The interleukin-2 receptor: a target for monoclonal antibody treatment of human T-cell lymphotrophic virus I-induced adult T-cell leukemia

Adult T-cell leukemia (ATL) is a malignancy of mature lymphocytes caused by the retrovirus human T-cell lymphotrophic virus-I (HTLV-I). It is an aggressive leukemia with an overall mortality rate of 50% within 5 months; no conventional chemotherapy regimen appears successful in inducing long-term disease-free survival in ATL patients. However, ATL cells constitutively express high-affinity interleukin-2 receptors (IL-2Rs) identified by the anti-Tac monoclonal antibody, whereas normal resting cells do not. To exploit this difference in receptor expression, we administered anti-Tac intravenously (IV) to 19 patients with ATL. In general the patients did not suffer untoward reactions, and in 18 of 19 cases did not have a reduction in normal formed elements of the blood. Seven patients developed remissions that were mixed (1 patient), partial (4 patients), or complete (2 patients), with partial and complete remissions lasting from 9 weeks to more than 3 years as assessed by routine hematologic tests, immunofluorescence analysis, and molecular genetic analysis of T-cell receptor gene rearrangements and of HTLV-I proviral integration. Furthermore, remission was associated with a return to normal serum calcium levels and an improvement of liver function tests. Remission was also associated in some cases with an amelioration of the profound immunodeficiency state that characterizes ATL. Thus the use of a monoclonal antibody that blocks the interaction of IL-2 with its receptor expressed on ATL cells provides a rational approach for treatment of this aggressive malignancy.     

A multi-level developmental approach towards understanding adolescent mental health and behaviour: rationale,design and methods of the LIFECOURSE study in Iceland

Purpose

Identifying and understanding modifiable risk and protective factors that can inform early detection and intervention to prevent adolescent emotional problems and harmful behaviours is among the most pressing modern-day public health challenges. This paper describes the rationale, objectives, methods, and anticipated outcomes of the LIFECOURSE study, a multi-level, bio-psychosocial prospective study designed to advance our understanding of factors that shape adolescent mental health and behaviour.

Methods

Conducted by the Icelandic Centre for Social Research and Analysis at Reykjavik University, LIFECOURSE is a longitudinal population-based developmental study of Icelandic adolescents born in 2004. The study utilizes a comprehensive multi-informant assessment of individual, societal and biological factors measured across the lifespan. Data assembly and collection were conducted from 2016–2020 and utilize both retrospective and prospective data sources: (a) retrospective registry data assembled from seven national databases, (b) prospectively collected social surveys and (c) biomarker samples.

Results

Of the 3914 eligible adolescents, 60.8% (n = 2378) provided informed parental consent and student assent to participate in the study, with approximately half of the participants being female (n = 1175, 49.4%) and the majority being born in the capital area (n = 1455; 61.2%). The coverage of available data from the national databases and participation in the social surveys ranged from 81.7 to 100%.

Conclusions

Major gaps remain in our knowledge of how individual, societal and biological factors across the lifespan—from early life to adolescence—interact and shape the risk for emotional problems and harmful behaviours during adolescence. The LIFECOURSE study was designed to address this knowledge gap.

     

Human Rh D monoclonal antibodies (BRAD-3 and BRAD-5) cause accelerated clearance of Rh D+ red blood cells and suppression of Rh D immunization in Rh D- volunteers

The use of prophylactic anti-D to prevent Rh D immunization in Rh D- women and subsequent hemolytic disease in Rh D+ infants is widespread, but has led to shortages of the anti-D Ig. With the aim of substituting monoclonal anti-D for Rh D prophylaxis, we have compared the abilities of monoclonal and polyclonal anti-D to clear Rh D+ red blood cells (RBCs) infused into Rh D- male volunteers and to suppress Rh D immunization. Two human monoclonal antibodies (MoAbs), BRAD-3 (IgG3) and BRAD-5 (IgG1), produced from stable Epstein-Barr virus-transformed B-lymphoblastoid cell lines, were selected because of their proven in vitro activity in promoting RBC lysis in antibody-dependent cell- mediated cytotoxicity assays. RBC clearance was assessed by intravenous injection of 3 mL of 51chromium-labeled D+ RBCs into 27 volunteers 48 hours after intramuscular injection of monoclonal or polyclonal anti-D. Further 3-mL injections of unlabeled D+ cells were administered at 6 and 9 months to induce immunization. Blood samples were taken throughout the 12-month period of study for the serologic detection of anti-D. The mean half-life (t50%) of RBCs in 7 recipients of 300 micrograms BRAD-5 (5.9 hours) was similar to that in 8 recipients of 500 IU polyclonal anti-D (5.0 hours), whereas D+ cells were cleared more slowly in some of the 8 subjects injected with 300 micrograms BRAD- 3 (mean t50% 12.7 hours) and in 1 individual administered 100 micrograms BRAD-3 (t50% 41.0 hours). The rate of RBC clearance in both groups administered 300 micrograms monoclonal anti-D correlated with the amount of antibody bound per cell, determined by flow cytometry. There was no evidence of primary immunization having occurred in any subject after 6 months of follow-up. Five of 24 subjects produced anti- D after one or two further injections of RBCs, confirming that they were responders who had been protected by the monoclonal or polyclonal anti-D administered initially. Four of these responders were recipients of monoclonal anti-D (3 BRAD-3, 1 BRAD-5). One individual who received BRAD-5 produced accelerated clearance of D+ RBCs at the third unprotected RBC challenge but did not seroconvert. This study shows that the human MoAbs BRAD-3 and BRAD-5 can prevent Rh D immunization, and indicates that they may be suitable replacements for the polyclonal anti-D presently used in prophylaxis of Rh D hemolytic disease of the newborn.(ABSTRACT TRUNCATED AT 400 WORDS)     

The L4F3 antigen is expressed by unipotent and multipotent colony- forming cells but not by their precursors

Antibody L4F3 is a murine monoclonal antibody that recognizes an antigen expressed on in vitro colony-forming cells, including virtually all CFU-GM, CFU-Meg, BFU-E, and CFU-Mix. In the present study we examined whether cells that do not express the L4F3 antigen include precursors of hematopoietic colony-forming cells. Colony-forming cells were depleted from marrow by treatment with L4F3 and complement. The remaining cells generated CFU-GM, BFU-E, and CFU-Mix when cultured in the presence of irradiated adherent cell layers from long-term marrow cultures. Marrow cells not expressing the L4F3 antigen, which were separated by cell-sorting techniques, were depleted of colony-forming cells but nevertheless generated CFU-GM when cultured over irradiated adherent cell layers. These data suggest that there are marrow precursors that do not express the L4F3 antigen and that give rise to colony-forming cells of multiple types. Negative selection techniques should allow the enrichment of these precursors of colony-forming cells, thereby enabling direct studies of these immature stem cells.     

The Landscape of Overweight and Obesity in Icelandic Adolescents: Geographic Variation in Body-Mass Index Between 2000 and 2009

The prevalence of overweight and obesity has increased globally. This study examined the geographic variation in overweight and obesity trends among Icelandic adolescents in urban and rural areas. Data from two cross-sectional population-based samples of 14- and 15-year-old students attending the compulsory 9th and 10th grades of the Icelandic secondary school system in 2000 and 2009 were used to calculate body mass index (BMI). Overweight and obesity rates were represented for 17 zones on maps created with the ArcGis geographic information and imaging software. Results were that males had higher rates of overweight and obesity than females in both 2000 and 2009, with a significant difference for both genders between years. Mean BMI was higher for rural areas than urban areas in both study years. Out of 17 geographic zones, the prevalence of obesity increased between 2000 and 2009 for males in 16; however, the one remaining zone had the highest increase in overweight. Obesity increased in 13 zones for girls and decreased in four from 2000 to 2009. Mean BMI rose between the study years but fewer zones differentiated from each other in 2009 than 2000. The prevalence of overweight and obesity increased among Icelandic adolescents in both urban and rural areas; however, rural areas have higher rates of obesity, overweight, and mean BMI than urban areas. Because of diminishing differences between areas from 2000 to 2009 the increase in mean BMI, increases in overweight, and obesity appear to be more rapid in urban areas than rural areas.