PNPLA3 Single Nucleotide Polymorphism Prevalence and Association with Liver Disease in a Diverse Cohort of Persons Living with HIV

Diagnostic Ability of Simple Noninvasive Blood Tests to Predict Increased Liver Stiffness in People Living With HIV and Steatotic Liver Disease

INTRODUCTION

Steatotic liver disease is common in people with HIV (PWH). Identifying those with advanced fibrosis (AF, bridging fibrosis or cirrhosis), F3-4, is important. We aimed to examine the performance of FIB-4 and nonalcoholic fatty liver disease (NAFLD) fibrosis score (NFS) in PWH to identify those with AF assessed by liver stiffness measurement (LSM).

METHODS

We prospectively collected data on adults participating in 2 National Institute of Health-sponsored HIV NAFLD networks. All had HIV on antiretroviral therapy (ART) ≥6 months with HIV RNA <200 copies/mL. Those with viral hepatitis, other liver disease, excessive alcohol use, or hepatic decompensation were excluded. Vibration-controlled transient elastrography for LSM was performed, and AF defined as ≥11 kPa was compared with FIB-4 and NFS at predefined thresholds (<1.3 and >2.67 for FIB-4 and <-1.455 and >0.675 for NFS).

RESULTS

A total of 1,065 participants were analyzed: mean age 51.6 years, 74% male, 28% White, 46% Black, 22% Hispanic, with 34% overweight (body mass index 25-29 kg/m 2 ) and 43% obese (body mass index ≥30 kg/m 2 ). Features of the metabolic syndrome were common: hyperlipidemia 35%, type 2 diabetes 17%, and hypertension 48%. The median CD4 + T-cell count was 666 cells/mm 3 , 74% had undetectable HIV RNA, and duration of HIV-1 was 17 years with most taking a nucleoside reverse transcriptase inhibitor (92%) and an integrase inhibitor (83%). The mean LSM was 6.3 kPa, and 6.3% had AF. The area under the receiver characteristic curve for FIB-4 and NFS to identify AF were 0.70 and 0.75, respectively. While both had high negative predictive values (97%-98%), the sensitivity at low thresholds and specificity at high thresholds were 64% and 97% for FIB-4 and 80% and 96% for NFS, respectively. Neither FIB-4 nor NFS at either threshold had good positive predictive value to detect AF.

DISCUSSION

FIB-4 and NFS have excellent specificity and negative predictive value for detecting AF, and thus can be used as screening tools in PWH to exclude those with AF who do not need further testing (LSM) or referral to hepatologist.

Genetic variants associated with steatohepatitis and liver fibrosis in HIV-infected patients with NAFLD

Background and aims: Nonalcoholic fatty liver disease (NAFLD) is a common cause of liver damage in people living with HIV (PLWHIV). Several studies have investigated candidate genes for susceptibility to NAFLD and to steatohepatitis. PNPLA3, TM6SF2, and MBOAT7-TMC4 have been reported to be associated with elevated ALT levels and the histologic parameters of nonalcoholic steatohepatitis and severity of fibrosis. Our objective was to analyze the relationship between PNPLA3, TM6SF2, and MBOAT7-TMC4 and steatosis, steatohepatitis, and liver fibrosis in PLWHIV with NAFLD.

Method: A cohort of PLWHIV with persistently elevated aminotransferase levels and suspected NAFLD who underwent liver biopsy and determination of genetic variants was assessed at two large centers in Spain. All participants included in the current study were genotyped for rs738409 (PNPLA3), rs58542926 (TM6SF2), and rs641738 (MBOAT7-TMC4).

Results: The study population comprised PLWHIV who were on stable antiretroviral therapy [7.7% women; median age, 49.3 years (44–53.4)]. The median CD4 count was 829 (650–980), 60% had metabolic syndrome, and 18.5% were diabetic. The median BMI was 28.9 (25.5–30.8). Patients with liver steatosis (any grade) vs. nonsteatosis tended to harbor the PNPLA3 G allele variant [57.6% vs. 16.7% (p = 0.09)], but not TM6SF2 or MBOAT7-TMC4 variants. However, those with steatohepatitis vs. nonsteatohepatitis significantly more frequently had the PNPLA3 G allele variant [69.4% vs. 39.1% (p < 0.05)] and the MBOAT7-TMC4 A allele variant [75% vs. 42% (p < 0.05)]. In our cohort, the TM6SF2 gene variant was not associated with steatosis or steatohepatitis. The PNPLA3 G allele variant was associated with steatohepatitis [OR 4.9 (1.3–18); p 0.02] and liver fibrosis [OR 4.3 (1.1–17.4); p 0.04], and the MBOAT7-TMC4 A allele variant was associated with steatohepatitis [OR 6.6 (1.6–27.6); p 0.01].

Conclusion: The PNPLA3 G allele variant and MBOAT7-TMC4 A allele variant were associated with steatohepatitis and liver fibrosis in PLWHIV with persistently elevated aminotransferases and NAFLD. We recommend routine genotyping for PNPLA3 and MBOAT7-TMC4 in PLWHIV with NAFLD to identify those at higher risk of progression.