as thalassemia and sickle cell disease. A 2026 narrative review describes cultivated limbal epithelial transplantation, from the patient or a donor, as an approach to limbal stem cell deficiency, a rare and often progressive eye condition.

Uses promoted by clinics

A 2023 analysis of online advertising identified 38 businesses promoting purported stem cell and exosome products for COVID-19, operating or facilitating access to 60 clinics, more than 75% of them in the United States and Mexico. Thirty-six marketed the products for Long COVID, six as immune boosters, five for acute infection and two as preventive. Listed patient costs ranged from $2,950 to $25,000, averaging $11,322. Case reports in the safety literature describe injections offered for macular degeneration and multiple sclerosis, and injections into joints. The ISSCR guide lists marketing one treatment for many different diseases as a warning sign.

Established transplantation

The ISSCR guide describes blood stem cell transplantation for blood cancers and immune disorders as well established and efficacious. A 2019 review says many recipients survived hematological malignancies or diseases that would otherwise have been fatal, while others suffered serious side effects, of which graft-versus-host disease has been the most challenging. This evidence concerns specific diseases and a specific hospital procedure; it is not evidence for the clinic injections discussed below.

Knee osteoarthritis: pooled randomized trials

A 2026 meta-analysis in Clinical Rheumatology pooled 28 randomized trials of intra-articular stem cell-based therapy. Pain on a visual analogue scale fell more than with control (mean difference -1.67), but WOMAC, quality of life and Lequesne scores showed no significant difference and MRI-based structural scores did not improve significantly. Injection-site pain (risk ratio 2.04) and joint swelling (3.39) were more common, while serious complications such as infection were uncommon and not significantly increased. The authors describe a symptom-modifying rather than structure-modifying role.

A 2026 meta-analysis of six trials with 551 patients found lower WOMAC totals with autologous adipose-derived cells at 3 months (-8.14, 95% CI -13.33 to -2.95), and lower pain scores through 12 months. It noted heterogeneity in comparators, blinding and cell products and said the results do not establish efficacy of a specific standardized product. A 2026 network meta-analysis of 18 trials found that adding mesenchymal cells to platelet-rich plasma did not differ significantly from plasma alone (WOMAC -0.80, 95% CI -12.85 to 11.25).

Cochrane reviews in other conditions

A 2025 Cochrane review of stem cells for decompensated cirrhosis included 12 trials with 823 adults and rated all evidence as very low certainty. The effect on all-cause mortality was uncertain (risk ratio 0.52, 95% CI 0.24 to 1.11), and non-serious adverse events were more frequent with stem cells (risk ratio 6.50, 95% CI 1.96 to 21.56, five studies). The authors could not determine effects with certainty and listed twelve ongoing trials.

A 2019 Cochrane review of cell-based therapy for amyotrophic lateral sclerosis found two eligible trials with 112 participants, both funded by biotechnology companies. In the one trial that contributed data, 64 participants given bone marrow mesenchymal cells plus riluzole improved slightly more on a functional scale (mean difference 3.38 points) at six months, with low-certainty evidence, and the authors say a small phase II trial cannot establish efficacy. A 2023 Cochrane review on newborn stroke found no completed or ongoing randomized trials.

An early-phase eye study

In a 2014 phase 1 study, six people with retinal vascular occlusion, hereditary or nonexudative macular degeneration or retinitis pigmentosa received intravitreal autologous CD34+ bone marrow cells prepared under Good Manufacturing Practice conditions, with 6 months of follow-up. The authors reported no intraocular inflammation or hyperproliferation and no worsening of best-corrected visual acuity, with mild progression of geographic atrophy in the macular degeneration participants. They concluded the approach merits further exploration. Six participants and no control group cannot show benefit, and the cells and setting differ from the clinic injections described below.

What the searches did not find

The searches run for this page, covering PubMed terms for exosome products, marketed umbilical and amniotic products, and Cochrane stem cell reviews, returned advertising analyses and case reports for exosome and perinatal products but no controlled trial of those marketed products. That reflects the limits of the search, not proof that none exists. The sources reviewed also do not address skin grafts in any detail.

Injections into the eye

A 2017 case series in the New England Journal of Medicine reported severe bilateral vision loss in three women aged 72, 78 and 88 with macular degeneration after same-day intravitreal injections of adipose-derived cells at a US clinic, each paying $5,000. Findings included ocular pressures of 66 and 59 mm Hg in one patient, hemorrhagic retinopathy, vitreous hemorrhage, retinal detachment and lens dislocation. Before injection acuity ranged from 20/30 to 20/200; after one year it ranged from 20/200 to no light perception.

Infection, immune reaction and tumor-like growth

A 2023 report describes Mycobacterium abscessus meningitis in a woman in her 30s with multiple sclerosis after two intrathecal injections of donor umbilical cord cells at a clinic in Mexico; identifying and treating it took 8 weeks. The report cites 20 culture-confirmed bacterial infections linked to donor cord blood products proposed for orthopedic conditions. A 2019 report describes septic arthritis needing an antibiotic spacer and hip replacement after a cord blood product injection, and a likely immune-mediated reaction after placental tissue injected at a chiropractic office.

A 2016 letter reports a glioproliferative spinal cord lesion as a complication of stem cell tourism; only the record was read, not the text. The ISSCR guide says undifferentiated pluripotent cells are unsafe to inject because they could cause tumors.

Transplant risks and clinic warning signs

For hospital transplantation the NCI lists nausea, fatigue and mouth sores in the short term and infertility, cataracts, secondary cancers and organ damage in the long term. Graft-versus-host disease can injure skin, liver and intestines, and infection risk rises during recovery.

The ISSCR guide warns that many clinics lack standards for monitoring and reporting side effects or long-term follow-up, and lists patient testimonials, one cell type for many diseases, claims of no risk and hidden costs as warning signs. A 2018 review found published adverse-event reporting for such interventions scattered across case reports and media. None of this replaces necessary medical care.