Prognostic implications for direct platelet-associated IgG in childhood idiopathic thrombocytopenic purpura

To determine the value of the direct platelet associated IgG (PAIgG) level as a prognostic indicator in childhood idiopathic thrombocytopenia purpura (ITP), 18 children with ITP were studied. Ten of the 18 had PAIgG levels measured at diagnosis, before any therapy. Of these 10 patients, six (Group I) had an acute course, with a mean initial platelet count of 15 X 10(9)/liter and a mean initial PAIgG level of 330.9 fg/plt. Four patients (Group II) had a chronic course, with a mean initial platelet count of 11 X 10(9)/liter and a mean initial PAIgG level of 38.3 fg/plt. There was no significant difference between the mean initial platelet count of Groups I and II (p greater than 0.10), but the initial PAIgG levels in those patients with an acute course were significantly higher than the levels in those patients with a chronic course (p less than 0.05). Of the original 18 patients, nine were splenectomized for chronic thrombocytopenia, with normalization of the platelet count in all instances. Of these splenectomized patients, five had platelet counts and PAIgG levels measured before and after splenectomy. All five had normal PAIgG levels following splenectomy. The PAIgG level is a good prognostic indicator for the clinical course of childhood ITP. A high PAIgG level suggests an acute course while a modestly elevated level suggests a chronic course. The PAIgG level normalizes in remission after splenectomy.     

Platelet antibody in prolonged remission of childhood idiopathic thrombocytopenic purpura

Evaluations were performed in 20 patients with childhood idiopathic thrombocytopenic purpura (ITP) who remained in remission longer than 12 months. The mean duration of follow-up from diagnosis was 39 months (range 17 to 87 months). Eleven patients (four girls) in group 1 had an acute course of ITP, defined as platelet count greater than 150 X 10(9)/L within 6 months of diagnosis. Nine patients (five girls) in group 2 had a chronic course, defined as platelet count less than 150 X 10(9)/L for greater than or equal to 1 year or requiring splenectomy in an attempt to control hemorrhagic symptoms. Mean age at diagnosis and duration of follow-up were similar for both groups. Platelet count and serum (indirect) platelet-associated IgG (PAIgG) levels were normal in all 20 patients at follow-up. Both direct and indirect PAIgG levels were measured using a 125I-monoclonal anti-IgG antiglobulin assay. All had normal direct PAIgG levels, except for one patient in group 1 who had a borderline elevated value of 1209 molecules per platelet. These data suggest that the prevalence of elevated platelet antibodies is low during sustained remission without medication in patients with a history of childhood ITP. These data may be relevant for pregnant women with a history of childhood ITP, with regard to the risk of delivering an infant with thrombocytopenia secondary to transplacental passage of maternal platelet antibody.     

Platelet-associated immunoglobulin G in childhood idiopathic thrombocytopenic purpura

Platelet-associated IgG was studied in children with acute and chronic ITP and in patients with thrombocytopenic SLE, using the microtiter solid-phase radioimmunoassay. Of the children with acute ITP, 85% had elevated PAIgG levels. The degree of elevation of PAIgG at onset of disease did not correlate with the development of chronicity. Of the children with acute ITP, clinically and hematologically indistinguishable from the rest, 15% had normal PAIgG values. All of 22 children with chronic ITP had elevated PAIgG values. Although there was good correlation between the platelet count and the PAIgG value in children with chronic ITP, the association was not as striking in those with acute ITP; thus, factors in addition to the level of PAIgG may contribute to the thrombocytopenia in the latter group. Patients with SLE and thrombocytopenia had higher values of PAIgG than would be predicted from the platelet count; the PAIgG value is probably not the only factor determining the degree of immune thrombocytopenia.     

Platelet-Associated IgG in Children - Values and Evaluation of PAIgG in Various Thrombocytopenias -

Platelet-associated IgG (PAIgG) levels were measured in 60 children with ITP (46-chronic, 14-acute) using Fab-anti Fab radioimmunoassay method described by McMillan et al. In some patients platelet binding IgG in serum (PBIgG) was also determined at the same time. Patients with ITP had significantly greater PAIgG levels than 30 normal subjects and 13 non-immune thrombocytopenic controls. Elevated PAIgG values did not correlate with parameters of platelet size (mean platelet volume; MPV and percentage of large platelet; PLP) and so these data indicated that high levels of PAIgG in ITP were not due to nonspecific adhesion of serum IgG to megathrombocytes usually increased in this disorder, but due to specific immunological reaction. PBIgG IgG values were also elevated in patients with pretreated chronic ITP, but high levels remained even after successful splenectomy. Furthermore, serial determination of PAIgG values were obtained in some patients with chronic ITP who underwent splenectomy and with acute ITP who achieved spontaneous remission. PAIgG returned to normal levels when thrombocytopenia disappeared. PAIgG seems to be the most reproducible indicator which reflects transition of the clinical picture in this disorder.     

Idiopathic thrombocytopenic purpura: predictors of chronic disease.

We studied the extent to which patient characteristics influenced outcome in childhood idiopathic thrombocytopenic purpura in a historical cohort of 289 children over a 20 year period (1968-87). Outcome was classified as acute or chronic depending on whether the platelet count had returned to normal (150 X 10(9)/l) by six months after diagnosis. Fifty three cases (18%) had chronic idiopathic thrombocytopenic purpura. The likelihood of chronic disease was determined by logistic regression analysis of five patient variables: age, sex, season of onset of symptoms, history of recent viral illness, and duration of symptoms at presentation. A history of symptoms of greater than 14 days at presentation, adjusted for the other variables, was strongly predictive of chronic idiopathic thrombocytopenic purpura; the other variables did not significantly affect outcome. At 28 days after diagnosis 138 (47%) of the study cohort had normal platelet counts. Children whose platelet counts were less than 150 X 10(9)/l had a threefold risk of progressing to chronic idiopathic thrombocytopenic purpura, which increased to fivefold if counts were less than 50 X 10(9)/l. Two thirds of patients in the chronic group, irrespective of treatment, remained thrombocytopenic two years after diagnosis. We conclude that a history of symptoms for greater than two weeks at presentation is strongly predictive of chronic idiopathic thrombocytopenic purpura. If platelet counts are subnormal 28 days after diagnosis the risk of chronic idiopathic thrombocytopenic purpura is increased with prolonged thrombocytopenia being very likely if platelet counts remain low three months after diagnosis.     

Platelet-associated immunoglobulin G in childhood idiopathic thrombocytopenic purpura

Childhood ITP is an acquired hemorrhagic disorder with a heterogeneous clinical course. We measured PAIgG levels in 20 children with ITP (7 acute, 13 chronic). Both groups had significantly greater PAIgG values than age-matched normal subjects and thrombocytopenic controls (P less than 0.001). In addition, PAIgG values in chronic ITP were significantly lower than those in acute ITP (P less than 0.003). Serial PAIgG values were obtained in some patients; most returned to normal in association with clinical recovery. The measurement of PAIgG is useful in the diagnosis and follow-up of childhood ITP. PAIgG values may assist in differentiating acute and chronic disease in children.     

Duration and morbidity of newly diagnosed idiopathic thrombocytopenic purpura in children: A prospective Nordic study of an unselected cohort

OBJECTIVE: To determine the duration of the risk period with platelet counts <20 x 10(9)/L and the frequency of bleeding episodes in unselected children with idiopathic thrombocytopenic purpura (ITP). STUDY DESIGN: We established a registry for patients with newly diagnosed ITP in the five Nordic countries, enrolling children aged 0 to 14 years with platelet counts <30 x 10(9)/L. Treatment centers prospectively reported presenting features, management details, and disease-related events during the first six months after diagnosis. RESULTS: At presentation (n=501), more than half of the children had a platelet count <10 x 10(9)/L, but only 15 (3.0%) had a hemorrhage requiring blood transfusion. During follow-up of 409 patients, thrombocytopenia resolved uneventfully in 277. A risk period was present in 376 cases. Among 283 with self-limiting ITP, 26 were at risk >1 month and 25 had 30 events. Among 93 patients with chronic ITP, 73 were at risk >1 month and 44 had 111 events. Events occurred with an average frequency of 0.39 per month at risk. Life-threatening hemorrhages did not occur in the first six months after diagnosis. CONCLUSION: Most children with ITP are at risk for serious bleeding for less than one month. Continuing severe thrombocytopenia is associated with little morbidity, bleeding episodes being infrequent and very rarely serious.     

Alpha-interferon therapy induces improvement of platelet counts in children with chronic idiopathic thrombocytopenic purpura

PURPOSE: To investigate alpha-interferon (IFN) therapy for children with chronic idiopathic thrombocytopenic purpura (ITP). PATIENTS AND METHODS: Patients with refractory ITP lasting more than 12 months from diagnosis were included if they had platelet counts <50 x 10(9)/L and had received no treatment during the past month. Patients received IFN (3 x 10(6) U/m2 per dose), three times per week for 4 weeks; if partial (<150 x 10(9)/L) or no response was obtained, the same dose was continued for another 8 weeks. In patients with favorable response and subsequent decrease to pre-treatment values, an additional 4 weeks of treatment could be administered. RESULTS: Fourteen patients (ages 4-20 y) receiving 17 IFN courses were included. Mean initial platelet count was 29 +/- 15 x 10(9)/L. A significant increase was achieved during 14 of 17 courses (82.4%). All but two responses were transitory, and platelets returned to initial values after IFN discontinuation (mean 44 +/- 26 days). Considering the best response achieved by each patient, we observed: 1) 10 patients who achieved a sustained improvement of platelet count throughout the treatment period, decreasing to initial values after therapy was stopped; 2) one patient who achieved platelet count >150 x 10(9)/L, remaining with normal platelets at 18 months; 3) one patient who achieved platelet count >150 x 10(9)/L, remaining with platelets between 100 and 140 x 10(9)/L at 48 months; 4) one patient who had no response; and 5) one patient in whom therapy worsened the thrombocytopenia. A mild to moderate flu-like syndrome and a moderate decrease of the absolute neutrophil count were the only side effects observed. CONCLUSION: Interferon therapy induces a significant increase of platelet count and seems to be a valid alternative therapy to attempt the achievement of prolonged remission in refractory ITP, to defer splenectomy in younger children, or to improve platelet count before planned splenectomy.     

Agenesis of the Corpus Callosum and Neural Crest Tumors

Hematologic abnormalities, including thrombocytopenia, are seen in HIV infection. Mi have previously reported elevated platelet-associated IgG (PAIgG) in thrombocytopenia in children associated with human immunodeficiency virus (HIV). In this study we prospectively monitored 40 HIV-infected infants and children to determine the significance of elevated PAIgG levels as they relate to thrombocytopenia. We also examined platelet eluatesfor the presence of HIV antibody and antigen. Of 16 patients with thrombocytopenia, 15 (93.7%) had elevated PAIgG. Of 24 patients with normal platelet counts, 21 (87.5%) had elevated PAIgG. On follow-up, none of the children with normal platelet counts and elevated PAIgG levels developed thrombocytopenia. Examination of the platelet eluates was negative for HIV antibody or P24 antigen. Although the sensitivity of an elevated PAIgG level in predicting thrombocytopenia is 93%, its specificity is only 13%. Elevated PAIgG levels are therefore not causally related to the development of thrombocytopenia in children.     

Platelet-Associated IgG in Pediatric HIV Infection

Hematologic abnormalities, including thrombocytopenia, are seen in HIV infection. Mi have previously reported elevated platelet-associated IgG (PAIgG) in thrombocytopenia in children associated with human immunodeficiency virus (HIV). In this study we prospectively monitored 40 HIV-infected infants and children to determine the significance of elevated PAIgG levels as they relate to thrombocytopenia. We also examined platelet eluatesfor the presence of HIV antibody and antigen. Of 16 patients with thrombocytopenia, 15 (93.7%) had elevated PAIgG. Of 24 patients with normal platelet counts, 21 (87.5%) had elevated PAIgG. On follow-up, none of the children with normal platelet counts and elevated PAIgG levels developed thrombocytopenia. Examination of the platelet eluates was negative for HIV antibody or P24 antigen. Although the sensitivity of an elevated PAIgG level in predicting thrombocytopenia is 93%, its specificity is only 13%. Elevated PAIgG levels are therefore not causally related to the development of thrombocytopenia in children.     

Childhood ITP: 12 months follow-up data from the prospective registry I of the Intercontinental Childhood ITP Study Group (ICIS)

BACKGROUND: Acute and chronic idiopathic thrombocytopenic purpura (ITP) is traditionally based on the duration of thrombocytopenia at the cut-off point of 6 months after diagnosis. Registry I evaluated the diagnosis, definition, management, and follow-up of childhood ITP. This report focuses on children with thrombocytopenia persisting more than 6 months. PROCEDURE: Data were collected by questionnaires to the physicians caring for children with ITP, at diagnosis, 6, and 12 months later. Data were compared regarding initial features and follow-up with emphasis on children with persistent thrombocytopenia, and those with ITP who recovered their platelet counts between 7 and 12 months from diagnosis. RESULTS: At 12 months from diagnosis, 79 of 308 (25.6%) evaluable children recovered from ITP and 229 had ongoing ITP. Children with recovered ITP were younger than children with ongoing ITP (P = 0.043) and exhibited a lower frequency of bleeding symptoms during the first 6 months after diagnosis (P = 0.018). Frequency of hospitalization, bone marrow aspiration, and drug treatment differed regionally. CONCLUSIONS: The high rate of recovery from ITP between 7 to 12 months demonstrates, that the cut-off point of 6 months for the definition of chronic ITP does not adequately differentiate chronic from acute ITP. The majority of children with ITP have variable time to recovery with gradual improvement of platelet counts and disappearance of bleeding signs. ITP is a heterogeneous disorder with a diverse natural history and diverse pattern of treatment response.     

Epstein-Barr virus associated with immune thrombocytopenic purpura in childhood: a retrospective study

OBJECTIVE: Although Epstein-Barr virus (EBV) is known to cause immune thrombocytopenic purpura (ITP), the epidemiology of this pathogen in children with ITP is not known. In the present study, the clinicoepidemiology and laboratory characteristics of EBV-associated ITP in childhood were analysed retrospectively. METHODS: The study cohort consisted of 108 children in whom ITP was diagnosed between 1990 and 1998. Patients were divided into EBV or non-EBV groups according to their serological status at diagnosis. RESULTS: Thirty-five (32.4%) of 108 children had ITP associated with acute EBV infection. The clinical manifestations and laboratory data were similar in children with and without acute EBV. Responses to various modalities of therapy were analysed. The average time to achieve complete remission (platelet count > or =150 x 10(9)/L) in EBV and non-EBV groups was 26 and 16 days, respectively. CONCLUSIONS: The incidence of childhood ITP associated with acute EBV infection is relatively high in Taiwan. Patients with EBV-associated ITP tended to resolve more slowly than those without EBV infection.     

The clinical course of immune thrombocytopenic purpura in children who did not receive intravenous immunoglobulins or sustained prednisone treatment

OBJECTIVE: To demonstrate the result of watchful waiting without specific therapy in unselected children with acute immune thrombocytopenic purpura (ITP). STUDY DESIGN: Between May 1992 and October 1999, 55 consecutive children (aged 2 months to 16 years; 28 boys and 27 girls) with acute ITP did not receive intravenously administered immune globulin G (IVIG) or sustained prednisone treatment. Patients with extensive mucosal bleeding were given prednisone, 2 mg/kg/d, for 3 days. RESULTS: In 37 of 55 patients the initial platelet count was <10,000/microL. Ten of these patients had active mucosal bleeding. Five additional patients with bleeding had platelet counts between 10,000 and 20,000/microL. Four patients were given a 3-day course of prednisone. Chronic ITP occurred in 7 (13%) of the patients; 29 patients achieved remission within 6 weeks, and 19 patients, between 6 weeks and 6 months. No life-threatening bleeding occurred, and no patient died. CONCLUSION: Most children with severe thrombocytopenia do not have active mucosal bleeding. This management approach, which did not administer specific therapy, avoided side effects, reduced cost, and was effective.     

Childhood immune thrombocytopenic purpura: diagnosis and management

Immune thrombocytopenic purpura (ITP) is an autoimmune disorder characterized by a low circulating platelet count caused by destruction of antibody-sensitized platelets in the reticuloendothelial system. ITP can be classified as childhood versus adult, acute versus chronic, and primary versus secondary. Persistence of thrombocytopenia defines the chronic form of the disorder. Secondary causes of ITP include collagen vascular disorders, immune deficiencies, and some chronic infections. This review focuses on the diagnosis and management of children who have acute and chronic ITP. Emphasis is placed on areas of controversy and new therapies.     

Immune thrombocytopenic purpura in childhood in Norway: a prospective, population-based registration

A prospective, population-based registration of children with immune thrombocytopenic purpura (ITP) was performed in Norway in 1996 and 1997. Ninety-two cases were identified, indicating an incidence of 5.3 per 100,000 children under 15 years. The sex ratio (female/male) was 1.2/1. Fifty-six percent presented with cutaneous signs only. The lowest platelet count was < 20 x 10(9)/L in 91%. In spite of mild bleeding symptoms, medical treatment was given in 68%, in most cases (57/63) with intravenous immunoglobulin. A total of 41/44 patients with platelet counts of < or = 5 x 10(9)/L were treated, regardless of whether they had mucous bleedings or not. Eighteen percent had platelet counts < 150 x 10(9)/L at 6 months, and 9% at 12 months following diagnosis. One patient with therapy-resistant chronic ITP died 16 months after diagnosis from an anesthesia complication related to profound epistaxis. This study shows a relatively high incidence. As in other studies, there was a tendency to treat platelet counts rather than bleeding symptoms.     

Thrombopoietin has a primary role in the regulation of platelet production in preterm babies.

Thrombocytopenia in the first days of life, in association with evidence of reduced megakaryocytopoiesis and platelet production at birth, is common in sick preterm babies. Thrombopoietin (Tpo) is the major regulator of platelet production in adults. However, these babies have low Tpo levels at birth, suggesting that the Tpo response to thrombocytopenia may be impaired. To test this hypothesis we 1) measured Tpo levels, 2) measured circulating megakaryocyte progenitors serially over the first 12 d of life in 13 preterm babies with early onset thrombocytopenia and in 14 control babies with evidence of normal megakaryocytopoiesis, and 3) measured Tpo levels in thrombocytopenic children (n = 13). In control babies, platelet counts and progenitor numbers remained normal and Tpo levels were consistently low-d 1:160+/-23 pg/mL (mean+/-SEM), d 4/5: 154+/-18 pg/mL and d 12: 150+/-58 pg/mL. In thrombocytopenic babies, platelet counts and megakaryocyte progenitor numbers were significantly lower than controls at d 1: platelets 130+/-14 x 10(9)/L versus 255+/-20 x 10(9)/L (p < 0.001) and megakaryocyte progenitors 552 versus 3907 colonies/mL (mean, p < 0.001), and fell further to nadir on d 4/5: platelets 76+/-6 X 10(9)/L versus 259+/-21 x 10(9)/L (p < 0.001) and MK progenitors 479 versus 2742 colonies/mL (p < 0.05). Tpo levels were only slightly raised on d 1:247+/-52 pg/mL (p = 0.24), but then rose sharply by d 4/5: 425+/-75 pg/mL (p < 0.001). By d 12, platelet count, megakaryocyte progenitors and Tpo level (145+/-29 pg/mL) had returned to control levels. Tpo levels at platelet nadir in thrombocytopenic babies were significantly lower than in thrombocytopenic children: mean 425 versus 1383 pg/mL (p < 0.001). These data show that Tpo is important in platelet homeostasis in preterm babies, with a close reciprocal relationship with platelet count and progenitor numbers during thrombocytopenia. However, the increase in Tpo levels seen in these babies was modest, despite significantly impaired megakaryocytopoiesis, and when compared with that seen in children with thrombocytopenia. This offers further evidence that preterm babies have an impaired Tpo response to thrombocytopenia and suggests that recombinant human Tpo may have a role in the prevention/treatment of preterm thrombocytopenia.     

Oral Megadose Methylprednisolone Versus Intravenous Immunoglobulin for Acute Childhood Idiopathic Thrombocytopenic Purpura

Twenty children with acute idiopathic thrombocytopenic purpura (ITP) were randomized to receive either oral megadose methylprednisolone (MDMP) or intravenous immunoglobulin G (IV IgG). Normal platelet counts (150 × 10⁹/l) were obtained in 6 patients of each group in 3 days and in 8 and 9 patients treated with oral MDMP and with IV IgG within 1 week, respectively. It is concluded that oral MDMP could easily be used for the early elevation of platelet counts, which is important for ITP treatment.     

Clinical impact of neonatal thrombocytopenia

In a 1-year prospective study, the outcome in infants with a platelet count less than 100 X 10(9)/L (n = 97) was compared with the outcome in an age-, weight-, and disease-matched nonthrombocytopenic control group (n = 80). The hemostatic impact of the thrombocytopenia was assessed by modified template bleeding time, hemorrhage score, and determination of the presence and extent of intraventricular hemorrhage (IVH) in thrombocytopenic infants weighing less than 1500 at birth (n = 39) compared with all nonthrombocytopenic infants less than 1500 g (n = 122) admitted during the study period. The development outcome in infants less than 1500 g was compared at 12 months after delivery. Neonatal thrombocytopenia had a major impact on hemostatic integrity: bleeding time was inversely related to platelet count (r = -0.56, P less than 0.001) and became prolonged when the platelet count fell to less than 100 X 10(9)/L. In addition, many infants (40%) had evidence of platelet dysfunction with prolonged bleeding times despite only moderately reduced platelet counts (75 to 150 X 10(9)/L). The hemorrhage score was greater in the thrombocytopenic infants compared with the sick control infants, and increased as the platelet count fell (r = -0.58, P less than 0.001). The incidence of IVH in thrombocytopenic infants less than 1500 g was 78%, compared with 48% in the nonthrombocytopenic infants (P less than 0.01). In addition, the more severe grades of IVH were more frequent in the thrombocytopenic infants. The serious neurologic morbidity for the surviving infants less than 1500 g was 41% in the thrombocytopenic infants and 7% in the nonthrombocytopenic infants. Thus, on the basis of three indices of abnormal bleeding, thrombocytopenic infants are at greater risk for bleeding than equally sick nonthrombocytopenic infants. The thrombocytopenia itself may have contributed to the high mortality and neurologic morbidity.     

儿童特发性血小板减少性紫癜患儿Th2相关细胞因子IL-4、IL-10与血小板相关抗体的检测及意义研究

探讨Th2相关细胞因子IL 4、IL 1 0与血小板相关抗体PAIgG、PAIgM在儿童ITP的发病机理中的作用。方法是采用双抗体夹心酶联免疫吸附试验 [ELISA]技术检测 30例ITP患儿血浆中IL 4、IL 1 0水平 ,同时检测PAIgG、PAIgM的水平 ,研究IL 4、IL 1 0对PAIgG、PAIgM的调节作用。结果显示 :( 1 )急性期ITP患儿IL 4、PAIgG、PAIgM水平均高于对照组 (P <0 .0 5)。( 2 )慢性ITP病例半年后IL 4、PAIgG、PAIgM仍然高于对照组 (P <0 .0 5) ,IL 4与血小板相关抗体水平呈显著正相关。 ( 3)病程中IL 1 0与对照组无明显变化。结论 :ITP患儿IL 4表达增加 ,提示Th2相关细胞因子比例失调 ,使血小板相关抗体增高为重要的致病因素之一。     

血小板相关抗体与儿童特发性血小板减少性紫癜转归的相关性分析

目的探讨血小板相关抗体(PAIg)与儿童特发性血小板减少性紫癜(ITP)转归的相关性。方法选择2008年12月-2010年12月江西省儿童医院收治的急性ITP患儿200例,应用ELISA方法检测患儿初诊时及治疗前后PAIg的表达,并与临床疗效相比较。结果 ITP患儿初诊时PAIgG、PAIgA及PAIgM抗体表达水平高于正常对照组;PAIgG、PAIgM、PAIgA表达水平与血小板计数之间均呈负相关。难治组ITP患儿初诊时PAIgM抗体水平要明显高于激素治疗有效的急性ITP患儿,并且PAIgM异常增高或合并PAIgG增高的比例显著高于急性ITP患儿(P<0.05)。治疗后,PAIgG和PAIgM同时升高的ITP患儿,治愈和显效组两种抗体水平均有显著下降(P<0.05),难治组两种抗体水平下降不明显(P>0.05)。结论 ITP的发生与血小板抗体水平增高密切相关,初诊ITP患儿PAIgM单独或合并PAIgG异常增高常提示预后不良。