Viremia levels in hepatitis C infection among Egyptian blood donors and implications for transmission risk with different screening scenarios

BACKGROUND

Knowledge about the viral load (VL) distributions in different stages of hepatitis C virus (HCV) infection is essential to compare the efficacy of serologic screening and nucleic acid testing (NAT) in preventing transfusion transmission risk. We studied HCV-RNA levels in Egyptian blood donors in the preseroconversion window period (WP) and in later anti-HCV-positive stages of infection.

STUDY DESIGN AND METHODS

Subsets of individual-donation (ID)-NAT and anti-HCV-yield samples from a screening study among 119,756 donors were tested for VL by quantitative polymerase chain reaction (qPCR). Low viremia levels below the quantification limit of qPCR were determined by probit analysis using the proportion of reactive results on replicate NATs. Poisson distribution statistics were used to estimate transmission risk in different stages of HCV infection based on 50% minimum infectious doses (MID50 ) of 3.2 (1-10) and 316 (100-1000) virions in the absence and presence of anti-HCV, respectively.

RESULTS

Rates of total HCV infections and WP-NAT-yield donations in two Egyptian blood centers varied between 2.6% to 4.5% and 1:3100 to 1:9500, respectively. VLs ranged from 82 to 3 × 10(7) copies/mL in WP and from fewer than 1600 to 1.6 × 10(6) copies/mL in anti-HCV-positive carrier donations. Only two (1.1%) of 175 donors with probable resolved infection had detectable RNA on replicate testing (estimated VLs of 0.5 and 1.8 copies/mL). This translates to an estimated transmission risk of 0.028% if ID-NAT-nonreactive, anti-HCV-positive donations would be used for RBC transfusions.

CONCLUSION

Almost 99% of anti-HCV-reactive donations without detectable HCV-RNA on initial ID-NAT screening had eradicated the virus from the circulation, while 1% had extremely low VLs and are likely not infectious. The incremental safety offered by serologic testing of ID-NAT-screened blood seems minimal.

Occult hepatitis B virus infection among Egyptian blood donors

AIM

To identify blood donors with occult hepatitis B virus (HBV) infection (OBI) to promote safe blood donation.

METHODS

Descriptive cross sectional study was conducted on 3167 blood donors negative for hepatitis B surface antigen (HBsAg), hepatitis C antibody (HCV Ab) and human immunodeficiency virus Ab. They were subjected to the detection of alanine aminotransferase (ALT) and aspartate transaminase (AST) and screening for anti-HBV core antibodies (total) by two different techniques; [Monoliza antibodies to hepatitis B core (Anti-HBc) Plus-Bio-Rad] and (ARC-HBc total-ABBOT). Positive samples were subjected to quantitative detection of antibodies to hepatitis B surface (anti-HBs) (ETI-AB-AUK-3, Dia Sorin-Italy). Serum anti-HBs titers > 10 IU/L was considered positive. Quantitative HBV DNA by real time polymerase chain reaction (PCR) (QIAGEN-Germany) with 3.8 IU/mL detection limit was estimated for blood units with negative serum anti-HBs and also for 32 whose anti-HBs serum titers were > 1000 IU/L. Also, 265 recipients were included, 34 of whom were followed up for 3-6 mo. Recipients were investigated for ALT and AST, HBV serological markers: HBsAg (ETI-MAK-4, Dia Sorin-Italy), anti-HBc, quantitative detection of anti-HBs and HBV-DNA.

RESULTS

525/3167 (16.6%) of blood units were positive for total anti-HBc, 64% of those were anti-HBs positive. Confirmation by ARCHITECT anti-HBc assay were carried out for 498/525 anti-HBc positive samples, where 451 (90.6%) confirmed positive. Reactivity for anti-HBc was considered confirmed only if two positive results were obtained for each sample, giving an overall prevalence of 451/3167 (14.2%) for total anti-HBc. HBV DNA was quantified by real time PCR in 52/303 (17.2%) of anti-HBc positive blood donors (viral load range: 5 to 3.5 x 10(5) IU/mL) with a median of 200 IU/mL (mean: 1.8 x 10(4) ± 5.1 x 10(4) IU/mL). Anti-HBc was the only marker in 68.6% of donors. Univariate and multivariate logistic analysis for identifying risk factors associated with anti-HBc and HBV-DNA positivity among blood donors showed that age above thirty and marriage were the most significant risk factors for prediction of anti-HBc positivity with AOR 1.8 (1.4-2.4) and 1.4 (1.0-1.9) respectively. Other risk factors as gender, history of blood transfusion, diabetes mellitus, frequent injections, tattooing, previous surgery, hospitalization, Bilharziasis or positive family history of HBV or HCV infections were not found to be associated with positive anti-HBc antibodies. Among anti-HBc positive blood donors, age below thirty was the most significant risk factor for prediction of HBV-DNA positivity with AOR 3.8 (1.8-7.9). According to HBV-DNA concentration, positive samples were divided in two groups; group one with HBV-DNA ≥ 200 IU/mL (n = 27) and group two with HBV-DNA < 200 IU/mL (n = 26). No significant difference was detected between both groups as regards mean age, gender, liver enzymes or HBV markers. Serological profiles of all followed up blood recipients showed that, all were negative for the studied HBV markers. Also, HBV DNA was not detected among studied recipients, none developed post-transfusion hepatitis (PTH) and the clinical outcome was good.

CONCLUSION

OBI is prevalent among blood donors. Nucleic acid amplification/HBV anti core screening should be considered for high risk recipients to eliminate risk of unsafe blood donation.

Application of bioaffinity technology in therapeutic extracorporeal plasmapheresis and large-scale fractionation of human plasma

This paper describes the increasingly unique and powerful role that affinity chromatography is occupying both as a tool for the treatment of extracorporeal plasma exchange (to discard biological compounds with noxious metabolic or immunologic effects in patients) and as a purification tool in the production of therapeutic plasma protein derivatives. Management of both applications requires careful monitoring of the parameters applied to the plasma material, to avoid immunological stimulation or activation of the coagulation cascade. Examples of direct current applications of affinity ligands in therapeutic removal and industrial production of plasma compounds are presented.