New methods to minimize allopurinol side effects

[Keith Taylor]

For at least 2 years, rheumatologists recommend pre-allopurinol screening for at-risk groups: http://www.goutpal.com/gout-treatment/avoid-gout/allopurinol/minimize-allopurinol-side-effects/

This screening helps avoid genetic risks of severe allopurinol side effects, known as Cutaneous Adverse Drug Reactions.

Now, a new screening test has been developed, as reported in Detection of HLA-B*58:01 with TaqMan assay and its association with allopurinol-induced sCADR.

Abstract Background:
The HLA-B*58:01 allele is associated with allopurinol-induced severe cutaneous adverse drug reactions (sCADR) in certain geographic regions, but the diversity of the correlation is large. In addition, the currently available HLA-B*58:01 testing methods are too laborious for use in routine clinical detection.

The objective of this study was to develop a new, convenient method for the detection of HLA-B*58:01 and to investigate the association of HLA-B*58:01 with allopurinol-induced sCADR in a Han Chinese population.

Methods:
A new method combining sequence-specific primers (SSP) and TaqMan probe amplification was developed in this study and was used to detect the HLA-B*58:01 in 48 allopurinol-induced sCADR, 133 allopurinol-tolerant, and 280 healthy individuals. The accuracy, sensitivity, and specificity were assessed by a commercial PCR-SSP HLA-B typing kit. The low limit of detection was detected by serial dilution of an HLA-B*58:01-positive DNA template.

Results:
The new method successfully identified HLA-B*58:01 in thousands of HLA-B alleles, and the results for 344 DNA samples were perfectly concordant with the results of the commercial PCR-SSP HLA-B kit. The analytical sensitivity is 100% and the specificity is over 99%. The low limit of detection of this assay is 100 pg DNA, which was 10 times more sensitive than the commercial PCR-SSP kit. HLA-B*58:01 was present in 93.8% of the patients with sCADR, 7.5% of the allopurinol-tolerant patients, and 12.1% of the healthy controls. The frequency of HLA-B*58:01 was significantly higher in the sCADR group than in the control group (p<0.0001). However, there was no significant difference between the allopurinol-tolerant and control groups (p=0.1547).

Conclusions:
HLA-B*58:01 has a strong association with allopurinol-induced sCADR in Han Chinese. The newly developed method is reliable for HLA-B*58:01 detection prior to allopurinol therapy.

If you are in one of the high-risk groups, what information about pre-allopurinol screening have you received?

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