HLA-DQ Typing Kits in Diagnosis and Screening for Celiac Disease

Aim: Celiac disease (CD) is strongly associated with HLA-DQ2.2, HLA-DQ2.5, and HLA-DQ8. Up to 99.7% of all CD patients are positive for either one or two of these genetic markers, demonstrating a high negative predictive value. This has led to the development of diagnostic kits that, instead of providing a full HLA-DQ typing, detect only these three HLA-DQ types. Our aim was to compare three different kits for their performance, utilization, and costs. Because 0.4-3.6% of all CD patients test positive for HLA-DQ7 and negative for the aforementioned types, information provided by the kits regarding DQ7 alpha and beta chains was evaluated as well. Materials and Methods: Fifty DNA samples previously typed with the SSCP method were analyzed using three commercial kits. Results and Discussion: All kits report hetero- or homozygosity for HLA-DQ2.5. The XeliGen kit directly detects HLA-DQ7, but is relatively expensive. The MLPA kit is the least expensive in terms of reagents and may indirectly detect HLA-DQ7. The CeliaSCAN kit is easy to use and provides indirect information about HLA-DQ7.5. Conclusion: All kits correctly identify the CD risk genes. The resources of the laboratory and the intended use should determine the preference for any of the HLA-DQ typing kits herein described.