Response to: regarding the significance of anti-COVID-IgA antibody response in COVID-19 breakthrough infection.

In response to Chen et al.'s comments on our paper regarding the significance of anti-COVID-IgA antibody response in COVID-19 breakthrough infection in vaccinated patients, we have highlighted the role and the scope of this paper in this correspondence. The role of anti-COVID-19-IgA is already known. The objective of the previous study was to see its role in breakthrough-infected patients. To analyse this effect, we recruited patients with COVID-19 infection after they were fully vaccinated and compared them with the vaccinated group who did not get the infection. Both groups were equally exposed to the virus as all of them were health care workers. We also showed that the anti-COVID-19-NP-IgA was absent in the healthy cohort of our study groups, signifying the absence of natural infection in them during this period. The article also highlights the importance of vaccinating all individuals including those who are immunosuppressed, as it prevents severe COVID-19 infection in these individuals. The physicians should be aware of the fact that immunosuppressed patients are more likely to get COVID-19 breakthrough infection. However, proper vaccination with booster doses prevents severe infection in them.

Significance of Anti-COVID-IgA antibody response in COVID-19 breakthrough infection in vaccinated patients - a single-centered study from Pakistan.

An increasing number of breakthrough-COVID-19-vaccinated individuals are being reported across the world. Humoral immunity has a crucial role in combating infection. In this study, we aimed to assess the importance of anti-COVID-S1-IgA and anti-COVID-NP-IgA in confirmed COVID-19 after vaccination (breakthrough infection group). Blood samples were collected from the breakthrough infection group within one week of breakthrough infections (n = 34). A second sample was also collected after 4 to 8 weeks (n = 27). Blood samples of healthy individuals (n = 29) were collected 4-8 weeks after the completion of vaccination. Anti-COVID-S1-IgA and anti-COVID-NP-IgA were detected by ELISA. Statistical analysis was performed using IBM SPSS version 24. In this study, we found a higher positivity rate for anti-COVID-S1-IgA in the breakthrough infection group (70% vs. 28% in healthy individuals). Anti-COVID-NP-IgA was not found in the control group (11% in the breakthrough infection group vs. 0 in healthy individuals). In the breakthrough-infected group, the positivity rate of anti-COVID-NP-IgA decreased significantly (median titers 16.9 IU/ml decreased to 4.2 IU/ml) p = 0.001), while anti-COVID-S1-IgA increased over a period of 4-8 weeks (9.35-16.35 IU/ml). Importantly, IgA response to both COVID-19 NP and S1 antigens was not found in 13 patients at initial testing. The findings of this study show that serum IgA may have a role both in breakthrough infections and also in the prevention of severe infection. Sluggish anti-COVID-19-IgA antibody response may be responsible for the occurrence of COVID-19 infection in breakthrough infection. On the other hand, more sustained anti-COVID-19-S1-IgA over a longer period of time may have a role in preventing these patients from severe infections and hospitalization. However, a study on a larger sample size including patients with severe disease after vaccination is required to prove this hypothesis. To the best of our knowledge, this is the first study reporting the importance of serum IgA in breakthrough-infected patients from our region.

Ethyl acetate extract of Clausena excavata induces growth inhibition of non-small-lung cancer, NCI-H460, cell line via apoptosis.

CONTEXT: Clausena excavata Burm. f is a plant used in folklore medicine for the treatment of various ailments in South East Asia. The plant parts contain chemical components that are cytotoxic to many cancer cells. OBJECTIVE: The study investigated the cytotoxic effects of ethyl acetate, methanol and chloroform C. excavata leaf extracts on the non-small-lung cancer, NCI-H460, cell line. METHODS: Based on the 3-(4,5-dimethylthiazol-2-yl)-2,5,-diphenyltetrazolium bromide (MTT) assay, among extracts, ethyl acetate C. excavata leaf extract (EACE) was the most potent anti-NCI-H460 cells, with IC50 value of 47.1 ± 6.1 µg/ml. The effects of EACE on NCI-H460 cells were also determined by clonogenic, 4', 6-diamidino-2-phenylindole (DAPI), and annexin-V-fluorescein isothiocyanate/propidium iodide-PI flow cytometric assays. Reactive oxygen species (ROS) production and apoptotic gene expressions was determined via flow cytometry and real-time quantitative PCR, respectively. RESULTS: EACE-treated NCI-H460 cells after 48 h underwent apoptosis as evident by loss of cell viability, cell shrinkage, and chromatin condensation. The results also showed EACE mediated increase in ROS production by the NCI-H460 cells. After 48 h treatment, EACE increased the pro-apoptotic BAX and decreased the anti-apoptotic Bcl-2, Survivin and c-Myc gene expressions. CONCLUSIONS: EACE is a potential anti-lung cancer by increasing cancer cell ROS production and apoptosis.