Multicenter Evaluation of the Clinical Performance and the Neutralizing Antibody Activity Prediction Properties of 10 High-Throughput Serological Assays Used in Clinical Laboratories.

As the coronavirus disease 2019 (COVID-19) pandemic second wave is emerging, it is of the upmost importance to screen the population immunity in order to keep track of infected individuals. Consequently, immunoassays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with high specificity and positive predictive values are needed to obtain an accurate epidemiological picture. As more data accumulate about the immune responses and the kinetics of neutralizing-antibody (nAb) production in SARS-CoV-2-infected individuals, new applications are forecast for serological assays such as nAb activity prediction in convalescent-phase plasma from recovered patients. This multicenter study, involving six hospital centers, determined the baseline clinical performances, reproducibility, and nAb level correlations of 10 commercially available immunoassays. In addition, three lateral-flow chromatography assays were evaluated, as these devices can be used in logistically challenged areas. All assays were evaluated using the same patient panels in duplicate, thus enabling accurate comparison of the tests. Seven immunoassays examined in this study were shown to have excellent specificity (98 to 100%) and good to excellent positive predictive values (82 to 100%) when used in a low (5%)-seroprevalence setting. We observed sensitivities as low as 74% and as high as 95% at ≥15 days after symptom onset. The determination of optimized cutoff values through receiver operating characteristic (ROC) curve analyses had a significant impact on the diagnostic resolution of several enzyme immunoassays by increasing the sensitivity significantly without a large trade-off in specificity. We found that spike-based immunoassays seem to be better correlates of nAb activity. Finally, the results reported here will add to the general knowledge of the interlaboratory reproducibility of clinical performance parameters of immunoassays and provide new evidence about nAb activity prediction.

Isolation and characterization of rat skeletal myoblast mutants resistant to lectins.

Mutants resistant to the lethal action of the lectins phytohemagglutinin A (PHA) and wheat germ agglutinin (WGA) have been made in a line of differentiating rat skeletal myoblasts. The WGA mutants are of two types, WGArII, resistant to low concentrations of the lectin, and WGArI, resistant to high concentrations of the lectin. WGArII and PHAr mutants are unable to differentiate, whereas WGArI mutants differentiate normally. WGArII mutants are not impaired in the binding of wheat germ agglutinin, but WGArI mutants bind the lectin only to the extent of about 50% of the wild-type values. All of the mutants are cross-resistant to lectins other than those used in their selection.

Absence of the A1252G mutation in alpha 1-antichymotrypsin in a North American population suffering from dementia.

Associations have been reported between polymorphisms in the gene for alpha 1-antichymotrypsin (ACT) and both Alzheimer's disease (AD) and cerebrovascular disease. An A-to-G substitution at nucleotide position 1,252 of ACT that produces a methionine to valine substitution at codon 389 has been found previously in four of 32 individuals with cerebrovascular disease from a Japanese population. We genotyped 194 individuals [59 controls, 35 with non-AD-type dementia (primarily vascular) and 100 with Alzheimer's-type dementia] for this polymorphism and found none that carry this polymorphism. Therefore, the allelic association of the A1252G mutation of ACT with cerebrovascular disease may be confined to the Japanese population and is not generalizable to other populations.

N-acetylation among HIV-positive patients and patients with AIDS: when is fast, fast and slow, slow?

BACKGROUND: The discrepancy between genotype and expressed phenotype of the polymorphic N-acetyltransferase (NAT2) has been suggested by separate genotypic and phenotypic studies in populations with human immunodeficiency virus (HIV). Only one study has examined both genotype and phenotype in the same population, and no discrepancies were observed. METHODS: In a cross-sectional study, 105 HIV-positive patients and patients with acquired immunodeficiency syndrome (AIDS) were phenotyped for NAT2 activity with use of caffeine as an in vivo probe; 50 of these patients were also genotyped by restriction mapping and allele-specific amplification. In a longitudinal study, 23 patients were phenotyped at least twice during the 2-year study. RESULTS: The distribution of the NAT2 phenotype among the 105 patients was unimodal and skewed toward slow acetylators as opposed to the bimodal distribution observed in healthy white populations. The genotype distribution was 26:24 slow:fast. There were 18 discrepancies between genotype and phenotype: 12 slow acetylators with fast genotypes and six fast acetylators with slow genotypes. No drug-related effects on NAT2 activity were apparent, but the role of disease progression was evident. Among the slow acetylators whose genotype was fast, the incidence of AIDS was higher (six of 12) than that among the fast acetylators whose genotype was fast (two of 14). Among patients phenotyped more than once (mean time between samples, 10.4 months) changes in phenotype from fast to slow were associated with progression of HIV infection. CONCLUSIONS: Disease progression in HIV infection and AIDS may alter expression of the NAT2 gene. The genotype and the phenotype are not interchangeable measurements. In the HIV population, to know the genotype is useful only if the phenotype is also known and vice versa.

Vitamin B-12 deficiency after gastric surgery for obesity.

Low serum vitamin B-12 concentrations after gastric bypass (GB) surgery for obesity were observed in 11 of 28 patients without detectable impairment of crystalline vitamin B-12 absorption. This was observed in 2 of 19 patients with vertical banded gastroplasty (VBG). In contrast, protein-bound vitamin B-12 absorption was markedly impaired, as demonstrated in eight of these patients after GB (n = 7) and VBG (n = 1). Correction of this impaired absorption occurred when protein-bound vitamin B-12 was incubated with an enzyme mixture before consumption. Simultaneous ingestion of the enzyme mixture with protein-bound vitamin B-12 did not improve absorption of the vitamin. In a separate experiment, 10 patients with a normal result from the Schilling test failed to correct low serum vitamin B-12 concentrations with a quantity of oral crystalline vitamin B-12 equal to the recommended dietary allowance of 2 micrograms, taken twice daily for 3 mo. Serum total homocysteine values declined during this interval. An oral daily dose of 350 micrograms crystalline vitamin B-12 raised the average serum vitamin B-12 concentration to an amount greater than the lower reference limit. A dose > 350 micrograms/d was required to raise all patients' vitamin B-12 concentrations above this concentration rather than just above the population mean. We conclude that because concentrations of oral crystalline vitamin B-12 were required to normalize serum vitamin B-12 concentrations, that a mechanism other than formation of a vitamin B-12 intrinsic factor complex is responsible for crystalline vitamin B-12 absorption after GB for obesity.

Relation of coronary artery disease in women < 60 years of age to the combined elevation of serum lipoprotein (a) and total cholesterol to high-density cholesterol ratio.

After age 40 years, coronary artery disease (CAD) is the leading cause of death in both women and men, yet in women the factors associated with, or leading to, CAD have been less extensively studied. This study examined the strength of association of a number of risk factors to CAD in groups of women < 60 years of age with (n = 108) and without (n = 66) angiographically documented significant narrowing of coronary arteries. In univariate analyses, there were significant differences between control subjects and patients with regard to age (49 +/- 6 vs 52 +/- 7 years) and total lipids and apolipoproteins measured. The relative frequency of cigarette smoking and diabetes was higher and that of estrogen replacement therapy lower in patients with CAD than in control subjects. In multivariate analysis the following factors were independently associated with CAD (adjusted odds ratios and 95% confidence intervals): total cholesterol to high-density lipoprotein (HDL) cholesterol (1.91; 1.56 to 2.34); lipoprotein (a) (10.66; 3.51 to 32.35); estrogen replacement (0.24; 0.11 to 0.54); age (1.12; 1.04 to 1.18); and smoking (1.50; 0.98 to 2.29). The nonadjusted odds ratio of CAD, based on combined tercile values of lipoprotein (a) serum level and total cholesterol to HDL cholesterol ratio, was very low (0.15; 0.06 to 0.36) when both values were within the first tercile, but very high (16.63; 3.54 to 78.07) when both were in the third tercile.(ABSTRACT TRUNCATED AT 250 WORDS)

Fasting hyperinsulinism, insulin resistance syndrome, and coronary artery disease in men and women.

A large segment of the population gradually develops insulin resistance, and the related metabolic syndrome is one of the most frequent causes of atherosclerosis. Searching for a practical indicator of insulin resistance, we studied the correlations between fasting serum insulin level, the general manifestations of insulin resistance syndrome, and various aspects of coronary artery disease in 797 men and 322 women. After we classified patients according to the quartiles of serum insulin level, we noted in the top quartile the presence of practically all manifestations of insulin resistance syndrome in persons of both sexes (e.g., increased waist/hip ratio, body mass index, glucose, uric acid, triglycerides, apolipoprotein B and decreased high-density lipoprotein cholesterol levels as well as apolipoprotein A-I/B ratios, and so forth). We also noted a higher prevalence of hypertension, diabetes mellitus, and type IV hyperlipidemia. Significantly more women in the fourth than in the first quartile had angiographically documented significant stenosis of the coronary arteries (p = 0.0016, odds ratio 2.9, 95% confidence interval 1.5 to 5.6) and previous myocardial infarction (p = 0.0297, odds ratio 2.1, 95% confidence interval 1.1 to 4.1). Men in both the first and the fourth quartile had a more disturbed lipid profile and a higher prevalence of significant stenoses of coronary arteries and/or previous myocardial infarction than women; there was a tendency toward a lower prevalence of alcohol consumption (p = 0.0503), a higher prevalence of gout (p = 0.0634), and previous myocardial infarction (p = 0.0791) in men in the fourth than in the first quartile.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic polymorphisms in methylenetetrahydrofolate reductase and methionine synthase, folate levels in red blood cells, and risk of neural tube defects.

Folic acid administration to women in the periconceptional period reduces the occurrence of neural tube defects (NTDs) in their offspring. A polymorphism in the gene encoding methylenetetrahydrofolate reductase (MTHFR), 677C-->T, is the first genetic risk factor for NTDs in man identified at the molecular level. The gene encoding another folate-dependent enzyme, methionine synthase (MTR), has recently been cloned and a common variant, 2756A-->G, has been identified. We assessed genotypes and folate status in 56 patients with spina bifida, 62 mothers of patients, 97 children without NTDs (controls), and 90 mothers of controls, to determine the impact of these factors on NTD risk. Twenty percent of cases and 18% of case mothers were homozygous for the MTHFR polymorphism, compared to 11% of controls and 11% of control mothers, indicating that the mutant genotype conferred an increased risk for NTDs. The risk was further increased if both mother and child had this genotype. The MTR polymorphism was associated with a decreased O.R. (O.R.); none of the cases and only 10% of controls were homozygous for this variant. Red blood cell (RBC) folate was lower in cases and in case mothers, compared to their respective controls. Having a RBC folate in the lowest quartile of the control distribution was associated with an O.R. of 2.56 (95% CI 1.28-5.13) for being a case and of 3.05 (95% CI 1.54-6.03) for being a case mother. The combination of homozygous mutant MTHFR genotype and RBC folate in the lowest quartile conferred an O.R. for being a NTD case of 13.43 (CI 2.49-72.33) and an O.R. for having a child with NTD of 3.28 (CI 0.84-12.85). We propose that the genetic-nutrient interaction--MTHFR polymorphism and low folate status--is associated with a greater risk for NTDs than either variable alone.

Impact of transfusion of mediastinal shed blood on serum levels of cardiac enzymes.

BACKGROUND: Infusion of shed mediastinal blood using an autotransfusion system is a widely applied technique of blood conservation in cardiac surgery. Serial determinations of serum creatine kinase (CK), its MB isoenzyme (CK-MB), and lactate hydrogenase (LDH) levels have been used to monitor perioperative myocardial injury. We investigated the impact of postoperative autotransfused blood infusion on serum levels of these enzymes. METHODS: We performed a retrospective analysis of postoperative serum CK, CK-MB, and LDH levels of 300 patients who had elective uncomplicated aortocoronary bypass grafting. Shed mediastinal blood samples from 26 patients were analyzed for CK, CK-MB (enzymatic activity and mass), and LDH levels before infusion. RESULTS: High postoperative serum levels of CK and LDH were observed after infusion of autotransfused blood. Shed mediastinal blood contained extremely high levels of these enzymes, particularly from patients who had internal mammary artery dissection. There was a strong correlation (r = 0.96) between measured CK-MB enzyme activities and those calculated from the CK-MB mass units. CONCLUSIONS: Infusion of autotransfused blood containing high concentrations of CK and LDH results in elevated serum levels of these enzymes. Hemolysis, frequently present in shed blood, does not interfere with the routine biochemical assays for CK and CK-MB enzyme activities. Caution should be taken when postoperative cardiac enzyme levels are used to determine myocardial injury after aortocoronary bypass grafting if autotransfusion is used as a method of blood conservation.

The place of ferritin among risk factors associated with coronary artery disease.

BACKGROUND: Prospective studies of East Finnish men demonstrated an increased risk of myocardial infarction in association with elevated serum ferritin levels (> or = 200 micrograms/l). The present study was designed to explore whether serum ferritin concentrations are related to angiographically determined coronary artery disease or to a past history of myocardial infarction. METHODS: We studied 225 men and 74 women, most of them of French-Canadian origin, undergoing elective coronary arteriography, and classified them according to the presence, absence, and severity of angiographic findings. A history of myocardial infarction was defined as clinical and electrocardiographic and/or enzymatic evidence of a myocardial infarction occurring more than 12 weeks previously or akinesia of the left ventricle. Serum ferritin was measured with the Baxter Stratus II immunoassay system. RESULTS: There were no significant differences in ferritin levels between patients with > or = 50% diameter stenosis (195 men, 48 women) and those with intact or minimally affected arteries (31 men, 26 women) either in men or in women. There was no correlation between the quartiles of serum ferritin and the severity of coronary artery disease. There were no differences in ferritin levels in patients with (95 men, 25 women) or without (71 men, 43 women) a history of myocardial infarction. However, serum lipid levels were significantly related to all the above conditions. CONCLUSION: In a French-Canadian population, serum ferritin levels, unlike serum lipids, were not related to the presence or severity of angiographically determined coronary artery disease, nor to a history of myocardial infarction.

'True' fasting serum insulin level, insulin resistance syndrome and coronary artery disease.

BACKGROUND: Increased fasting serum insulin level not associated with hypoglycemia is considered to be a practical indicator of the insulin resistance syndrome, a frequent risk factor for atherosclerosis in industrialized countries. However, in most studies, insulin was measured by using antibodies which cross-react with proinsulin and 31/32, 32/33 split products of insulin. We re-examined the correlations between the insulin resistance syndrome and 'true' fasting serum insulin level. METHODS: We studied 242 post-menopausal women (age 63 +/- 8 years), a population in whom insulin resistance syndrome is particularly frequent. Serum insulin was measured by a recent specific microparticle immunoassay. RESULTS: There was a significant correlation between elevated 'true' fasting serum insulin level and various constituents of the insulin resistance syndrome, such as obesity, dyslipidemia (hypertriglyceridemia, increased apolipoprotein B and decreased high-density lipoprotein cholesterol and apolipoprotein A1 concentrations), increased serum glucose, uric acid levels, and plasminogen activator inhibitor type I concentration, as well as increased frequency of diabetes. There was also a correlation between insulin level and various manifestations of coronary artery disease: patients in the highest quartile of 'true' insulin level had significantly more entirely occluded coronary arteries than in the lowest one. Similarly, in the highest insulin quartile more patients had occluded arteries with lumen diameter stenoses greater than 50% (P < 0.05) and more of them had history of previous myocardial infarction approaching the level of significance (P = 0.0587) than in the lowest one. Most of these correlations were also noted in nondiabetic people. CONCLUSIONS: An increase of 'true' fasting serum insulin level is a useful practical index to identify patients with the insulin resistance syndrome exposed to increased risk of coronary artery disease.

A physical chemical approach to the analysis of acid-base balance in the clinical setting.

We evaluated the clinical application of a model of acid-base balance, which is based on quantitative physical chemical principles (Stewart model). This model postulates that acid-base balance is normally determined by the difference in concentration between strong cations and anions (strong ion difference [SID]), PCO2, and weak acids (primarily proteins). We measured electrolytes and blood gases in arterial blood samples from 21 patients in a medical or surgical intensive care unit or emergency room of a tertiary care hospital. The measured SID frequently differed from SID calculated from the measured blood components, which indicates that unmeasured cations or anions are present; these could not be accounted for by lactate, ketones, or other readily identifiable ions. We used an approach to acid-base analysis that is based on changes in base excess or deficit due to changes in: (1) free water as assessed by [Na+]; (2) in [Cl-]; (3) protein concentration; and (4) "other species" (ie, anion and cations other than [Na+], [K+], and [Cl-]). The contribution of "other species" was obtained from the difference between the SID measured and that predicted from Stewart's equation. It could also be calculated from the difference between the standard Siggaard-Anderson calculation of base excess and base excess attributable to free water, [Cl-], and proteins (ie, base-excess gap). Our results indicate that the SID gap, base excess gap, and anion gap reflect the presence of unmeasured ions, and both the anion-gap and base-excess gap provide readily available estimates of the SID gap. This provides a simple bedside approach for using the Stewart model to analyze the nonrespiratory component of clinical acid-base disorders and indicates that, in addition to unmeasured anions, unmeasured cations can be present.

The role of cardiac troponin T and other new biochemical markers in evaluation and risk stratification of patients with acute chest pain syndromes.

BACKGROUND AND HYPOTHESIS: Increased serum creatinine kinase (CK) and CK-MB enzyme levels have been used for years to detect myocardial infarction (MI). However, serum myoglobin and CK-MB mass or protein levels may indicate MI earlier; cardiac troponin T is the most specific marker of myocardial injury and it can detect even minor myocardial necrosis. The diagnostic and prognostic utility of the traditional and new markers of cardiac injury in the emergency evaluation of patients with acute chest pain syndromes were therefore compared. METHODS: One hundred and fifteen consecutive patients with an acute coronary syndrome, and 64 controls recruited during the same period, were examined. The time elapsed from onset of symptoms to blood collection was recorded. Cardiac markers were measured in specimens collected upon arrival (0 h), and 2 and 5-9 h, and later in cases of longer observation. The major cardiac events occurring up to 40 months after the index examination were recorded. RESULTS: cTnT levels provided unique information: they were the most specific indicators of myocardial damage and identified unstable angina patients at high risk of future major events. Up to 6 h after the onset of chest pain, the new markers were elevated more frequently than the traditional ones and permitted earlier MI recognition. The worst prognosis (nonfatal myocardial infarction or death) was noted in subjects with chest pain at rest within 48 h before the index examination and elevated cTnT levels. CONCLUSIONS: The new markers, particularly cardiac troponin T, offer considerable advantages and they should be more widely used in the diagnosis and risk stratification of acute coronary syndromes.

Metabolic labelling of oligosaccharide chains of glycoproteins in a rat myoblast cell line and its lectin resistant mutants.

We have determined the experimental conditions under which optimum hydrolysis of the various oligosaccharides of membrane glycopeptides can be achieved in a permanent line of rat skeletal myoblasts and its wheat germ agglutinin resistant mutants. The labelled glycopeptides were isolated by extensive pronase digestion of whole cells. Labelling studies demonstrated that label from fucose and galactose remained largely in these two sugars, while glucosamine labelled sialic acid and N-acetylglucosamine. Mannose label was found in both mannose and fucose.

Coordinate control by vitamin A of keratin gene expression in human keratinocytes.

In the present study, we examine the effects of vitamin A on keratin protein and mRNA levels in human keratinocytes. In epidermal keratinocytes, the levels of keratins 5, 6, 14, and 17 decrease and keratins 13 and 19 increase in response to increasing concentrations of a potent synthetic trans-retinoic acid analog, arotinoid Ro 13-6298. In tracheal keratinocytes, a similar suppression is observed for keratins 5, 6, 14, 17, and 18 and an increase in keratin 19. Both induction and suppression responses show identical kinetics and both processes are half-maximal at 5 nM arotinoid and maximal at 10 nM. Utilizing cDNAs specific for keratins 5, 6, 13, and 19, we demonstrate that the mRNA levels for these keratins change coordinately with the corresponding amount of keratin protein, indicating that the control of keratin protein expression most likely resides at the level of mRNA synthesis and/or degradation. The identical kinetics for all of the responses, both inductive and suppressive, suggests that a common mechanism controls the expression of these genes. These results indicate that vitamin A produces more sweeping changes in keratinocyte function than previously appreciated in that many and perhaps all keratins are modulated by vitamin A. Moreover, these responses are 10- to 100-fold less sensitive to retinoid than the process of envelope formation, suggesting that at least two sets of processes with different sensitivities to vitamin A are present in keratinocytes.

Relationship between cell surface asparagine-linked glycoproteins and myoblast differentiation. Analysis of wheat germ agglutinin-resistant mutants.

Alterations in the oligosaccharides of complex surface glycoproteins have been studied in wild-type rat skeletal myoblasts (L6-9/1) and two wheat germ agglutinin resistant mutants, selected for either high level of resistance (WGARI) or low level of resistance (WGARII). All three lines possessed high mannose oligosaccharides of the structure Man(n)GlcNAc, where n = 6, 7, or 8. L6-9/1 had complex oligosaccharides of the type (+/- NeuNAc alpha 2-3Gal beta GlcNAc beta)n-Man3GlcNAc(+/- Fuc)GlcNAc where n = 3 or 4, in addition to small amounts of biantennary and higher order structures. WGARII, the mutant with low resistance to wheat germ agglutinin, possessed similar complex oligosaccharides except that they had undergone some base-sensitive modification which rendered them resistant to Clostridium perfringens sialidase. WGARI, mutant of high resistance to wheat germ agglutinin, possessed complex oligosaccharides of the type (GlcNAc beta)nMan3GlcNAc(+/- Fuc)GlcNAc, with n = 2, 3, or 4. Since the WGARI mutants were unaltered in differentiation, it is concluded that the terminal sialic acid and galactose residues on the protein-bound oligosaccharides are not required for differentiation.

Bioassay of retinoids using cultured human conjunctival keratinocytes.

The biological action of retinoids has been assayed using the differentiated properties of cultured human conjunctival keratinocytes. The effects measured were the suppression of envelope cross-linking and the promotion of synthesis of a keratin of molecular weight 40,000. Among the retinoids tested, the most powerful was the arotinoid Ro 13-6298, which reduced envelope formation detectably at 10(-11) M and by 90% at a concentration of 2 X 10(-10) M. The arotinoid was about 15 times more potent than trans-retinoic acid. The order of effectiveness of the retinoids in suppressing envelope cross-linking was the same as the order of effectiveness in promoting the synthesis of the 40-kd keratin.

Alpha1-antitrypsin deficiency with fatal intracranial hemorrhage in a newborn.

A 4-week-old boy had a fatal intracranial hemorrhage resulting from vitamin K deficiency. The infant had received no vitamin K prophylaxis and was exclusively breastfed. At autopsy, examination of the liver showed cholestasis and fibrosis. DNA was isolated from a blood spot on a Gutherie sample card obtained from the infant for routine metabolic screening. This DNA was used for alpha1-antitrypsin genotyping studies. Genotyping studies identified homozygosity for the point mutation 9989G-->A, confirming a diagnosis of alpha1-antitrypsin deficiency (ZZ phenotype), and resulted in appropriate screening of siblings born after this child's death. Alpha1-antitrypsin deficiency should be considered in the differential diagnosis of infants with late hemorrhagic disease of the newborn. Use of blood from the metabolic screening card as a source of DNA allowed confirmation of this diagnosis after the infant's death.

In vitro and in vivo inactivation of transcobalamin II receptor by its antiserum.

Rabbits injected with pure human placental transcobalamin II-receptor (TC II-R) failed to thrive with no apparent tissue or organ damage, but a 2-fold elevation of the metabolites, homocysteine, methylmalonic acid, and the ligand, transcobalamin II, in their plasma. Exogenously added transcobalamin II-[57Co]cyanocobalamin bound very poorly (2-5%) to the affected rabbit liver, kidney, and intestinal total or intestinal basolateral membrane extracts relative to the binding by membrane extracts from normal rabbit tissues. The activity was restored to normal values following a wash of affected rabbit tissue membranes with pH 3 buffer containing 200 mM potassium thiocyanate. Immunoblot analysis of normal and affected rabbit kidney and liver total membranes revealed similar amounts of 124-kDa TC II-R dimer protein. The neutralized and dialyzed extract from the affected rabbit membranes inhibited the binding of the ligand to pure TC II-R and the harvested affected rabbit serum inhibited the uptake of TC II-[57Co]cobalamin (Cbl) from the basolateral side of human intestinal epithelial (Caco-2) cells and decreased the utilization of [57Co]Cbl as coenzymes by the Cbl-dependent enzymes. The loss of exogenously added ligand binding or the binding of 125I-protein A occurred with the intestinal basolateral, but not the apical membranes. Based on these results, we suggest that circulatory antibodies to TC II-R cause its in vivo functional inactivation, suppress Cbl uptake by multiple tissues, and thus cause severe Cbl deficiency and the noted failure to thrive.

Plasmapheresis in the treatment of an acute pancreatitis due to protease inhibitor-induced hypertriglyceridemia.

The use of protease inhibitors such as ritonavir to treat HIV-infected individuals has been associated with lipodystrophy, combined hyperlipidemias, and hypertriglyceridemia-induced pancreatitis. We report here on the treatment by plasmapheresis of a HIV-patient who presented with a rapid onset of severe ritonavir-induced hypertriglyceridemia complicated with an acute pancreatitis. A 35-year-old HIV-1 positive male following 3 weeks of ritonavir treatment presented with nausea, abdominal pain, a distended abdomen, and the following laboratory values: amylase (238 U/L), lipase (864 U/L), total cholesterol (27.1 mmol/L), and triglycerides (62.9 mmol/L). Following two plasmaphereses, the levels of total cholesterol, triglycerides, lipase, and amylase declined drastically and the patient was discharged home after 4 days with lipid and pancreatic enzyme levels within the reference range. To our knowledge, this is the first case of pancreatitis due to a PI-induced hyperlipidemia in a HIV-patient treated with plasmapheresis in an acute setting.