Introduction

Intrauterine blood transfusion of anaemic fetuses represents one of the great successes of fetal therapy. The therapeutic success of other potential therapies for HDFN, such as plasmapheresis, intravenous immune globulin, immunoabsorption, oral tolerance and chemotherapeutic agents, has been met with more mixed views.

Plasmapheresis and intravenous immune globulin

Plasmapheresis

An interest in plasmapheresis for the in utero treatment of HDFN preceded the improved perinatal survival realized in the late 1980s with modern intrauterine transfusion techniques. Most of the literature has reported single cases or relatively small case series (Table 10.1). Many of the studies used the historical control of the outcome of the patient's previous affected pregnancy to assess a therapeutic effect. In addition, plasmapheresis has often been combined with intrauterine transfusion or intravenous immune globulin (IVIG) making assessment of its effect more difficult. Despite these limitations, a review of the published cases reveals a perinatal survival of 69%. This would appear to warrant further scientific investigation into the use of plasmapheresis as an adjunct in the management of the severely alloimmunized patient. A randomized clinical trial was attempted by the Canadian Apheresis Study Group, but, unfortunately, insufficient enrolment necessitated premature termination of the study.

Reported protocols vary considerably but all involve repeated procedures due to a rebound increase in antibody titre. In animal studies, Bystryn and coworkers experimentally lowered antibody levels by exchange transfusion. Antibody levels were noted to rebound to over 200% of the initial levels with increases of up to 50–80% being seen even in the first 48 hours.