Concordance between radioimmunoassay and fixed cell-based assay in subjects without myasthenia gravis: optimizing the diagnostic approach.

BACKGROUND AND PURPOSE: Acetylcholine receptor antibody (AChR-Ab) detection is crucial in myasthenia gravis (MG) diagnosis and, currently, the radioimmunoassay (RIA) is the gold standard. However, RIA may detect AChR-Ab against nonpathogenic intracellular epitopes. In this study, we performed fixed cell-based assay (F-CBA) in RIA-AChR-Ab positive subjects without MG symptoms, to assess whether F-CBA could show a higher specificity compared to RIA in detecting pathogenic Abs. METHODS: We reviewed medical records of patients referred to our MG outpatient clinic because of RIA-AChR-Ab detection. MG diagnosis was based on clinical examination, electrophysiology and Ab detection. AChR-Abs were tested by RIA in the whole cohort. Serum samples from RIA-positive asymptomatic subjects were retested by F-CBA. RESULTS: Of 605 subjects who tested RIA-AChR-Ab positive, MG diagnosis was confirmed in 599. Six subjects were RIA-AChR-Ab positive although they had never had MG symptoms; in four of these subjects AChR-Abs were not detected by F-CBA, whereas the remaining two (both non-MG thymoma cases) were positive also by F-CBA. CONCLUSIONS: RIA false positivity for AChR-Ab is very rare. Previous literature has demonstrated that F-CBA has higher sensitivity than RIA for MG, especially in ocular cases. Our preliminary results show that, in rare instances, F-CBA may be more specific than RIA for MG diagnosis.

A Black Swan in clinical laboratory practice: the analytical error due to interferences in immunoassay methods.

It is well known that the results of immunoassay methods can be affected by specific or non-specific interferences, ranging from 0.4% to 4.0%. The presence of interference may greatly compromise the accuracy of immunoassay analyses causing an error in the measurement, producing false-positive or false-negative results. From a clinical point of view, these analytical errors may have serious implications for patient care because they can cause misdiagnosis or inappropriate treatment. Unfortunately, it is a very difficult task to identify the irregular analytical errors related to immunoassay methods because they are not detectable by normal laboratory quality control procedures, are reproducible within the test system, may be clinically plausible and are relatively rare. The first line of defense against erroneous results is to use in laboratory practice only immunoassay systems with the highest level of robustness against interference. The second line of defense is always taking into account the possibility of interference in immunoassay results. A correct approach should be addressed on identification of samples at high risk of interference. The attainment of this goal requires a critical review of the test result in relation to patient's clinical conditions and literature data, taking into account the analytical characteristics of the immunoassay system. The experts in immunoassay systems should make every effort to find some specific and reliable quality indicators for irregular analytical errors in order to better detect and monitor erroneous immunoassay results due to specific or non-specific interferences.

Harmonization protocols for TSH immunoassays: a multicenter study in Italy.

BACKGROUND: Systematic difference between thyroid-stimulating hormone (TSH) immunoassays may produce misleading interpretation when samples of the same patients are measured with different methods. The study aims were to evaluate whether systematic differences are present among TSH immunoassays, and whether it is possible to obtain a better harmonization among TSH methods using results obtained in external quality assessment (EQA) schemes. METHODS: Seven Italian clinical laboratories measured TSH in 745 serum samples of healthy subjects and patients with thyroid disorders. These samples were also re-measured by two reference laboratories of the study with the six TSH immunoassays most popular in Italy after 2 months of storage at -80 °C. Moreover, these data were compared to 53,823 TSH measurements, obtained by laboratories participant to 2012-2015 EQA annual cycles in 72 quality control samples (TSH concentrations from about 0.1 mIU/L to 18.0 mIU/L). TSH concentrations were recalibrated using a mathematical approach based on the principal component analysis (PCA). RESULTS: Systematic differences were found between the most popular commercially available TSH immunoassays. TSH concentrations measured by the clinical laboratories were very closely correlated to those measured with the same method by reference laboratories after 2 months of storage at -80 °C. After recalibration using the PCA approach the variation of TSH values significantly decreased from a median pre-calibration value of 13.53% (10.79%-16.53%) to 9.63% (6.90%-13.21%) after recalibration. CONCLUSIONS: Our data suggest that EQA schemes are useful to improve harmonization among TSH immunoassays and also to produce some mathematical formulas, which can be used by clinicians to better compare TSH values measured with different methods.

Is intraoperative calcitonin monitoring useful to modulate the extension of neck dissection in patients with medullary thyroid carcinoma?

BACKGROUND: The extension of the compartment-oriented neck dissection at primary surgery in medullary thyroid carcinoma (MTC) is controversial. Because a <50 % decrease in intraoperative calcitonin levels (IO-CT) after total thyroidectomy plus central neck dissection (TT-CND) has been associated with residual disease, IO-CT monitoring has been proposed to predict the completeness of surgery. The goal of the present prospective study was to verify the accuracy of IO-CT monitoring. METHODS: All patients scheduled for primary surgery for suspected or proven MTC between November 2010 and January 2013 were included. Calcitonin was measured pre-incision (basal level), after tumor manipulation, at the time TT-CND was accomplished (ablation level), 10 and 30 min after ablation. A decrease >50 % with respect to the highest IO-CT level 30 min after ablation was considered predictive of cure. RESULTS: Twenty-six patients were included, and IO-CT monitoring identified 18 of 23 cured patients (true negative results) and 2 of 3 patients with persistent disease (true positive result). In 5 patients with normal basal and stimulated postoperative calcitonin levels, a decrease <50 % was observed (false positive results). In one of three patients with persistent disease a >50 % decrease in IO-CT was observed (false negative results). Specificity, sensitivity, and accuracy of IO-CT were 78.2, 66.6, and 76.9 %, respectively. CONCLUSIONS: Intraoperative calcitonin monitoring is not highly accurate in predicting the completeness of surgical resection. In the present series, relying on IO-CT would result in limited resection in about one third of the patients with residual neck disease and in unnecessary lateral neck dissection in about 20 % of the cured patients.

Solute Transporter OCTN1/Slc22a4 Affects Disease Severity and Response to Infliximab in Experimental Colitis: Role of Gut Microbiota and Immune Modulation.

BACKGROUND: Inflammatory bowel diseases are chronic disabling conditions with a complex and multifactorial etiology, still incompletely understood. OCTN1, an organic cation transporter, could have a role in modulating the inflammatory response, and some genetic polymorphisms of this molecule have been associated with increased risk of inflammatory bowel diseases. Until now, limited information exists on its potential in predicting/modulating patient's response to therapies. The aim of this study was to evaluate the role of OCTN1 in modifying gut microbiota and mucosal immunity in response to infliximab therapy in murine colitis. METHODS: A dextran sodium sulphate model of colitis was used to assess the clinical efficacy of infliximab administered intravenously in ocnt1 gene knockout mice and their C57BL/6 controls. Stool, colon, and mesenteric lymph node samples were collected to evaluate differences in gut microbiota composition, histology, and T cell populations, respectively. RESULTS: Octn1 -/- influences the microbiota profile and is associated with a worse dysbiosis in mice with colitis. Infliximab treatment attenuates colitis-associated dysbiosis, with an increase of bacterial richness and evenness in both strains. In comparison with wild type, octn1-/- mice have milder disease and a higher baseline percentage of Treg, Tmemory, Th2 and Th17 cells. CONCLUSIONS: Our data support the murine model to study OCTN1 genetic contribution to inflammatory bowel diseases. This could be the first step towards the recognition of this membrane transporter as a biomarker in inflammatory conditions and a predictor of response to therapies.

In this article, we evaluated the role of OCTN1, an organic cation transporter, in modifying gut microbiota and immune T cell populations, as well as its effects on experimental colitis and the response to infliximab treatment.

Genetic Characterization of a Cohort of Italian Patients with Congenital Adrenal Hyperplasia Due to 21-Hydroxylase Deficiency.

INTRODUCTION: Defects in the steroid 21-hydroxylase gene (CYP21A2) cause 21-hydroxylase deficiency (21OHD), the main cause of congenital adrenal hyperplasia (CAH). The disease shows a broad spectrum of clinical forms, ranging from severe or classical (salt wasting, SW, and simple virilizing, SV), to mild late onset or nonclassical (NC). 21OHD affects 1 in 15,000 in its severe classic form and 1 in 200-1000 in its mild NC form. There are many studies reporting the frequency of CYP21A2 pathogenic variants in different populations; however, few of them provide comprehensive information about Italian patients. Here, we present genetic results from a cohort of 245 unrelated Italian individuals with clinical diagnosis of CAH due to 21OHD. METHODS: A specific polymerase chain reaction (PCR) protocol combined with Sanger sequencing was used for CYP21A2 analysis. The multiplex ligation-dependent probe amplification (MLPA) assay was employed for copy number variation (CNV) determination. RESULTS: One hundred fourteen (46.5%) of the index cases had the NC form, 57 (23.3%) had the SV form, and 74 (30.2%) presented the SW form of the disease. The most prevalent variant found in NC patients was the p.Val282Leu (51.3%), while the most frequent variants in the classical form were p.Ile173Asn (8.6%) and c.293-13C>G (26.0%). In our study, the frequency of large rearrangements was 15.3%, with CAH-X alleles representing 40% of all DEL/CONV. In addition, 12 alleles carried rare variants, and 1 had a novel variant p.(Arg342Gln). We observed phenotype-genotype correlation in 94.7% of cases. A complete concordance was observed in Groups 0 (enzyme activity completely impaired) where all patients had the SW form as expected. In Group A (0-1% residual enzyme activity), 78.4% of patients had the anticipated SW form while 21.6% were diagnosed with the SV form. Within Group B (~ 2% residual enzyme activity), 93.4% of patients exhibited SV form and 6.5% SW disease. Finally, 92.6% and 7.4% of patients belonging to Group C (enzyme partially impaired to ~ 20-60% residual activity) exhibited NC and SV phenotypes, respectively. CONCLUSION: This work, representing a comprehensive genetic study, expanded the CYP21A2 variants spectrum of Italian patients with 21OHD and could be helpful in prenatal diagnosis and genetic counseling.

Comparison of Fixed and Live Cell-Based Assay for the Detection of AChR and MuSK Antibodies in Myasthenia Gravis.

BACKGROUND AND OBJECTIVES: Live cell-based assay (CBA) can detect acetylcholine receptors (AChRs) or muscle-specific tyrosine kinase (MuSK) antibodies (Abs) in a proportion of patients with radioimmunoassay (RIA)-double seronegative myasthenia gravis (dSN-MG). A commercial fixed CBA for AChR and MuSK Abs has recently become available; however, comparative studies on fixed and live CBAs are lacking. In this study, we compared the performance of fixed and live CBAs in patients with RIA-dSN MG and assessed their sensitivity in RIA-positive MG samples and their specificity. METHODS: AChR and MuSK Abs were tested in 292 serum samples from 2 Italian MG referral centers by live and fixed CBAs: 192 from patients with MG and 100 from controls. All samples had been previously assessed by RIA: 66 were AChR positive, 40 MuSK positive, and 86 dSN. All controls were negative. Two independent raters assessed the CBA results. Fixed and live CBAs were compared with the McNemar test; interrater and interlaboratory agreement were assessed with Cohen's kappa or interclass correlation coefficient (ICC), as appropriate. RESULTS: In 86 RIA-dSN samples, fixed CBA detected Abs in 10 cases (11.6%, 95% CI 5.7-20.3), whereas live CBA detected Abs in 16 (18.6%, 95% CI 11.0-28.5) (p = 0.0143). Of these sera, those positive by fixed CBA were also positive by live CBA. In addition, live CBA could detect MuSK Abs in 4 and AChR Abs in 2 samples that were negative by fixed CBA, providing an 8% (95% CI 2.9-16.6) further increase in the Ab detection rate. These results were confirmed by flow cytometry. In the RIA-positive cohort, the sensitivity for AChR Abs was 98.5% (95% CI 91.9%-99.9%) for fixed CBA and 100% (95% CI 94.6-100) for live CBA (p = 0.1573). For both assays, the sensitivity for MuSK Abs was 100% (95% CI 91.2-100), and the specificity was 100% (95% CI 96.4-100). Interrater agreement was almost perfect for live and fixed CBAs (Cohen's kappa 0.972 and 0.978, respectively), alike interlaboratory agreement. Interrater agreement for the CBA score ranged from good to excellent (ICC: 0.832-0.973). DISCUSSION: Fixed CBA represents a valuable alternative to RIA for AChR and MuSK Ab detection in patients with MG and could be considered as a first-step diagnostic test. Live CBA can be useful in the serologic evaluation of RIA- and fixed CBA-negative samples.

Combining early postoperative parathyroid hormone and serum calcium levels allows for an efficacious selective post-thyroidectomy supplementation treatment.

BACKGROUND: Optimal treatment protocol to prevent symptomatic hypocalcemia following total thyroidectomy is still matter of debate. We prospectively evaluated the efficacy of a selective supplementation protocol based on both early postoperative intact parathyroid hormone (iPTH) and serum calcium levels. METHODS: Two hundred thirty consecutive patients were divided in three different groups of treatment according to iPTH levels 4 h after total thyroidectomy (4 h-iPTH) and serum calcium levels in the first postoperative day (1PO-Ca): group A (4 h-iPTH > 10 pg/ml, 1PO-Ca ≥ 8.5 mg/dl), no treatment; group B (4 h-iPTH > 10 pg/ml, 1PO-Ca < 8.5 mg/dl), oral calcium (OC) 3 g per day; and group C (4 h-iPTH ≤ 10 pg/ml), OC 3 g + calcitriol (VD) 1 µg per day. Development of biochemical and/or symptomatic hypocalcemia was evaluated. RESULTS: Fifty-nine patients (25.6%) had subnormal 4 h-iPTH levels (≤10 pg/ml) (group C). Among patients with normal 4 h-iPTH levels, 25 (10.9%) had subnormal 1PO-Ca (<8.5 mg/dl) (group B). The remaining 146 patients (63.5%) had normal 4 h-iPTH and 1PO-Ca levels (group A). One patient in group A, 2 in group B, and 18 in group C developed biochemical hypocalcemia. Only one patient in group C experienced major symptoms. Treatment was discontinued within 1 month in all the patients in group B. At a mean follow-up of 303 days, five patients in group C were still under supplementation treatment. CONCLUSION: The proposed supplementation protocol seems efficacious in preventing symptomatic hypocalcemia. It could allow a safe and early discharge of most patients, thus avoiding the constraints and the costs of routine supplementation.

The biochemical diagnosis of acromegaly: revising the role of measurement of IGF-I and GH after glucose load in 5 questions.

INTRODUCTION: Acromegaly is a rare disorder characterized by the excessive secretion of growth hormone (GH), mostly caused by pituitary adenomas. While in full-blown cases the diagnosis is easy to establish, milder cases are more challenging. Additionally, establishing whether full cure after surgery is reached may be difficult. AREAS COVERED: In this article, we will review the challenges posed by the variability in measurements of GH and its main effector insulin-like growth factor I (IGF-I) due to both biological changes, co-morbidities, and assays variability. EXPERT OPINION: Interpretation of GH and IGF-I assays is important in establishing an early diagnosis of acromegaly, in avoiding misdiagnosis, and in establishing if cure is achieved by surgery. Physicians should be familiar with the variables that affect measurements of these 2 hormones, and with the performance of the assays available in their practice.

Does mild intrahepatic cholestasis of pregnancy require an aggressive management? Evidence from a prospective observational study focused on adverse perinatal outcomes and pathological placental findings.

OBJECTIVE: To ascertain the most effective approach in pregnancies complicated by mild intrahepatic cholestasis of pregnancy (mICP) by evaluating rates of adverse perinatal outcomes (APOs) and pathological placental findings. METHODS: A total of 89 pregnancies complicated by mICP (defined as total serum bile acids (TSBAs) levels <40 µmol/L) were included. One-drug (ursodeoxycholic acid [UDCA]) (n = 49, 55.1%) and combined (UDCA plus S-adenosyl methionine (SAMe)) (n = 40, 44.9%) therapies were compared. RESULTS: No differences were found in demographic, obstetric, and placental characteristics. In UDCA plus SAMe group, premature delivery was a common clinical decision (14.3 versus 25%, p-value = .201), with increased rates of instrumental vaginal delivery (VD; 28.6 versus 40%, p-value = .522), but similar cesarean section (CS) rates (26.5 versus 25%, p-value = .498). Mean placental weight was comparable (UDCA, mean 595.7 g, SD 213.1 g versus UDCA plus SAMe, mean 586.4 g, SD 102.9 g, p-value = .875). A total of 110 lesions were identified, 64 in 25 placentas of patients assigned to the UDCA and 46 in 15 placentas of patients managed by UDCA plus SAMe. Placental findings attributable to maternal malperfusion were found in 41/25 and 32/15 cases treated by UCDA and UDCA plus SAMe (165 versus 213%, p-value = .774), pathological fetal vascular supply in 17/25 and 8/15 placentas (68 versus 53%, p-value = .777), and inflammatory lesions in 6/25 and 6/15 cases (24 versus 40%, p-value = .757). CONCLUSIONS: Pregnancies complicated by mICP and managed by UDCA alone present similar APO rates and placental histopathology if compared with those treated by UDCA plus SAMe, failing to recognize advantages in the combined therapy. Further prospective studies and data sharing from ongoing RTCs could drive changes in therapeutic plan.

A Novel GCK Large Genomic Rearrangement in a Patient with MODY-2 Detected by Clinical Exome Sequencing.

Maturity-onset diabetes of the young (MODY) is a rare form of non-autoimmune diabetes with an autosomal dominant inheritance. To date, 14 genes have been reported as genetic basis of MODY. GCK gene, encoding the glucokinase enzyme, was the first MODY gene to be identified. GCK heterozygous inactivating variants cause the GCK-MODY or MODY2 subtype. However, partial or whole gene deletions have been rarely identified, showing it to be a rare cause of GCK-MODY. We reported the molecular evaluation of a Ukrainian patient with clinical diagnosis of MODY2. We performed the Next generation sequencing of the clinical exome using the Clinical Exome Solution® kit (SOPHiA Genetics), followed by the design of a 14 genes virtual panel related to the suggestive diagnosis of MODY. Bioinformatics analysis was performed using the SOPHiA DDM platform (SOPHiA Genetics). The SALSA MLPA kit for MODY (MRC-Holland) was used for relative quantification of GCK exons. From the molecular evaluation, no pathogenic sequence variants were detected in the investigated genes. Copy Number Variation analysis was able to identify a large deletion involving the last three exons of the GCK gene. This result was confirmed by MLPA. To the best of our knowledge, the identified rearrangement has never been reported in the literature.

Human growth hormone (GH) immunoassay: standardization and clinical implications.

BACKGROUND: The poor comparability of growth hormone (GH) results obtained using commercially available methods, is partly due to standard preparations used in calibration. The system relies on the use of the International Reference Preparation (IRP) international standard (IS) 80/505, of human pituitary origin, containing all GH isoforms. Recently, a 22K recombinant GH isoform IRP IS 98/574 was commercialized. Our aim was to evaluate the influence of both calibrators on GH results. METHODS: GH concentration in 97 serum samples from children undergoing a growth hormone releasing hormone+arginine stimulation test was measured using Siemens IMMULITE electro-chemiluminescence method, calibrated with both IS 80/505 and IS 98/574 (GRH Growth hormone-Recombinant 98/574-kit). RESULTS: Comparison of our results obtained with the two sets of calibrators showed good correlation, although we found higher percentage variation (var%) than that stated by Siemens. The mean var% value was confirmed when all results were sub-divided into subgroups based on both high and low GH concentrations. CONCLUSIONS: Since the GH assay is influenced by a variety of binding proteins, isoforms and conversion factors, standardization of the assay is strongly required. In Italy, the Agenzia Italiana del Farmaco 39 note provides GH laboratory values which are useful for therapy. On the basis of our results, we therefore propose to adjourn these GH values in order to ensure better management of patients with GH-related disorders.

Genes and Pseudogenes: Complexity of the RCCX Locus and Disease.

Copy Number Variations (CNVs) account for a large proportion of human genome and are a primary contributor to human phenotypic variation, in addition to being the molecular basis of a wide spectrum of disease. Multiallelic CNVs represent a considerable fraction of large CNVs and are strictly related to segmental duplications according to their prevalent duplicate alleles. RCCX CNV is a complex, multiallelic and tandem CNV located in the major histocompatibility complex (MHC) class III region. RCCX structure is typically defined by the copy number of a DNA segment containing a series of genes - the serine/threonine kinase 19 (STK19), the complement 4 (C4), the steroid 21-hydroxylase (CYP21), and the tenascin-X (TNX) - lie close to each other. In the Caucasian population, the most common RCCX haplotype (69%) consists of two segments containing the genes STK19-C4A-CYP21A1P-TNXA-STK19B-C4B-CYP21A2-TNXB, with a telomere-to-centromere orientation. Nonallelic homologous recombination (NAHR) plays a key role into the RCCX genetic diversity: unequal crossover facilitates large structural rearrangements and copy number changes, whereas gene conversion mediates relatively short sequence transfers. The results of these events increased the RCCX genetic diversity and are responsible of specific human diseases. This review provides an overview on RCCX complexity pointing out the molecular bases of Congenital Adrenal Hyperplasia (CAH) due to CYP21A2 deficiency, CAH-X Syndrome and disorders related to CNV of complement component C4.

Cortisol circadian rhythm and jet-lag syndrome: evaluation of salivary cortisol rhythm in a group of eastward travelers.

PURPOSE: The activity of the hypothalamus-pituitary-adrenal axis plays a crucial role as an endogenous stress-reactive system. Lifestyle and work often interfere with the endogenous circadian rhythms and can modify the physiological patterns of stress-hormones secretion, including cortisol. We evaluated the cortisol circadian rhythm in the "jet-lag syndrome" that is the most known condition associated with the desynchronization of the circadian rhythm. METHODS: To assess the modifications of cortisol secretion after a long-haul flight, we compared baseline and post-travel salivary cortisol rhythm in a group of 28 healthy eastward travelers (from the U.S.A. or Canada to Italy). The salivary samples were collected about 1 week before the departure at 11 p.m. on day 0 and at 8 a.m., 12 a.m. (midday) and 11 p.m. on day 1 (R0). The same samples were obtained after the landing, the day they flew back home (R1). RESULTS: Statistical analysis showed a significant difference between R0 and R1 for each sample considered (p < 0.005). In particular, the post-travel salivary cortisol levels detected at 11 p.m. both on day 0 and on day 1, were significantly higher than at baseline. Post-travel morning salivary cortisol levels were lower compared with basal rhythm and increased during the morning, reaching the acrophase at 12 a.m. CONCLUSIONS: In eastward travelers, crossing more than five time zones, the cortisol circadian rhythm after the return to the East "remained behind," being synchronized with the West time. This impaired cortisol secretion can contribute to the pathogenesis of the jet-lag syndrome.

Iodine Absorption in Celiac Children: A Longitudinal Pilot Study.

Background: non-autoimmune thyroid disorder is a common finding in celiac patients, more frequent than in the general population. An impairment of iodine absorption has been hypothesized, but it has never been investigated so far. We aimed to evaluate the iodine absorption in children and adolescents with newly diagnosed celiac disease. Methods: 36 consecutive celiac patients (age 7.4 years, range 2.4-14.5 years) before starting a gluten-free diet (GFD) were enrolled. We assayed the urinary iodine concentration (UIC) in a 24-h urine sample, at baseline (T0) after 3 (T1) and 12 months (T2) of GFD. Results: UIC at T0 was 64 µg/L (IQR 45-93.25 µg/L) with an iodine deficiency rate of 77.8%. UIC was not different according to histological damage, clinical presentation (typical vs atypical); we found no correlation with the thyroid function tests and auxological parameters. UIC was not statistically different at T1 (76 µg/L) and T2 (89 µg/L) vs T0. UIC at T2 was similar between patients with positive and negative anti-transglutaminase antibodies at T2. No patients presented overt hypothyroidism during the study. Conclusions: We found that iodine absorption in celiac children is impaired compared to the general population; it increases slightly, but not significantly, during the GFD. We should regularly reinforce the need for a proper iodine intake in celiac disease patients to reduce iodine deficiency risk.

Immunoassay Interference on Thyroid Function Tests During Treatment with Nivolumab.

Background: Immune checkpoint inhibitors (ICIs) are associated with several endocrine side effects. In particular, the use of programmed cell death protein-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) inhibitors is related to a higher incidence of thyroid dysfunction. Patient Findings: An 85 years-old patient, diagnosed with a metastatic melanoma treated with nivolumab, presented to our hospital with severe ICI-related thyrotoxicosis. Diagnosis was complicated by a biochemical interference on thyroid hormones assay, probably induced by nivolumab. Summary: Baseline laboratory examination conducted before onset of anticancer therapy showed normal thyroid function test (TFTs). A few days after receiving the second nivolumab administration, the patient developed a severe thyrotoxicosis. According to destructive thyroiditis, in a short period thyrotropin (TSH) levels normalized and rapidly increased, but free thyroxine (fT4) levels were inappropriately elevated and did not decrease as expected. The sample was processed by using a Siemens Centaur® immunoassay. We reanalyzed the same sample at another laboratory and with a different immunoassay method (Roche Elecsys®). The results obtained from this assay confirmed severe hypothyroidism with appropriately low fT4 levels. We suspected a possible nivolumab-associated interference on the fT4 assay. Therefore, we subjected the same sample to a polyethylene glycol (PEG) 6000 precipitation, a simple method for the removal of macromolecules, before assaying for fT4 levels. Evaluation of the post-PEG-precipitation sample (Siemens Centaur immunoassay) revealed appropriately low fT4 levels. The patient was started on levothyroxine (LT4) therapy, with monthly TFT monitoring using the Roche immunoassay. Approximately 9 months after starting nivolumab therapy, the patient was advised treatment cessation. A month later, the TFTs were retested on a Siemens Centaur immunoassay, and appropriate fT4 levels were observed in accordance with normal TSH levels on adequate LT4 replacement therapy. Conclusions: We report a possible novel nivolumab-induced biochemical interference on assays of fT4 levels. The hypothesis of a biochemical drug-induced interference is further supported by the disappearance of the interference after the withdrawal of nivolumab. Further studies are needed to prove the biochemical mechanisms of this interference.

Evaluation and cost estimation of laboratory test overuse in 43 commonly ordered parameters through a Computerized Clinical Decision Support System (CCDSS) in a large university hospital.

BACKGROUND: Computerized Clinical Decision Support Systems (CCDSS) have become increasingly important in ensuring patient safety and supporting all phases of clinical decision making. The aim of this study is to evaluate, through a CCDSS, the rate of the laboratory tests overuse and to estimate the cost of the inappropriate requests in a large university hospital. METHOD: In this observational study, hospital physicians submitted the examination requests for the inpatients through a Computerized Physician Order Entry. Violations of the rules in tests requests were intercepted and counted by a CCDSS, over a period of 20 months. Descriptive and inferential statistics (Student's t-test and ANOVA) were made. Finally, the monthly comprehensive cost of the laboratory tests was calculated. RESULTS: During the observation period a total of 5,716,370 requests were analyzed and 809,245 violations were counted. The global rate of overuse was 14.2% ± 3.0%. The most inappropriate exams were Alpha Fetoprotein (85.8% ± 30.5%), Chlamydia trachomatis Nucleic Acid Amplification (48.7% ± 8.8%) and Alkaline Phosphatase (20.3% ± 6.5%). The monthly cost of over-utilization was 56,534€ for basic panel, 14,421€ for coagulation, 4,758€ for microbiology, 432€ for immunology exams. All the exams, generated an estimated avoidable cost of 1,719,337€ (85,967€ per month) for the hospital. CONCLUSIONS: The study confirms the wide variability in over-utilization rates of laboratory tests. For these reasons, the real impact of inappropriateness is difficult to assess, but the generated costs for patients, hospitals and health systems are certainly high and not negligible. It would be desirable for international medical communities to produce a complete panel of prescriptive rules for all the most common laboratory exams that is useful not only to reduce costs, but also to ensure standardization and high-quality care.

Two novel CYP21A2 missense mutations in Italian patients with 21-hydroxylase deficiency: Identification and functional characterisation.

Steroid 21-hydroxylase deficiency is present in more than 90% of patients with congenital adrenal hyperplasia (CAH), an inherited metabolic disorder of adrenal steroidogenesis. Impaired enzymatic activity leads to the accumulation of metabolic intermediates (progesterone and 17-hydroxyprogesterone), which results in excessive androgen production and varied signs of virilisation. CYP21A2 is an active gene and encodes for the steroid 21-hydroxylase enzyme, whereas CYP21A1P is an inactive pseudogene that contains a series of deleterious mutations. The major part of disease- causing mutations in CYP21A2 alleles are CYP21A1P-derived sequence transferred to the active gene by macro or microconversion events. Only around 5% of all disease-causing CYP21A2 alleles harbour rare mutations that do not originate from the pseudogene. In this report, we report the characterisation of two novel CYP21A2 missense mutations (p.H119R and p.I194N) found in two unrelated Italian patients with nonclassic (NC) CAH clinical diagnosis. Functional in vitro assays for mutagenized CYP21 enzymes were performed in transiently transfected mammalian cells to test the residual enzyme activity and the apparent kinetic values. The residual activities obtained for p.H119R and p.I194N mutants allowed to classify them as NC-CAH associated mutations. These results correlate with the rate of severity of the patients' disease. Finally, the new p.H119R and p.I194N mutations should be included in the panel of those already listed for association with the NC form of 21-hydroxylase deficiency.

Functional analysis of two rare CYP21A2 mutations detected in Italian patients with a mildest form of congenital adrenal hyperplasia.

BACKGROUND: More than 90% of all cases of congenital adrenal hyperplasia (CAH) result from steroid 21-hydroxylase gene (CYP21A2) mutations. Most of these mutations result from intergenic recombinations between CYP21A2 and closely linked CYP21A1P pseudogene. Rare mutations not generated by gene conversion account for 5-10% of 21-hydroxylase deficiency alleles. OBJECTIVE: Functional analysis of two novel CYP21A2 missense mutations (p.R224W and p.D407N) was performed. DESIGN: Our study was composed of two Italian patients suffering from a very mild form of nonclassic CAH (NC-CAH). To assay the enzymatic activity of mutants, the in vitro analysis was performed in transiently transfected COS-1 cells. RESULTS: The residual activities obtained for p.R224W and p.D407N mutants allow their classification as NC-CAH mutations. These results correlate with the rate of severity of the patients' disease. CONCLUSIONS: In this paper, we report two novel CYP21A2 mutations in two Italian individuals affected by 21-hydroxylase deficiency. Based on the functional in vitro analysis we can classify these mutations as NC-CAH variants.