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British Journal of Healthcare and Medical Research - Vol. 11, No. 6

Publication Date: December 25, 2024

DOI:10.14738/bjhmr.116.18040.

Caimmi, P. P. & Mascaro, G. (2024). Convalecent - Hyperimmune Plasma Use and Immunological Charachteristics in the Covid-19

Pandemic: A Preliminary Experience of a Single Center in Italy as Fast Available Therapy Model in New Virus Pandemic. British

Journal of Healthcare and Medical Research, Vol - 11(6). 310-317.

Services for Science and Education – United Kingdom

Convalecent - Hyperimmune Plasma Use and Immunological

Charachteristics in the Covid-19 Pandemic: A Preliminary

Experience of a Single Center in Italy as Fast Available

Therapy Model in New Virus Pandemic

Philippe P. Caimmi

Medical Directorate, University Hospital of Novara,

Corso Mazzini 18, Novara, Italy and General Medical Practitioner,

Local trust of Biella (ASL Biella, Italian NHS), Italy

Gennaro Mascaro

Transfusion Service, University Hospital of Novara,

Corso Mazzini 18, Novara, Italy

ABSTRACT

Objectives: Hyperimmune - convalescent plasma transfusion appears to be a great

resource in the current SARS-CoV-2 coronavirus pandemic and seems to be one of

the few effective treatment modality available. However, its efficacy is variable and

dependent on antibody/plasma volume concentration. Methods & Results: This

single center analysis from a forefront COVID-19 Italian hospital in 43 convalescent

plasma donors demonstrated that this variability in neutralizing antibody (NAB)

levels is related to the harvesting period after SARS-CoV-2 recovery and

interestingly, on blood group type. Specifically, the optimal plasmaferesis time

point was approximately two weeks post test negativation with a significant drop

in NAB plasma levels (112±102 vs 60±26.9, p=0.003) observed at 30 days. In

contrast, no correlation between NAB and IgG plasma levels was observed over time

(r=0.48.). Subgroup analyses demonstrated that NAB levels where higher in male

(115.1±110.7, p=0.0001) and in blood group AB (200±138.6, p=0.036) donors while

group A patients (81.2±82.7, p=0.062) had the lower levels of NAB concentration.

Conclusion: This analysis demonstrated that male patient with a AB blood group

plasma which was donated within three weeks of convalescence contains the

highest therapeutic levels of antibodies and these patients should be actively

recruited to become donors.

Keywords: Convalescent - Hyperimmune Plasma, Blood Transfusion, COVID-19,

Pandemic, SARS-CoV-2 Corona Virus.

INTRODUCTION

In the recent literature, the data in favor of the use of COVID-19 convalescent - hyperimmune

plasma for the management of a SARS-CoV-2 infection are growing (1). However, it is becoming

increasingly clear that the efficacy of this therapeutic modality, which seems currently at the

same of monoclonal antibodies the only potentially effective one available, is possibly variable

and dependent on the concentration of virus specific neutralizing antibodies in the donated

plasma. It is obvious that during the subsequent pandemic peaks which seems will be of similar

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British Journal of Healthcare and Medical Research (BJHMR) Vol 11, Issue 06, December-2024

Services for Science and Education – United Kingdom

System (Terumo BCT, Lakewood, Colorado, USA). The collected units were stored at a

controlled temperature ranging from -40 to -25 °C (1).

Serological and immunological profiling was performed on the plasma from each donor. NAB

titers were obtained utilizing an in-house microneutralisation assay adapted to SARS-CoV-2

according to a previously reported method (1). In addition each volunteer’s blood was also

tested for IgG titers utilizing the LIAISON® SARS-CoV-2 S1/S2 IgG quantification test (DiaSorin,

Saluggia, Piedmont, Italy). This is an indirect chemiluminescence immunoassay (CLIA) which

automatically calculates SARS-CoV-2 S1/S2 IgG antibody concentrations expressed as arbitrary

units (AU/mL)

Statistical Analysis

Comparison between two groups was performed using the Student’s t-test while multiple

comparisons were done with one-way analysis of variance (ANOVA) assuming normal

distributions while Tukey’s post hoc test was used to identify specific group differences.

Continuous data are reported as mean ± standard deviation (SD). A p-value of 0.05 or less was

considered statistically significant. Statistical analysis was carried out with the SPSS v23.0

software (SPSS Inc., Chicago, IL).

RESULTS

A total of 53 recovering patients were screened for possible plasma donation of which ten

(19%) had NAB titers less than 1:40 and therefore were classified as non-responders.

Therefore, 43 convalescent plasma donors participated in the study. There were 38 male and

five female participants with a mean age of 40.5±9.7 years. Other demographic characteristics

and inclusion/exclusion criteria were determined by current guidelines and Italian law

regulating blood donation practice.

There was no statistical difference between the initial (day 15) average levels of NAB and IgG

(122.8±115.3 vs. 123±89, p=0.419). In truth, no relation seems to exist between NAB and IgG

levels with Pearson’s correlation coefficient r been 0.48. When a subgroup analysis of initial

NAB titers was performed according to blood group and gender, levels were significantly higher

in group AB (200±138.6, p=0.036) and in male (115.1±110.7, p=0.0001) donors (Table. 1). A

marginally significant, lower level of NAB was observed in blood group A donors (81.2±82.7,

p=0.062). No statistically significant differences were seen between the other blood or rhesus

groups (Table. 1).

An analysis of NAB titers by individual volunteer demonstrated 14 donors with titers of 1:40

for a total of 42 units of plasma, 13 donors had titers at 1:80 producing 39 units of plasma, 11

donors had NAB titers of 1:160 producing 33 units of convalescent plasma, four donors with

titers of 1:320 for a total of 12 units and one donor with NAB titer of 1:640 producing three

units of convalescent plasma.

When a comparison of NAB levels over time was performed a significant drop (112±102 vs.

60±26.9, p=0.003) was observed over a period of 30 days (from initial sampling to the 30 day

re-sampling), (Table 2). In contrast, IgG levels seemed to remain constant and did not exhibit

any statistically significant change thru time (Table 2).