Hemolytic adverse effects of intravenous immunoglobulin: modeling predicts risk reduction with anti‐A/B immunoaffinity chromatography and to a lesser extent with anti‐A donor screening

The utility of a monocyte monolayer assay in the assessment of intravenous immunoglobulin-associated hemolysis

BACKGROUND

Hemolysis following the administration of intravenous immunoglobulin (IVIG) is an important adverse event (AE). While the monocyte monolayer assay (MMA) has been used to predict in vivo hemolysis when serologically incompatible blood may be transfused, it has also been shown to correlate with IVIG-associated hemolysis. In this study, the MMA was examined for its utility in assessing the risk of hemolysis after IVIG.

STUDY DESIGN AND METHODS

Forty-two non-blood group O patients receiving high-dose IVIG (≥2 g/kg) were examined using an autologous and allogeneic MMA. Hemolysis was defined by a drop in hemoglobin of ≥1 g/L, a positive direct antiglobulin test (DAT) and eluate, and a decrease in haptoglobin or increase in lactate dehydrogenase and/or reticulocytes.

RESULTS

Forty-two patients provided 50 assessable postinfusion samples, with hemolysis observed in 20 (40%) of cases. Autologous MMA using post-IVIG red blood cells significantly correlated with clinical outcomes when compared to allogeneic MMA (P = .0320 vs .5806, t test). No significant difference in receiver operating characteristics was observed when comparing autologous MMA testing against DAT for the diagnosis of IVIG-associated hemolysis. However, when using samples collected 5 to 10 days after receipt of high-dose IVIG, the autologous MMA had higher sensitivity than the DAT.

CONCLUSION

MMA testing with autologous monocytes collected 5 to 10 days after receipt of high-dose IVIG can be used for the diagnosis of IVIG-associated hemolysis and may be of particular value in cases in which the Day 5 to 10 DAT is negative.

Measurement of isoagglutinins in immunoglobulins for intravenous application by flow cytometry

Isoagglutinins present in intravenous immunoglobulin (IVIG) products have been linked to haemolysis. Therefore, accurately assessing isoagglutinin content in IVIG products is important. The standard European Pharmacopoeia (Ph.Eur.) direct assay is limited by low precision. Here, we describe the development of a fluorescence-activated cell sorting (FACS) method for assessing isoagglutinin levels. Serially diluted IVIG samples were incubated with red blood cells (RBCs), RBC-bound anti-A and anti-B antibodies were detected using a fluorescently-labelled antibody and the median fluorescence intensity of samples was assessed by FACS. Results were compared with the Ph.Eur. direct assay. The method was used to determine isoagglutinins in commercial products produced with and without isoagglutinin reduction steps. Assay precision, reported as the coefficient of variation, for the FACS method was 14% and 8% for anti-A and anti-B, respectively versus 33% and 20% with the Ph.Eur. direct assay. Application of the method on commercially available IVIGs revealed differences in isoagglutinin content between products produced with and without isoagglutinin reduction steps. This FACS assay allows for quantification of isoagglutinin concentrations in IVIGs with higher precision than the Ph.Eur. direct assay. Also the FACS assay confirms differences in isoagglutinin levels between IVIG products and the efficacy of isoagglutinin reduction measures.

Hemolysis From Intravenous Immunoglobulin in Obese Patients With Kawasaki Disease

Objective: We assessed the risk of IVIG-associated hemolytic anemia in patients with acute Kawasaki disease (KD) and evaluated the risk of weight-based dosing in our obese patients. Methods: IVIG-associated hemolytic anemia was assessed in acute KD patients treated with IVIG at Rady Children's Hospital-San Diego. Patients in whom hemolytic anemia was suspected had a decrease in z-score of their hemoglobin (zHgb) at least two standard deviations below the cohort's mean change in zHgb from baseline to 2 weeks post-IVIG treatment. These patients were further evaluated for spherocytosis, blood type, need for transfusion, red cell distribution width, reticulocytosis, and direct Coombs test. Body mass index was calculated. Results: Of the 30 IVIG-resistant KD patients who received a second dose of IVIG, 2 (6.7%) developed hemolytic anemia after a total of 4 g/kg of IVIG dosed on actual body weight, or a mean of 4.6 g/kg of IVIG based on lean body mass. Compared to 496 non-obese KD patients who received a single dose of IVIG with no cases of hemolytic anemia, two (5.6%) of 36 obese KD patients developed hemolytic anemia after a single dose of IVIG (2 g/kg) dosed on actual body weight, or a mean of 2.7 g/kg IVIG based on lean body mass. Conclusions: In addition to following patients carefully for hemolytic anemia after a second dose of IVIG, physicians should consider IVIG dosing based on lean body mass for obese patients.

Safety considerations with current and emerging antiviral therapies for cytomegalovirus infection in transplantation

Introduction: Human cytomegalovirus (HCMV) is a major contributor of morbidity and mortality, and its management is essential for the successful outcome of solid organ and hematopoietic stem cell transplantation. Areas covered: This review discusses the safety profiles of currently available and emerging antiviral drugs and the other strategies for HCMV prevention and treatment after transplantation. Expert opinion: Strategies for management of HCMV rely largely on the use of antiviral agents that inhibit viral DNA polymerase (ganciclovir/valganciclovir, foscarnet, and cidofovir/brincidofovir) and viral terminase complex (letermovir), with different types and degrees of adverse effects. An investigational agent, maribavir, exerts its anti-CMV effect through UL97 inhibition, and its safety profile is under clinical evaluation. In choosing the antiviral medication to use, it is important to consider these safety profiles in addition to overall efficacy. In addition to antiviral drugs, reduction of immunosuppression is often generally needed in the management of HCMV infection, but with a potential risk of allograft rejection or graft-versus-host disease. The use of HCMV-specific or non-specific intravenous immunoglobulins remains debated, while adoptive HCMV-specific T cell therapy remains investigational, and associated with unique set of adverse effects.