First reported case of congenital thrombotic thrombocytopenic purpura in Taiwan with novel mutation of ADAMTS13 gene.

Congenital thrombotic thrombocytopenic purpura (cTTP) is a rare disease that is defined as biallelic mutations of ADAMTS13 causing persistent absence of ADAMTS13 activity. The confirmed diagnosis requires a genetic study, and cTTP has never been previously reported in Taiwan. Our patient was a 29-year-old Taiwanese woman who presented with severe hyperbilirubinemia at birth. She had severe thrombocytopenia and hemolytic anemia at the age of 1, and another acute TTP event at the age of 7 triggered by an upper airway infection. Regular plasma replacement was started at age 12 based on a presumptive diagnosis of cTTP. Clinical diagnosis of cTTP, with undetectable ADAMTS13 activity and absence of ADAMTS13 inhibitor, was confirmed at age 27. A genetic study showed a previously reported mutation c.1921G to A, inherited from her father, and a maternally inherited, novel mutation at exon 12, c.1435+1dupG, which results in a splicing site change and frame shift. Reports of cTTP from East Asia, except Japan, are scarce. Some prevalent ADAMTS13 mutations are also race or region specific. With this report, we hope to raise awareness among physicians in Taiwan, promote early, proper diagnosis of cTTP, and reveal the true prevalence of cTTP in the Taiwanese population.

Response to influenza vaccine in children with leukemia undergoing chemotherapy.

BACKGROUND AND PURPOSE: To assess the ability of children with acute lymphoblastic leukemia (ALL) to develop an antibody response after influenza vaccination. METHODS: A total of 65 children under 15 years old were studied, including 25 children with ALL undergoing chemotherapy, 30 with asthma in remission who were regularly followed at clinics, and 10 healthy children. The influenza vaccine contained antigens B/Yamanashi/166/98, A/New Caledonia/20/99 (H1N1), and A/Panama/2007/99 (H3N2). RESULTS: Children with ALL developed significant antibody titers to A/Panama /2007/ 99 antigen 4 weeks after the second immunization. Seroconversion rates after two doses of vaccine were 57.1 to 84.6% and seroresponse rates were between 24 and 60% in children with ALL. Compared to children with asthma in remission, who were regarded as immunocompetent individuals, the ALL children had less seroconversion and lower seroresponse rates to A/New Caledonia/20/99 (H1N1). The seroconversion and seroresponse rates to B/Yamanashi/166/98 and A/ Panama/2007/99(H3N2) antigens were comparable in asthmatic and leukemic children. On the other hand, the antibody response in children with ALL who received reinduction chemotherapy suggests that the therapy did not impair seroresponse rates. CONCLUSION: Our data suggest that the influenza vaccine is safe and effective in children with either ALL or asthma in Taiwan.