Prevalence of Severe Acute Respiratory Syndrome Coronavirus 2 Neutralizing Antibodies in Egyptian Convalescent Plasma Donors.

Using convalescent plasma as immunotherapy is an old method for treatment of infectious diseases. Several countries have recently allowed the use of such therapy for the treatment of COVID-19 patients especially those who are critically ill. A similar program is currently being tested in Egypt. Here, we tested 227 plasma samples from convalescent donors in Egypt for neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using a microneutralization (MN) assay. A third of the tested samples did not have antibody titers and 58% had titers between 1:10 and 1:80. Only 12% had titers >1:160. We also compared MN assays using different virus concentrations, plaque reduction neutralization (PRNT) assays, and a chemiluminescence assay that measures immunoglobulin G (IgG) binding to N and S proteins of SARS-CoV-2. Our results indicated that a MN assay using 100 TCID50/ml provides comparable results to PRNT and allows for high throughput testing.

The impact of Fc gamma receptor IIa and IIIa gene polymorphisms on the therapeutic response of rituximab in Egyptian adult immune thrombocytopenic purpura.

Background In chronic immune thrombocytopenic purpura (ITP), rituximab removes the harmful autoantibodies through antibody-dependent cellular cytotoxicity. The response to rituximab in ITP is variable; the effectiveness of rituximab is influenced by the process of activation of effector fragment C gamma receptors (FcγRs). Genetic factors may affect the response to rituximab. Objectives The influence of FcγRIIa (H131R) and FcγRIIIa (V158F) gene polymorphisms on the response to rituximab in ITP. Methods One hundred ITP patients were genotyped for FcγRIIa (H131R) and FcγRIIIa (V158F) gene polymorphisms using the polymerase chain reaction-restriction fragment length polymorphism assay. The response at the end of the third month was assessed by direct platelets count. Polymorphisms were analyzed in relation to the response. Results The mean platelets count at end of weeks 1-4 of rituximab was statistically significantly higher in patients who achieved complete response (CR) than partial response or no response (P-value = .001). Although RR (44.4%) and HR (38.9%) genotypes were observed to be higher in patients who achieved CR compared with the wild (HH) genotype (16.7%), it was not statistically significantly different (P-value = .648). Conclusion The higher platelet count achieved early is predictive for a better response to rituximab later. FCγRIIA polymorphisms did not significantly influence response to rituximab in ITP.