Newborn Screening and Haematopoietic Stem Cell Transplantation

Introduction

Newborn screening refers to a blood test carried out on newborns for the purpose of identifying the possibility of treatable disorders among babies. This procedure was developed out of the fact that many newborns may look quite healthy, but have one or more of the 22 rare disorders which include the severe combined immunodeficiency. The disorder could if not treated early, cause a number of health issues including but not limited to growth problems, mental disorders, sudden death among infants and other health problems. Detection of these rare disorders among infant proves to be important in making easy for prevention or treatment of such disorders. Haematopoietic stem cell transplantation on the other hand, refers to infusion of hematopoietic stems for the purpose of establishing immune and marrow functioning among patients with different inherited and acquired disorders including the (SCID). The method is also employed in supporting patients who undergo high-dose chemotherapy in treatment of specific solid tumors to reinforce the effectiveness of drugs. The two approaches HSCT and newborn screening have significantly contributed to the diagnosis, and management of severe combined immunodeficiency (SCID).

Newborn Screening

Severe combined immunodeficiency (SCID) is among the rare disorders which are quite dangerous if they are not diagnosed early and treated in a proper way. Apparently, newborn screening programs have been very effective in states and or countries where they have been employed in facilitating diagnosis and improving outcomes for this particular disorder. Indeed, there are many features of SCID that makes it one of the disorders fulfilling the criteria for newborn screening as espoused by Jungner and Wilson. As we have already reiterated, effective treatment of this disorder necessitates early diagnosis and when diagnosed, the disease could be fatal. The novel technology in newborn screening subsequently facilitates a brisk genetic diagnosis which facilitates in making decisions in regard to designing an appropriate treatment plan.

Severe Combined Immune Deficiency (SCID) could result in serious complications unless there is a restoration of the immune system through gene therapy, bone marrow transplant, or enzyme replacement. In the past, infants with SCID and who do not harbour a family history have been diagnosed after developing serious complications (Patel et al, 2010).

The lack of antibody immunity and T-cells facilitates the development of severe infections, diarrhoea and even death. These are just some of the complications associated with SCID among infants. In most cases, the infections associated with SCID are mostly caused by organisms that can only attack a child with a weak immune system such as opportunistic and pathogenic organisms. Notarangelo (2010) explains that SCID had always been fatal before the first successful bone marrow transplant which occurred in 1968. Bone marrow stem cell transplant is until now an effective way of treating SCID. Other methods of treatment include gene therapy and enzyme replacement.

Understanding the inheritance of SCID has enlightened many families on the need to diagnose their children at birth or before birth in order to avert the tragic loss of their loved ones after experiencing such cases either involving them, closer ones or significant others. Evidence shows that early diagnosis and treatment of SCID enables children to avoid the related infections and that the survival rate for such children is quite high with lesser or no complications. Newborn screening for SCID is based on the understanding that diagnosing the symptoms and condition and early treatment would significantly improve the survival rate for children born with SCID including those who have inherited the condition.

Screening test differs from individual clinical tests in the sense that while the former is used due to the suspicion of a particular disease through clinical information or genetics the latter looks for a rare but serious disorder for infants, the majority of whom may not harbour the disorder. Therefore, failure to identify exact cases must be maintained at a minimum. Conversely, false-positive results may lead to anxiety and necessitate follow-up testing to further confirm the case. Nonetheless, a positive result allows infants to receive timely treatments while avoiding the devastating infections associated with the infection.

This, therefore, makes it necessary to identify SCID early enough through newborn screening to facilitate life-saving intervention prior to the occurrence of infections. In the United States, a number of states have effectively incorporated a T-cell receptor excision circle (TREC) assay as a means of screening newborns on a regular basis. Apparently, TREC screening has effectively worked in identifying babies with SCID and hence designing mechanisms of treating them. It is suspected that many infants could have succumbed to death due to SCID were it not for the screening programs. States that are yet to take this initiative must do so in order to save the young generation from the effects associated with SCID, as well as the costs related to treatment of this condition.

HSCT

Bone marrow transplantation using either T-cell–depleted haploidentical parental marrow or HLA-identical marrow has been the common standard used to treat SCID. Clinical evidence has shown that severe combined immunodeficiency could be successfully cured through stem cell transplantation generated from donors (Fisher et al, 2013). According to Larie et al (2002), the survival rate is approximately 80%, and a majority of the deaths that occurs afterwards are a result of opportunistic infections which were acquired before the procedure. More studies on this topic have as well noted that the immune reconstitution and survival rate could be improved for infants with SCID who receive stem cell transplantation during the first 3 weeks of their life before they develop the related infections.

The other reason why HSCT could be ideal for newborns is that unlike transplant of a solid organ such as liver or kidney, there is no surgery involved in HSCT transplant. Instead, it is more or less like a blood transfusion though it differs from a blood transfusion in the sense that the fluid involved has to contain HSCT (Fisher et al, 2013).

Conclusion

It is apparent that early diagnosis of SCID through newborn screening is not only beneficial to the condition, but also to all other immunodeficiency diseases. The effectiveness of this program has been confirmed by various states in the U.S whereby; newborn screening has proved to have a clinical utility. There have been reports of many infants being found with SCID which were initially suspected to have been successfully treated. Effective treatment of SCID has been facilitated by Hematopoietic stem cell transplantation (HSCT) which until currently, remains the mainstay treatment of this condition. Reports could have been negative were these programs not in place.