Low dose intravenous immunoglobulin for acute immune thrombocytopenic purpura in children.

Acute immune thrombocytopenic purpura (ITP) is a self-limited autoimmune disorder to platelets. The disease responds well to intravenous immunoglobulin (IVIG) treatment. We studied the efficacy of low dose (1 g/kg) IVIG to treat acute ITP in children. Of 17 children with ITP and platelet counts < 20,000/microl, 13 (76%) had rapid platelet count recovery, reaching safe level (> 50,000/microl) within 4 days after 1 g/kg IVIG. Four children needed a second dose. In 5 of 15 patients, platelet counts recovered to normal without recurrence, while in 10 patients, platelet counts declined again 2-3 weeks after the initial treatment; 6 of whom (40%) needed re-treatment. All but one patient had complete recovery of the platelet count by 6 months. Adverse effects of low dose IVIG were minimal. We recommend that for childhood ITP, 1 g/kg IVIG should be tried initially. If inadequate response is seen (platelet count < 30,000/microl) by 48 hours, a second dose is needed.

Cytomegalovirus infection in immunocompromised children in Thailand.

Cytomegalovirus (CMV) constitutes the most widespread cause of congenital and perinatal viral infections on a global scale, exceeding a 90%-prevalence among blood donors in Thailand. The present study was aimed at determining the prevalence of CMV in the sera of 113 immunocompromised children by means of serology, as well as polymerase chain reaction using nested primers. Our results showed anti-CMV IgG, i.e. latent infection, prevalent in an age-dependent manner irrespective of the disorder underlying the children's immunocompromised condition, whereas anti-CMV IgM was equally prevalent throughout all age groups and disease patterns and, therefore, unreliable as a marker. Detection of serum CMV DNA by PCR represented the most exact diagnostic parameter by far, indicating active infection long before clinical symptoms may appear. In conclusion, based on the high prevalence of latent CMV infection among the general population in Thailand, we recommend especially the sera of immunocompromised patients be examined for the presence of viral DNA by means of PCR in order to provide clinical guidelines for their proper management.

Insufficient evidence of TT-viral etiology of post hepatitis aplastic anemia.

Post-hepatitis aplastic anemia is a rather rare pathologic condition of as yet unclear etiology especially as hepatitis viruses A to G have been excluded as the potential agents responsible. The novel TT virus, a single-stranded DNA virus first isolated from the serum of a patient with post-transfusion hepatitis in Japan might cause this condition. Therefore, our group subjected the sera of two children with post-hepatitis aplastic anemia to semi-nested PCR using primers specific for detection of TTV DNA. Although TTV DNA was not detectable in either sample it might be speculated that, like hepatitis viruses A to G, TTV could be found associated with this condition whereas it certainly does not constitute its sole etiologic agent.

Clearance of hepatitis TT virus infection among thalassemia children and IVDU.

The novel transfusion transmissible hepatitis virus TTV first isolated by a group from Japan has predominantly been detected in members of groups at high risk for contracting blood borne viruses. Aside from elevated liver enzymes, the symptoms associated with its infection have been reported to range from asymptomatic to hepatic failure. The purpose of the present study was to determine if and to what extent the host's immune response is capable of clearing TTV infection. Hence, we extracted DNA from sera obtained from altogether 201 intravenous drug users (IVDU) and 80 thalassemia children--both groups at high risk of parenteral exposure--and performed PCR using semi-nested primers. Those positive for TTV DNA were once again subjected to PCR after approximately one year in order to determine how many still harbored the virus. Our results showed TTV DNA to be absent in merely 20.6% of the formerly positive IVDU, whereas it was still present in all the thalassemia children who could be tested for the second time. Based on the small sample size and the high-risk environment, these results ought to be interpreted with caution and definitely merit further investigation.

Immunophenotyping of acute lymphoblastic leukemia in pediatric patients by three-color flow cytometric analysis.

Immunophenotyping of acute lymphoblastic leukemia (ALL) in children using three-color flow cytometry was carried out at Chulalongkorn Hospital, Bangkok, Thailand. Of 38 patients with acute lymphoblastic leukemia, 65.8% were identified as common ALL, 15.8% were B-ALL, and 18.4% were T-ALL. Of these 38 cases, there were 4 cases of infantile leukemia. Relapsed cases of leukemia were found most in B-ALL up to 3 out of 6 cases and to a lesser extent in T-ALL (1 of 7 cases) and c-ALL (1 of 25 cases). Our data showed the CD markers expression for common ALL (c-ALL) were CD19+/10+ (100%), CD20+ (24%), CD22+ (100%), HLA-DR+ (70.1%), and CD34+ (58.8%). CD markers expression for B-ALL were CD19+ (100%), CD20+ (33.3%), CD22+ (80%), and HLA-DR+ (80%). CD markers expression for T-ALL were CD3+ (42.9%), CD5+ (100%), CD7+ (85.7%). Myeloid aberrant expressions were found in c-ALL (25-37.5%), B-ALL (20%), and T-ALL (14.3%). The significance of the aberration is discussed. The immunophenotyping classification of ALL as c-ALL, B-ALL, and T-ALL is useful in prognosis and treatment.

Cardiac dysfunction in beta-thalassemic children.

The biventricular systolic function was evaluated by M mode and Doppler echocardiography in 16 patients with homozygous beta-thalassemia and beta-thalassemia Hb E disease, aged 5-14 yrs (9.9 +/- 2.4 yr). The left ventricular end-diastolic dimension and left ventricular mass were increased in 88 per cent of the patients. Left ventricular fractional shortening and cardiac index were normal in all but one patient. Fifteen patients had evidence of pulmonary artery hypertension manifested by abnormality in the ratio of right ventricular acceleration time to ejection time (AT/ET). There was good correlation between platelets count and AT/ET (r = -0.70, P = 0.002). Thrombocytosis was noted in 4 patients. Our findings indicated that in beta-thalassemic children, right ventricular dysfunction was detected earlier than left ventricular dysfunction and platelets may play a role in the pathogenesis of pulmonary artery hypertension.