Management of infants born with severe neonatal alloimmune thrombocytopenia: the role of platelet transfusions and intravenous immunoglobulin.

BACKGROUND: Neonatal alloimmune thrombocytopenia (NAIT) is a fetomaternal incompatibility most commonly induced by maternal anti-HPA-1a alloantibodies. Transfusion of immunologically compatible platelets (PLTs) to prevent cerebral hemorrhage, the most severe complication in affected newborns, is usually recommended. Such PLT concentrates, however, are often not readily available. STUDY DESIGN AND METHODS: The efficacy of random-donor PLT transfusions and intravenous immunoglobulin (IVIG) for the management of 17 neonates across four centers with unexpected, severe NAIT was evaluated. Neonates were treated with random-donor PLTs alone (n=7), random-donor PLTs with IVIG (n=8), or matched HPA-1bb PLTs (n=2). RESULTS: All but one patient (treated with random PLTs and IVIG) achieved a posttransfusion PLT count of higher than 30 × 10(9) /L after the first PLT transfusion. The PLT count remained higher than 30 × 10(9) /L for longer than 24 hours in five of seven, seven of eight, and two of four newborns who received random-donor PLTs alone, random-donor PLTs with IVIG, or matched HPA-1bb PLTs, respectively. None of the newborns developed major bleeding or intracranial hemorrhage. IVIG did not appear to improve either posttransfusion PLT counts or total PLT transfusion requirements. CONCLUSION: Transfusion of random-donor PLTs alone was effective at correcting critically low PLT counts and should be considered as first-line treatment of newborns with unexpected severe NAIT.

The Canadian Transfusion Surveillance System: what is it and how can the data be used?

Hemovigilance systems are important programs for: monitoring trends of known risks; evaluating effectiveness of steps taken to reduce risks; providing data to support recommendations for change and guideline development; and contributing overall to the safety of transfusion. The Transfusion Transmitted Injury Surveillance System is the hemovigilance system implemented in Canada. It evolved in 1999 as a pilot program and expanded across Canada in 2005. Each province reports their adverse reactions to the transfusion of blood products and plasma proteins to the Public Health Agency of Canada (PHAC) at predetermined intervals. PHAC reconciles, summarizes the data and publishes a report approximately 2 years after the data are collected. This is considered a passive reporting system but in spite of the delays, the program provides useful information to address a variety of questions. Examples include: assessing the impact of a provincial patient transfusion history registry in Québec on reporting of hemolytic transfusion reactions; identifying trends of bacterial contamination of blood products and assessing the impact of interventions on these events; and the impact of male-only plasma on the incidence of Transfusion Related Acute Lung Injury. Although hemovigilance data has been successfully used to improve blood safety, we must continue to explore ways to utilize such data to improve and implement safe transfusion practices.

Misleading hepatitis B test results due to intravenous immunoglobulin administration: implications for a clinical trial of rituximab in immune thrombocytopenia.

BACKGROUND: Rituximab may cause reactivation of hepatitis B virus (HBV) even in patients with remote HBV infection. Thus, the presence of hepatitis B core antibodies (anti-HBc) was an exclusion criterion for a randomized trial of rituximab for patients with immune thrombocytopenia. A high seroprevalence of anti-HBc observed among patients screened for the trial prompted this substudy to investigate for an association between anti-HBc seropositivity and exposure to intravenous immunoglobulin (IVIG). STUDY DESIGN AND METHODS: This was a retrospective case-control study that was a substudy of a randomized controlled trial. RESULTS: Of 24 trial participants screened at one center, 11 (45.8%) were anti-HBc positive and of those, 10 (90.0%) had received IVIG in the preceding 4 weeks. Of 13 seronegative patients screened, five (38.5%) had received IVIG (odds ratio, 16; 95% confidence interval, 1.5-166.1). Seven (70%) of 10 seropositive participants subsequently reverted to negative upon repeat testing. Serial testing before and after IVIG (n = 2) demonstrated transient anti-HBc that lasted for up to 11 weeks after the last dose of IVIG. Samples from three of five different IVIG products were found to contain anti-HBc. CONCLUSIONS: Passive transfer of anti-HBc from certain IVIG products may lead to misinterpretation of hepatitis test results with implications for treatment and clinical trial eligibility. To avoid misleading test results, anti-HBc should be measured before or 3 months after IVIG administration; alternatively an IVIG product known to be free of anti-HBc should be used.

Hypotensive transfusion reactions can occur with blood products that are leukoreduced before storage.

BACKGROUND: Leukoreduction before storage, rather than bedside white blood cell filtration, is recommended to prevent hypotensive transfusion reactions. STUDY DESIGN AND METHODS: Investigation of hypotensive transfusion reactions during radical prostatectomy in two patients on angiotensin-converting enzyme inhibitors. In Patient A, hypotension occurred during the transfusion of each of the following blood products: 2 units of autologous blood deposited and leukoreduced (LR) before storage; 3 units of allogeneic red cells LR before storage; and 2 units of non-LR acute normovolemic hemodilution (ANH) whole blood. When each of the transfusions was stopped, the blood pressure recovered. In Patient B, hypotension occurred during the transfusion of non-LR ANH whole blood. All implicated units were administered rapidly using a blood infuser at 37 degrees C. Bradykinin (BK) and des-Arg9-BK formation and degradation and the activity of kinin-degrading metallopeptidases were measured in plasma samples from both patients. RESULTS: Degradation of des-Arg9-BK was severely impaired and the activity of aminopeptidase P severely reduced in Patient A, but not in Patient B. BK degradation was mildly impaired in both patients. CONCLUSION: Hypotensive reactions can occur with blood products that are LR before storage and non-LR ANH. An inherent defect in the metabolism of kinins may be a risk factor for the development of hypotensive transfusion reactions.