Autoantibodies against CYP-2C19: A Novel Serum Marker in Pediatric De Novo Autoimmune Hepatitis?

Figure 1

(a-b) Indirect immunofluorescence (IF) results using the patient serum diluted at 1 : 640 in phosphate buffered saline and overlaid on rat liver (a) and kidney (b) sections (photomicrograph; lens 10x). For immune staining, a goat anti-human Ig FITC-conjugate antiserum was used at 1 : 100 dilution. The new LM antibody staining pattern involved mainly hepatocytes of the pericentral zone ((a), white arrow points to the central vein) and extended to the mid-lobule zone of the liver ((a), white circle, yellow arrows indicate the surrounding negative zone) while sparing the renal proximal tubular cells ((b), white arrows). (c) Immunoblotting results using human liver microsomal proteins separated in PAGE. Lane 1, LKM positive control serum from a patient affected by type 2 idiopathic AIH, main protein band recognized at ~50 kD; lane 2, LM positive serum from the reported case affected by de novo AIH, main protein band recognized at >51 kD; lane 3, atypical LKM positive control serum from a post-OLT patient, no protein band recognized. Markers on the left indicate the molecular weight standards in kilodaltons (kD). (d) Immunoblotting results using six recombinant cytochromes P450. Lanes from the left to the right: CYP-2D6, CYP-2C9, CYP-2C19, CYP-1A2, CYP-2A6, and CYP-3A4. (A) Results observed using the LM positive serum from the reported case affected by de novo AIH, autoantigen recognized: CYP-2C19. (B) Results observed using a LKM positive control serum from a patient affected by type 2 idiopathic AIH, autoantigen recognized: CYP-2D6. Markers on the left indicate the molecular weight standards in kilodaltons (kD).

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