HLA Typing for Sickle Cell Transplant: What It Is and How to Get It Done in Africa

Race does not affect the outcome. African sickle cell patients present with more severe sickling compared to Indian sickle cell patients, but the transplant outcome is the same — leukaemia treated in Africa versus leukaemia treated in India has the same outcome. Transplant outcome is mainly affected by patient factors (disease stage and comorbidity), donor factors (full match, half match, or mismatch), and treatment factors (right conditioning, right immunosuppression, right supportive care). Get those right and outcomes across the globe are similar, whether the transplant is done in America, Tokyo, or India.

We encourage good nutrition — patients can eat whatever they like, there is no prohibition, other than avoiding street food. Any hygienic food eaten at home, with good nutrition and a good amount of protein, is good for transplant outcome — the same as for any ordinary healthy human being.

I will circulate full information from my lab on the prerequisites for an HLA sample — what temperature it should be kept at, how many hours it can take to transport, and how many ml of blood sample or a buccal swab is required, so the sample can safely reach India for testing. Laboratory networks such as Metropolis and Lancet already exist in Kenya, Ghana and Uganda, though coverage is patchier in countries such as Nigeria and the DRC.

The stem cell itself has no pathology — it is the mother cell present in every human being that produces blood, the haematopoietic stem cell. Sickle cell disease is a defect in a single gene, a single base-pair defect in the beta-haemoglobin chain, so it is the haematopoietic stem cell that is defective, and we need to replace it with a healthy one. As for effects: about 70% of patients have no major complications and 30% will have graft-versus-host disease. In the acute phase there can be neutropenia leading to sepsis, mucositis (mouth ulceration causing pain, vomiting, diarrhoea), and haemorrhagic cystitis (blood in urine from the conditioning chemotherapy or radiation), which usually recovers with hydration and prevention. Veno-occlusive disease of the liver can also occur. The two most important complications are acute and chronic graft-versus-host disease — chronic GVHD causes dry eyes, dry skin, dry mouth and lung problems, and impairs quality of life. Infertility is another complication, meaning inability to reproduce, not sexual dysfunction — sexual and social life are not affected after transplant, only ovarian or testicular failure affecting spermatogenesis and ovulation.

No. Sickle cell disease is a gene defect — there are sickle cell carriers and sickle cell disease patients. Disease means both parents were carriers; a carrier has only one gene affected and can pass it to their children if their partner is also a carrier. Other than gene therapy, there is no treatment for asymptomatic carriers — no cure or treatment is needed, because they reach adulthood and live a normal life. Since there is no phenotypic expression of the genotypic disorder, no treatment is warranted, because every treatment carries a risk of morbidity and mortality.

HLA proteins let the immune system distinguish the body's own cells from foreign ones. For a transplant to work, donor and patient must match at key HLA points, which is tested with a blood sample or buccal swab from both.

Whether a sibling is a full match, or whether a parent can serve instead as a haploidentical donor.

Samples can be transported to the transplant centre's laboratory, following a specific protocol covering sample type, correct tubes, storage temperature, and packaging needed to keep the sample viable during travel.

It is the first step, not the last. Starting early, before the patient's condition deteriorates, gives families the most time and options: if a match is confirmed, evaluation can move forward immediately, and if not, haploidentical transplant using a parent can be explored.