After undergoing chemotherapy to treat his leukaemia, a 46-year-old man received a bone marrow transplant from his sister, who luckily was found to be a match. But not long after the operation the recipient experienced, for the first time in his life, an allergic reaction to kiwi fruits. It appears that his sister’s allergy to the fruit was transferred to him along with her bone marrow.
While this is not the first time an allergy has been transferred like this, according to the authors of a new study, it is the first time that researchers have been able to conclusively prove that the allergy was due to the donor’s cells. The case is reported in the Journal of the European Academy of Dermatology and Venereology.
When patients undergo intensive treatment for acute lymphocytic leukaemia, the high doses of chemotherapy used to kill the cancer cells also destroys the bone marrow cells. These include a specific stem cell, known as a hematopoietic stem cell, which divides and gives rise to every type of cell found in your blood, from red blood cells to white blood cells. This means that the leukaemia patients then have to undergo a bone marrow transplant from a donor in order to have their bones repopulated with the hematopoietic stem cells.
Allergies are caused when white blood cells produce antibodies in an adverse immune response to a harmless substance, such as pollen, nuts, or in this case, kiwi fruit. Previous bone marrow transplants have shared allergies from a donor to the recipient, but scientists were not sure if this was because they had simply transferred some of the antibodies to the specific substance, and that over time these would be broken down and the recipient will lose the allergy.
But this time round, the researchers were able to trace where the antibodies that were reacting to the kiwi fruit actually originated from using a technique known as fluorescence in situ hybridization. This allowed the researchers to trace the origin of the antibody to the two X-chromosomes in the male patient (who’s own cells are all XY), which means that they had to come from his sister who donated her bone marrow, and thus meaning that the allergy originated in her hematopoietic stem cells.
While allergy transfer from bone marrow transplants is a rare occurrence, this is the first time that this has been conclusively proven. The study opens the door to more investigations into how allergies can be spread and potentially treated, by looking into patients' bone marrow and the hematopoietic cells contained within.
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