Monitoring treatment response of childhood precursor B-cell acute lymphoblastic leukemia in the AIEOP-BFM-ALL 2000 protocol with multiparameter flow cytometry: predictive impact of early blast reduction on the remission status after induction.

Treatment response is a strong outcome predictor for childhood acute lymphoblastic leukemia (ALL). Here, we evaluated the predictive impact of flow cytometric blast quantification assays (absolute blast count, BC, and blast reduction rate, BRR) in peripheral blood (pB) and/or bone marrow (BM) at early time points of induction therapy (days 0, 8 and 15) on the remission status in the AIEOP-BFM-ALL 2000 protocol. At the single parameter level (905 patients), the strongest predictive parameter for the remission status as a dichotomous minimal residual disease (MRD) parameter (positive/negative) has been provided by the BC at day 15 in BM (cutoff: 17 blasts/microl; 50 vs 15%; odds ratio: 5.6; 95% confidence interval: 4.1-7.6, P<0.001), followed by the BRR at day 15 in BM and by the BC at day 8 in pB (odds ratios: 3.8 and 2.6, respectively). In the multiple regression analysis (440 patients), BC in pB (d0 and d8) and in BM (d15) as well as BRR at day 8 in pB provided significantly contributing variables with an overall correct prediction rate of 74.8%. These data show that the quantitative assessment of early response parameters, especially absolute BCs at day 15 in BM, has a predictive impact on the remission status after induction therapy.

Drug-induced immunophenotypic modulation in childhood ALL: implications for minimal residual disease detection.

Assessment of minimal residual disease (MRD) by flow cytometry is considered to be based on the reproducibility of the leukemic immunophenotype detected at diagnosis. However, we previously noticed modulation of surface antigen expression in acute lymphoblastic leukemia (ALL) during the early treatment. Hence, we investigated this in 30 children with B-cell precursor ALL consecutively enrolled in the AIEOP-BFM ALL 2000 protocol. Quantitative expression of seven antigens useful in MRD monitoring was studied at diagnosis and compared to that measured at different time points of remission induction therapy. Downmodulation in the expression of CD10 and CD34 occurred at follow-up. By contrast, upmodulation of CD19, CD20, CD45RA, and CD11a was observed, while the expression of CD58 remained stable. Despite this, we could unambiguously discriminate leukemic cells from normal residual B cells. This holds true when bone marrow (BM) samples from similarly treated T-ALL patients, but not from healthy donors, were used as reference. Our results indicate that immunophenotypic modulation occurs in ALL during the early phases of BFM-type protocols. However, the accuracy of MRD detection by flow cytometry seems not negatively affected if adequate analysis protocols are employed. Investigators should take this phenomenon into account in order to avoid pitfalls in flow cytometric MRD studies.

In vivo cytoreduction studies and cell sorting--enhanced tumor-cell detection in high-risk neuroblastoma patients: implications for leukapheresis strategies.

PURPOSE: To improve autologous leukapheresis strategies in high-risk neuroblastoma (NB) patients with extensive bone marrow involvement at diagnosis. PATIENTS AND METHODS: Anti-G(D2) immunocytochemistry (sensitivity, 1 in 10(5) to 10(6) leukocytes) was used to evaluate blood and bone marrow disease at diagnosis and during the recovery phase of the first six chemotherapy cycles in 57 patients with stage 4 NB and bone marrow disease at diagnosis. A total of 42 leukapheresis samples from the same patients were evaluated with immunocytology, and in 24 of these patients, an anti-G(D2) immunomagnetic enrichment step was used to enhance tumor-cell detection. RESULTS: Tumor cytoreduction was much faster in blood compared with bone marrow (3.2 logs after the first cycle and 2.1 logs after the first two cycles, respectively). Bone marrow disease was often detectable throughout induction, with a trend to plateau after the fourth cycle. By direct anti-G(D2) immunocytology, a positive leukapheresis sample was obtained in 7% of patients after either the fifth or sixth cycle; when NB cell immunomagnetic enrichment was applied, 25% of patients had a positive leukapheresis sample (sensitivity, 1 in 10(7) to 10(8) leukocytes). CONCLUSION: Standard chemotherapy seems to deliver most of its in vivo purging effect within the first four cycles. In patients with overt marrow disease at diagnosis, postponing hematopoietic stem-cell collection beyond this point may not be justified. Tumor-cell clearance in blood seems to be quite rapid, and earlier collections via peripheral-blood leukapheresis might be feasible. Immunomagnetically enhanced NB cell detection can be highly sensitive and can indicate whether ex vivo purging should be considered.

Evidence of subclinical intestinal inflammation by 99m technetium leukocyte scintigraphy in patients with HLA-B27 positive juvenile onset active spondyloarthropathy.

OBJECTIVE: The concept that gut inflammation is implicated in the pathogenesis of spondyloarthropathies (SpA) has long been considered. Subclinical intestinal inflammation has been reported in adult patients with SpA by histological examination of intestinal biopsies. We assessed the presence of gut inflammation by abdominal 99mTc-hexamethyl propylene amine oxime (99mTc-HMPAO) labeled leukocyte scintigraphy in a group of children and adolescents with HLA-B27 positive SpA without gastrointestinal (GI) symptoms, and correlated the scintigraphic results to disease activity. METHODS: Abdominal scintigraphy with 99mTc-HMPAO labeled leukocytes was performed in 27 HLA-B27 positive children and adolescents with SpA without GI symptoms. Patients were divided into 2 groups according to the presence of active or inactive joint disease: Group A, 17 patients with active disease, and Group B, 10 patients with inactive disease. Patients with positive abdominal scintigraphy underwent complete bowel investigation by means of small bowel barium follow-through, abdominal ultrasound scan, and ileocolonoscopy with mucosal biopsies. RESULTS: Thirteen of 27 patients (48%) had scintigraphy indicating the presence of bowel inflammation. All patients with abnormal scan had active joint disease, whereas no patient with inactive disease had a positive intestinal uptake of labeled leukocytes. Bowel investigation revealed the presence of aspecific mucosal inflammatory changes in the majority of patients with positive scintigraphy. CONCLUSION: The presence of intestinal leukocyte uptake only in patients with active joint disease, even if intestinal inflammatory changes were minimal and clinical gut manifestations were absent, supports the role of gut inflammation in the pathogenesis of joint disease in HLA-B27 positive patients with SpA.

Acute febrile cholestasis as an inaugural manifestation of Kawasaki's disease.

We report a child who developed acute febrile cholestasis with jaundice and pruritus as the inaugural manifestation of Kawasaki's disease (KD). The severe obstructive icterus and hydrops of the gallbladder required cholecystectomy that was not followed by remission of the fever and cholestasis. KD was suspected after the exclusion of all infectious, metabolic and neoplastic conditions responsible for acute cholestasis. The administration of intravenous gammaglobulin (IVGG) promptly induced defervescence and improvement of the patient's general condition. Mucocutaneous alterations, peeling of the digits, right cervical lymph node enlargement and bilateral non-suppurative conjunctivitis supporting the diagnosis of KD developed 14 days after the appearance of jaundice. No coronary abnormalities had developed after 2 years of follow-up. We conclude that this syndrome should be suspected in any child with febrile cholestasis of unknown origin, in order that coronary involvement may be prevented by the administration of IVGG.

Epidemiology of insect venom sensitivity in children and its correlation to clinical and atopic features.

The aim of this study was to obtain more accurate figures of the prevalence of cutaneous sensitivity to Hymenoptera venoms (HV) and its correlation with other parameters of atopy in a population of primary schoolchildren. Parents filled out a structured questionnaire and children were tested with a panel of inhalant and food allergens as well as standardized freeze-dried extracts of HV. Among the 1175 children who completed the study there was a personal history of rhinoconjunctivitis in 242 (20.8%) and a current wheezing in 114 (9.78%). Two-hundred twenty-eight (19.40%) children had a history of Hymenoptera sting (HS) reactions (224 or 19.06% of local reactions and 4 or 0.34% of local and systemic reactions). Positive skin-prick tests (SPT) to any given HV extract were present in 43 children (3.66%). Most subjects had positive SPT to honey bee venom (35/1175; 2.98%); 17/1175 (1.45%) had positive SPT to wasp and only 12 subjects (1.02%) had positive SPT to polistes venom. There was a correlation between a positive SPT to HV and the history of clinical reactions to HS (P=0.0026). Positive SPT to at least one of the inhalant and food allergens tested were found in 353 subjects (30.04%). Factors such as age, sex, reactions to HV, positive SPT to mite, cat dander, grass, Alternaria, Parietaria, cow's milk, egg white and wheat were significantly associated with a positive SPT to HV using a univariate regression analysis. Only age, reactions to HV, a positive SPT to grass, Parietaria, cow's milk, and egg white were significantly associated with a positive SPT to HV using a multiple regression analysis. In this study, the frequency of immunological sensitization to HV in a population of unselected children is not so high as in adults. There is an association between the presence of positive SPT to HV and an atopy linked humoral IgE response. The presence of a significant and independent association between positive SPT to food of animal origin and positive SPT to HV is surprising and needs further study.

Prevalence and risk factors of latex sensitization in an unselected pediatric population.

BACKGROUND: The prevalence of latex sensitization has been investigated in population groups considered at high risk, but it has not been systematically surveyed among the general population. OBJECTIVE: We sought to determine the prevalence of and the risk factors associated with latex sensitization in a general pediatric population. METHODS: We investigated 1175 children (mean age +/- SD, 105 +/- 17.5 months) in 11 elementary schools in Tuscany (Italy). All parents answered a questionnaire, and children underwent skin prick tests (SPTs) with latex, six aeroallergens (Dermatophagoides pteronyssinus, D. farinae, cat, grass pollen, Alternaria tenuis, and Parietaria judaica), three food allergens (milk, egg white, and wheat), and three insect venoms (honeybee, wasp, and Polistes). RESULTS: Eight subjects (0.7%; mean age +/- SD, 123 +/- 9.28 months) had positive SPT responses to latex. No children showed allergic reactions to latex. One or more positive SPT responses to aeroallergens were present in 340 children (28.9%); one or more positive SPT responses to food allergens were present in 26 (2.2%); one or more positive SPT responses to aeroallergens, food allergens, or both were present in 353 (30.0%); and one or more positive SPT responses to one or more insect venoms were present in 43 subjects (3.7%). Significant (p < 0.05) risk factors associated with latex sensitization included: positive SPT responses to aeroallergens, food allergens, or both; a positive response to one or more insect venoms; a positive response to mite, milk, egg white, wheat, honeybee venom, wasp venom, Polistes venom, or a combination thereof; and increased age. CONCLUSION: This report shows a very low prevalence of latex sensitization with an absence of clinical symptoms to latex. This study demonstrates a significant association between latex sensitization and the presence of one or more positive SPT responses to aeroallergens, food allergens, or both; one or more positive SPT responses to one or more insect venoms; and increased age.