Autoimmune hemolytic anemia in Kawasaki disease: a case report

A 3-year-old boy presented with the fever, conjunctivitis, rash, and lymphadenopathy diagnostic of Kawasaki disease. Treatment with antibiotics, aspirin, and intravenous immunoglobulin was instituted. The hematocrit decreased from 35 percent on admission to 11 percent by hospital Day 10, and the white cell count had increased from 13.7 to 42 × 10(3) per microL, and the patient had a leukoerythroblastic blood smear. The direct antiglobulin test demonstrated IgG but not complement on the red cell (RBC) surface. An acid eluate reacted (titer of 4) with all panel cells in the antiglobulin phase. Intravenous immunoglobulin from the same lot used for treatment did not contain antibody that reacted with the patient's group O RBCs or a panel of group O RBCs, but did contain IgG anti-A and -B (titer of 4). The patient received a transfusion and was given methylprednisone. The direct antiglobulin test and acid eluate were negative 4 days later. The patient had an uneventful recovery. The distinction between antibody-mediated hemolytic anemia and autoimmune hemolytic anemia is important in the treatment of this disease.     

示指桡侧指背动脉逆行岛状皮瓣移植修复示指缺损

目的:观察示指桡侧指背动脉逆行岛状皮瓣移植对示指指端缺损的修复效果。方法:选择2002-08/2005-09南华大学附属第一医院急诊收治的外伤性示指末节部分缺损患者13例,手术方法的选择在术前均得到患者同意,且得到医院伦理道德委员会批准。组织缺损大小在1.5cm×1.0cm～2.0cm×1.5cm之间,所有缺损均有指骨和(或)大部分的指腹组织缺损,采用示指桡侧指背动脉逆行岛状皮瓣移植修复,皮瓣设计:旋转点位于近侧指间关节的近端,皮瓣轴为示指的桡背侧,皮瓣部分设计在第2掌指关节的近侧,蒂宽约0.8mm。术后定期随访,主要观察皮瓣质地和感觉的恢复情况,将感觉恢复的评估标准分为5级:S1:无感觉;S5:在神经单一分布区恢复两点鉴别能力。结果:13例患者全部进入结果分析,无脱落。①术后随访三四个月者10例,随访五六个月者3例。②术后9例皮瓣完全成活;4例皮瓣远端部分坏死,经换药表皮爬行创面愈合。③外形基本满意,皮瓣色泽、质地良好。④术后1个月随访时,3例患者两点辨别觉大于6.0mm,感觉恢复S4;术后五六个月随访时,3例患者两点辨别觉4.0～6.0mm,感觉恢复S5。结论:示指桡侧指背动脉逆行岛状皮瓣设计的旋转点位于近侧指间关节的近端,可以简化手术而不影响皮瓣存活,是示指部分缺损修复的可选方法。     

Erythrocytapheresis therapy to reduce iron overload in chronically transfused patients with sickle cell disease

Chelation therapy with deferoxamine is effective in preventing the risk of transfusional iron overload, but treatment failure is common because of noncompliance. To reduce the transfusional iron load, we have evaluated longterm erythrocytapheresis in 14 subjects with sickle cell disease and stroke (11) or other complications (3) as an alternative to simple transfusion. Subjects were treated with erythrocytapheresis using the Haemonetics V50 (Haemonetics Corp, Braintree, MA) to maintain the target pretransfusion hemoglobin S (Hb S) level less than 50% for 6 to 71 months. The transfusional iron load and the donor blood usage were analyzed for a 6- to 36-month study period and were compared with similar data from a subset of 7 subjects previously treated with conventional (target Hb S < 30%) and modified (target Hb S < 50%) simple transfusion protocols. The effect of erythrocytapheresis on iron accumulation was determined by assessment of serum ferritin levels in the absence of iron chelation. The mean transfusional iron load and donor blood usage with erythrocytapheresis were 19 +/- 14 mg iron/kg/yr (range, 6 to 50) and 188.4 +/- 55.2 mL packed-red blood cells (RBC)/kg/yr (range, 107 to 281), respectively. Of 6 subjects receiving no iron chelation therapy, 5 maintained normal or nearly normal serum ferritin levels during 11 to 36 months of erythrocytapheresis. In comparison with conventional simple transfusion and modified simple transfusion, erythrocytapheresis reduced iron loading by 87% (P < .01) and 82% (P < .01), respectively, but increased donor blood usage by 23% and 73%, respectively. Subjects with pre-erythrocytapheresis Hb levels > or = 8.0 g/dL had lower iron accumulation (P < .001) and less donor blood usage (P < .005) than subjects with Hb levels < or = 8.0 g/dL. Although donor blood usage is increased in comparison with simple transfusion, long-term erythrocytapheresis markedly reduces or prevents iron accumulation. This form of transfusion therapy allows the cessation of iron chelation in well-chelated subjects and, if used as the initial form of transfusion therapy, may prevent long-term complications of sickle cell disease without risk of iron overload and the need for chelation therapy.     

Single-strand conformation polymorphism analysis is a rapid and effective method for the identification of mutations and polymorphisms in the gene for glycoprotein IIIa

Glanzmann thrombasthenia (GT) is the most common inherited disorder of platelets. Most of the molecular defects previously identified in GT have been caused by point (or other small) mutations in the genes for glycoprotein (GP) IIb or GPIIIa. We have used single-strand conformation polymorphism (SSCP) analysis to rapidly identify single- base changes in the GPIIIa gene. Using genomic DNA from normal individuals and patients with GT, each GPIIIa exon and a short stretch of flanking intronic sequence was amplified, heat-denatured, and separated in nondenaturing acrylamide gels. Only those fragments with an abnormal migration pattern were isolated and the nucleotide sequence determined. Using SSCP, we detected the polymorphism in the HPA-1 (P1A) system and all three known silent polymorphisms in the GPIIIa gene. Screening 14 GPIIIa exons from 5 patients with GT, one mutant allele was identified. The nucleotide sequence of the abnormal 240-bp SSCP fragment was determined and a G-->A substitution in the splice donor site of exon iv was identified. Analysis of platelet RNA resulting from this mutation showed two mRNA species: one contained a deletion of exon iv, whereas the other had a 27-bp addition to exon iv due to the use of a cryptic splice site in the downstream intron. Single-base substitutions are the most common mutation in GT and often result in abnormal mRNA splicing. SSCP is a rapid and sensitive technique for identifying mutations or polymorphisms in the GPIIIa gene.     

Bedside filtration of blood products in the prevention of HLA alloimmunization--a prospective randomized study. Alloimmunisation Study Group

To test the efficacy of poststorage bedside leucodepletion of blood products in the prevention of primary HLA alloimmunization and its clinical sequelae, 172 patients with hematologic malignancy requiring intensive red blood cell and platelet support were randomized to receive either standard or filtered red blood cells and platelets. Quality control of bedside filtration was explored by sequential sampling downstream of the filter, but this did not predict the total number of leucocytes transfused. After exclusions, 123 evaluable patients were assessed every two weeks until the end of therapy. HLA antibodies developed in 21 of 56 (37.5%) nonfilter (NF) and 15 of 67 (22%) filter (F) patients (risk ratio estimate, 0.60 [95% confidence interval, 0.34 to 1.05]; P = .07). Patients with acute myeloid leukemia (AML; n = 53) had higher alloimmunization rates in both arms of the study, with a greater effect of filtration (62.5% NF and 31.0% F; P = .025). Bedside filtration did not affect the overall incidence of febrile transfusion reactions (FTRs; 37% NF and 34% F; P = .71) or of platelet refractoriness assessed in 50 patients (30% NF and 26% F), despite an association between broad HLA reactivity and both FTRs and refractoriness. However, FTRs were also seen in 28 patients without HLA antibodies. Five alloimmunized refractory patients (2 F and 3 NF) required HLA-selected platelets. This report, the first prospective study of bedside filtration, has failed to show clear clinical benefit. Methodological limitations may account in part for this failure, notably the difficulties in accurately assessing the number of leucocytes transfused.     

Intra-luminal nicotine reduces smooth muscle tone and contractile activity in the distal large bowel

BACKGROUND: Nicotine may be of therapeutic value in ulcerative colitis (UC), although its mechanism of action has not been established. OBJECTIVE: To examine the effect of a solution of nicotine on sustained resting pressure (tone) and contractile activity in the human colon. METHODS: Ten healthy volunteers, and seven with UC in symptomatic remission took part; all were non-smokers. All 17 subjects were given nicotine or placebo solution on two separate occasions in a randomized sequence. A water-perfused manometry catheter, with openings at 5, 10 and 15 cm from the tip, was placed by rigid sigmoidoscopy in the recto-sigmoid region. Baseline tone and activity were measured for 15 min prior to instillation of 20 ml of saline alone or with nicotine, 1.2 mg, at pH 4.5. Observations were made over the subsequent 15-20 min. RESULTS: Baseline spontaneous activity in all subjects showed both high- and low-frequency components; in three patients with UC, the low-frequency activity was of high amplitude. The nicotine reduced both tone and activity in all subjects, with reduction or abolition of the large contractions in UC. Tone in all 17 subjects was reduced significantly at 3 min after nicotine (P = 0.000015, sign test); the rate of recovery varied in individuals. Results from normals and UC did not differ significantly from each other. No significant change in tone or activity was observed with the saline solution. CONCLUSION: Intra-luminal nicotine significantly reduces both smooth muscle tone and contractile activity in the recto-sigmoid colon in both normal subjects and patients with UC.     

Antiretroviral pill count and clinical outcomes in treatment‐naïve patients with HIV infection

Objectives

Treatment guidelines recommend single‐tablet regimens for patients with HIV infection starting antiretroviral therapy. These regimens might be as effective and cost less if taken as separate drugs. We assessed whether the one pill once a day combination of efavirenz, emtricitabine and tenofovir reduces the risk of disease progression compared with multiple‐pill formulations of the same regimen.

Methods

We selected treatment‐naïve patients starting one‐, two‐ or three‐pill formulations of this regimen in data from the Antiretroviral Therapy Cohort Collaboration. These patients were followed until an AIDS event or death or until they modified their regimen. We analysed these data using Cox regression models, then used our models to predict the potential consequences of exposing a future population to either a one‐pill regimen or a three‐pill regimen.

Results

Among 11 739 treatment‐naïve patients starting the regimen, there were 386 AIDS events and 87 deaths. Follow‐up often ended when patients switched to the same regimen with fewer pills. After the first month, two pills rather than one was associated with an increase in the risk of AIDS or death [hazard ratio (HR) 1.39; 95% confidence interval (CI) 1.01‐1.91], but three pills rather than two did not appreciably add to that increase (HR 1.19; 95% CI 0.84‐1.68). We estimate that 77 patients would need to be exposed to a one‐pill regimen rather than a three‐pill regimen for 1 year to avoid one additional AIDS event or death.

Conclusions

This particular single‐tablet regimen is associated with a modest decrease in the risk of AIDS or death relative to multiple‐pill formulations.

     

Leukocyte depletion of random single-donor platelet transfusions does not prevent secondary human leukocyte antigen-alloimmunization and refractoriness: a randomized prospective study

We studied the value of leukocyte depletion of platelet transfusions for the prevention of secondary human leukocyte antigen (HLA)- alloimmunization in patients with a high-risk of prior immunization induced by pregnancies. Seventy-five female patients with hematologic malignancies (mostly acute leukemia) and a history of pregnancy were randomized to receive either standard random single-donor platelet transfusions (mean leukocytes, 430 x 10(6) per transfusion) or leukocyte-depleted random single-donor platelet transfusions. Leukocyte depletion to less than 5 x 10(6) leukocytes per platelet transfusion (mean leukocytes, 2 x 10(6) per transfusion) was achieved by filtration. Of the 62 evaluable patients, refractoriness to random donor platelets occurred in 41% (14 of 34) of the patients in the standard group and in 29% (8 of 28) of the patients in the filtered group (P = .52); anti-HLA antibodies developed in 43% (9 of 21) of individuals in the standard group and 44% (11 of 25) of cases in the filtered group. The time toward refractoriness and development of anti- HLA antibodies was similar for both groups. We conclude that leukocyte depletion of random single-donor platelet products to less than 5 x 10(6) per transfusion does not reduce the incidence of refractoriness to random donor platelet transfusion because of boostering of anti-HLA antibodies.     

Increased red blood cell deformability due to isoxsuprine administration decreases platelet adherence in a perfusion chamber: a double-blind cross-over study in patients with intermittent claudication

Platelet transport towards the vessel wall is influenced by the hematocrit, red blood cell (RBC) size, and shape. Recent in vitro studies have indicated that RBC deformability may also influence platelet transport. The observation that isoxsuprine, a known vasodilating drug, caused increased RBC deformability in vitro and decreased platelet transport in vitro prompted us to study the effects of this drug in vivo. The study was performed in a double-blind cross- over study of isoxsuprine v placebo in ten patients with peripheral arterial insufficiency. RBC deformability was estimated from viscosity measurements using the blood viscosity equation of Dintenfass and expressed as T value. Platelet transport was studied in an annular perfusion chamber according to Baumgartner. Human umbilical arteries were used as blood vessels. Perfusion studies were performed with whole blood or with RBCs of the patients mixed with normal platelets and plasma at a standardized hematocrit and platelet count. An increase in RBC deformability concomitant with a decrease in platelet adherence was observed in patients on isoxsuprine with a drop in T value of approximately 0.06 (from 0.91 toward 0.86), and a concomitant decrease in platelet adherence of 20% to 40%. These observations differed significantly from the results in the placebo group and showed a significant group-period interaction at the cross-over of medication (analysis of variance). The effects on platelet adherence were observed at high vessel wall shear rate (1,800 s-1) with perfusates consisting of patients' RBCs and donor plasma and platelets at standardized hematocrit and platelet count. No differences were observed under these conditions at a shear rate of 300 s-1. When whole blood of patients was used, nonsignificant effect was observed at shear rates of 300 s-1 and 1,800 s-1. This was probably caused by the added noise due to variations in hematocrit and platelet number. These data demonstrate that isoxsuprine increases RBC deformability, and they suggest the possibility of decreasing platelet-vessel wall interaction in vivo by manipulation of RBC deformability.