Rubella vaccine-induced granulomas are a novel phenotype with incomplete penetrance of genetic defects in cytotoxicity.

BACKGROUND: Rubella virus-induced granulomas have been described in patients with various inborn errors of immunity. Most defects impair T-cell immunity, suggesting a critical role of T cells in rubella elimination. However, the molecular mechanism of virus control remains elusive. OBJECTIVE: This study sought to understand the defective effector mechanism allowing rubella vaccine virus persistence in granulomas. METHODS: Starting from an index case with Griscelli syndrome type 2 and rubella skin granulomas, this study combined an international survey with a literature search to identify patients with cytotoxicity defects and granuloma. The investigators performed rubella virus immunohistochemistry and PCR and T-cell migration assays. RESULTS: This study identified 21 patients with various genetically confirmed cytotoxicity defects, who presented with skin and visceral granulomas. Rubella virus was demonstrated in all 12 accessible biopsies. Granuloma onset was typically before 2 years of age and lesions persisted from months to years. Granulomas were particularly frequent in MUNC13-4 and RAB27A deficiency, where 50% of patients at risk were affected. Although these proteins have also been implicated in lymphocyte migration, 3-dimensional migration assays revealed no evidence of impaired migration of patient T cells. Notably, patients showed no evidence of reduced control of concomitantly given measles, mumps, or varicella live-attenuated vaccine or severe infections with other viruses. CONCLUSIONS: This study identified lymphocyte cytotoxicity as a key effector mechanism for control of rubella vaccine virus, without evidence for its need in control of live measles, mumps, or varicella vaccines. Rubella vaccine-induced granulomas are a novel phenotype with incomplete penetrance of genetic disorders of cytotoxicity.

JAK2V617F mutation status identifies subtypes of refractory anemia with ringed sideroblasts associated with marked thrombocytosis.

BACKGROUND: Refractory anemia with ringed sideroblasts and marked thrombocytosis (RARS-T) was recently shown to be a JAK2-V617F mutation-related disorder. To determine the frequency and the prognostic significance of this mutation, we retrospectively evaluated 23 patients with platelet counts more than 600 x 10(9)/L, 15% ringed sideroblasts or more, and at least erythroid marrow dysplasia. DESIGN AND METHODS: An allele-specific polymerase chain reaction for JAK2-V617F was used to determine the allelic ratio of the mutated JAK2 allele in DNA samples extracted from bone marrow biopsies. Hematologic and survival data of the JAK2-V617F positive vs. the JAK2-V617F negative patients were statistically analyzed. Allele-specific polymerase chain reaction was also used to screen for MPL-W515 mutations. RESULTS: The JAK2-V617F mutation was present in 11 patients (48%) and was associated with significantly higher erythrocyte and white blood cell counts (p=0.009 and 0.011, respectively). In 6/11 RARS-T patients the allelic ratio of JAK2-V617F was above 50%, indicating the presence of cells homozygous for the mutation. In two of these patients a transition from JAK2-V617F heterozygosity to homozygosity was documented and was accompanied by rising platelet counts in sequential samples. The MPL-W515L mutation was detected in one JAK2-V617F negative patient. The relative risk of death was found to be lower in the mutation-positive group than in the mutation-negative group. CONCLUSIONS: RARS-T patients with JAK2-V617F have a more favorable prognosis than those without the JAK2 mutation. The prevalence of homozygous JAK2-V617F mutation in RARS-T suggests that this entity is biologically distinct from essential thrombocythemia.

Numerical and structural centrosome aberrations are an early and stable event in the adenoma-carcinoma sequence of colorectal carcinomas.

AIMS: Numerical and structural centrosome changes have been described for and linked with genetic instability in solid tumors. Here, we specifically address centrosome aberrations in the adenoma-carcinoma sequence of colorectal cancer by detailed evaluation of gamma-tubulin staining patterns. METHODS: Formalin-fixed and paraffin-embedded specimens (normal colonic epithelium n=21; low-grade intraepithelial neoplasia n=27, high-grade intraepithelial neoplasia n=16 and invasive adenocarcinomas n=33) were stained by an anti-gamma-tubulin antibody using standard immunofluorescence. Three-dimensional image stacks of the stainings were recorded (Zeiss LSM510 confocal microscope), followed by numerical and structural data analysis (DIAS software package) and statistical evaluation (NCSS-software). RESULTS: The mean centrosome signal per cell differed significantly (P<0.0001) between normal colonic epithelium (0.8775) and each low-grade intraepithelial neoplasia (1.787), high-grade intraepithelial neoplasia (2.259) and invasive carcinomas (2.267). Similarly, both the centrosomes' structural entropy (SE) and minimal spanning tree (MST) differed significantly (P<0.001) between normal (SE=3.956, MST=38.78) and each low- (SE=6.39, MST=26) and high-grade intraepithelial neoplasia (SE=5.75, MST=26.97) and invasive carcinoma (SE=6.86, MST=28.08). CONCLUSION: Numerical and structural centrosome dysregulation is seen as early as in low-grade dysplastic lesions of the adenoma-carcinoma sequence of colorectal carcinomas and may, as such, play an initial role in the carcinogenic process.

Coordinated expression of cyclin D1 and LEF-1/TCF transcription factor is restricted to a subset of hepatocellular carcinoma.

BACKGROUND: While the Wnt pathway has been widely implicated in hepatocarcinogenesis, the role of cyclin D1 as a direct downstream target gene of beta-catenin-lymphoid enhancer factor-1 (LEF-1)/T-cell factor (TCF) signaling is controversely discussed. METHODS: By immunohistochemical analyses we studied the subcellular localization of LEF-1/TCF and cyclin D1 in 162 hepatocellular carcinoma (HCC). Single- and double-label imaging by brightfield and confocal laser scanning microscopy was quantitated and correlated with beta-catenin, the Ki67(+) proliferation fraction (PF), tumor size, grade, the Okuda stage and patient survival. RESULTS: The frequency of nuclear cyclin D1 expression was 28% and closely correlated with LEF-1/TCF (P<0.0001) and the Ki67(+) PF (P=0.03). Nuclear LEF-1/TCF expression was observed in 52% of all cases, but was also present in 42% of cyclin D1(-) cases. Nuclear beta-catenin was identified in 37% of all HCCs and correlated with LEF-1/TCF (P=0.04). The expression of cyclin D1, LEF-1/TCF or beta-catenin did not correlate with other clinico-pathological data. CONCLUSIONS: A large proportion of HCCs does not appear to be linked to a deregulation of cyclin D1. However, the coordinated expression of cyclin D1 and LEF-1/TCF in some cases suggests the role of cyclin D1 as a Wnt target gene in a subset of HCCs.