Germ cell damage and Leydig cell insufficiency in recipients of nonmyeloablative transplantation for haematological malignancies

Most bone marrow transplant recipients are infertile due to reversible or irreversible testicular failure. However, little is known about the gonadotoxic potential of the newly introduced nonmyeloablative transplants. We undertook a 24-month longitudinal study in a cohort of 32 recipients of nonmyeloablative transplantation to test whether the combined regimen of fludarabine, melphalan and CAMPATH-1H can induce damage to germ cell (GC) and Leydig cell (LC) compartments. Testicular function was assessed immediately prior to transplantation and at four time points post-transplant to compare hormonal levels before and after the procedure. Two other groups treated with BEAM- and TBI-related regimes were also included in the study group for comparative purposes. GC function was assessed by measuring basal serum follicle stimulating hormone (FSH). LC function was assessed by measuring basal luteinising hormone (LH) and testosterone (T) levels. LC reserve was assessed by measuring the T/LH ratio. As a group, patients who received a non myeloablative transplant sustained severe damage to the GC compartment, as evident from a substantial elevation in the FSH level post-transplant (12 IU/l vs 18.4 IU/l, P<0.001). Similar to the GC injury, patients as a group sustained significant damage to the LC compartment following the transplant (5.4 IU/l vs 9.6 IU/l, P<0.001). In general, patients had reduced LC reserve post-BMT, as evident from a diminished T/LH ratio (2.6 pretransplant vs 1.6 post-transplant P=0.05). Patients who received a nonmyeloablative transplant had a similar effect on the GC and LC compartments compared to those who had a BEAM autograft. On the other hand, patients who received a TBI-based transplant sustained more damage to their GC and LC compartments compared to those who received a nonmyeloblative transplant; however, this was not statistically significant (P=0.09). Our data suggest that this type of regimen is potentially gonadotoxic and consideration should be given to fertility counselling and testosterone replacement therapy post-transplant.