LOTUS study

Introduction

The mainstay for the treatment of fetal anemia is intrauterine blood transfusion. The Leiden University Medical Center is the single national referral center in the Netherlands for the management of pregnancies complicated by severe fetal anemia. The main causes of fetal anemia are maternal red blood cells (RBC) alloimmunization and, less frequent, Parvo B19 infection and feto-maternal hemorrhage.

Alloimmunization is a major transfusion problem and deliberate transfusions may induce multiple (HLA, HPA, RBC) alloantibodies. Intra-uterine transfusions (IUT) for alloimmune hemolytic disease (HDFN) are associated with a high immunization rate despite the usually small volumes of the feto-maternal hemorrhage (FMH) of just a few milliliters. Although it has not been systematically studied, pregnancy-induced antibodies, in contrast to transfusion-induced RBC antibodies, can persist for many years. These antibodies complicate both transfusion therapy and future pregnancies. Patients who develop RBC antibodies are high responders with a more than 20-fold increased risk for additional antibody formation.

Most study groups report perinatal survival rates in RBC alloimmunization treated with IUTs above 90%. To date only a few small studies have reported on the long-term neurodevelopmental outcome. The main limitation of these studies is the small number of patients included (range 16 to 69).

Rationale

Some transfusion recipients seem more susceptible for alloimmunization, but with respect to red cell antibodies the mechanisms have hardly been investigated. IUTs are associated with increased FMH, transmitting not only donor red cells but also viable HLA-haplo-identical fetal blood cells. After IUT treatment more than 20% of mothers have formed new RBC antibodies and more than 70% have multiple antibody specificities. Although data are lacking, immunological changes in pregnancy may enhance antibody formation. It is not known whether a combination of factors enhances antibody formation and whether post-pregnancy chimerism contributes to maintenance of antibody production.

As perinatal survival is improving, attention is now shifting towards short-term and long-term outcome in surviving children. Although hydrops fetalis has been reported to be associated with increased mortality, not much is known on the association between the severity of fetal anemia and long-term neurodevelopmental outcome.

Objective

The first part of this study addresses several putative mechanisms associated with blood group alloimmunization in these mothers. The second part of this study determines the incidence of long-term neurodevelopment impairment (NDI) and associated risk factors in children treated with IUT.

Study design

Observational cohort study.

Study population

All mothers and their children who were treated with intra-uterine RBC transfusions over the past 20 years.

Intervention

One-time visit to the LUMC for sampling, examination and questionnares

Main study parameters/endpoints

Primary

MHC class II allele association with antibodies against particular RBC antigens
Determination of the long-term neuromotor development, cognitive development and psychosocial well-being

Secondary

Association of RBC immunization with high antibody responders in general, estimated from HLA/HPA antibodies and polymorphisms for accessory genes.
Persistence of RBC antibodies related to feto-maternal chimerism 
Association of adverse long-term outcome with risk factors, including: gestational age at birth, cause and severity of fetal anemia, presence and severity of hydrops fetalis, and number of IUT procedures.
Maternal long term health effects.

Procedure of the research (study protocol)

Patients and their off-springs will be asked to come to the LUMC where a one-time blood sample, mouth swap or saliva sample will be taken. 
Maternal health and childrens’ neuromotor development will be assessed by questionnares and neurological and psychosocial examination.

Exclusion criteria

Women with no live-born ‘IUT’-children.

Time schedule

Not applicable

Investigators

• H. Schonewille PhD
• A. Brand MD PhD
• I.I.N Doxiadis MD PhD
• E. Lopriore MD PhD
• D. Oepkes MD PhD

Participating hospitals

Leiden University Medical Center (LUMC), Leiden, The Netherlands; Departments of  Immunohematology and Blood Transfusion, Pediatrics and Obstetrics.

Projectleader

• H. Schonewille PhD

Publications

• De Jong EP, Lindenburg IT, van Klink JM, Oepkes D, van Kamp IL, Walther FJ, Lopriore E. Intrauterine transfusion for parvovirus B19 infection: long-term neurodevelopmental outcome. Am J Obstet Gynecol. 2012;206:204.e1-5.
• Lindenburg IT, Smits-Wintjens VE, van Klink JM, Verduin E, van Kamp IL, Walther FJ, Schonewille H, Doxiadis II, Kanhai HH, van Lith JM, van Zwet EW, Oepkes D, Brand A, Lopriore E; LOTUS study group. Long-term neurodevelopmental outcome after intrauterine transfusion for hemolytic disease of the fetus/newborn: the LOTUS study. Am J Obstet Gynecol. 2012;206:141.e1-8.
• Verduin EP, Lindenburg IT, Smits-Wintjens VE, van Klink JM, Schonewille H, van Kamp IL, Oepkes D, Walther FJ, Kanhai HH, Doxiadis II, Lopriore E, Brand A. Long-Term follow up after intra-Uterine transfusionS; the LOTUS study. BMC Pregnancy Childbirth. 2010;10:77.