Letter to the Editor: Is Nodular Regenerative Hyperplasia an Immune-Mediated Phenomenon?

Tip of the iceberg: A comprehensive review of liver disease in Inborn errors of immunity

Inborn errors of immunity (IEIs) consist of numerous rare, inherited defects of the immune system that affect about 500,000 people in the United States. As advancements in diagnosis through genetic testing and treatment with targeted immunotherapy and bone marrow transplant emerge, increasing numbers of patients survive into adulthood posing fresh clinical challenges. A large spectrum of hepatobiliary diseases now present in those with immunodeficiency diseases, leading to morbidity and mortality in this population. Awareness of these hepatobiliary diseases has lagged the improved management of the underlying disorders, leading to missed opportunities to improve clinical outcomes. This review article provides a detailed description of specific liver diseases occurring in various inborn errors of immunity. A generalized approach to diagnosis and management of hepatic complications is provided, and collaboration with hepatologists, immunologists, and pathologists is emphasized as a requirement for optimizing management and outcomes.

Nodular regenerative hyperplasia in X-linked agammaglobulinemia: An underestimated and severe complication

BACKGROUND

Late-onset complications in X-linked agammaglobulinemia (XLA) are increasingly recognized. Nodular regenerative hyperplasia (NRH) has been reported in primary immunodeficiency but data in XLA are limited.

OBJECTIVES

This study sought to describe NRH prevalence, associated features, and impact in patients with XLA.

METHODS

Medical records of all patients with XLA referred to the National Institutes of Health between October 1994 and June 2019 were reviewed. Liver biopsies were performed when clinically indicated. Patients were stratified into NRH+ or NRH- groups, according to their NRH biopsy status. Fisher exact test and Mann-Whitney test were used for statistical comparisons.

RESULTS

Records of 21 patients with XLA were reviewed, with a cumulative follow-up of 129 patient-years. Eight patients underwent ≥1 liver biopsy of whom 6 (29% of the National Institutes of Health XLA cohort) were NRH+. The median age at NRH diagnosis was 20 years (range, 17-31). Among patients who had liver biopsies, alkaline phosphatase levels were only increased in patients who were NRH+ (P = .04). Persistently low platelet count (<100,000 per μL for >6 months), mildly to highly elevated hepatic venous pressure gradient and either hepatomegaly and/or splenomegaly were present in all patients who were NRH+. In opposition, persistently low platelet counts were not seen in patients who were NRH-, and hepatosplenomegaly was observed in only 1 patient who was NRH-. Hepatic venous pressure gradient was normal in the only patient tested who was NRH-. All-cause mortality was higher among patients who were NRH+ (5 of 6, 83%) than in the rest of the cohort (1 of 15, 7% among patients who were NRH- and who were classified as unknown; P = .002).

CONCLUSIONS

NRH is an underreported, frequent, and severe complication in XLA, which is associated with increased morbidity and mortality.

Pathologic Manifestations of Gastrointestinal and Hepatobiliary Injury in Immune Checkpoint Inhibitor Therapy

CONTEXT.—

Immune checkpoint inhibitors (CPIs), including cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors and the programmed death receptor-1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors, are being increasingly used for treating many advanced malignancies. However, CPI therapy is also associated with gastrointestinal and hepatobiliary adverse effects.

OBJECTIVES.—

To review the adverse effects of CPI therapy on the gastrointestinal tract and hepatobiliary system. To describe histopathologic patterns and discuss differential diagnostic considerations in the diagnosis of CPI injuries.

DATA SOURCES.—

Published peer-reviewed literature in the English language and personal experience in the diagnosis of CPI injuries.

CONCLUSIONS.—

The pathologic manifestations of CPI therapy-induced gastrointestinal and hepatobiliary injury are broad. The patterns of esophageal CPI injury include lymphocytic inflammation and ulcerative esophagitis, while those of gastric injury include chronic active gastritis, lymphocytic gastritis, focal enhancing gastritis, and periglandular inflammation. The duodenal injury may present as duodenitis with villous blunting and granulomas. We also noticed active colitis, microscopic colitis, chronic active colitis, increased apoptosis, ischemic colitis, and nonspecific inflammatory reactive changes in colonic injuries. The reported histologic features of hepatobiliary injuries are panlobular hepatitis, centrilobular necrosis, portal inflammation with bile duct injury, steatosis, nodular regenerative hyperplasia, and secondary sclerosing cholangitis. In summary, we discuss the pathologic features and differential diagnosis of CPI therapy-induced gastrointestinal and hepatobiliary injury. Recognition of CPI injury is important to determine the proper management that often includes cessation of CPI therapy, and administration of steroids or other immunosuppressive agents, based on severity of injury.