Diagnosis and management of thrombotic thrombocytopenic purpura (TTP) in Australia: findings from the first 5 years of the Australian TTP/thrombotic microangiopathy registry.

BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) is a rare, life-threatening thrombotic microangiopathy (TMA). In 2009, the Australian TTP/TMA registry was established to collect data on patients presenting with TTP/TMA throughout Australia. AIM: To summarise information on the diagnosis and management of patients with TTP collected in the first 5 years (2009-2014) of the Australian TTP registry. METHODS: Registry data from June 2009 to October 2014 were reviewed. RESULTS: Fifty-seven patients were identified with TTP (defined as ADAMTS13 activity <10%), accounting for 72 clinical episodes. ADAMTS13 inhibitor testing was performed in nine out of 57 patients (16%), reflecting the limited availability of accredited testing facilities. Sixty-seven out of 72 episodes were treated with therapeutic plasma exchange (PEx) using cryodepleted plasma (40% of episodes), fresh frozen plasma (36%) or a mixture (22%). Median exposure to plasma products was 55.9 L. PEx was commenced ≥2 days from stated diagnosis in 15% of episodes. Adverse reactions to PEx were common with documented allergic reactions (including life threatening) in 21% of episodes. Adjunctive immunosuppression was documented in 76% of episodes (corticosteroid 71% and rituximab 39%). Platelet transfusion was administered in 15% of episodes. CONCLUSIONS: Data from the Australian TTP/TMA registry suggest a heterogenous approach to the diagnosis and management of TTP in Australia over the assessed period. These observations highlight areas for improvement and standardisation of practice, including comprehensive diagnostic testing, more immediate access to PEx and a more uniform approach to adjunctive immunosuppression and supportive care.

The residual risk of transfusion-transmitted cytomegalovirus infection associated with leucodepleted blood components.

BACKGROUND AND OBJECTIVES: Cytomegalovirus poses a risk to transfusion safety as its transmission to an immunocompromised recipient may lead to significant clinical sequelae. Once infection is established, it is lifelong and generally asymptomatic. Strategies to reduce the risk of transfusion-transmitted CMV (TT-CMV) include donor serological testing and blood component leucodepletion to deplete the transmissible reservoir. We estimate the residual risk for non-CMV antibody screened, leucodepleted (LD-only) fresh blood components. MATERIALS AND METHODS: We established an approach to estimate the risk of TT-CMV under various scenarios. We estimated the probability of an infectious component, for both red cells and platelets, as a function of the observed WBC filter failure rate and the probability that such a unit was also contaminated with infectious virus. RESULTS: Using this model, the estimated combined residual risk of LD-only red cell and platelet units was very low, 1 in 13 575 000 (95%CI:1 in 1 344 167 000-1 in 1 730 000) as was the individual residual risk estimate for LD-only red cells, 1 in 7 790 000 (95%CI: 1 in 771 307 000-1 in 993 000) and LD-only platelets, where a zero risk was estimated (95%CI: 0-1 in 1 074 000). CONCLUSION: We describe a novel approach to assess the residual risk of LD-only components. This can be applied generally using local data. Our risk estimate for LD-only blood components in Australia is below the threshold of 1 in 1 million, generally considered negligible. This provides a useful indicator of the relative safety of LD-only components to assist clinical decisions when serologically screened inventory is unavailable.

A 'dangerous' group O donor: severe hemolysis in all recipients of organs from a donor with multiple red cell alloantibodies.

Alloimmune hemolysis is a recognized but infrequent complication of solid organ transplantation, particularly where there is incompatibility within the ABO blood group system. We describe severe hemolysis due to passenger lymphocyte syndrome (PLS) in all three recipients of organs from a single donor with multiple red cell (RC) alloantibodies. The first patient, a liver transplant recipient, required augmentation of immunosuppression to treat immune hemolysis due to anti-B, -D, -C and -Cellano (k). This is the first description of PLS caused by alloantibody to the high incidence RC antigen, k. The two single lung transplant recipients developed hemolysis due to anti-D. Both required escalation of immunosuppression and early transfusion support. Three months posttransplant, all three patients have ongoing evidence of compensated hemolysis. This series highlights the potential for severe non-ABO-mediated immune hemolysis following solid organ transplantation. A positive donor RC antibody screen should prompt careful monitoring of organ recipients for hemolysis.

Hepatitis B immunity in a population of drug and alcohol users.

The objective of this study was to determine the level of immunity from Hepatitis B infection in an Australian population of drug and alcohol users, and the validity of self-reported immune status. A cross-sectional survey was employed of drug and alcohol users presenting for treatment, who were clients of De Paul House, a community-based drug and alcohol withdrawal service in Victoria. Outcome measures were: hepatitis B serology and personal reports of hepatitis B immunity. A total of 118 people were enrolled; 22% were injecting drug users and 48% reported past injecting drug use, while 55% were alcohol users; 51% had no general practitioner; 73% of participants were unaware of whether they were protected from hepatitis B infection, while 19.5% believed they were protected. However, serology demonstrated that 52.2% of those who believed they were protected were not immune. Only 21% of participants were immune. This is the first study in an Australian setting since the 1970s to examine the effectiveness of vaccination targeted to this population, and demonstrates low rates of immunity. New strategies are needed to deliver vaccination to this group. These will need to take account of the often chaotic nature of their lives, the poor validity of self-reported immunity, and the lack of primary care links.

Cardiac involvement in Henoch-Schönlein purpura.

Cardiac involvement is not regarded as a feature of Henoch-Schönlein purpura (HSP). We report a patient with HSP who developed significant cardiac symptoms, which resolved with immunosuppression. We review previous cases of HSP with cardiac features, none of which showed a response to treatment, and discuss evidence that cardiac involvement is more common than recognized. The implications for investigation and treatment of this condition are discussed.

Expression of "suppressor of cytokine signalling" (SOCS) genes in the developing and adult mouse nervous system.

Growth factor and cytokine signalling in the developing nervous system has multiple effects, ranging from cell differentiation and cell survival to modulation of cell phenotype. Molecules that can regulate growth factor signalling pathways will therefore be of importance in determining the cellular response to factor stimulation. Members of a recently described gene family, the suppressor of cytokine signalling (SOCS) family, can regulate signalling events downstream of predominantly cytokine stimulation and may have important roles in the nervous system. We have examined the temporal and spatial expression of SOCS-1, SOCS-2, and SOCS-3 in the developing and adult nervous system by use of Northern analysis and in situ hybridisation. All three genes were expressed in the brain, with maximal expression from embryonic day 14 to postnatal day 8 and declining thereafter, with SOCS-2 being the most highly expressed. In situ hybridisation analysis showed that SOCS-1 and SOCS-3 had a low and widespread pattern of expression, whereas SOCS-2 expression was higher and tightly regulated. Its expression pattern indicated that SOCS-2 was expressed exclusively in neurons and that it was switched on developmentally at the time of neuronal differentiation.