Steven M. Holland

Abnormal Regulation of Interferon-γ, Interleukin-12, and Tumor Necrosis Factor-α in Human Interferon-γ Receptor 1 Deficiency

Mycobacterial infections are critically controlled by interferon-gamma (IFN-gamma) and the cellular responses it elaborates, as shown by patients with mutations in the IFN-gamma receptor ligand-binding chain (IFN-gamma R1) who have disseminated nontuberculous mycobacterial infections. The immunologic sequelae of IFN-gamma R1 deficiency were characterized in 2 unrelated patients from the Indian subcontinent with novel homozygous recessive IFN-gamma R1 mutations. In vitro, these patients peripheral blood mononuclear cells produced 10% of normal IFN-gamma and interleukin-12 (IL-12) in response to phytohemagglutinin (PHA) but normal amounts of IFN-gamma in response to PHA plus IL-12. Tumor necrosis factor-alpha (TNF-alpha) production was normal in response to endotoxin and to PHA but was not augmented by the addition of IFN-gamma. An abnormal phenotype was not found in heterozygous patient relatives. These patients demonstrate the critical role that the IFN-gamma receptor plays in the regulation of IFN-gamma, IL-12, and TNF-alpha.

Spleen and Liver Volumetrics as Surrogate Markers of Hepatic Venous Pressure Gradient in Patients With Noncirrhotic Portal Hypertension

Noncirrhotic portal hypertension (NCPH) is a rare disease that may lead to serious clinical consequences. Currently, noninvasive tools for the assessment of NCPH are absent. We investigated the utility of spleen and liver volumetrics as a marker of the presence and severity of portal hypertension in this population. A cohort of NCPH patients evaluated between 2003 and 2015 was retrospectively studied. The association of spleen and liver volumes with the hepatic venous pressure gradient (HVPG) level was evaluated using locally weighted scatterplot smoothing curves. A cohort of patients with viral hepatitis‐related liver disease was used as controls. Of the 86 patients with NCPH evaluated during the study period, 75 (mean age, 35 ± 17; 73% males) were included in the final analysis. Patients with portal hypertension had significantly higher spleen and liver to body mass index (BMI) ratios compared to patients with HVPG <5 mm Hg (39.5 ± 27.9 versus 22.8 ± 10.6 cm3/kg/m2, P = 0.003; 91.1 ± 40.1 versus 71.4 ± 16.7 cm3/kg/m2, P = 0.014, for spleen/BMI and liver/BMI, respectively). In contrast to the patients with viral hepatitis, a positive linear correlation was observed in the NCPH cohort between spleen/BMI and liver/BMI (above a cutoff of 25 and 80 cm3/kg/m2, respectively) and HVPG level. Additionally, only in the NCPH cohort was an increase in spleen/BMI range quartile predictive of a higher prevalence of portal hypertension and clinically significant portal hypertension (trend, P = 0.014 and 0.031, respectively). Conclusion: Spleen and liver volumetrics may have utility in the assessment of NCPH as a noninvasive biomarker that can be performed using routine radiologic examinations. Further studies are needed to validate these findings. (Hepatology Communications 2018; 00:000‐000)

ArticlesClinical features of dominant and recessive interferon γ receptor 1 deficiencies

BACKGROUND n nInterferon gamma receptor 1 (IFNgammaR1) deficiency is a primary immunodeficiency with allelic dominant and recessive mutations characterised clinically by severe infections with mycobacteria. We aimed to compare the clinical features of recessive and dominant IFNgammaR1 deficiencies. n nMETHODS n nWe obtained data from a large cohort of patients worldwide. We assessed these people by medical histories, records, and genetic and immunological studies. Data were abstracted onto a standard form. n nFINDINGS n nWe identified 22 patients with recessive complete IFNgammaR1 deficiency and 38 with dominant partial deficiency. BCG and environmental mycobacteria were the most frequent pathogens. In recessive patients, 17 (77%) had environmental mycobacterial disease and all nine BCG-vaccinated patients had BCG disease. In dominant patients, 30 (79%) had environmental mycobacterial disease and 11 (73%) of 15 BCG-vaccinated patients had BCG disease. Compared with dominant patients, those with recessive deficiency were younger at onset of first environmental mycobacterial disease (mean 3.1 years [SD 2.5] vs 13.4 years [14.3], p=0.001), had more mycobacterial disease episodes (19 vs 8 per 100 person-years of observation, p=0.0001), had more severe mycobacterial disease (mean number of organs infected by Mycobacterium avium complex 4.1 [SD 0.8] vs 2.0 [1.1], p=0.004), had shorter mean disease-free intervals (1.6 years [SD 1.4] vs 7.2 years [7.6], p<0.0001), and lower Kaplan-Meier survival probability (p<0.0001). M avium complex osteomyelitis was more frequent in dominant than in recessive patients (22/28 [79%] vs 1/8 [13%], p=0.002), and this disorder without other organ involvement arose only in dominant patients (9/28 [32%]). Disease caused by rapidly growing mycobacteria was present in more recessive than dominant patients (7/22 [32%] vs 1/38 [3%], p=0.002). n nINTERPRETATION n nRecessive complete and dominant partial IFNgammaR1 deficiencies have related clinical phenotypes, but are distinguishable by age at onset, dissemination, and clinical course of mycobacterial diseases. A strong correlation exists between IFNGR1 genotype, cellular responsiveness to interferon gamma, and clinical disease features.