CD11a Expression on Lymphocytes, Disease Severity and Response to Therapy in Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disorder and there is a need to further enhance the understanding of the pathogenesis of ITP and look for newer targets for better treatment and outcome. We aimed to estimate the MFI (Mean Fluorescence Intensity) of CD11a on lymphocytes and correlate with the disease severity, and response to therapy in ITP. This case-control study was conducted at a tertiary care center in Northern Bharat. The patients aged more than 12 years with a diagnosis of ITP, confirmed as per ASH guidelines, were included in the study. Healthy volunteers were included as controls for the study. Statistical analysis was done using StatsModels 0.13.5 package of Python 3.11. Paired t test was used to compare pre and post treatment means of level of CD11a in patients who responded. The present study was conducted among 66 cases (ITP) and 36 controls. The result showed low MFI of the CD11a on CD19, CD3, and CD4 in ITP as compared to the healthy control, especially the statistically significant low MFI on CD3 cells (p < 0.05). Further, CD11a MFI showed a linear relationship with platelet count and there was a statistically significant reduction in CD11a MFI on CD3 cells in severe ITP as defined by WHO Bleeding Grade 3 when compared with WHO Bleeding Grade 1 and 2 (p < 0.05). Though statistically insignificant, the baseline MFI of the CD11a on CD4 was lower but on CD19, and CD3 it was higher in patients who were refractory to therapy. On follow-up (after treatment), the mean MFI of the CD11a on CD19, CD4, and CD3 was lower in refractory cases as compared to the non-refractory cases. The comparison of the baseline and after-treatment MFI of CD11a on CD19, CD3, and CD4 showed a slight increase. When stratified with refractory status: The CD11a on CD19 increased after treatment in both the groups however, the increase was higher in the non-refractory group. We conclude that the CD11a has a linear relationship with platelet count and there is statistically significant low MFI of CD11a on CD3 cells in severe ITP characterized by WHO Bleeding Grade 3. While on therapy, the lack of increase in CD11a MFI predicts poor response to the therapy.