Specificity and sensitivity of RHD genotyping methods by PCR-based DNA amplification

Area of Science:

• Genetics
• Molecular Biology
• Immunology

Background:

• Accurate RHD gene detection is crucial for transfusion medicine and prenatal diagnostics.
• Existing PCR methods for RHD genotyping exhibit variable sensitivity and specificity.
• D variants and population-specific genetic differences pose challenges in RHD gene detection.

Purpose of the Study:

• To compare the sensitivity and specificity of four distinct PCR methods for RHD gene detection.
• To evaluate the performance of these methods across different RHD variants and populations.
• To recommend an optimal PCR strategy for reliable RHD genotyping.

Main Methods:

• Four PCR methods (I-IV) were developed using primers targeting divergent regions of RHD and RHCE genes (exon 10, 7, 4, and intron 4).
• Sensitivity was assessed using D-positive/D-negative cell mixtures and DNA from single cells.
• Specificity was evaluated using various D variants, Rh(null) samples, and DNA from Caucasian and non-Caucasian populations.

Main Results:

• Methods I-III demonstrated high sensitivity, detecting as little as 0.001% D-positive cells; Method II was exceptionally sensitive, detecting DNA from three cells.
• False-negative results occurred with specific D variants (D(IVb), D(VI), DFR) using methods II-IV, but not method I.
• False-positive results were observed in Rh(null) cases and in certain Caucasian and non-Caucasian RhD-negative individuals, with varying frequencies across methods.

Conclusions:

• No single PCR method is universally accurate for RHD genotyping due to variant and population-specific challenges.
• Methods I-III offer superior sensitivity, while Method I shows better specificity for certain variants.
• A PCR strategy employing at least two methods is recommended for robust and reliable RHD genotyping.