This paper aims to present an overview of MICA and natural killer group 2 member D (NKG2D) genetic and functional interactions and their impact on kidney transplant outcome. Organ transplantation has gone from what can accurately be called a “clinical experiment” to a routine and reliable practice, which has proven to be clinically relevant, life-saving and cost-effective when compared with non-transplantation management strategies of both chronic and acute end-stage organ failures. The kidney is the most frequently transplanted organ in the world (transplant-observatory1). The two treatment options for end-stage renal disease (ESRD) are dialysis and/or transplantation. Compared with dialysis, transplantation is associated with significant improvements in quality of life and overall longevity. A strong relationship exists between allograft loss and human leukocyte antigens (HLA) antibodies (Abs). HLA Abs are not the only factor involved in graft loss, as multiple studies have shown that non-HLA antigens are also involved, even when a patient has a good HLA matche and receives standard immunosuppressive therapy. A deeper understanding of other biomarkers is therefore important, as it is likely to lead to better monitoring (and consequent success) of organ transplants. The objective is to fill the void left by extensive reviews that do not often dive this deep into the importance of MICA and NKG2D in allograft acceptance and their partnership in the immune response. There are few papers that explore the relationship between these two protagonists when it comes to kidney transplantation. This is especially true for the role of NKG2D in kidney transplantation. These reasons give a special importance to this review, which aims to be a helpful tool in the hands of researchers in this field.

The HLA-G and MICA genes are stimulated under inflammatory conditions and code for soluble (sMICA and sHLA-G) or membrane-bound molecules that exhibit immunomodulatory properties. It is still unclear whether they would have a synergistic or antagonistic effect on the immunomodulation of the inflammatory response, such as in chronic kidney disease (CKD), contributing to a better prognosis after the kidney transplantation. In this study, we went from genetic to plasma analysis, first evaluating the polymorphism of MICA , NKG2D and HLA-G in a cohort from Southern Brazil, subdivided in a control group of individuals (n = 75), patients with CKD (n = 94), and kidney-transplant (KT) patients (n = 64). MICA , NKG2D and HLA-G genotyping was performed by polymerase chain reaction with specific oligonucleotide probes, Taqman and Sanger sequencing, respectively. Levels of soluble forms of MICA and HLA-G were measured in plasma with ELISA. Case-control analysis showed that the individuals with haplotype HLA-G*01 : 01/ UTR-4 have a lower susceptibility to develop chronic kidney disease (OR = 0.480; p = 0.032). Concerning the group of kidney-transplant patients, the HLA-G genotypes +3010 GC ( rs1710 ) and +3142 GC ( rs1063320 ) were associated with higher risk for allograft rejection (OR = 5.357; p = 0.013 and OR = 5.357, p = 0.013, respectively). Nevertheless, the genotype +3010 GG (OR = 0.136; p = 0.041) was associated with kidney allograft acceptance, suggesting that it is a protection factor for rejection. In addition, the phenotypic analysis revealed higher levels of sHLA-G ( p = 0.003) and sMICA ( p < 0.001) in plasma were associated with the development of CKD. For patients who were already under chronic pathological stress and underwent a kidney transplant, a high sMICA ( p = 0.001) in pre-transplant proved to favor immunomodulation and allograft acceptance. Even so, the association of genetic factors with differential levels of soluble molecules were not evidenced, we displayed a synergistic effect of sMICA and sHLA-G in response to inflammation. This increase was observed in CKD patients, that when undergo transplantation, had this previous amount of immunoregulatory molecules as a positive factor for the allograft acceptance.

HLA-E, a class I nonclassical HLA molecule, is expressed in all tissues and is involved in the regulation of both innate (by interaction with the CD94/NKG2 receptor expressed mainly in NK cells) and adaptive immunity (by interaction with T CD8 + cells), suggesting a possible role in the solid organ transplantation context. Transplanted patients with chronic kidney disease and their respective donors (N = 107 pairs) were genotyped for exons 2 and 3 of the HLA-E locus by sequence-based typing (SBT). Groups' genotype frequencies were compared regarding episodes of clinical rejection by global G test, and binary logistic regression was made to demonstrate the contribution of genetic variables vs epidemiological variables. Comparisons of donors' genotype frequencies showed significant differences (P = .0230), revealing a protective profile of E*01:01/*01:01 compared to the other genotypes (P = .0099; OR = 0.3088; CI [95%] = 0.1333-0.7157). The same happened when the aforementioned genotype was combined with the E*01:01/*01:01 recipients' genotype (P = .0065; OR = 0.1760; CI [95%] = 0.0517-0.5987). A binary logistic regression analysis was performed, and, of all variables considered, only two were included in the resulting model (P = .007; R 2 Cox and Snell = 0.243; R 2 Nagelkerke = 0.328)-"End-Stage

Metaplastic breast cancer (MpBC) is a rare, aggressive type of breast cancer, often classi ed as triple negative (TN). Scarce information is available about germline testing in MpBC. We retrospectively reviewed MpBC patients counseled at our Institute and found to harbor germline pathogenic variants (PVs), and we revised literature data. We identi ed a germline PV in 15 MpBC patients: 13 in BRCA1 (86.7%), one in TP53 (6.7%), one in MLH1 (6.7%) genes. Eight MpBC PV carriers in BRCA1 have been previously described, including a patient with a PV in both BRCA1 and TP53. MpBC histological subtype in PV carriers was heterogeneous. All MpBCs were TN but 13.3% in our series showed HER2 overexpression.We described the largest series of MpBCs with germline PVs. As previously reported, we observed that BRCA1 is the mainly involved gene in MpBC patients who underwent germline testing according to speci c selection criteria. Additional studies on unselected patients are required to assess the authentic role of germline BRCA1 PVs in MpBCs and to explore the possible involvement of other genes in MpBC predisposition. Unraveling a speci c MpBC molecular landscape is a starting point for the de nition of new therapeutic strategies, since these tumors have a poor prognosis.

Metaplastic breast cancer (MpBC) is a rare, aggressive type of breast cancer, often classified as triple negative (TN). Scarce information is available about germline testing in MpBC. We retrospectively reviewed MpBC patients counseled at our Institute and found to harbor germline pathogenic variants (PVs), and we revised literature data. We identified a germline PV in 15 MpBC patients: 13 in BRCA1 (86.7%), one in TP53 (6.7%), one in MLH1 (6.7%) genes. Eight MpBC PV carriers in BRCA1 have been previously described, including a patient with a PV in both BRCA1 and TP53. MpBC histological subtype in PV carriers was heterogeneous. All MpBCs were TN but 13.3% in our series showed HER2 overexpression. We described the largest series of MpBCs with germline PVs. As previously reported, we observed that BRCA1 is the mainly involved gene in MpBC patients who underwent germline testing according to specific selection criteria. Additional studies on unselected patients are required to assess the authentic role of germline BRCA1 PVs in MpBCs and to explore the possible involvement of other genes in MpBC predisposition. Unraveling a specific MpBC molecular landscape is a starting point for the definition of new therapeutic strategies, since these tumors have a poor prognosis.