How are donors screened?

Before the tissue is accepted, the donor goes through a medical history review and laboratory screening for infectious diseases, including HIV 1 and 2, hepatitis A, B and C, syphilis, cytomegalovirus, toxoplasmosis, herpes simplex types I and II, chlamydia and Chagas disease. Screening related to genetic diseases is also performed. After processing, the cells themselves are tested for sterility, mycoplasma, endotoxins, identity, genetic stability and viability before they are released for clinical use.

Donor screening is one of the most important safety steps in any treatment that uses donated cells or tissue. Patients often ask about it, especially when they learn that our cells are allogeneic, which means they come from a donor rather than from their own body. This guide explains who the donors are, how they are screened, how the cells are tested afterwards and how this compares with international standards.

Who are the donors?

The umbilical cord connects the baby to the placenta during pregnancy and is usually discarded after birth as medical waste. Our donors are mothers who, after a healthy, full-term pregnancy, voluntarily donate the umbilical cord with informed consent. The collection takes place after the birth and does not involve any procedure on the mother or the newborn, so it does not change the delivery in any way.

Several characteristics make this source safe and practical:

• Young tissue: the cells come from newborn tissue that has not been exposed to decades of aging, illness or medications.
• Noninvasive collection: unlike bone marrow or fat, collecting the cord requires no procedure on the donor.
• Ethical source: the tissue would otherwise be discarded, and our cells are not embryonic and do not come from fetal tissue.

A review in the World Journal of Stem Cells on umbilical cord-derived MSCs highlights these advantages and notes that, because the donor is a newborn, confirming the health of the donor is an essential step. This is exactly what donor screening does.

Step 1: medical history and consent

Before a cord is accepted, the donor's medical history is reviewed. This step helps exclude donors with conditions or risk factors that could affect the safety of the tissue. The mother gives informed consent for the donation and for the testing required to qualify the tissue.

Step 2: infectious disease testing

The donor is tested for infectious diseases. In the example certificate of analysis we share with patients, the donor screening shows negative results for:

Only tissue from donors with negative results moves forward.

Step 3: genetic screening

Screening related to genetic diseases is also part of the donor and cell evaluation. In addition, once the cells are expanded, they are tested for genetic stability, as explained below.

Step 4: testing the cells

Donor screening is the first layer of safety. The second layer is the testing of the cells themselves after they are isolated and expanded in the laboratory. According to our example certificate of analysis, this includes:

• Sterility: testing for aerobic bacteria, fungi and yeasts, with negative results.
• Mycoplasma: negative. Mycoplasma are very small bacteria that can contaminate cell cultures.
• Bacterial endotoxins: negative. Endotoxins are bacterial components that can cause fever and inflammation.
• Identity: positive for MSC markers such as CD44, CD73, CD90 and CD105, and negative for blood and immune cell markers such as CD34, CD45, CD14, CD11b, CD19 and HLA-DR.
• Genetic stability: normal karyotype and normal p53, and negative results for c-MYC, c-MYB and K-RAS.
• Viability: 98% in our example certificate, measured by trypan blue exclusion with an automated cell counter.

Each batch goes through screening, testing and quality control before it is released for clinical use.

From donation to your treatment

The path of the cells, from the donated cord to your treatment, follows a clear sequence:

1. Donation: after a healthy, full-term birth, the mother donates the umbilical cord with informed consent.
2. Donor qualification: the medical history is reviewed and the infectious disease and genetic screening is completed.
3. Isolation: the Wharton's jelly is separated, and the mesenchymal stem cells are isolated from the tissue.
4. Expansion: the cells are expanded in the laboratory under controlled, low-oxygen conditions until they reach therapeutic doses.
5. Quality control: each batch is tested for sterility, mycoplasma, endotoxins, identity, genetic stability and viability.
6. Preservation: approved cells are preserved through controlled cryopreservation.
7. Preparation for your date: your dose is prepared for your scheduled treatment and handled under controlled conditions until the application.

Each step adds a layer of safety, and only cells that pass every check reach a patient.

How this compares with international standards

Regulations for donated cells and tissues share a common principle: the donor must be screened and tested before the tissue is used.

• In the United States, the Code of Federal Regulations (21 CFR Part 1271, Subpart C) sets donor eligibility requirements for human cells and tissues. It includes screening and testing for relevant communicable diseases, such as HIV, hepatitis B, hepatitis C and syphilis, and, for some cell types, cytomegalovirus and HTLV.
• The International Society for Cell and Gene Therapy (ISCT) published the minimal criteria for defining mesenchymal stromal cells, which are the reference for confirming cell identity.
• The International Society for Stem Cell Research (ISSCR) encourages patients to ask where cells come from and how donors and products are tested.

Our donor and cell screening covers the main infectious diseases included in these frameworks and adds several more, such as toxoplasmosis, herpes simplex, Chagas disease and chlamydia.

Where the cells are processed

Our cells are processed by a certified laboratory located in the same building as our clinic in Tijuana. In the information we share with patients, our laboratory partners are described as operating under Good Manufacturing Practice (GMP) and Good Laboratory Practice (GLP) standards, with ISO 9001 quality management systems. The cells are preserved through a controlled cryopreservation process until they are prepared for your treatment date.

Why donor screening matters to you

• Protection against infection: testing the donor and the cells reduces the risk of transmitting an infectious disease.
• Consistent quality: screening and testing every batch helps make sure that each dose meets the same standards.
• Confidence in an allogeneic treatment: because the cells come from a carefully screened donor, your treatment does not depend on the age or quality of your own stem cells.

Do I need to match the donor?

No. Mesenchymal stem cells have low immunogenicity, which means they carry low levels of the molecules that usually trigger rejection. For this reason, there is no need for a blood type or DNA match before treatment.

Can I see the screening results?

Yes. Before you book, your advisor can send you an example of our certificate of analysis, which shows the donor screening panel and the tests performed on the cells. The quality-control information that applies to the cells used in your treatment can be shared in a redacted format, since the laboratory's internal documentation is confidential.

Common questions

Is the baby affected in any way? No. The cord is collected after birth, and the collection does not involve any procedure on the newborn.

Could a disease be transmitted through the cells? Donor screening and cell testing are designed to minimize this risk. Every donor is tested for the infectious diseases listed above, and every batch is tested for sterility, mycoplasma and endotoxins before release.

Do you use embryonic cells? No. Our cells are mesenchymal stem cells from donated umbilical cord tissue.

Questions to ask your advisor

• Can you send me an example of your certificate of analysis?
• Which infectious diseases are included in the donor screening?
• What tests are done on the cells before release?
• Where are the cells processed?

Bottom line

Our donors are mothers who voluntarily donate the umbilical cord after a healthy, full-term birth. Before the tissue is accepted, the donor goes through a medical history review and testing for infectious diseases, including HIV, hepatitis A, B and C, syphilis, cytomegalovirus, toxoplasmosis, herpes simplex, chlamydia and Chagas disease, together with screening related to genetic diseases. The cells are then tested for sterility, mycoplasma, endotoxins, identity, genetic stability and viability before release. A medical evaluation can help determine whether this type of regenerative treatment is appropriate for your condition, goals and medical history.