Reasons for deferral of COVID-19 convalescent plasma donors

ABSTRACT

Background: Taking into consideration historic success of convalescent plasma in prophylaxis and treatment of various infectious diseases over the century and expansion of COVID-19 pandemics, we started the COVID-19 convalescent plasma program in our country. Aims: The aim of our study was to show the reasons for deferral of the COVID-19 convalescent plasma (CCP) donors. Methods: This is a prospective study organized in the Institute for Transfusion Medicine of Republic of North Macedonia since 30 April 2020 till July 2021. CCP donors eligible for donation were donors without a history of blood transfusion, female donors who have never been pregnant, or who have been tested and found negative for anti- HLA antibodies, age 18-65, in good health that fulfil all other criteria for regular blood donors. All potential donor were tested for negative RT-PCR for SARSCoV-2 before donation, anti-SARS-CoV-2 antibodies, anti-HLA antibodies (where applicable), blood count, blood group, TTI and biochemistry. Antibody testing was performed at the Institute for Immunobiology and Human Genetics in Skopje using CLIA method with Snibe Maglumi SARS-CoV-2 S-RBD IgG with IgG cut-off for CCP donation larger than 5 AU/ml (cut-off for regular positive result was larger than 1 AU/ml). All donors signed inform consent for donation and inclusion in the study. Results: There were 1462 potential CCP donors, of which 762(52.1%) did not fulfil criteria for CCP donation, 424(55.6%) women and 338 (44.4%) men. There were 454(59.6%) potential CCP donors that did not have enough anti-SARS-CoV-2 S-RBD IgG antibodies (Ab), of which 223(49.1%) had Ab concentration less than 1 AU/ml (29.3% of all deferred donors) and 231(50.9%) had Ab concentration between 1 and 5 AU/ml (30.3% of all deferred donors). In this subgroup of deferred donors, there were 227 women (50%) and 227 men (50%), with mean age 37.2 ± 10.1 (range 18-63). There were statistical significant correlation between the gender and the Ab concentration less than 1 AU/ml and from 1 to 5 AU/ml (Pearson Chi-square 3.88667, df = 1, p = 0.048671). Multiple regression analysis showed that gender is independently connected with the Ab concentration, OR = 1.4495 (95%CI 1.0016-2.0976), i.e. male gender increases the chance for increased Ab concentration for one and a half times. According to the age group, the majority of deferred CCP donors, because of low Ab concentration, are in the age group from 30 till 39(39.6%), followed by age group from 40 till 49(23.8%), and least deferred donors were in 50 and above age group (13.2%). The most of these deferred donors were treated at home, 451(99.3%) and had symptoms 240(52.9%). Distribution according to blood group in CCP donors deferred due to low Ab concentration was blood group A- 182(40.1%), blood group O-153(33.7%), blood group B-69(15.1%) and blood group AB-42(9.3%). In the whole investigated group, 65 (8.5%) potential donors were deferred because of low haemoglobin level (less than 12.5 g/dl for women and less than 13.5 g/dl for men), 26 (3.4%) were deferred because of positive TTI markers and 102 (13.4%) women of the total number of deferred donors were deferred because of presence of HLA antibodies (i.e. 24% of investigated women). Summary/Conclusions: There is large percentage of deferred CCP donors mostly because of low Ab concentration, presence of HLA antibodies and low haemoglobin level, but starting of COVID-19 convalescent plasma program was a big success for our institution and our country and helped a lot of patients.