Key Points• Detection of multiple HY-Abs at 3 months post-F→M HCT predicts cGVHD incidence, severity, and nonrelapse mortality.• Patients with a high HY score may be good candidates for cGVHD prevention trials, especially those targeting allogeneic B cells.Allogeneic antibodies against minor histocompatibility antigens encoded on the Y chromosome (HY-Abs) develop after hematopoietic cell transplant (HCT) of male recipients with female donors (F→M). However, the temporal association between HY-Ab development and chronic graft-versus-host disease (cGVHD) has yet to be elucidated. We studied 136 adult F→M HCT patients, with plasma prospectively collected through 3 years posttransplant, and measured immunoglobulin G against 6 H-Y antigens. Multiple HY-Abs were frequently detected beginning at 3 months posttransplant: 78 (57%) of F→M patients were seropositive for at least 1 of the 6 HY-Abs, and 3-month seropositivity for each HYAb was associated with a persistent seropositive response throughout the posttransplant follow-up period (P < .001 in each). There were no associations between pretransplant features and 3-month overall HY-Ab development. Detection of multiple HY-Abs at 3 months (represented by HY score) was significantly associated with an increased risk of cGVHD (P < .0001) and nonrelapse mortality (P < .01). Compared to clinical factors alone, the addition of HY score to clinical factors improved the predictive potential of cGVHD (P < .01). Monitoring HY-Ab development thus stratifies cGVHD risk in F→M HCT patients and may support preemptive prophylaxis therapy for cGVHD beginning at 3 months posttransplant. (Blood. 2015;125(20):3193-3201)

H-Y antigens are a group of minor histocompatibility antigens encoded on the Y-chromosome with homologous H-X antigens on the X-chromosome. The disparate regions of the H-Y antigens are highly immunogenic and play an important role in understanding human alloimmunity. In this review, we investigate the history of H-Y antigen discovery along with their critical contributions in transplantation and pregnancy. In hematopoietic cell transplantation, male recipients with female donors who become seropositive for B-cell responses as H-Y antibodies following transplantation have increased rates of chronic graft-versus-host disease and decreased rates of relapse. Conversely, female patients who receive male kidney allografts are more likely than other gender combinations to develop H-Y antibodies and reject their allografts. Finally, in the setting of pregnancy, mothers who initially gave birth to boys are more likely to have subsequent pregnancy complications, including miscarriages, in association with H-Y antibody development. H-Y antigens continue to serve as a model for alloimmunity in new clinical scenarios. Our development of more sensitive antibody detection and next-generation DNA sequencing promises to further advance our understanding and better predict the clinical consequences of alloimmunity.

Background B-cells play a significant role in chronic graft-versus-host disease (cGVHD). Male patients with female donors (F→M) are at a higher risk of developing cGVHD. B cell responses against minor histocompatibility antigens encoded on the Y chromosome, called H-Y antigens, develop following F→M HCT patients in association with cGVHD (Miklos, Blood. 2005 & Sahaf, PNAS. 2013). Here we present our novel HY microarray and use this sensitive technology to determine temporal development of HY antibody (Ab) preceding cGVHD. Multivariate analyses demonstrate that HY-Ab detection 3 months (3m) post HCT predicts cGHVD incidence and non-relapse mortality (NRM). Methods We studied 136 adult male recipients of F→M HCT between 2005 and 2012 who survived without relapse for at least 3m post-HCT with 3m plasma available. Median patient age was 53 (21-74). Related donors were transplanted in 85 (63%) and 128 (94%) were PBSC grafts. Reduced intensity conditioning accounted for 61 (45%) and anti-thymocyte globulin (ATG) was used in 71 (52%). Thirty-one patients (23%) experienced grade II-IV acute GVHD. We measured IgG against six HY antigens (DBY, UTY, ZFY, SMCY, EIF1AY, and RBS4Y) from plasma collected 3m post-HCT using a novel proteomic microarray here presented for the first time. The cut-off value for seropositivity was defined as the third quartile + 2x the interquartile range, determined from plasma of 60 male donors. HY-score was defined as the cumulative number of HY antigen targeted by Abs at 3m post-HCT. Results The frequencies of HY antigen-specific Ab are presented in Table 1, showing that SMCY and UTY were most frequently detected and overall, 78 (57%) had developed allo-Ab against any of these 6 HY antigens. Each HY-Ab was significantly associated with the development of cGVHD and DBY was greatest. LASSO analysis suggested that DBY, UTY, and ZFY were the most predictive for the development of cGVHD (Table 1). Univariate analysis failed to identify associations between clinical features and the development of HY-Ab at 3m. The detection of HY-Ab gradually increased within the 1st year post HCT and seropositivity for each HY-IgG (except RPS4Y) persisted. Considering each HY-IgG response by principal component analysis, a higher HY-score was associated with an increased risk for the development of cGVHD and NRM, after adjusting for usual alloHCT clinical factors (Table 2). In addition, the severity of cGVHD was significantly associated with the HY-score: the proportion of severe/moderate cGVHD was 33% in 0, 30% in 1, 60% in 2-3, and 70% in 4-6 (P<0.01). Receiver operating characteristic (ROC) curve analysis revealed that HY-score in combination with clinical factors enhanced the predictive potential for the development of cGVHD [area under the curve (AUC): 0.76], in comparison with either of only HY-score (AUC: 0.66) or clinical factors (AUC: 0.69). Conclusion Here, we show that HY Ab detection 3m following sex-mismatch HCT actually predicts the development of cGVHD, independently from clinical risk factors. In addition, the combination of HY-score and clinical factors had a greater predictive potential than clinical factors alone for the development of cGVHD in F→M HCT. HY-Ab development 3m post HCT may stratify cGVHD risk and support B-cell-depletion therapy beginning 3 months or earlier to prevent cGVHD development. Disclosures: No relevant conflicts of interest to declare.

Background: TSH-secreting pituitary adenoma is an incredibly rare cause of hyperthyroidism. Most patients with TSHomas present with clinical hyperthyroidism, but some patients may have atypical signs. Here we present the case of a patient who had been suffering from low libido and insomnia who was found to have secondary hyperthyroidism from a TSH-secreting pituitary adenoma. Clinical Case: A 47-year-old man presented with complaints of progressive headache, fatigue, depression, insomnia, low libido and erectile dysfunction. After questioning, he noted the presence of intentional tremor for more than 5 years. He denied anxiety, palpitations, heat intolerance, hyper defecation, proximal muscle weakness, local compressive symptoms of the neck and ocular symptoms. Physical exam was notable for fine tremor and mild thyromegaly, but otherwise patient had no evidence of anxiety, exophthalmos, hyperreflexia or diaphoresis. The patient was found to have a normal free testosterone (46 pg/mL, n 30-140 pg/mL) but had an elevated TSH (6.302 IU/mL, n 0.4-5 IU/mL), elevated Free T4 (3.6 ng/dL, n 0.6-1.2 ng/dL) and an elevated T3 (422 ng/dL, n 73-178 ng/dL). Further lab work revealed elevated alpha-subunit (4.4 ng/mL, n &lt;0.5 ng/mL) suggestive of TSH-secreting pituitary adenoma. Prolactin and IGF-1 levels were normal. Patient had an MRI pituitary which showed a 2.3 cm sellar mass abutting the optic chiasm without involvement of the cavernous sinus. Patient proceeded to trans-sphenoidal resection. Post-operatively, TSH had dropped from 6.534 to 0.002 IU/mL (n 0.4-5 IU/mL) and Free T4 had dropped from 3.1 to 0.5 ng/dL (n 0.6-1.2 ng/dL). Interestingly, immunohistochemical staining was negative for TSH but the specimen did show histologic features characteristic of TSH-producing adenoma including extensive stromal fibrosis and nuclear pleomorphism. Patient was seen in clinic post-operatively where he noted a dramatic improvement in his headache and insomnia. He did show signs of hypothyroidism including constipation and weight gain. Patient was started on levothyroxine 75 mcg PO daily. Conclusion: This demonstrates the case of a patient with a TSH-secreting pituitary adenoma who presented with minimal thyrotoxic symptoms despite elevated thyroid hormones. Patients with this condition may present with atypical symptoms, thus requiring clinicians to have a high index of suspicion for this rare tumor. References: (1) Beck-Peccoz, P., Lania, A., Beckers, A. et al. 2013 European thyroid association guidelines for the diagnosis and treatment of thyrotropin-secreting pituitary tumors. Eur Thyroid J 2013; 2:76. (2) Cossu, G., Daniel, R.T., Pierzchala, K. et al. Thyrotropin-secreting pituitary adenomas: a systematic review and meta-analysis of postoperative outcomes and management. Pituitary 2019; 22:79.

results suggest that post-transplant IL-22 administration represents a novel strategy to reduce gut GVHD by direct protection of intestinal epithelium without limiting immune function post-transplant.