
Henry Kaplan, M.D.
Secondary Adjunct Professor
Department of Ophthalmology
Studies on uveitis and retinal disorders.
Research Interests
We are interested in cone rescue in retinitis pigmentosa as well as the role of signaling pathways in the induction of autoimmune uveitis. We have also studied the contribution of retinal astrocytes to the aberrant angiogenesis in retinopathy of prematurity (ROP).
Recent Publications
Role of Complement in the Onset of Age-Related Macular Degeneration
Role of Complement in the Onset of Age-Related Macular Degeneration
Age-related macular degeneration (AMD) is a progressive degenerative disease of the central retina and the leading cause of severe loss of central vision in people over age 50. Patients gradually lose central visual acuity, compromising their ability to read, write, drive, and recognize faces, all of which greatly impact daily life activities. Quality of life is significantly affected in these patients, and there are worse levels of depression as a result. AMD is a complex, multifactorial disease in which age and genetics, as well as environmental factors, all play a role in its development and progression. The mechanism by which these risk factors interact and converge towards AMD are not fully understood, and therefore, drug discovery is challenging, with no successful therapeutic attempt to prevent the development of this disease. In this review, we describe the pathophysiology of AMD and review the role of complement, which is a major risk factor in the development of AMD.
Response to “Re: ‘Comparison of Endobronchial Intubation Versus Bronchial Blockade for Elective Pulmonary Lobectomy of Congenital Lung Anomalies in Small Children'”
Response to “Re: ‘Comparison of Endobronchial Intubation Versus Bronchial Blockade for Elective Pulmonary Lobectomy of Congenital Lung Anomalies in Small Children'”
Risk Reduction Strategy to Decrease Incidence of Retained Surgical Items
Risk Reduction Strategy to Decrease Incidence of Retained Surgical Items
Retained surgical items (RSIs) are rare but serious events associated with significant morbidity and costs. We assessed the effectiveness of radiofrequency (RF) detection technology and Team Strategies and Tools to Enhance Performance and Patient Safety (TeamSTEPPS) in reducing the incidence of RSIs.
Bidirectional Effect of IFN-γ on Th17 Responses in Experimental Autoimmune Uveitis
Bidirectional Effect of IFN-γ on Th17 Responses in Experimental Autoimmune Uveitis
Pro- and ant-inflammatory effects of IFN-γ have been repeatedly found in various immune responses, including cancer and autoimmune diseases. In a previous study we showed that the timing of treatment determines the effect of adenosine-based immunotherapy. In this study we examined the role of IFN-γ in pathogenic Th17 responses in experimental autoimmune uveitis (EAU). We observed that IFN-γ has a bidirectional effect on Th17 responses, when tested both and . Anti-IFN-γ antibody inhibits Th17 responses when applied in the initial phase of the immune response; however, it enhances the Th17 response if administered in a later phase of EAU. In the current study we showed that IFN-γ is an important immunomodulatory molecule in γδ T cell activation, as well as in Th17 responses. These results should advance our understanding of the regulation of Th17 responses in autoimmunity.
TLR ligand ligation switches adenosine receptor usage of BMDCs leading to augmented Th17 responses in experimental autoimmune uveitis
TLR ligand ligation switches adenosine receptor usage of BMDCs leading to augmented Th17 responses in experimental autoimmune uveitis
The extracellular level of adenosine increases greatly during inflammation, which modulates immune responses. We have previously reported that adenosine enhances Th17 responses while it suppresses Th1 responses. This study examined whether response of DC to adenosine contributes to the biased effect of adenosine and determined whether adenosine and TLR ligands have counteractive or synergistic effects on DC function. Our results show that adenosine is actively involved in both in vitro and in vivo activation of pathogenic T cells by DCs; however, under adenosine effect DCs’ capability of promoting Th1 versus Th17 responses are dissociated. Moreover, activation of A2ARs on DCs inhibits Th1 responses whereas activation of A2BRs on DC enhances Th17 responses. An intriguing observation was that TLR engagement switches the adenosine receptor from A2ARs to A2BRs usage of bone marrow-derived dendritic cells (BMDCs) and adenosine binding to BMDCs via A2BR converts adenosine’s anti-to proinflammatory effect. The dual effects of adenosine and TLR ligand on BMDCs synergistically enhances the Th17 responses whereas the dual effect on Th1 responses is antagonistic. The results imply that Th17 responses will gain dominance when inflammatory environment accumulates both TLR ligands and adenosine and the underlying mechanisms include that TLR ligand exposure has a unique effect switching adenosine receptor usage of DCs from A2ARs to A2BRs, via which Th17 responses are promoted. Our observation should improve our understanding on the balance of Th1 and Th17 responses in the pathogenesis of autoimmune and other related diseases.