RISK-FACTORS FOR CHOROIDAL NEOVASCULARIZATION IN YOUNG-PATIENTS - A CASE-CONTROL STUDY

A pair-matched, case-control design was used to study exposure to Hist oplasma capsulatum and other environmental factors, and to determine v arious host characteristics including human leukocyte antigen (HLA) ty pings in 94 young patients with macular choroidal neovascularization ( CNV) and in 94 controls with other eye diseases. Patients with two typ es of retinal patterns were studied: Type I, or those with CNV with on e or no chorioretinal atrophic spots in the posterior pole or peripher y (n = 51), and Type II, or those with CNV and 2 or more chorioretinal atrophic spots (n = 43). Our purpose was to explore whether these two variants of idiopathic CNV have different and distinguishable epidemi ologies which may or may not be related to prior exposure to Histoplas ma. We found that histoplasmin skin tests were negative in all but two Type I cases. The combination of the HLA-B7 and HLA-DR2 markers (but not either marker alone) was significantly increased in Type I cases. Among Type II cases, HLA-B7, HLA-DR2, HLA-DQ1, a positive histoplasmin skin test, myopic refractive error, prior residence in a histoplasmos is endemic area, occupations involving exposure to animals, and hypert ension were all significantly increased. Histoplasmin skin test respon ses were positive in 18 Type II cases (45%). In the multivariate analy sis, only DR2 and the combined presence of DQ1 and a positive histopla smin skin test remained predictive of Type II disease. Our findings su ggest that histoplasmin sensitivity is associated with some, but not a ll, cases of Type II disease. However, histoplasmin sensitivity appear s to have no relationship to Type I disease. HLA factors may play a ro le in both disease types, possibly by producing a modified immune resp onse to Histoplasma and/or other unidentified agents.