One thousand seventy antibodies detected only by a 2-stage papain test: wanted and unwanted positive reactions.

Despite the wide use of the antibody detection test for unexpected antibodies, controversy still remains regarding the use of enzyme-treated red blood cells. Over a 6-year period, 72,573 samples from 49,863 patients submitted for pretransfusion compatibility testing were examined for unexpected antibodies. The antibody detection tests included a low-ionic-strength solution (LISS) indirect antiglobulin test and a two-stage papain (2SP) test. One thousand and seventy of the 2267 (47%) antibodies tested by 2SP were reactive only by the 2SP test. Overall, the 2SP test detected only 0.6% of antibodies considered to be clinically significant (10 examples of anti-c and 2 examples of anti-e). The slight additional safety provided by detection of clinically-significant antibodies is overshadowed by the high number of clinically-insignificant antibodies detected by the 2SP test.

[Thrombocytopenic thrombotic purpura. Retrospective study of 22 consecutive occurrences in 16 patients]. / Púrpura trombótica trombocitopénica. Estudio retrospectivo de 22 episodios consecutivos en 16 pacientes.

BACKGROUND: Thrombotic Thrombocytopenic Purpura (TTP) is an uncommon clinical syndrome with high mortality rate in the absence of treatment. Despite the therapeutic efficacy of plasma exchange, patients often relapse even after long periods of time in remission. Over the last few years, late relapses in previously diagnosed patients have been seen in our hospital. PATIENTS AND METHODS: We analyzed retrospectively 22 episodes of TTP in 16 patients diagnosed during a four-year period. We reviewed the clinical features at diagnosis as well as the therapeutic results. In all but one, the treatment included daily plasma exchange. Other treatments, including vincristine, were also used in addition to plasma exchange, in 18 of 21 episodes. RESULTS: A complete remission was obtained in eighty-two percent of the episodes treated by plasma exchange. The median number of plasma exchange to achieve a complete remission was 6. In 4 episodes, 20 or more plasma exchange were required before achieving a satisfactory response. A complete remission was obtained in 78% of episodes where vincristine was used, versus 84% response rate in episodes where vincristine was not used. In four patients the cause death was directly related to TTP, while a fifth patients died of progressive lymphoma without evidence of TTP. Five of the eleven surviving patients relapsed with a median time to relapse of 24.6 months. Relapsing episodes presented with a less severe clinical picture including less clear signs of microangiopathic hemolytic anemia (MAHA), when compared with the initial ones. All patients in relapse responded promptly to treatment. The variables analyzed failed to predict either the response to treatment or the probability of relapse. CONCLUSIONS: The therapeutic efficacy of plasma exchange in the treatment of TTP has been demonstrated in our series as previously observed by many other groups. We have observed some slow responders where the prolongation of treatment by plasma exchange succeeded in achieving a complete remission. The use of vincristine did not show any therapeutical advantage in our experience.

Evaluation of RNA and E2 antibodies in prospectively followed recipients of hepatitis G virus-infected blood.

BACKGROUND: Hepatitis G virus (HGV) has recently been cloned and tests for HGV RNA and envelope antibodies (anti-E2) have been developed. HGV infection is widespread among blood donors worldwide, but the clinical and serologic outcome of transfusion-associated HGV infection has not been fully characterized. STUDY DESIGN AND METHODS: Consecutive blood donors (n = 2210) were investigated for HGV markers (RNA and anti-E2). The recipients of HGV RNA-positive blood were followed for 1 year after transfusion. RESULTS: Forty-two blood donors (1.9%) were positive for HGV RNA. Eight recipients of HGV RNA-positive blood were retrospectively identified within 2 weeks of transfusion and prospectively followed. In four patients, the presence of anti-E2 before transfusion or an early antibody response protected them from reinfection or prevented HGV persistence, while, in the remaining four patients, transient or persistent viremia was detected shortly after exposure. None of the infected recipients had any evidence of liver disease. CONCLUSION: These results do not support the screening of donors to prevent transfusion-associated HGV infection.