Structure-guided engineering of immunotherapies targeting TRBC1 and TRBC2 in T cell malignancies.

Peripheral T cell lymphomas are typically aggressive with a poor prognosis. Unlike other hematologic malignancies, the lack of target antigens to discriminate healthy from malignant cells limits the efficacy of immunotherapeutic approaches. The T cell receptor expresses one of two highly homologous chains [T cell receptor ß-chain constant (TRBC) domains 1 and 2] in a mutually exclusive manner, making it a promising target. Here we demonstrate specificity redirection by rational design using structure-guided computational biology to generate a TRBC2-specific antibody (KFN), complementing the antibody previously described by our laboratory with unique TRBC1 specificity (Jovi-1) in targeting broader spectrum of T cell malignancies clonally expressing either of the two chains. This permits generation of paired reagents (chimeric antigen receptor-T cells) specific for TRBC1 and TRBC2, with preclinical evidence to support their efficacy in T cell malignancies.

Exploration of T cell immune responses by expression of a dominant-negative SHP1 and SHP2.

SHP1 and SHP2 are SH2 domain-containing proteins which have inhibitory phosphatase activity when recruited to phosphorylated ITIMs and ITSMs on inhibitory immune receptors. Consequently, SHP1 and SHP2 are key proteins in the transmission of inhibitory signals within T cells, constituting an important point of convergence for diverse inhibitory receptors. Therefore, SHP1 and SHP2 inhibition may represent a strategy for preventing immunosuppression of T cells mediated by cancers hence improving immunotherapies directed against these malignancies. Both SHP1 and SHP2 contain dual SH2 domains responsible for localization to the endodomain of inhibitory receptors and a protein tyrosine phosphatase domain which dephosphorylates and thus inhibits key mediators of T cell activation. We explored the interaction of the isolated SH2 domains of SHP1 and SHP2 to inhibitory motifs from PD1 and identified strong binding of both SH2 domains from SHP2 and more moderate binding in the case of SHP1. We next explored whether a truncated form of SHP1/2 comprising only of SH2 domains (dSHP1/2) could act in a dominant negative fashion by preventing docking of the wild type proteins. When co-expressed with CARs we found that dSHP2 but not dSHP1 could alleviate immunosuppression mediated by PD1. We next explored the capacity of dSHP2 to bind with other inhibitory receptors and observed several potential interactions. In vivo we observed that the expression of PDL1 on tumor cells impaired the ability of CAR T cells to mediate tumor rejection and this effect was partially reversed by the co-expression of dSHP2 albeit at the cost of reduced CAR T cell proliferation. Modulation of SHP1 and SHP2 activity in engineered T cells through the expression of these truncated variants may enhance T cell activity and hence efficacy in the context of cancer immunotherapy.

Novel Fas-TNFR chimeras that prevent Fas ligand-mediated kill and signal synergistically to enhance CAR T cell efficacy.

The hostile tumor microenvironment limits the efficacy of adoptive cell therapies. Activation of the Fas death receptor initiates apoptosis and disrupting these receptors could be key to increasing CAR T cell efficacy. We screened a library of Fas-TNFR proteins identifying several novel chimeras that not only prevented Fas ligand-mediated kill, but also enhanced CAR T cell efficacy by signaling synergistically with the CAR. Upon binding Fas ligand, Fas-CD40 activated the NF-κB pathway, inducing greatest proliferation and IFN-γ release out of all Fas-TNFRs tested. Fas-CD40 induced profound transcriptional modifications, particularly genes relating to the cell cycle, metabolism, and chemokine signaling. Co-expression of Fas-CD40 with either 4-1BB- or CD28-containing CARs increased in vitro efficacy by augmenting CAR T cell proliferation and cancer target cytotoxicity, and enhanced tumor killing and overall mouse survival in vivo. Functional activity of the Fas-TNFRs were dependent on the co-stimulatory domain within the CAR, highlighting crosstalk between signaling pathways. Furthermore, we show that a major source for Fas-TNFR activation derives from CAR T cells themselves via activation-induced Fas ligand upregulation, highlighting a universal role of Fas-TNFRs in augmenting CAR T cell responses. We have identified Fas-CD40 as the optimal chimera for overcoming Fas ligand-mediated kill and enhancing CAR T cell efficacy.

Dual targeting of CD19 and CD22 against B-ALL using a novel high-sensitivity aCD22 CAR.

CAR T cells recognizing CD19 effectively treat relapsed and refractory B-ALL and DLBCL. However, CD19 loss is a frequent cause of relapse. Simultaneously targeting a second antigen, CD22, may decrease antigen escape, but is challenging: its density is approximately 10-fold less than CD19, and its large structure may hamper immune synapse formation. The characteristics of the optimal CD22 CAR are underexplored. We generated 12 distinct CD22 antibodies and tested CARs derived from them to identify a CAR based on the novel 9A8 antibody, which was sensitive to low CD22 density and lacked tonic signaling. We found no correlation between affinity or membrane proximity of recognition epitope within Ig domains 3-6 of CD22 with CART function. The optimal strategy for CD19/CD22 CART co-targeting is undetermined. Co-administration of CD19 and CD22 CARs is costly; single CARs targeting CD19 and CD22 are challenging to construct. The co-expression of two CARs has previously been achieved using bicistronic vectors. Here, we generated a dual CART product by co-transduction with 9A8-41BBζ and CAT-41BBζ (obe-cel), the previously described CD19 CAR. CAT/9A8 CART eliminated single- and double-positive target cells in vitro and eliminated CD19- tumors in vivo. CAT/9A8 CART is being tested in a phase I clinical study (NCT02443831).

In ovo protective effects of chicoric and rosmarinic acids against Thiacloprid-induced cytotoxicity, oxidative stress, and growth retardation on newly hatched chicks.

Thiacloprid (TH) is a neonicotinoid insecticide employed in agriculture to protect fruits and vegetables against different insects. It showed different deleterious effects on the general health of non-target organisms including birds and animals, however, its developmental toxicity has yet to be fully elucidated. Chicoric (CA) and rosmarinic (RA) acids are polyphenolic compounds with a wide range of beneficial biological activities. In this study, the possible protective effects of CA and RA were investigated in chick embryos exposed in ovo to TH (1µg/egg) with or without CA (100 µg/egg) or RA (100 µg/egg) co-exposure. TH reduced the hatchling body weight, body weight/egg weight, and relative weight of bursa of Fabricius in the one-day-old hatchlings. Examination of the 7-day-old chicks revealed a decline in feed intake, daily weight gain, feed conversion ratio (FCR), and plasma levels of T3, T4, and growth hormone. Serum ALT, AST activities, and total cholesterol levels showed significant elevations. Hepatic MDA was increased with a reduction in SOD activity and GSH level and downregulation of the liver SOD and GST gene expression pattern. Serum IgG and IgM levels were reduced, and various histopathological alterations were noticed in the liver. Co-administration of CA or RA with TH mitigated the toxic effects on hatchlings. When both CA and RA are combined, they present a synergistic protective effect. CA and RA can be used as protective agents against TH toxicity as they improve growth performance and have hepatoprotective and immunostimulant effects in newly hatched chicks.

Effect of dietary modulation of fiber and fat level on liver and kidney functions, lipid profile, antioxidant and immune parameters in growing Egyptian geese.

Determining the optimal requirements from dietary fiber and fat for Egyptian geese is a matter of great concern regarding health, production and growth. Therefore, the current study estimated the effects of different dietary fiber and fat levels on functions of liver and kidney, lipid profile, immunity and antioxidant measurements of the growing Egyptian geese. 150 Egyptian goslings (4 weeks old), with almost the same body weights were randomly allocated into 6 groups (25 goslings/group). All groups were subdivided into five replicates, each replicate contains five geese. Liver and kidney functions, immunity and antioxidant parameters were not significantly affected the different studied levels of fiber and fat or by their interaction. Various levels of fiber significantly affected total cholesterol, triglycerides, LDL-cholesterol and VLDL-cholesterol in a concentration-dependent manner and the lowest the lipid profile values were obtained at 12%. In conclusion, the present findings show that use of dietary fiber up to 12% and 5% dietary fat showed no detrimental effects on the immune status and general health of geese and resulted in the preferable lipid profile. This experiment provides a base for further study about the optimal requirements from dietary fiber and fat for the growing Egyptian geese.

Mitigating the detrimental effects of heat stress in poultry through thermal conditioning and nutritional manipulation.

The poultry industry faces several obstacles and challenges, including the changes in global temperature, increase in the per capita demand for meat and eggs, and the emergence and spread of various diseases. Among these, environmental challenges are one of the most severe hurdles impacting the growth and productivity of poultry. In particular, the increasing frequency and severity of heat waves over the past few years represent a major challenge, and this is expected to worsen in the coming decades. Chickens are highly susceptible to high ambient temperatures (thermal stress), which negatively affect their growth and productivity, leading to enormous economic losses. In the light of global warming, these losses are expected to increase in the near future. Specifically, the worsening of climate change and the rise in global temperatures have augmented the adverse effects of heat on poultry production worldwide. At present, the world population is approximately 7.9 billion, and it has been predicted to reach 9.3 billion by 2050 and approximately 11 billion by 2100, implying a great demand for protein supply; therefore, strategies to mitigate future poultry challenges must be urgently devised. To date, several mitigation measures have been adopted to minimize the negative effects of heat stress in poultry. Of these, thermal acclimation at the postnatal stage or throughout the embryonic stages has been explored as a promising approach; however, for large-scale application, this approach warrants further investigation to determine the suitable temperature and poultry age. Moreover, molecular mechanisms governing thermal conditioning are poorly understood. To this end, we sought to expand our knowledge of thermal conditioning in poultry, which may serve as a valuable reference to improve the thermotolerance of chickens via nutritional management and vitagene regulation. Vitagenes regulate the responses of poultry to diverse stresses. In recent years, nutritionists have paid close attention to bioactive compounds such as resveratrol, curcumin, and quercetin administered alone or in combination. These compounds activate vitagenes and other regulators of the antioxidant defense system, such as nuclear factor-erythroid 2-related factor 2. Overall, thermal conditioning may be an effective strategy to mitigate the negative effects of heat stress. In this context, the present review synthesizes information on the adverse impacts of thermal stress, elucidating the molecular mechanisms underlying thermal conditioning and its effects on the acquisition of tolerance to acute heat stress in later life. Finally, the role of some polyphenolic compounds, such as resveratrol, curcumin, and quercetin, in attenuating heat stress through the activation of the antioxidant defense system in poultry are discussed.

Clinical lessons learned in constitutional hypopituitarism from two decades of experience in a large international cohort.

CONTEXT: The international GENHYPOPIT network collects phenotypical data and screens genetic causes of non-acquired hypopituitarism. AIMS: To describe main phenotype patterns and their evolution through life. DESIGN: Patients were screened according to their phenotype for coding sequence variations in 8 genes: HESX1, LHX3, LHX4, PROP1, POU1F1, TBX19, OTX2 and PROKR2. RESULTS: Among 1213 patients (1143 index cases), the age of diagnosis of hypopituitarism was congenital (24%), in childhood (28%), at puberty (32%), in adulthood (7.2%) or not available (8.8%). Noteworthy, pituitary hormonal deficiencies kept on evolving during adulthood in 49 of patients. Growth Hormone deficiency (GHD) affected 85.8% of patients and was often the first diagnosed deficiency. AdrenoCorticoTropic Hormone deficiency rarely preceded GHD, but usually followed it by over 10 years. Pituitary Magnetic Resonance Imaging (MRI) abnormalities were common (79.7%), with 39.4% pituitary stalk interruption syndrome (PSIS). The most frequently associated extrapituitary malformations were ophthalmological abnormalities (16.1%). Prevalence of identified mutations was 7.3% of index cases (84/1143) and 29.5% in familial cases (n = 146). Genetic analysis in 449 patients without extrapituitary phenotype revealed 36 PROP1, 2 POU1F1 and 17 TBX19 mutations. CONCLUSION: This large international cohort highlights atypical phenotypic presentation of constitutional hypopituitarism, such as post pubertal presentation or adult progression of hormonal deficiencies. These results justify long-term follow-up, and the need for systematic evaluation of associated abnormalities. Genetic defects were rarely identified, mainly PROP1 mutations in pure endocrine phenotypes.

Amer's classification of territories of facial nerve injury in early cases and strategies for the management of different territories.

Early cases of facial nerve injury are best treated by restoring the neural pathway to the same existing facial muscles. Knowledge of the exact territory of facial nerve injury is required to design a plane for the reconstruction of these injuries and to compare results. The current study aims to design a classification system for territories of facial nerve injury based on the location of nearest healthy fascicles to the site of injury both proximally and distally. Two hundred-one patients with early facial nerve injury were assessed for treatment. According to the results of the exploration, 13 territories of injury were identified. The management strategy was planned according to the territory of injury. The current classification system is a simple, easy and effective method for the classification of territories of facial nerve injury. The classification system accurately describes the nearest possible healthy proximal and distal fascicles and can be employed to easily report cases and implement a management plan. This classification scheme also allows us to more effectively compare results.

Normal Growth despite Combined Pituitary Hormone Deficiency.

BACKGROUND: The paradox of normal growth despite a lack of growth hormone (GH) is an unexplained phenomenon described in some pathological (sellar, suprasellar, and hypothalamic disorders) and overgrowth syndromes. It has been suggested that the paradoxical growth is due to other GH variants, GH-like moieties, prolactin, insulin, insulin-like growth factors (IGFs), and unidentified serum factors or growth mechanisms. The objective of this study was to determine the mechanism underlying this normal growth without GH. CASE DESCRIPTION: We describe here growth, hormonal, and genetic analyses for an adolescent boy with panhypopituitarism who achieved an adult height above his genetic potential. RESULTS: Normal growth was observed despite low serum GH, IGF-I, IGF-II, IGF binding protein 3 (IGFBP-3) and acid labile subunit (ALS) concentrations, but the IGF-II/IGFBP-3 molar ratio was slightly high. Panhypopituitarism was associated with a heterozygous missense mutation of HESX1, with variable penetrance in heterozygous relatives. Exome analysis detected heterozygous missense mutations of various genes involved in intracellular signaling pathways. The growth-promoting activity of the patient's serum was unable to induce AKT phosphorylation in the MCF-7 cell line. CONCLUSION: The high IGF-II/IGFBP-3 molar ratio was not the cause of the sustained high growth velocity, due to the low affinity of IGF-II for IGF type 1 receptor. The key finding was the HESX1 mutation, as similar cases have been described before, suggesting a common mechanism for growth without GH. However, the variable penetrance of this variant in heterozygous relatives suggests that modifier genes or mechanisms involving combinations with mutations of other genes involved in intracellular signaling pathways might be responsible.

An overview of Jatropha curcas meal-induced productive and reproductive toxicity in Japanese quail: Potential mechanisms and heat detoxification.

The present study was carried out to investigate the toxic effects of dietary inclusion of raw Jatropha cucas meal [RJM, 3.5%] on productive and reproductive performances of laying Japanese quail and the influence of physical treatment of jatropha meal by heating at [100 oc] for 24 or 48 h [JH24 or JH48 respectively] on reducing these effects. The inclusion of RJM in quail diets significantly decreased the egg production, fertility and hatchability percentages and resulted in a high mortality rate. While heat-treated jatropha meal [JH24 or JH48] improved such undesirable effects. The levels of hepatic proteins related to lipid synthesis, cholesterol metabolism and those related to lipid synthesis and transporting to egg yolk were increased in JH24 and JH48 groups than RJM group. Hepatic contents of vitellogenin [VGT-II] and estrogen receptor α [ERα] and circulating estradiol [E2] were improved in JH48 than RJM and JH24 groups however still under the control values. On the other hand, estrogen receptor ß [ERß] were restored to normal control value in both JH24 and JH48 groups. Histopathological investigation revealed that RJM produced various alterations in the histoarchitecture of liver, ovary and oviducts but these alterations were reduced in both JH24 and JH48 groups. From the obtained data we concluded that heating of jatropha meal for 24 h improved its nutritive value and increasing the time of heating is preferable for reduction of the most of toxic impacts indicating that heat treatment can convert toxic jatropha meal to an alternative protein source for livestock feed in a cheap and clean way without combining any other types of treatments.

The split hypoglossal nerve versus the cross-face nerve graft to supply the free functional muscle transfer for facial reanimation: A comparative study.

Long-standing cases of facial paralysis are currently treated with free functional muscle transfer. Several nerves are mentioned in the literature to supply the free muscle transfer. The aim of this study is to compare the split hypoglossal nerve and the cross-face nerve graft to supply the free functional muscle transfer in facial reanimation. Of 94 patients with long-standing, unilateral facial palsy, 49 were treated using the latissimus dorsi muscle supplied by the split hypoglossal nerve, and 45 patients were treated using the latissmus dorsi muscle supplied by healthy contralateral buccal branch of the facial nerve. The excursion gained by the free muscle transfer supplied by the split hypoglossal nerve (mean 19.20 ± 6.321) was significantly higher (P value 0.001) than that obtained by the contralateral buccal branch of the facial nerve (mean 14.59 ± 6.245). The split hypoglossal nerve appears to be a good possible option to supply the free vascularised muscle transfer in facial reanimation. It yields a stronger excursion in less time than the contralateral cross-face nerve graft.

Pegvisomant-primed growth hormone (GH) stimulation test is useful in identifying true GH deficient children.

OBJECTIVE: Provocative stimulation tests for growth hormone (GH) assessment have poor reproducibility and can often elicit false positive results in normal children. The aim of our study was to confirm the capability of pegvisomant as an enhancer of GH secretion in unmasking false-positive results in short children (height <-2.0 standard deviation score, SDS) undergoing GH testing. DESIGN: A prospective study was conducted between March and August 2016. Twenty short children (10 males and 10 females), aged 4.6-13.4 years, previously diagnosed as GH deficient (GHD) were included in the study. All subjects received 1 mg/kg of pegvisomant subcutaneously; three days later an insulin tolerance test (ITT) was performed. Insulin-like growth factor-I (IGF-I) was evaluated before and three days after pegvisomant administration. RESULTS: After pegvisomant priming and the ITT stimulation test, 12 out of the 20 children initially classified as GHD showed a GH peak of more than 10 ng/ml and were thus reclassified as short normal. Furthermore, a significant reduction of IGF-I was observed in the GHD group (pre IGF-I: median (IQR) 144.0 (109-248) ng/ml, post IGF-I: 98 (49-165) ng/ml; p<0.001) after pegvisomant administration. CONCLUSIONS: Pegvisomant priming before GH stimulation tests can be used to improve the reliability of the diagnostic work-up in GH deficiency.

Productive performance, egg quality, blood constituents, immune functions, and antioxidant parameters in laying hens fed diets with different levels of Yucca schidigera extract.

This study evaluated the effect of Yucca schidigera extract on productive performance, egg quality, blood metabolites, immune function, and antioxidant parameters in laying hens. A total of 96 36-week-old hens were allocated into four groups, the control diet or the diet supplemented with 50, 100, or 150 mg/kg of yucca extract, from 36 to 52 weeks of age. Hens were divided into four equal groups replicated six times with four hens per replicate. As a result of this study, there were no linearly or quadratically differences in body weight change (BWC), feed consumption (FC), feed conversion ratio (FCR), and egg weight (EW) due to yucca treatments at different ages, except FCR and EW that were improved with yucca supplementation during 36-40 weeks of age. Supplemental dietary yucca up to 100 mg/kg diet led to significant improvement in egg number (EN) and egg mass (EM). Egg qualities were not linearly or quadratically affected by yucca treatments except shell thickness was quadratically (P < 0.001) increased with increasing yucca level up to 100 mg/kg diet. Dietary supplementation of yucca exhibited a positive impact on albumin and immunoglobulin G (IgG). Comparing to the control group, yucca addition to laying hen diets resulted in a significant linear (P < 0.001) and quadratic (P = 0. 010) decrease in blood ammonia-N and urea-N, respectively. The activity of superoxide dismutase (SOD) and reduced glutathione (GSH) level in serum were quadratically improved in yucca groups. The malondialdehyde (MDA) concentration was decreased with yucca addition in comparison with the control group. In conclusion, yucca supplemented up to 100 mg/kg diet can be used as effective feed additive to improve productive performance, blood profile, and antioxidant enzyme activities in laying hens.

Penile length and genital anomalies in Egyptian male newborns: epidemiology and influence of endocrine disruptors.

This is an attempt to establish the normal stretched penile length and prevalence of male genital anomalies in full-term neonates and whether they are influenced by prenatal parental exposure to endocrine-disrupting chemicals. A thousand newborns were included; their mothers were subjected to the following questionnaire: parents' age, residence, occupation, contact with insecticides and pesticides, antenatal exposure to cigarette smoke or drugs, family history of genital anomalies, phytoestrogens intake and history of in vitro fertilization or infertility. Free testosterone was measured in 150 neonates in the first day of life. Mean penile length was 3.4±0.37 cm. A penile length <2.5 cm was considered micropenis. Prevalence of genital anomalies was 1.8% (hypospadias 83.33%). There was a higher rate of anomalies in those exposed to endocrine disruptors (EDs; 7.4%) than in the non-exposed (1.2%; p<0.0001; odds ratio 6, 95% confidence interval 2-16). Mean penile length showed a linear relationship with free testosterone and was lower in neonates exposed to EDs.

Effect of GnRH analogue on height potential in patients with severe growth hormone insensitivity syndrome treated with IGF-I.

Children with growth hormone insensitivity syndrome (GHIS) who receive insulin-like growth factor 1 (IGF-1) treatment and enter puberty with inadequate height gain are unlikely to reach adult height within the normal range. Final height standard deviation score (SDS) in most treated children is < or = -5. Combining IGF-1 with gonadotrophin-releasing hormone analogue (GnRHa) therapy may help to improve their final height. Three patients on IGF-1 treatment, two with primary GHI and one with secondary GHI, were started on GnRHa therapy at the onset of puberty. Their ages ranged from 6.4 years to 12.9 years at the start of IGF-1 therapy (120 microg/kg twice daily by subcutaneous injection). Gains in height/bone age SDSs under GnRHa therapy ranged from 0 to 0.9. Growth velocity on GnRHa therapy ranged from 4 cm/year to 4.8 cm/year. Bone maturation (measured as change in bone age divided by change in chronological age, deltaBA/deltaCA) decreased after the start of GnRHa therapy. Predicted adult height (PAH) improved in two patients and was maintained in one. Bone mineral density showed gradual improvement from baseline. Treatment with GnRHa resulted in a gain in PAH. Final height results will provide the definite answer on the effectiveness of this combined treatment.

Breast cancer with low FDG uptake: characterization by means of dual-time point FDG-PET/CT.

BACKGROUND: Malignant breast lesions usually are differentiated by FDG-PET with a semiquantitative FDG standardized uptake value (SUV) of 2.5. However, the frequency of breast cancer with an SUV of less than or equal to 2.5 is noteworthy, and often present diagnostic challenges. This study was undertaken to evaluate the accuracy of dual-time point FDG-PET/CT with FDG standardized uptake value (SUV) calculation in the characterization of such breast tumors. METHODS: Forty-nine female patients with newly diagnosed breast cancer were found to have primary breast cancer with minimally increased FDG uptake and met the criteria for inclusion in this study by having borderline levels of increased FDG uptake (SUV max less than or equal to 2.5) in the initial FDG-PET/CT images. Consequently, they underwent further delayed phase FDG-PET/CT scan for better evaluation of the disease. RESULTS: Of the 49 cancer lesions; the majority were found to have rising or unvarying dual-time changes in SUV max (75.5%). The median value of SUV max increases by 25% between the early and delayed scan. The means+/-S.D. of the SUV max1, the SUV max2, and the Delta SUV max% were 1.2+/-0.6%, 1.3+/-0.9%, and 5.1+/-22.4%, respectively. The receiver-operating-characteristic (ROC) analysis proved that the highest accuracy for characterization of malignant breast lesions was obtained when a Delta SUV max% cut-off value 0.0% was used as criteria for malignant FDG uptake-change over time with sensitivity 75.5%, and false-positive rate 20.4%. CONCLUSION: These results suggested that dual-time FDG-PET/CT imaging with standardized uptake value (SUV) estimation can improve the accuracy of the test in the evaluation of breast cancer with low FDG uptake.

Positron emission tomography and breast lesions: low FDG activity in early phase imaging is not essentially benign.

The frequency of malignancy with low FDG uptake is significant and often presents diagnostic challenges. The usefulness of dual-time point FDG-PET/CT imaging (including early "after 45 minutes" and delayed "after 100 minutes," phases after radionuclide administration) for detection of such tumors has been documented. The authors present 2 cases of pathologically proven breast cancer with minimally increased FDG uptake on the initial scan (maximum standardized uptake value; SUVmax <2.5). Detection was improved by performing a dynamic PET study with early and delayed scans. Patients with a poorly visualized breast lesion due to minimal FDG uptake on the initial FDG-PET images should not be considered as benign and deserves further delayed phase imaging.

Bone mineral density and calcium metabolism in adolescents with beta-thalassemia major.

Bone disease in thalassemia in the form of low bone mass remains a frequent, debilitating and poorly understood problem, even among well transfused and chelated pre-pubertal and adult patients. In this work we attempted to delineate calcium status and bone mineral density in a group of transfusion dependent thalassemic adolescents of both sexes. Bone mineral density (BMD) at both the lumbar spine and femoral neck was measured in 40 adolescents with beta thalassemia major (TM) by DXA scanning and correlated to biochemical parameters including calcium, phosphorus, alkaline phosphatase, bone alkaline phosphatase, intact parathyroid hormone and 25-OH vitamin D as well as vitamin D receptor (VDR) gene polymorphisms at exon 2 (Fok1). Z-score of BMD at the lumbar spine (-3.3, +/-1.4) was significantly lower than at the femoral neck (-0.68, -/+1.3), (p=0.001). Serum ferritin and VDR genotype were related to BMD only at the femoral neck indicating that the factors determining the BMD at these 2 sites might be different. Seventy-five percent of patients had a low calcium level and hypoparathyroidism was present in 72.5% of patients. The low calcium level was probably caused by a combination of hypoparathyroidism and osteomalacia evidenced by elevated bone alkaline phosphatase presumably resulting from deficient calcium intake. To optimize BMD in TM, it is important to ensure adequate iron chelation and adequate intake of calcium and vitamin D.