Prenatal therapy in transient abnormal myelopoiesis: a systematic review

OBJECTIVE

To systematically review current evidence regarding prenatal diagnosis and management of transient abnormal myelopoiesis (TAM) in fetuses with trisomy 21. A novel case of GATA1-positive TAM, in which following serial in utero blood transfusion clinical improvement and postnatal remission were observed, is included.

SEARCH STRATEGY AND DATA COLLECTION

A systematic search of electronic databases (inception to October 2014) and reference lists, hand-searching of journals and expert contact. All confirmed cases of prenatal TAM were included for analysis. Data on study characteristics, design and quality were obtained.

RESULTS

Of 73 potentially relevant citations identified, 22 studies were included, describing 39 fetuses. All studies included comprised single case or small cohort studies; overall quality was 'very low'. Fetal/neonatal outcome was poor; 12 stillbirths (30.8%), 4 neonatal deaths (10.2%) and 7 infant deaths (17.9%). In two cases, the pregnancy was terminated (5.1%). TAM was primarily detected in the third trimester (79.4%), and in 14 a retrospective diagnosis was made postpartum. Ultrasound features indicative of TAM included hepatomegaly±splenomegaly (79.5%), hydrops fetalis (30.8%), pericardial effusion (23.1%) and aberrant liquor volume (15.4%). When performed, liver function tests were abnormal in 91.6% of cases.

CONCLUSIONS

Prenatal TAM presents a challenging diagnosis, and prognosis is poor, with consistently high mortality. A low threshold to measure haematological and biochemical markers is advised when clinical features typical of TAM are detected in the context of trisomy 21. Larger prospective studies are warranted to accurately ascertain the role of GATA1 analysis and potential value of prenatal therapy.

Missed opportunities for preventing group B streptococcus infection

BACKGROUND

Group B streptococcus (GBS) is the most common cause of early onset (EO) neonatal infection in the UK. National guidelines for its prevention were introduced in 2003. We assessed the opportunities for prevention amongst cases of EO GBS using the electronic Neonatal Infection Surveillance Network (NeonIN).

METHODS

Culture proven EO GBS cases occurring between 2004 and 2007 were identified prospectively in eight neonatal units participating in NeonIN. Data concerning risk factors, intrapartum antibiotic (IAP) use and infant outcome were collected retrospectively.

RESULTS

There were 48 cases of GBS over the 4 years (0.52/1000 live-births); 22 male, median gestation 38 weeks. The most common clinical presentation was sepsis and the GBS-attributable mortality was 6%. Risk factors were present in 67% (32) and adequate IAP was given to six of these mothers (19%). If all women with risk factors received prophylaxis, 23 cases (48%) may have been prevented.

CONCLUSIONS

Better GBS prevention strategies are required in the UK.

Palivizumab: an overview

Respiratory syncytial virus (RSV) affects almost all children in their first 2 years of life and can cause severe or even life-threatening disease in some at-risk infants. Treatment is limited and there is currently no safe or effective vaccine. However, a new monoclonal antibody, palivizumab, reduces RSV hospitalization by 55% in at-risk groups if given prophylactically throughout the RSV season.

Neurexin is expressed on nerves, but not at nerve terminals, in the electric organ

Neurexins are highly variable transmembrane proteins hypothesized to be nerve terminal-specific cell adhesion molecules. As a test of the hypothesis that neurexin is restricted to the nerve terminal, we examined neurexins in the electric organ of the elasmobranch electric fish. Specific antibodies generated against the intracellular domain of electric fish neurexin were used in immunocytochemical and Western blot analyses of the electromotor neurons that innervate the electric organ. Our results indicate that neurexin is not expressed at electric organ nerve terminals, as expected by the neurexin hypothesis. Instead, neurexin is expressed by electromotor neurons and on myelinated axons. This neurexin has a molecular weight of 140 kDa, consistent with an alpha-neurexin. In addition, we find that perineurial cells of the electromotor nerve also express a neurexin. These cells surround bundles of axons to form a diffusion barrier and are thought to be a special form of fibroblast. The results of the study argue against a universal role for neurexins as nerve terminal-specific proteins but suggest that neurexins are involved in axon-Schwann cell and perineurial cell interactions.