Validation of a Multiplex Assay for Measuring Specific IgG4

Purpose@#Specific IgG4 (sIgG4) increases with allergen specific immunotherapy and may reflect a state of immune tolerance in food allergy. While ImmunoCAP® has been widely used to measure sIgG4 to a single allergen, PROTIATM Specific IgG4® has been designed as a multiplex assay for measuring sIgG4. This study sought to validate this assay in comparison to ImmunoCAP®. @*Materials and Methods@#Measurements of sIgG4 were compared between PROTIATM Specific IgG4® and ImmunoCAP® using sera from 519 allergy patients (asthma: 114, allergic rhinitis: 318, food allergy: 146) with 731 paired tests. sIgG4 was measured against nine inhalant allergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat dander, dog dander, birch pollen, oak pollen, ragweed pollen, mugwort pollen, and Alternaria alternata spores) and nine food allergens (egg white, casein, wheat, peanut, walnut, crab, shrimp, apple, and peach). @*Results@#PROTIATM Specific IgG4® showed 95.6% agreement rate with ImmunoCAP® in the positivity comparison. For sIgG4 positivity to each individual allergen, an agreement rate of more than 84.8% was observed. In Cohen’s kappa analysis, these assays displayed substantial correlations [Cohen’s kappa coefficient (κ) ≥0.699], except for shrimp (κ=0.448). Furthermore, both assays displayed strong correlations in quantitative comparisons [correlation coefficients value (ρ) ≥0.8014], except for apple (ρ=0.6571, p=0.175). Serial dilution tests also showed consistency between the assays. @*Conclusion@#PROTIATM Specific IgG4® showed high consistency with ImmunoCAP® in measuring sIgG4. This assay is applicable to various clinical fields, including allergen immunotherapy and food allergy.

Validation of PROTIA™ Allergy-Q 64 Atopy® as a Specific IgE Measurement Assay for 10 Major Allergen Components

PURPOSE: Component-resolved diagnostics (CRD) is expected to provide additional diagnostic information in allergic patients. PROTIA™ Allergy-Q 64 Atopy®, a recently developed CRD-based multiplex specific immunoglobulin E (sIgE) assay, can quantitatively measure sIgE to major allergen components. METHODS: The sIgE detection by PROTIA™ Allergy-Q 64 Atopy® and ImmunoCAP® assays was compared using the sera of 125 Korean allergic patients. Group 1 and 2 allergens of house dust mites (HDMs; Dermatophagoides farinae (Der f) 1 and Der f 2 in PROTIA™ Allergy-Q 64 Atopy®, Dermatophagoides pteronyssinus (Der p) 1 and Der p 2 in ImmunoCAP®), Bet v 1, Fel d 1, Que a 1, ω-5 gliadin, α-lactalbumin, β-lactoglobulin, casein and α-Gal were measured by both assays. RESULTS: Comparing the results from the 2 assays, the agreement rate for all the 10 allergens was > 88% (group 1 HDM allergen, 100%; group 2 HDM allergen, 94.6%; Bet v 1, 97.4%; Fel d 1, 90.5%; Que a 1, 89.2%; α-lactalbumin, 96%; β-lactoglobulin, 88%; casein, 88%; ω-5 gliadin, 96%; α-Gal, 100%). Correlation analysis indicated that, all the 10 allergen sIgEs showed more than moderate positive correlation (Pearson correlation coefficients > 0.640). Additionally, intra-class comparison showed more than high correlation for all the 10 allergens (Spearman's rank correlation coefficients > 0.743). CONCLUSIONS: PROTIA™ Allergy-Q 64 Atopy® is reliable and comparable to the ImmunoCAP® assay for component-resolved diagnosis.

Proteomic Analysis of Haptoglobin and Amyloid A Protein Levels in Patients with Vivax Malaria

Advancements in the field of proteomics have provided great opportunities for the development of diagnostic and therapeutic tools against human diseases. In this study, we analyzed haptoglobin and amyloid A protein levels of vivax malaria patients with combinations of depletion of the abundant plasma proteins, 2-dimensional gel electrophoresis (2-DE), image analysis, and mass spectrometry in the plasma between normal healthy donors and vivax malaria patients. The results showed that the expression level of haptoglobin had become significantly lower or undetectable in the plasma of vivax malaria patients due to proteolytic cleavage when compared to healthy donors on 2-DE gels. Meanwhile, serum amyloid A protein was significantly increased in vivax malaria patient's plasma with high statistical values. These 2 proteins are common acute phase reactants and further large scale evaluation with a larger number of patient's will be necessary to establish the possible clinical meaning of the existential changes of these proteins in vivax malaria patients. However, our proteomic analysis suggests the feasible values of some plasma proteins, such as haptoglobin and serum amyloid A, as associating factor candidates for vivax malaria.

Evaluation of LG Malaria Anti-PvTM for Diagnosis of Plasmodium vivax Malaria in the Republic of Korea / 대한임상병리학회지

BACKGROUND: In the Republic of Korea, Plasmodium vivax malaria, which had disappeared since 1984, re-emerged in 1993. Currently, malaria is becoming a serious public health problem in the Republic of Korea. The diagnosis of malaria has relied on microscopic examination such as thin and thick blood smears. However, even for expert microscopists, this test is a laborious and time-consuming procedure. Therefore, the development of a reliable, easy, and convenient diagnostic test is crucial. Recently, the LG malaria anti-PvTM enzyme-linked immunosorbent assay (ELISA) kit for the detection of a specific antibody against the merozoite surface protein (MSP) of P. vivax was developed. The aim of this study was to evaluate the diagnostic kit for P. vivax malaria in the Republic of Korea. METHODS: To determine the usefulness of the LG malaria anti-PvTM as a diagnostic kit for vivax malaria, a total of 59 serum samples from patients with P. vivax malaria were tested. The patients were diagnosed microscopically and the parasitemia index of their blood was calculated. Sera from 203 uninfected healthy blood donors, which were microscopically negative for Plasmodium vivax, were used as negative controls. RESULTS: The sensitivity and specificity of the LG malaria anti-PvTM were 98.31% (58/59) and 98.03% (199/203), respectively. The false-positive and false-negative rates were 1.97% (4/203) and 1.69% (1/59), respectively. CONCLUSIONS: The diagnostic kit, LG malaria anti-PvTM, might be a useful tool for diagnosis and screening of P. vivax malaria in Korea.

Positive Rate of HCV RNA in Anti-HCV Immunoblot Indeterminate Samples from Blood Donors and Analysis of Reactivity of Enzyme Immunoassay Kits to Indeterminate Samples / 대한수혈학회지

BACKGROUND: Positive rate of HCV RNA in anti-HCV immunoblot indeterminate samples from Korean blood donors was investigated in this study. Futhermore, reactivity of enzyme immunoassay kits was evaluated according to patterns of band reactivity and RNA positivity of indeterminate samples. METHODS: HCV RNA was tested from a total of 180 samples that had been repeatedly reactive to LG HCD 3.0 or DONG-A HCV 3.0 and further confirmed to be indeterminate by LG HCD CONFIRM at 14 Korean Red Cross Blood Centers in 1997. Correlation between HCV RNA and reactivity to each recombinant antigens was analysed. Three kinds of EIA kits such as HCD 3.0, DONG-A HCV 3.0 and Cobas Core Anti-HCV EIA kits were tested of their reactivity to 56 samples that had shown single band positivity on LG HCD CONFIRM. RESLUTS: HCV RNA was detected in 11 (6.1%) of 180 samples. Positivity of 897 band showed positive correlation with HCV RNA positivity (p<0.001), while Core518 showed negative correlation (p<0.001). DONG-A HCV 3.0 showed negative reaction to two samples with anti-897 specificity and HCV RNA, while LG HCD 3.0 and Cobas Core HCV showed negative reaction to one sample with anti-EIE2NS4 and HCV RNA. CONCLUSION: Positive rate of anti-HCV immunoblot indeterminate samples from Korean blood donors was 6.1%. In case of indeterminate results by LG HCD CONFIRM, positive reaction to 897 band highly suggests the presence of HCV RNA, while Core518 the absence of HCV RNA. It is highly recommended that specificity of Core518 antigen be increased in LG HCD 3.0 or LG HCD CONFIRM and sensitivity of recombinant antigen from the 3rd non-structural region of HCV genome be increased in DONG-A HCV 3.0.