Fatal Human Rabies Infection With Suspected Host-Mediated Failure of Post-Exposure Prophylaxis Following a Recognized Zoonotic Exposure-Minnesota, 2021.

BACKGROUND: No human rabies post-exposure prophylaxis (PEP) failure has been documented in the United States using modern cell culture-based vaccines. In January 2021, an 84-year-old male died from rabies 6 months after being bitten by a rabid bat despite receiving timely rabies PEP. We investigated the cause of breakthrough infection. METHODS: We reviewed medical records, laboratory results, and autopsy findings and performed whole-genome sequencing (WGS) to compare patient and bat virus sequences. Storage, administration, and integrity of PEP biologics administered to the patient were assessed; samples from leftover rabies immunoglobulin were evaluated for potency. We conducted risk assessments for persons potentially exposed to the bat and for close patient contacts. RESULTS: Rabies virus antibodies present in serum and cerebrospinal fluid were nonneutralizing. Antemortem blood testing revealed that the patient had unrecognized monoclonal gammopathy of unknown significance. Autopsy findings showed rabies meningoencephalitis and metastatic prostatic adenocarcinoma. Rabies virus sequences from the patient and the offending bat were identical by WGS. No deviations were identified in potency, quality control, administration, or storage of administered PEP. Of 332 persons assessed for potential rabies exposure to the case patient, 3 (0.9%) warranted PEP. CONCLUSIONS: This is the first reported failure of rabies PEP in the Western Hemisphere using a cell culture-based vaccine. Host-mediated primary vaccine failure attributed to previously unrecognized impaired immunity is the most likely explanation for this breakthrough infection. Clinicians should consider measuring rabies neutralizing antibody titers after completion of PEP if there is any suspicion for immunocompromise.

High mobility group A1 (HMGA1) protein and gene expression correlate with ER-negativity and poor outcomes in breast cancer.

PURPOSE: The high mobility group A1 (HMGA1) chromatin remodeling protein is required for metastatic progression and cancer stem cell properties in preclinical breast cancer models, although its role in breast carcinogenesis has remained unclear. To investigate HMGA1 in primary breast cancer, we evaluated immunoreactivity score (IRS) in tumors from a large cohort of Asian women; HMGA1 gene expression was queried from two independent Western cohorts. METHODS: HMGA1 IRS was generated from breast tumors in Korean women as the product of staining intensity (weak = 1, moderate = 2, strong = 3) and percent positive cells (< 5% = 0, 5-30% = 1, 30-60% = 2, > 60% = 3), and stratified into three groups: low (< 3), intermediate (3-6), high (> 6). We assessed HMGA1 and estrogen receptor (ESR1) gene expression from two large databases (TCGA, METABRIC). Overall survival was ascertained from the METABRIC cohort. RESULTS: Among 540 primary tumors from Korean women (181 ER-negative, 359 ER-positive), HMGA1 IRS was < 3 in 89 (16.5%), 3-6 in 215 (39.8%), and > 6 in 236 (43.7%). High HMGA1 IRS was associated with estrogen receptor (ER)-negativity (χ2 = 12.07; P = 0.002) and advanced nuclear grade (χ2 = 12.83; P = 0.012). In two large Western cohorts, the HMGA1 gene was overexpressed in breast cancers compared to non-malignant breast tissue (P < 0.0001), including Asian, African American, and Caucasian subgroups. HMGA1 was highest in ER-negative tumors and there was a strong inverse correlation between HMGA1 and ESR1 gene expression (Pearson r = - 0.60, P < 0.0001). Most importantly, high HMGA1 predicted decreased overall survival (P < 0.0001) for all women with breast cancer and further stratified ER-positive tumors into those with inferior outcomes. CONCLUSIONS: Together, our results suggest that HMGA1 contributes to estrogen-independence, tumor progression, and poor outcomes. Moreover, further studies are warranted to determine whether HMGA1 could serve as a prognostic marker and therapeutic target for women with breast cancer.

PD-L1 expression and the immune microenvironment in primary invasive lobular carcinomas of the breast.

Tumor-infiltrating lymphocytes and immune checkpoint proteins such as PD-L1 are potential prognostic factors and therapeutic targets in breast cancer. Most studies characterizing the breast tumor immune microenvironment have focused on ductal carcinomas. Here we investigate the tumor microenvironment of primary invasive lobular carcinomas. Previously constructed tissue microarrays of 47 lobular carcinomas were labeled by immunohistochemistry for PD-L1, CD8, CD20, and FoxP3. The stromal immune infiltrate density was qualitatively scored as a percentage of tumor area: 1+ (<5%); 2+ (5-10%); 3+ (10-15%); or 4+ (>50%). The average immune cell subtype per high-power field was quantitatively scored. The percentage PD-L1 labeling on tumor-infiltrating lymphocytes was scored as none, focal (<5%), moderate (10-24%), or diffuse (50-100%). The percentage of membranous carcinoma cell PD-L1 labeling was also recorded, with <5% considered negative. All lobular carcinomas contained PD-L1+ tumor-infiltrating lymphocytes with the majority showing 1+ immune infiltrates with focal-moderate PD-L1 labeling. PD-L1 was expressed by tumor cells in 17% of lobular carcinomas. In contrast to ductal carcinomas, there was no correlation between the immune infiltrate density, the PD-L1 expression by lobular carcinoma cells, tumor grade, or the expression of estrogen receptor or human epidermal growth factor receptor-2. However, both the tumor-infiltrating lymphocyte density and the average CD8+ T-cell counts correlated with immune cell PD-L1 status (P=0.004 and 0.03, respectively). Similar to breast ductal carcinomas, PD-L1+ lobular breast carcinomas had higher numbers of PD-L1+ tumor-infiltrating lymphocytes (63%) than PD-L1- lobular carcinomas (23%; P=0.04). These data show that a subset of primary breast lobular carcinomas both express PD-L1 on tumor cells and contain PD-L1+ tumor-infiltrating lymphocytes, suggesting the possibility of both constitutive and adaptive PD-L1 expression. Together, these results support immunotherapy as a potential treatment for a subset of patients with primary invasive lobular breast carcinomas.

A subset of fat-predominant angiomyolipomas label for MDM2: a potential diagnostic pitfall.

Angiomyolipomas (AMLs) are typically benign mesenchymal tumors with variable histologic composition. Fat-predominant AMLs can mimic well-differentiated liposarcomas (WDLSs) both radiographically and histologically because of the abundance of fat with admixed atypical cells resembling lipoblasts. However, the treatment and prognosis of AMLs and WDLSs are vastly different. Immunohistochemistry for murine double minute 2 (MDM2) has been used to support a diagnosis of WDLS; however, MDM2 labeling has not been specifically evaluated in fat-predominant AMLs. Here, we evaluated MDM2 immunohistochemistry in 36 AMLs (including 14 conventional AMLs, 13 fat-predominant AMLs, 6 fat-rich AMLs, 3 epithelioid AMLs) and 10 WDLSs. In addition, we labeled cases for HMB45, calponin, or actin, which are immunostains traditionally used to label AML. We performed fluorescence in situ hybridization (FISH) for MDM2 amplification on selected cases. By immunohistochemistry, 14% (5/36) of AMLs were MDM2+, including 23% (3/13) of fat-predominant AMLs. All MDM2+ AMLs evaluated by FISH (n=4) were negative for MDM2 amplification. By immunohistochemistry, 90% of WDLSs were MDM2+, and both MDM2+ WDLSs evaluated by FISH (n=2) were MDM2 amplified. All 36 AMLs labeled with HMB45 and calponin or actin. No WDLS labeled with HMB45; however, 80% of WDLSs labeled with calponin or actin. Although uncommon, MDM2 labeling is seen in a subset of fat-predominant AMLs and is a potential diagnostic pitfall in the evaluation of fatty tumors of the retroperitoneum. HMB45 is more sensitive and specific for AML than calponin or actin, and an immunopanel containing both HMB45 and MDM2 may be warranted to distinguish between fat-predominant AML and WDLS in histologically ambiguous cases.

NKX3.1 is expressed in ER-positive and AR-positive primary breast carcinomas.

AIMS: NKX3.1 is an androgen-regulated tumour suppressor gene that is downregulated in prostate carcinoma. Immunohistochemistry for NKX3.1 is primarily specific for prostatic-derived tumours and tissue but is reported in a small number of breast carcinomas. NKX3.1 is also shown to inhibit estrogen receptor (ER) signalling in breast carcinoma models. Here, we investigate labelling of NKX3.1 in invasive ductal (IDC) and lobular (ILC) carcinomas of the breast with full characterisation of ER, progesterone receptor (PR), androgen receptor (AR) and Her2 status. METHODS: Tissue microarrays of 86 primary IDC and 37 ILC were labelled for NKX3.1. The IDC consisted of 20 luminal A, 7 luminal B, 14 Her2, and 45 triple negative carcinomas. The ILC consisted of 34 luminal A and 3 luminal B cases. NKX3.1 expression was scored as percentage nuclear labelling and labelling intensity. RESULTS: Nuclear NKX3.1 labelling was seen in 2 IDC (2%) and 10 ILCs (27%). labelling intensity was weak in all cases (1­100% nuclear positivity). Positive NKX3.1 labelling was significantly associated with ILC (p<0.0001). NKX3.1 labelling was seen only in ER and AR-positive carcinomas, which showed a significant correlation (p=0.0003 and p=0.0079, respectively). Expression was not correlated with tumour stage, size, Her2 expression, presence of lymph node metastases or age. CONCLUSIONS: This is the first study to evaluate NKX3.1 expression in breast carcinomas with known ER, PR, AR and Her2 status. Further studies are needed to evaluate what potential role NKX3.1 plays in ER and AR signalling and hormonal treatment response in breast carcinomas.