HTLV-1/2 Infection in Blood Donors from a Non-Endemic Area (Catalonia, Spain) between 2008 and 2017: A 10-Year Experience.

Human T-cell lymphotropic virus type 1 and 2 (HTLV-1/2) screening is not mandatory in Spanish blood banks. In Catalonia, selective screening was introduced in 2008, followed by universal screening in 2011. We present herein a 10-year experience of HTLV testing in blood donors. HTLV-1/2 selective screening was performed using Ortho-Clinical Diagnostics HTLV-I/HTLV-II Ab-Capture ELISA between February 2008 and May 2009, then Abbott Prism HTLV-I/ HTLV-II assay until December 2010. Abbott Architect rHTLV-I/II assay was then used for HTLV-1/2 universal screening in pooled samples. INNO-LIA HTLV I/II Score (Fujirebio) and in-house HTLV-1/2 proviral DNA real-time PCR were used in reactive samples. Follow-up was offered to confirm HTLV-1/2 donors in Vall d'Hebron Hospital. Between 2008 and 2017, 51 blood donors were confirmed HTLV positive (46 HTLV-1, 4 HTLV-2 and 1 HTLV) out of 2,114,891 blood donations (1 in 41,468). Sixty-nine percent were female, median age was 40 years and most were born in Latin America (69%), followed by Europe (25%), Africa (4%) and Asia (2%). Screening of relatives and partners identified 12 additional HTLV-1 cases. Lookback studies did not show any HTLV-1/2 transmission. HTLV infections found in blood donors mirror epidemiological changes in the population of Spain. Consequently, HTLV should be considered a potential risk for recipients and calls for the design of optimal strategies to ensure transfusion safety.

Epidemiological trends of HIV-1 infection in blood donors from Catalonia, Spain (2005-2014).

BACKGROUND: Human immunodeficiency virus 1 (HIV-1) subtype B is predominant in Spain. However, the recent arrival of immigrant populations has increased the prevalence of non-B subtypes and circulating recombinant forms. The objective of this study was to determine the prevalence of HIV-1 subtypes and transmitted drug-resistance mutations in blood donors from the Catalonian region (northeastern Spain). STUDY DESIGN AND METHODS: HIV-1-positive blood donors identified in Catalonia from 2005 to 2014 were included. Demographic variables and risk factors for HIV-1 acquisition were recorded. HIV-1 subtyping was carried out by HIV-1 DNA polymerase region sequencing, and phylogenetic analyses were performed using the neighbor-joining method. RESULTS: During the study period, 2.8 million blood donations were screened, and 214 HIV-1-positive donors were identified, yielding an overall prevalence of 7.7 per 100,000 donations (89% men; mean age, 34 ± 10 years). Most HIV-1-positive donors were native to Spain (81%), and 61% were regular blood donors. When risk factors were known, 62% reportedly were men who had sex with men. HIV-1 subtyping was possible in 176 HIV-1-positive individuals: 143 (81%) had HIV-1 subtype B, and 33 (19%) had non-B subtypes. Most HIV-1 non-B subtypes were circulating recombinant forms (n = 20; 61%). Factors associated with HIV-1 subtype B were male sex (p = 0.007) and men who had sex with men (p < 0.001). The overall prevalence of transmitted drug-resistance mutations was 14%. CONCLUSION: Non-B subtypes, circulating recombinant forms, and transmitted drug-resistance mutation sequences circulate among HIV-1-positive blood donors in Catalonia. Continuous local epidemiological surveillance is required to implement optimal prevention strategies for controlling transfusion-transmitted HIV and to improve health policies regarding HIV infection.

Doubtful Role of IL28B Polymorphism in Occult Hepatitis B Infection.

AIMS: To investigate the influence of IL28B polymorphism in occult hepatitis B infection (OBI) and whether IL28B genetic variants are associated with hepatitis B virus (HBV)-specific T-cell responses. PATIENTS AND METHODS: The rs12979860 IL28B genotype was determined in 34 OBI blood donors, 22 spontaneous HBV resolvers, 36 inactive HBV carriers and 25 seronegative donors. T-cell responses to HBV recombinant proteins were assessed by interferon-γ enzyme-linked immunospot assay. RESULTS: The frequency of the IL28B CC genotype among OBI patients was similar to that of inactive carriers [41 vs. 39%, respectively, p = 0.961; odds ratio (OR) = 1.10; 95% confidence interval (CI) = 0.42-2.86; p = 0.845]. The IL28B CC genotype was found more frequently in spontaneous resolvers, although the differences were not significant (45 vs. 39%, spontaneous resolvers and inactive carriers, respectively; p = 0.828; OR = 1.31; 95% CI = 0.45-3.83; p = 0.622). HBV-specific T-cell responses were detected in OBIs, and significantly stronger T-cell responses towards hepatitis B envelope antigen were observed in those with the IL28B CC genotype. In spontaneous resolvers and inactive carriers, IL28B CC did not correlate with the magnitude of T-cell responses. CONCLUSIONS: In OBI donors, IL28B CC correlates with the intensity of HBV-specific T-cell responses. In this study, IL28B CC is not statistically associated with OBI or with HBV clearance, but a larger number of cases is needed before completely ruling out its role in HBV infection.

Seroprevalence of hepatitis E virus (HEV) and detection of HEV RNA with a transcription-mediated amplification assay in blood donors from Catalonia (Spain).

BACKGROUND: Hepatitis E virus (HEV) is an emerging threat to the safety of blood transfusion. The aim of this study was to determine HEV immunoglobulin (Ig)G and RNA prevalence in Catalan blood donors. STUDY DESIGN AND METHODS: Nearly 10,000 samples were collected from anonymized, unpaid donors at the Banc de Sang i Teixits (Barcelona, Spain) from June to December 2013. For the serology study, a subset of 1082 donations was tested in parallel for HEV IgG using Wantai and Mikrogen enzyme-linked immunosorbent assay tests. Samples were tested individually (individual-donation nucleic acid test [ID-NAT]) for HEV RNA using the Procleix HEV assay (95% limit of detection 7.9 IU/mL). Procleix repeat-reactive donations were confirmed by an in-house real-time polymerase chain reaction (PCR) test. RESULTS: The prevalences of IgG anti-HEV in Catalan blood donors were 19.96% (Wantai assay) and 10.72% (Mikrogen assay). Screening of 9998 samples with the Procleix HEV assay yielded three real-time PCR-confirmed and IgM and IgG anti-HEV-positive donations with viral loads of 250, 564, and 2755 IU/mL. The donation with highest viral load was genotype 3f. HEV RNA positivity rate was one per 3333 donations (0.03%; 95% confidence interval, 0.01%-0.09%). CONCLUSION: The Procleix HEV ID-NAT screening system has provided evidence of HEV RNA presence in Catalan blood donors. Further data are needed to assess the impact of HEV infection in at-risk patients to design the best strategy to increase blood safety.

T cell responses and viral variability in blood donation candidates with occult hepatitis B infection.

BACKGROUND & AIMS: Occult HBV infection (OBI) is defined by the presence of HBV DNA in the liver and/or serum and negative HBsAg testing. Since the implementation of highly sensitive HBV DNA screening, OBI is also detected in healthy blood donors. The aims of this study were to investigate HBV-specific immune responses and genetic variability in donors with OBI, established by HBV DNA in serum. METHODS: HBV-specific T-cell responses to HBV antigens were tested in 34 OBI donors by IFN-γ ELISpot, cytometric bead array, and intracellular cytokine staining. As comparison populations, 36 inactive HBV carriers, 22 donors with spontaneously resolved HBV infection, 24 vaccinated donors, and 25 seronegative donors were also included. Surface, pre-S, and pre-c/core genes from 44 genotype D isolates (24 OBI and 20 HBsAg-positive) were sequenced. RESULTS: The immune response of OBI donors to the 3 HBV antigens was 29-41%, similar to the response in subjects with resolved HBV infection and higher than that in HBsAg-positive subjects. On sequence analysis, OBI donors presented a higher HBsAg mutation rate than HBsAg-positive subjects. Mutations were clustered in the major hydrophilic region of HBsAg, and no stop codons or relevant mutations that could affect antigen formation or detection were observed. CONCLUSIONS: Our results suggest that immune response can suppress viral replication to low levels and HBsAg expression to undetectable levels in OBI blood donors. Relevant mutations were not found in the genomic HBsAg coding region. Hence, the fact that HBsAg was not detected in OBI is likely due to low HBsAg production, rather than to a failure of laboratory reagents.

Hepatitis C virus (HCV)-specific T-cell responses among recombinant immunoblot assay-3-indeterminate blood donors: a confirmatory evidence of HCV exposure.

BACKGROUND: Blood donors are routinely screened for hepatitis C virus (HCV) infection. Some show weak anti-HCV responses, often restricted to a single antigen on confirmatory immunoblot (recombinant immunoblot assay [RIBA]) testing. The aim of this study was to investigate the extent to which such RIBA-indeterminate donors had previously been exposed to HCV. STUDY DESIGN AND METHODS: T-cell responses to HCV recombinant proteins (core, NS3, and NS3 helicase) were analyzed using an interferon-gamma (IFN-gamma) enzyme-linked immunospot (ELISpot) assay and quantification of cytokines in culture supernatants in 27 RIBA-indeterminate donors, 60 RIBA-confirmed donors (48 with and 12 without HCV RNA), and 30 RIBA-negative donors. RESULTS: HCV-specific T-cell responses were identified in 13 (48%) RIBA-indeterminate donors, 33 (55%) RIBA-confirmed donors, and 4 (13%) RIBA-negative controls (p = 0.008 and p < 0.001, respectively). The magnitude of the T-cell response among indeterminate donors was similar to that of RIBA-confirmed donors for all HCV antigens and the specificity of the ELISpot results was confirmed by antigen-specific cytokine production (interleukin-2 and IFN-gamma) in short-term culture supernatants. CONCLUSIONS: These findings confirm that approximately half of RIBA-indeterminate donors have resolved a previous HCV infection and suggest that ELISpot might be a useful tool to clarify the status of such donors and help in their counseling and management.

Characterization of occult hepatitis B virus from blood donors carrying genotype A2 or genotype D strains.

BACKGROUND/AIMS: Nucleic acid testing (NAT) for hepatitis B virus (HBV) DNA in blood donations identified occult HBV infection (OBI) as a potential threat to blood safety. METHODS: A collaborative study was undertaken to explore the molecular basis of OBIs prevalent in Europe in relation to clinical and serological data. RESULTS: Ninety-one percent of 77 donor samples of European origin HBV DNA positive but HBV surface antigen (HBsAg) negative were confirmed. Viral load ranged between unquantifiable and 5640 IU/mL (median 25 IU/mL). Fifty-two strains were genotyped (14 HBV(A2) and 38 HBV(D)). Compared to HBsAg+ samples, genotype D was significantly more frequent than genotype A2 in OBIs from Poland or Italy (P<0.04). Amino acid substitutions were concentrated in the immunologically active parts of the Pre-S/S proteins (P<0.0001) affecting both cellular CD8 T-cell epitopes and B-cell neutralizing Major Hydrophilic Region epitopes. Substitutions were more frequent in OBIs than in HBsAg+ strains of both genotype D (P<0.001) and A2 (P<0.01), in OBIs of genotype D than A2 in the 'a' region (P<0.001) but not cellular epitopes, and in anti-HBs+ than anti-HBs- OBIs (P<0.001). CONCLUSIONS: Results support the hypothesis that humoral and cellular immune pressure on the HBV envelope proteins are major mechanisms generating OBI.

Seroprevalence of Trypanosoma cruzi infection in at-risk blood donors in Catalonia (Spain).

BACKGROUND: The increasing arrival of Latin Americans to Europe and, particularly, to Spain has led to the appearance of new pathologies, such as Chagas disease, a zoonotic infection endemic to rural areas of Central and South America. In the absence of the triatomid vector, one of the main modes of transmission of Chagas disease in nonendemic regions is through blood transfusion. STUDY DESIGN AND METHODS: The Catalonian Blood Bank has implemented a screening program for Chagas disease in at-risk blood donors and has performed a study to determine the seroprevalence of Trypanosoma cruzi infection in the donor population. The two commercial tests used in all samples were the ID-PaGIA Chagas antibody test (DiaMed) and the bioelisa Chagas assay (Biokit). RESULTS: Overall seroprevalence was 0.62 percent, with 11 donors confirmed positive among the 1770 at-risk donors studied; the highest rate (10.2%) was in Bolivian donors. Interestingly, 1 of the 11 positive donors was a Spaniard who had resided various years in a Chagas disease endemic area. Furthermore, 1 of the positive donors presented detectable parasitemia. CONCLUSION: The results of this study emphasize the need for T. cruzi screening in at-risk blood donors in nonendemic countries. An important finding is the relevance of including in the at-risk category persons who have resided in, but were not necessarily born in, an endemic region. If T. cruzi screening is not routinely performed in all donations, it remains highly dependent on proper identification of at-risk donors during the predonation interview.

Resultados preliminares del estudio en Banco de Sangre, Cataluña / No disponible

El aumento de población inmigrante procedente de zonas endémicas de Chagas ha creado la necesidad de una actuación en los bancos de sangre de nuestro país. Además, el reciente real decreto sobre hemodonación permite aceptar las donaciones de riesgo siempre que se realice el cribado para marcadores de T. cruzi. El objetivo principal del estudio iniciado en septiembre de 2005 en el Banc de Sang i Teixits es determinar la seroprevalenciade la infección por Trypanosoma cruzi en la población de donantes de riesgo en Cataluña. Se incluyeron en el estudio los donantes de riesgo de Chagas (nacidos, transfundidos o hijos de madre procedente de área endémica) y viajeros/residentes en estancias superiores a un mes. El test de cribado utilizado fue el ID-PaGIA Chagas antibody test (DiaMed). Como test suplementarios se utilizaron el método Bioelisa Chagas (Biokit) y un ELISA in-house con antígenos nativos. Entre Septiembre 2005 y Septiembre 2006,se han analizado 1770 donantes. Por grupos de riesgo, hubo 1524 (86%)donantes nacidos en área endémica, 37 españoles de madre originaria dezona endémica (2%) y 209 (12%) viajeros. Hubo 21 donantes inicialmente positivos en el cribado, de los cuales 11 se confirmaron positivos (0,62%).La mayoría de donantes positivos fueron bolivianos (AU)

The increasing population coming from Chagasic areas has forced blood banksin Spain to take preventive measures. The recent Blood Donation regulation provides with the guidelines to screen blood donations at risk for anti-T. cruziantibodies. The aim of the present study was to determine the prevalence of infection by Trypanosoma cruzi in blood donors at risk in Catalonia. The risk groups included were donors born or transfused in endemic areas and donors whose mother was born in endemic area. Travellers or residents in endemic areas for more than one month were also included. The screening method was ID-PaGIA Chagas antibody test (DiaMed). As supplementary test, Bioelisa Chagas (Biokit) and an in-house ELISA test with native antigens were used. Between September 2005 and September 2006, 1770 donor sat risk were screened. According to risk groups, 1524 (86%) were donorsborn in endemic areas, 37 (2%) were donors whose mother was born in an endemic area and 209 (12%) donors had travelled or lived in endemic areas. Twenty-one donors were initially positive in the screening, of which11 were confirmed positive for the presence of T. cruzi antibodies (0.62%).The majority of T. cruzi positive donors were Bolivians (AU)

Development of a real-time PCR assay for Trypanosoma cruzi detection in blood samples.

The aim of this study was to develop a real-time PCR technique to detect Trypanosoma cruzi DNA in blood of chagasic patients. Analytical sensitivity of the real-time PCR was assessed by two-fold serial dilutions of T. cruzi epimastigotes in seronegative blood (7.8 down to 0.06 epimastigotes/mL). Clinical sensitivity was tested in 38 blood samples from adult chronic chagasic patients and 1 blood sample from a child with an acute congenital infection. Specificity was assessed with 100 seronegative subjects from endemic areas, 24 seronegative subjects from non-endemic area and 20 patients with Leishmania infantum-visceral leishmaniosis. Real-time PCR was designed to amplify a fragment of 166 bp in the satellite DNA of T. cruzi. As internal control of amplification human RNase P gene was coamplified, and uracil-N-glycosylase (UNG) was added to the reaction to avoid false positives due to PCR contamination. Samples were also analysed by a previously described nested PCR (N-PCR) that amplifies the same DNA region as the real-time PCR. Sensitivity of the real-time PCR was 0.8 parasites/mL (50% positive hit rate) and 2 parasites/mL (95% positive hit rate). None of the seronegative samples was positive by real-time PCR, resulting in 100% specificity. Sixteen out of 39 patients were positive by real-time PCR (41%). Concordance of results with the N-PCR was 90%. In conclusion, real-time PCR provides an optimal alternative to N-PCR, with similar sensitivity and higher throughput, and could help determine ongoing parasitaemia in chagasic patients.

Real-time PCR using fluorescent resonance emission transfer probes for HLA-B typing.

HLA genotyping by polymerase chain reaction (PCR) has some inherent labor-intensive and effort-demanding limitations. To overcome them, we have developed a real-time PCR with hybridization probes approach able to obtain a medium-low resolution HLA-B genotyping with fewer tubes and probes and with a shorter time requirement. Our strategy used 18 simultaneous reactions amplifying HLA-B alleles and an internal control. Monitorization of both amplifications in each tube is performed by the simultaneous application of two fluorescent resonance emission transfer probes: the first probe, different for each tube, is specific for the HLA-B locus and the second probe detects the control gene. A medium-low resolution (300 HLA-B allelic groups) typing is obtained for each sample by analyzing the melting curve patterns. Because some alleles may be determined without using the complete set of reactions, we present an alternative strategy: a first round of seven reactions and, according to the result, a second (or third) round of PCRs to solve the ambiguities. This method was validated in pretyped clinical samples and the results were completely concordant. Moreover, fewer ambiguous results were obtained. In summary, we present a new, faster, and more accurate method than currently used PCR techniques to type HLA-B alleles.

Development of a new HLA-DRB real-time PCR typing method.

Polymerase chain reaction (PCR)-based human leukocyte antigen (HLA) typing methods currently used in most histocompatibility laboratories, such as PCR-sequence-specific primers (PCR-SSP) and PCR-sequence-specific oligonucleotide probes (PCR-SSO), are time-consuming and are at risk of contamination during the post-PCR process. The aim of this study was to develop a real-time PCR (rtPCR)-based HLA-DRB1 and -DRB3/4/5 low-medium resolution typing method to avoid these problems. This new method combined the use of specific primers and probes for HLA-DRB alleles. One pair of DRB gene primers and two DRB-specific probes (FAM and VIC) were used per reaction in each of a set of 16 PCR reaction tubes. To provide an internal positive control, each tube also contained a pair of primers and a TET probe for glyceraldehyde phosphate dehydrogenase. This allowed a very significant reduction in the number of reactions and the processing time, whereas typing resolution increased. After successful testing on 100 samples, the technique was validated in 200 clinical samples that had previously been typed for HLA-DRB using a standard PCR-based method. Identical results were obtained with all samples. This new method also reduced ambiguous results and was faster and less cumbersome than currently used PCR-SSP or PCR-SSO techniques.

HLA-B27 genotyping by fluorescent resonance emission transfer (FRET) probes in real-time PCR.

Several polymerase chain reaction (PCR)-based human leukocyte antigen (HLA) genotyping methods are in use, but none is fully satisfactory. The introduction of real-time PCR (rt-PCR) with fluorescence resonance energy transfer (FRET) probes provides a powerful tool to overcome the drawbacks of current methods such as the long processing time and the requirement for post-PCR manual procedures. Here we present evidence that the FRET-fluorotyping principle may resolve HLA-B27 variants, providing a higher resolution in less time than the techniques currently in use. The protocol uses between one and three consecutive amplification reactions depending on the resolution required. The first reaction, aimed at detecting HLA-B27-positive samples, uses beta-globin coamplification as control. The second reaction, aimed at resolving most frequent B27 alleles, uses two hybridization probes whose melting temperatures curves allow the classification of HLA-B27 alleles into eight groups. By adding a third reaction, even the rarest alleles associated and not associated to ankylosing spondylitis (AS) may be discriminated. The technique was blindly tested on 60 samples from individuals previously typed and confirmed by standard PCR sequence-specific oligoprobes-PCR sequence and PCR-based typing PCR-SBT (30 B27+, 30 non-B27). There was a complete concordance rate, thus confirming the potential of this new technique for clinical HLA-B27 typing and for HLA typing in general.