Allelic Discrimination by TaqMan-PCR for Genotyping of Human Neutrophil Antigens

Human neutrophil antigens: Nature, clinical significance and detection

Granulocytes are an essential part of both the innate and adaptive immune systems. Human neutrophil antigens (HNAs) are a family of epitopes that are located on glycoproteins that are mostly expressed on human granulocytes. Antibodies that recognize these epitopes have been associated with neutropenia, transfusion complications, haematopoietic stem cell transplant nonengraftment and renal transplant rejection. Currently, there are fourteen recognized HNA alleles across five antigen systems (HNA-1 through HNA-5), the molecular basis of which are located on the genes FCGR3B, CD177, SLC44A2, ITGAM and ITGAL, respectively. Elucidation of the associated genes has permitted the development of testing strategies for HNA typing and aided understanding of the associated epitopes. This review will outline the associated clinical conditions that require HNA investigation and how these are performed in specialized laboratories. Investigations provided are both reactive for patients with a variety of existing or suspected neutropenias and proactive in the testing of blood component donors in order to reduce the potential risk to patients who require transfusion.

Variants in MCT10 protein do not affect FT3 levels in athyreotic patients

PURPOSE

Several single-nucleotide polymorphisms in genes encoding for transporters have been associated with serum thyroid hormone concentrations with inconsistent results. The aim of this study was to assess the clinical significance of the rs17606253 in SLC16A10 gene alone and in combination with the DIO2 Thr92Ala variation in athyreotic patients.

METHODS

One-hundred patients submitted to total thyroidectomy and treated with levothyroxine were included. Pre- and post surgical serum TSH levels did not differ by more than ± 0.5 mIU/l.

RESULTS

Both patients carrying the wild-type allele or heterozygous for rs17606253 in SLC16A10 gene had a significant reduction in FT3 post surgical levels (p = 0.01 and p < 0.0001, respectively) while Thr92Ala in DIO2 gene was associated with reduced FT3 levels for heterozygous and rare homozygous patients (p < 0.0001 and p = 0.01, respectively). We identified two groups ("FT3 unchanged" and "FT3 reduced") using a cutoff of at least 0.5 pg/ml as a significant variation between pre- and post surgical FT3 values. In this case, the rs17606253 was not statistically associated with reduced FT3 levels at genotype and allele levels. On the contrary, the Thr92Ala in DIO2 gene was confirmed statistically associated with reduced FT3 levels after surgery with a p = 0.035 at genotype level and p = 0.014 at allele level.

CONCLUSIONS

We confirmed the role of DIO2 Thr92Ala polymorphism on T3 levels. On the contrary, SLC16A1 rs17606253 polymorphism did not impair hormone levels in athyreotic patients treated with levothyroxine therapy.

Hypothyroid Patients Encoding Combined MCT10 and DIO2 Gene Polymorphisms May Prefer L-T3 + L-T4 Combination Treatment - Data Using a Blind, Randomized, Clinical Study

OBJECTIVES

In previous studies, around half of all hypothyroid patients preferred levo-thyroxine (L-T4) + levo-triiodothyronine (L-T3) combination therapy, 25% preferred T4, and 25% had no preference. The reason for this is yet to be explored.

METHODS

A total of 45 overtly autoimmune, hypothyroid patients - now euthyroid on ≥6 months' L-T4 therapy - participated in a prospective, double-blind, cross-over study. The patients were randomized into 2 groups of either 3 continuous months' L-T4 therapy followed by 3 months' combination therapy or vice versa. In all periods, 50 μg L-T4 was blindly replaced by either (identical) 50 μg L-T4 or by 20 μg T3. L-T4 was hereafter adjusted to obtain normal serum TSH values. We investigated 3 single nucleotide polymorphisms (SNPs) on the type II iodothyronine deiodinase (DIO2) gene (rs225014 (Thr92Ala), rs225015, and rs12885300 (ORFa-Gly3Asp)) and 1 SNP on the cellular membrane transport-facilitating monocarboxylate transporter (MCT10) gene (rs17606253), and asked in which of the 2 treatment periods patients felt better (i.e., which treatment was preferred).

RESULTS

27 out of 45 patients (60%) preferred the combination therapy. Two polymorphisms (rs225014 (DIO2, Thr92Ala) and rs17606253 (MCT10)) were combined yielding 3 groups: none vs. 1 of 2 vs. both SNPs present, and 42 vs. 63 vs. 100% of our patients in the 3 groups preferred the combined treatment (Jongheere-Terpstra trend test, p = 0.009).

CONCLUSION

The present study indicates that the combination of polymorphisms in DIO2 (rs225014) and MCT10 (rs17606253) enhances hypothyroid patients' preference for L-T4 + L-T3 replacement therapy. In the future, combination therapy may be restricted or may be even recommended to individuals harbouring certain polymorphisms.