Abstract
Purpose:
Paraneoplastic exudative vitelliform polymorphous maculopathy (PEVPM) is a rare retinal disorder that occurs secondary to neoplastic disease. Autoantibodies to bestrophin 1 and other proteins in the retinal pigment epithelium (RPE) have been previously reported in PEVPM patients. We analyzed the serum of a patient with PEVPM secondary to multiple myeloma with kappa light chain deposition disease to test the hypothesis that she developed autoantibodies to human Bestrophin-1 (Best1).
Methods:
The medical records and serum of a patient with multiple myeloma and PEVPM were analyzed. HEK293 cells were transfected with Best1 and stained with either an antibody specific to Best1, or control or patient serum. Staining patterns were compared to those of untransfected cells stained with E6-6, patient serum, control serum, or secondary antibody alone. Western blots of RPE lysates were performed using E6-6, patient serum, control serum, or secondary antibody alone to demonstrate whether the patient’s serum contained anti-Best1 antibodies.
Results:
A 61-year-old female with multiple myeloma with kappa light chain deposition disease developed blurred vision approximately 3 years after myeloma diagnosis. Exam revealed multiple yellow-orange subretinal and sub-RPE deposits consistent with PEVPM on OCT and fundus autofluorescence. EOG revealed a sub-normal Arden ratio. Patient serum was tested for autoantibodies recognizing Best1. Immunofluorescence staining of HEK-293 cells or HEK-293 cells expressing Best1 did not differ between patient and control sera or show a staining pattern consistent with recognition of Best1, indicating a lack of Best1-specific autoantibodies. Both patient and control sera recognized antigens in untransfected HEK293 cells. Immunoblotting of human RPE lysate with patient serum did not identify Best1 (68 kDa) but did recognize a band at approximately 48 kDa that was absent in blots using control serum.
Conclusions:
While a prior report indicated that Best1 autoantibodies could be involved in PEVPM, we find no evidence for anti-Best1 autoantibodies in this case. Similar to other reports, however, we did identify autoantibodies against a 48-kDa RPE protein, suggesting that autoantibody formation is a component of PEVPM.