Pubertal development in thalassaemic patients after allogenic bone marrow transplantation

Differences in longitudinal growth patterns of children and adolescents with transfusion-dependent hemoglobin E/β-thalassemia and those achieving successful hematopoietic stem-cell transplantation

BACKGROUND

Short stature is a very common endocrinopathy among children with transfusion-dependent (TD) thalassemia. Hematopoietic stem-cell transplantation (HSCT) is the only effective curative treatment for TD thalassemia. This study aimed to identify and compare the longitudinal growth patterns of children with TD hemoglobin E (Hb E)/β-thalassemia against those of children successfully undergoing HSCT.

MATERIALS AND METHODS

We reviewed the medical records of 39 patients with TD Hb E/β-thalassemia receiving regular blood transfusions, and 39 post-HSCT patients. Longitudinal weight and height Z-scores at each year of age were recorded for TD patients, and longitudinal weight and height Z-scores at each year before and after HSCT were obtained for post-HSCT patients.

RESULTS

The mean weight and height Z-scores of TD patients decreased gradually and were lowest at age 13. However, post-HSCT subjects saw significant improvement in their mean weight and height Z-scores 6 and 3 years after HSCT, respectively, relative to pre-HSCT baseline values.

CONCLUSIONS

Longitudinal growth patterns differed between patients successfully undergoing HSCT and children and adolescents with TD Hb E/β-thalassemia. HSCT significantly improved height outcomes of children and adolescents with TD Hb E/β-thalassemia.

Indicators of male fertility potential in adult patients with beta-thalassemia major: a comparative study between patients undergone allogeneic stem cell transplantation and transfusion-dependent patients

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (HSCT) remains the only potentially curative treatment for thalassemia major (TM). Infertility and its indicators have been assessed in transfusion dependent TM men, but in this study, we sought to compare the fertility indicators of TM patients after HSCT with those in patients treated conventionally. The possible influential factors on reproductive capacity in TM patients undergone allogeneic HSCT were also evaluated.

PATIENTS AND METHODS

In this cross-sectional study, we compared the gonadal hormones level, testicular volume, Tanner stage and sperm analysis in transfusion-dependent thalassemia major (TDTM) patients who survived matched sibling HSCT (n = 43) with patients conventionally treated by transfusion and iron chelation (n = 52).

RESULTS

The patients' age range was between 16 to 41 years. Tanner stage 4-5 was seen in 39 patients (41%). The prevalence of hypogonadism in our patients was 32.63% but its frequency was not significantly different between the two groups (p = 0.35). Azospermia, oligospermia, astenospermia, teratospermia and even having dry and low volume ejaculate were all significantly more frequent in the post-transplant patients compared to TDTM group. In the post-HSCT group, neither patients' age at transplantation nor the conditioning regimen used in their transplant process did significantly affect their hormonal status and sperm parameters. Chronic graft versus host disease (GVHD) occurred in 14 (40%) patients. No significant difference was observed between the grade of chronic GVHD and hypogonadism (P = 0.853).

CONCLUSIONS

Thalassemia patients undergone allogeneic HSCT have lower fertility potential, mainly in sperm parameters compared with patients treated with blood transfusion and chelation. This information is important for thalassemic patients considering HSCT.

Hypogonadism in male thalassemia major patients: pathophysiology, diagnosis and treatment

Failure of pubertal growth, delay or absence of sexual development, infertility and sexual dysfunction due to hypogonadism and defective spermatogenesis are frequent and well recognized disturbances among male patients with transfusion dependent (TD) thalassaemia major (β-thal). These problems are attributed mainly to the damage caused by chronic anaemia and the deposition of excess iron in the pituitary gland and testicles. This is a short review of male pubertal disorders in patients with β-thal written by pediatric endocrinologists and haematologists with an interest and active involvement, in the diagnosis and management of these complications in this group of patients. A vigilant clinical evaluation of growth and puberty, as well as an appropriate hormonal evaluation in poly-transfused (TD β-thal) patients is strongly recommended for early detection and treatment of endocrine dysfunction. Of crucial importance also, is the implementation of an efficient chelation regime from early life, to prevent severe iron load and permanent damage to the endocrine glands, particularly those responsible for gonadal function.

Hypogonadism in thalassemia major patients

Despite recent advances in iron chelation therapy, excess iron deposition in pituitary gonadotropic cells remains one of the major problems in thalassemic patients. Hypogonadism, mostly hypogonadotropic hypogonadism, is usually detected during puberty. Early diagnosis and treatment are crucial for normal pubertal development and to reduce the complications of hypogonadism. The risks and benefits of hormonal replacement therapy, especially regarding the thromboembolic event, remain a challenge for providers caring for thalassemic patients.

Gonadal function of young patients with beta-thalassemia following bone marrow transplantation

Bone marrow transplantation (BMT) can induce short- and long-term impairment of gonadal function. Patients with beta-thalassemia represent a special group, as their primary diagnosis and its treatment modalities are responsible for gonadal dysfunction. To address the effect of BMT on puberty and gonadal function, we investigated 25 patients (12 males) with thalassemia who received allogenic BMT during childhood or adolescence and at the post-transplant evaluation were at an age that the pubertal process should have started. Pubertal stage by Tanner of breast and pubic hair, as well as testicular volume were assessed pre-BMT once and post-BMT at least twice. Menstrual history was recorded. FSH, LH, testosterone and estradiol levels were also determined. The impact of BMT appears to be different in the two sexes. Males seem to have higher tolerance, as all males who were pubertal at the time of BMT had normal testosterone, and all but one normal gonadotropin levels. From those who were prepubertal at BMT, 62% proceeded to normal pubertal development. Post-menarcheal females seem to be an extremely sensitive group to the deleterious effect of the transplantation process, as 100% of the post-menarcheal females exhibited amenorrhea and elevated gonadotropin levels. These findings are important for pre- and post-BMT counseling.

Endocrine complications of thalassemia

Growth, sexual development, fertility, bone mineral density, diabetes mellitus, hypothyroidism, hypoparathyroidism, and hypoadrenalism are the main issues to be addressed in the long-term follow-up of patients with thalassemia. During childhood, growth may be affected by anemia, and other potential endocrine complications. Puberty is the stage of the maximal growth insult. Beta thalassemia is associated with bone abnormalities characterized by bone marrow expansion of the medullary cavity, and osteopenia with cortical thickening and trabecular coarsening. Good nutrition with adequate vitamins and trace elements intake, along with calcium and vitamin D supplementation, can increase bone density and prevent bone loss. Endocrine abnormalities should be monitored carefully and a thorough endocrine evaluation should be carried out yearly in every patients to detect subclinical endocrinopaties.

Bone marrow transplantation for beta-thalassemia

Bone marrow transplantation in thalassemia represents the only form of radical cure of this disease. Patients younger than 17 years are divided into three classes of risk according to the presence or absence of portal fibrosis, hepatomegaly, and history of adequate chelation treatment. Patients older than 16 years are categorized as adult thalassemics. Survival and event-free survival are 93% and 91% for Class 1, 87% and 83% for Class 2, and 79% and 58% for Class 3, respectively. Adult patient survival is 66% and event-free survival is 62%.

Current status of stem cell therapy and prospects for gene therapy for the disorders of globin synthesis

Sickle cell anaemia and beta-thalassaemia are today curable through the use of stem cell transplantation. Nevertheless, the disadvantages inherent in stem cell transplantation underscore the need for better therapies. A recent finding of potentially major importance is that complete eradication of host haematopoiesis is not an absolute requirement for achieving therapeutic effects in thalassaemia and sickle cell anaemia. Future stem cell transplantation protocols will use less toxic conditioning regimens in an effort to achieve a state of stable mixed chimerism between donor and host haematopoietic elements. An improved understanding of globin gene regulation and stem cell biology will allow for the first gene therapy trials for sickle cell anaemia and beta-thalassaemia in the relatively near future. Initial gene therapy protocols will emphasize safety, are likely to target progenitor cells, and will involve repeated cycles of mobilization, transduction and reinfusion, with little or no conditioning. These first generation gene therapy trials are unlikely to confer major therapeutic benefits, but will provide the foundation upon which subsequent, more effective protocols will be based.

Thalassemia major 1995: older patients, new therapies

There have been many advances in supportive treatment used for beta-thalassemia major. Survival has increased substantially, and an increasing number of patients reach adolescence and adulthood. These older patients present new clinical challenges. Complications of transfusion, most commonly hepatitis C, are still a cause of mortality and morbidity. The achievement of optimal growth and development, including fertility, is an important goal of conservative management. Long-term survival has also been achieved with bone marrow transplantation. Assessment of growth, development and iron balance in the years after transplantation reveals residual problems requiring treatment despite cure of thalassemia. New therapies of beta-thalassemia are still being developed, both supportive and curative in nature. Supportive care improvements include oral chelation and methods to increase HbF production. Advances in curative modalities include use of new sources of stem cells, such as cord blood and fetal liver. In the future, gene therapy may allow for cure of the older patient without the mortality and morbidity of allogenic transplantation. Treatment of thalassemia major requires consideration of the available therapeutic options for each patient, and the risk/benefit ratio of a supportive versus curative approach.

Bone marrow transplantation in thalassemia

Early trials of allogeneic bone marrow transplantation (BMT) for homozygous beta-thalassemia and the analyses of results of transplantation in patients less than 16 years old have allowed us to identify three classes of risk based on the following criteria: (a) hepatomegaly, (b) presence of liver fibrosis at histological examination, and (c) quality of chelation treatment given before transplant. Patients with none of these adverse criteria were assigned to Class 1; patients with either one or two adverse criteria comprised Class 2; and patients for whom all three criteria were adverse constituted Class 3. Most patients older than 16 years have disease characteristics that place them in Class 3, with very few falling into Class 2. All patients with a histocompatibility leukocyte antigen (HLA)-identical donor are actually assigned to one of two conditioning regimens on the basis of the class they belong to at the time of BMT and independently of age. For Class 1, Class 2, and Class 3 patients, the probabilities of survival and event-free survival are 95 and 90%, 86 and 82%, and 87 and 63%, respectively. For those patients older than 16 years at the time of transplant, the probabilities of survival and of event-free survival are 78 and 74%, respectively. Allogeneic BMT is currently the only rational therapeutic modality for the eradication of beta-thalassemia.