Luminex technology for anti-HLA antibody screening: Evaluation of performance and of impact on laboratory routine

The recent introduction of new technologies such as Luminex has provided alternative methods to the Complement Dependent Cytotoxicity (CDC) test for HLA specific antibody detection. In this study we compared the results obtained with CDC to those obtained using a Luminex method with the aim of evaluating the impact of this new technology on antibody screening policies in our transplant setting.A total of 1,421 sera, acquired from patients on the waiting list for a kidney transplant or following transplantation, were tested by both methodologies. CDC was performed using a whole lymphocyte population comprising a panel of 52 cells. The percentage panel reactive antibodies (PRA) and antibody specificity were evaluated using Lambda Scan Analysis software. For the Luminex method sera screening and identification of antibody specificity were carried out using the LABScreen Mixed and LABScreen PRA respectively. The overall concordance between the results obtained using the CDC and the Luminex methods was 85%. HLA antibody specificity was confirmed in 96% of the sera which tested positive using the Luminex system and serum positivity corresponded with a previous sensitisation event in these individuals. Using the Luminex method 18% of patients on the waiting list were considered and managed as sensitised as compared to 7% when testing with CDC alone. The Luminex method was able to detect a number of antibody specificities significantly more frequently than the CDC method and in addition the CDC method failed to detect some of the antibody specificities detected by the Luminex system. Based on this comparison study we have incorporated the Luminex methodology into our screening strategy.

14th International HLA and Immunogenetics Workshop Prospective Chronic Rejection Project: a three-year follow-up analysis

The three-year follow-up of 4,144 patients of the 14th International Workshop Prospective Chronic Rejection study has reinforced the evidence that post-transplant HLA antibodies are predictive of long-term graft loss. Three years after a single testing for HLA antibodies, 10% of kidney recipients who were antibody-positive had lost their grafts, in contrast to only 5% of antibody-negative patients (p<0.0001). The adverse effect of post-transplant antibodies on graft survival was also observed in lung, heart, and liver transplants. Donor-specific antibodies and 'strong' non-DSA had stronger association with graft loss than 'moderate' non-DSA. Periodic antibody monitoring, combined with specificity and strength analysis, would help in the early identification of allograft recipients who are at high risk of graft failure.

Complete sequencing of the HLA-A*68020102 novel allele identified in two Caucasoid families

We describe here the isolation and the full-length sequence of the coding region of the HLA new variant at the HLA-A locus officially named A*68020102. This variant shows an 11 base pairs deletion within the 5' UTR region. The exon sequence is identical to that of A*6802 and the commercially available anti-A68 typing sera react with the antigen coded by the allele A*68020102. This variant was originally identified in two unrelated Caucasoid families because of discrepant HLA typing results between serology, Sequence Specific Oligonucleotide Probe (SSOP), and SBT. In fact, the A68 assigned by serology was undetectable with the molecular techniques. This has occurred because the deletion present in A*68020102 prevents specific amplification of HLA-A locus by some commercially available typing kits.

Increased prevalence of cardiovascular disease in Type 2 diabetic patients with non-alcoholic fatty liver disease

AIMS

To estimate the prevalence of cardiovascular disease (CVD) in Type 2 diabetic patients with and without non-alcoholic fatty liver disease (NAFLD), and to assess whether NAFLD is independently related to prevalent CVD.

METHODS

We studied 400 Type 2 diabetic patients with NAFLD and 400 diabetic patients without NAFLD who were matched for age and sex. Main outcome measures were prevalent CVD (as ascertained by medical history, physical examination, electrocardiogram and echo-Doppler scanning of carotid and lower limb arteries), NAFLD (by ultrasonography) and presence of the metabolic syndrome (MetS) as defined by the World Health Organization or Adult Treatment Panel III criteria.

RESULTS

The prevalences of coronary (23.0 vs. 15.5%), cerebrovascular (17.2 vs. 10.2%) and peripheral (12.8 vs. 7.0%) vascular disease were significantly increased in those with NAFLD as compared with those without NAFLD (P < 0.001), with no differences between sexes. The MetS (by any criteria) and all its individual components were more frequent in NAFLD patients (P < 0.001). In logistic regression analysis, male sex, age, smoking history and MetS were independently related to prevalent CVD, whereas NAFLD was not.

CONCLUSIONS

The prevalence of CVD is increased in patients with Type 2 diabetes and NAFLD in association with an increased prevalence of MetS as compared with diabetic patients without NAFLD. Follow-up studies are necessary to determine whether this higher prevalence of CVD among diabetic patients with NAFLD affects long-term mortality.

Vitamin C content and antioxidant activity of the fruit and of the Ayurvedic preparation of Emblica officinalis Gaertn

Emblica officinalis Gaertn. is one of the most important plants of Ayurved, the traditional Indian medicine. In this ancient medicine, the fruit of Emblica officinalis is processed according to a method named "Svaras Bhavana", whereby the therapeutic potential of the plant is enhanced by treating the main herb with its own juice. For many years, the activity of the fruits was attributed to the high content of ascorbic acid; however, this has recently been questioned. The aim of the paper is to clarify this matter. A reliable and feasible HPLC method with diode array detection has been developed for the determination of ascorbic acid in Emblica fruit and particularly in Emblica fruit processed according to the Ayurvedic method. The antioxidant effects have also been evaluated in comparison to the real levels of Vitamin C by different antioxidant tests. The data obtained show that the Emblica fruit contains ascorbic acid (0.4%, w/w), and that the Ayurvedic method of processing increases the healthy characteristics of the fruit thanks to a higher antioxidant activity and a higher content of ascorbic acid (1.28%, w/w). It has also been found that Vitamin C accounts for approximately 45-70% of the antioxidant activity.

HLA-DRB1 donor-recipient mismatch affects the outcome of hepatitis C disease recurrence after liver transplantation

BACKGROUND & AIMS

This study extends our previously reported observations that various immunological factors are associated with the occurrence of histologically proven recurrent hepatitis C. The two specific issues investigated were to confirm the associations of MHC alleles and donor/recipient mismatch with the occurrence of recurrent hepatitis C in an independent cohort of newly transplanted patients and to look for immunologic and nonimmunologic variables affecting the severity of the recurrent disease.

METHODS

Two separate cohorts of consecutive patients were studied: a look-back cohort (LC) of 120 patients and a cohort for studying the disease progression (CSDP) of 190 patients. Protocol liver biopsies were obtained at least 1, 3, 5, 7, and 10 years after liver transplantation (LT).

RESULTS

A fully mismatched donor/recipient pair at the DRB1 locus was confirmed to be associated with both the recurrence of histologic hepatitis in the LC (59% vs 23%, P = .0002) and its progression beyond stage 3 in the CSPD (71.4% vs 39.3%, P = .0003). Relevant immunologic and nonimmunologic variables were included into a multivariate Cox proportional model and three variables, namely, donor age, full HLA-DRB1 donor-recipient mismatch, and HLA B14, resulted in independent risk factors for the development of severe fibrosis.

CONCLUSION

This study provides evidence that DRB1 donor-recipient mismatch affects both the occurrence and progression of recurrent hepatitis C disease. This information is clinically relevant as it may help to better allocate organs and to recognize patients at risk for progression so that specific interventions can be implemented.

Kidney transplantation from anti-HBc+ donors: results from a retrospective Italian study

BACKGROUND

The risk of transmitting a hepatitis B virus (HBV) infection from donor kidneys with a past HBV serological profile may be negligible. Data on HBV transmission to kidney transplant recipients from donor organs that were anti-HBc/HBsAg in Italy has not been previously reported. Anti-HBc testing in cadaver organ donors has been mandatory in Italy since 2002, when anti-HBc determinations were included in the National Guidelines for donor evaluation. Therefore, prior to that date kidney recipients from anti-HBc/HBsAg donors can be identified retrospectively where stored serum is available for testing.

METHODS

The prevalence of anti-HBc Italian organ donors, the incidence of HBV transmission according to the recipients' HBV status (vaccinated, recovered, or naive), and the clinical impact (5-year graft and patient survival rates) in the North Italy Transplant program was evaluated by retrospectively screening for anti-HBc antibodies in the sera of cadaver kidney donors used in transplants from 1997 to 1999.

RESULTS

Two hundred and ten donors were found to have been anti-HBc. At the time of the study, no active infection was observed in any of the 344 HBsAg recipients, but 4/140 (2.86%) of the vaccinated recipients were found to have been anti-HBc/HBsAg. None of these patients, however, had any biochemical or clinical history of HBV infection. Patient and graft survival rates of anti-HBc or anti-HBc kidney recipients did not differ statistically.

CONCLUSION

Kidney grafts from anti-HBc donors should be considered in all recipients because the benefit obtained from the transplantation out weighs the negligible risk of HBV transmission.

Description of a new HLA-DRB1*1104, DRB1*110403

We report here the exon 2 sequence of the novel HLA-DRB1*110403 which differs from DRB1*110401 by a single synonymous nucleotide substitution at codon 78, where TAC is substituted by TAT. The variant originally identified in a Caucasoid individual was confirmed by cloning and sequencing.

Solid-papillary tumors of the pancreas: histopathology

A solid-pseudopapillary tumor is an uncommon and "enigmatic" pancreatic neoplasm, and the term encompasses the two most conspicuous histological features: solid and pseudopapillary areas. Grossly, it appears as a large solid, cystic or solid-cystic mass frequently having necrotic and hemorrhagic zones. Histologically, solid-pseudopapillary tumors are generally characterized by solid areas alternating with a pseudopapillary pattern, and cystic spaces which are the results of degenerative changes occurring in the solid neoplasm. Its immunohistochemical pattern is very distinctive and neoplastic cells are consistently vimentin-, CD10- and CD56-positive. Some cases express focal positivity for alpha-1-antitrypsin, alpha-1-antichymotrypsin, neuron-specific enolase and synaptophysin. Progesterone receptors are frequently present. Keratins are not expressed or are found only focally. Endocrine and pancreatic enzyme markers are absent; the origin of solid-pseudopapillary tumors has not yet been clarified. Many investigators favor the theory that solid-pseudopapillary tumors originate from multipotent primordial cells while others suggest an extra-pancreatic origin from genital ridge angle-related cells. Some controversy exists for both hypotheses. Solid-pseudopapillary tumors appear as a low malignancy tumor and only a small number of cases recur or develop metastases after resection. No pathological factors were found to correlate with the prognosis. Some histological features have recently been suggested to be associated with aggressive behavior.

Non-alcoholic fatty liver disease is associated with carotid artery wall thickness in diet-controlled type 2 diabetic patients

Non-alcoholic fatty liver disease (NAFLD) is closely associated with several metabolic syndrome (MetS) features. We assessed whether NAFLD is significantly associated with carotid artery intima-media thickness (IMT), as a marker of subclinical atherosclerosis, and whether such association is independent of classical cardiovascular risk factors and MetS features. We studied 100 diet-controlled Type 2 diabetic patients with ultrasonographically diagnosed NAFLD and 100 diabetic patients without NAFLD who were comparable for age and sex. Main outcome measures were carotid IMT (by ultrasonography), classical risk factors, insulin resistance [as estimated by homeostasis model assessment (HOMA)-IR] and MetS (as defined by the Adult Treatment Panel III criteria). NAFLD patients had a markedly greater carotid IMT (1.24 +/- 0.13 vs 0.95 +/- 0.11 mm; p < 0.001) than those without the condition. The MetS and all its clinical traits were more highly prevalent in those with NAFLD (p < 0.001). Adjustment for age, sex, smoking history, diabetes duration, glycosylated hemoglobin, LDL cholesterol, liver enzymes and microalbuminuria did not really affect the significant differences in carotid IMT that were observed between the groups. Further adjustment for the MetS also had little impact, but additional adjustment for HOMA-IR score consistently attenuated any statistical significance (p = 0.28). In multivariate regression analysis, HOMA-IR score along with age and MetS (principally raised blood pressure values) were independently related to carotid IMT, whereas NAFLD was not. In conclusion, these results suggest that among diet-controlled Type 2 diabetic individuals the significant increase of carotid IMT in the presence of NAFLD is largely explained by HOMA-estimated insulin resistance.

HLA-A*2626, a new allele identified through external proficiency-testing exercise

A new allele, officially named HLA-A*2626, has been detected in a blood sample belonging to a Caucasian subject human leucocyte antigen typed for Lombardy Region external proficiency-testing exercise. The DNA sequences of exons 2, 3 and 4 of this new allele are identical to those of HLA-A*2601 except at codon 259 of exon 4 (CCT-->CTT). This variation modifies the encoded protein from proline to leucine.

The long-term prognosis of renal transplantation in patients with lupus nephritis

BACKGROUND

Few data are available about the long-term outcome of renal transplantation in patients with systemic lupus erythematosus (SLE).

METHODS

Between June 1982 and 2004, a total of 33 adults with lupus nephritis received 35 kidney allografts. Outcomes of these grafts and those of 70 controls matched for age, sex, and donor source who underwent transplantation during the same period were compared.

RESULTS

Mean follow-up after renal transplantation was 91 +/- 59 months for patients with lupus and 90 +/- 64 months for controls. Actuarial 15-year patient (80% versus 83%) and death-censored graft survival rates (69% versus 67%) were not significantly different between patients with lupus and controls. Risks for acute and chronic rejection, arterial hypertension, and infection were not different between the 2 groups. Mean serum creatinine levels also were similar in the 2 groups at the last follow-up visit. Intravascular thrombotic events occurred in 9 patients with SLE (26%) and 6 controls (8.6%; P = 0.038). In the SLE group, 6 of 7 antiphospholipid (aPL) antibody-positive versus 3 of 17 aPL antibody-negative patients experienced thrombotic events ( P = 0.015). Recurrence of lupus nephritis was documented in 3 renal grafts (8.6%), but no graft was lost because of recurrent lupus nephritis.

CONCLUSION

Long-term patient and graft survival probabilities were similar in patients with SLE and matched controls. The risk for thrombotic complications was greater in patients with SLE, particularly aPL-positive patients. Nephritis recurred in less than 10% of patients with SLE and did not influence graft survival.

Risk of transmission of hepatitis B virus from anti-HBC positive cadaveric organ donors: a collaborative study

Organ donors with a serologic profile of recovered (HBsAg negative and/or anti-HBc IgG positive) hepatitis B virus infection (HBV) have been reported to transmit HBV to recipients. In Italy, up until 2002, anti-HBc determination was not mandatory. We retrospectively evaluated the incidence of HBV transmission among recipients transplanted with organs from anti-HBc positive donors from 1997 to 1999. Anti-HBc was screened in 886 available sera among 964 HBsAg and anti-HCV negative donors. HBV transmission was evaluated in 325 kidney, liver, and heart recipients according to their pretransplant HBV serum profile. Of 210 anti-HBc positive donors, 185 were anti-HBc positive/anti-HBs positive and 25 anti-HBc positive/anti-HBs negative with a prevalence of 20.8% and 2.8%, respectively. One hundred seven sera (51%) were collected from donors after transfusion of blood components, the remainder were either before transfusion or from nontransfused donors. The 210 anti-HBc positive subjects donated 356 kidneys, 117 livers and 117 hearts, among whom follow-up is presently available for 251 kidney, 61 liver, and 25 heart recipients. No HBV transmission was observed independent of the recipient immunological profile among the kidney or heart recipients. In liver recipients, no transmission was reported in recovered or vaccinated patients, while a high incidence (43%) of de novo hepatitis was observed among naive patients. In conclusion, there does not seem to be a risk of transmitting HBV through anti-HBc positive transplants in heart and kidney recipients; only naive liver recipients are at high risk of HBV infection.

Influence of environmental factors on composition of volatile constituents and biological activity of Helichrysum italicum (Roth) Don (Asteraceae)

The biovariability of Helichrysum italicum (Roth) Don grown wild in Calabria and Sardinia (Italy) was reported. This species has been characterized through the detection, isolation and quantitative evaluation of chemical markers (alpha-terpinolene, trans-cariophyllene and neryl acetate) by GC and GC-MS. Antioxidant activity of the methanolic H. italicum extracts using DPPH and beta-carotene bleaching test showed that the Calabrian samples were more active than those from Sardinia. The antibacterial activity of all extracts evidenced the best performance on the Gram positive bacteria particularly on Micrococcus luteus. Moreover, antifungal activity of all extracts was also tested evidencing important results particularly on the phytopathogene fungus Pythium ultimum. In general, as regards the antifungal activity, the extracts from Sardinia were more active than those from Calabria. The phytochemical analysis and the biological activity data suggested a possible use of these plant matrices in alimentary, cosmetic and pharmaceutical fields.

Phenylpropanoid glycosides in ItalianOrobanchespp., sect. Orobanche

We studied the occurrence of phenylpropanoid glycosides (PhG) in five species of the genus Orobanche L., collected in the Latium region of Italy. The presence of orobanchoside and verbascoside in all four species confirms that these PhGs are taxonomic markers of the genus. The results suggest that O. gracilis form. citrina could be a diverse entity.