Use of Convalescent Plasma for COVID-19 in Pregnancy Lessons from other Viruses

This family includes other members like SARS, H5N1, H1N1 and MERS, but COVID-19 got the fastest spread in comparison to them. Abstract Since the appearance of coronavirus disease-2019 (COVID-19), scientists and physicians work together to find any solution to the current pandemic. Up till now, there is neither definite curative treatment nor vaccine to this infection. Pregnant women are a vulnerable category of population. In normal situation, they need special care. This care must be needed now to protect them and their fetuses. In this review, we highlighted the use of Convalescent Blood Plasma (CBP) in the treatment of pregnant women with COVID-19 infection. It is not new for us to use CBP in the treatment of viral infections as we used before in the treatment of SARS, MERS and other members of coronaviruses family and showed great results in the cure of the patients.


Introduction
In December 2019, many cases of acute pneumonia of unknown cause appeared in Wuhan, China. This pneumonia got its chance to spread throughout China and then has invaded the whole world. After that it was discovered to be caused by a novel virus belongs to the coronaviruses family and the World Health Organization (WHO) named it coronavirus disease-2019 (COVID-19) [1].
This family includes other members like SARS, H5N1, H1N1 and MERS, but COVID-19 got the fastest spread in comparison to them.
In normal situations, pregnant females need special care seeking for the best pregnancy outcomes. But during the current situation of COVID-19 pandemic, those females need more care and attention especially after the appearance of adverse outcomes on the mother and her baby by this virus [2]. of breath, headache, and loss of sense of smell are other relevant symptoms [3]. However, mothers still can die from COVID-19 respiratory complications. Two mothers died after delivery due to respiratory complications [4].

Effect on fetus
Up to date, there is no evidence of intrauterine vertical transmission of COVID-19. Investigations like RT-PCR in cord blood, amniotic fluid or placenta were negative for the virus. However, there are reports of neonatal infection [5]. Those infants' blood samples had antiviral antibodies in their blood after birth [6]. Unfortunately, IgM antibodies are too large to transfer through the placenta to the fetus, and this raises the suggestion of postnatal infection [7]. A study of nine pregnant women who were infected with COVID-19 and had symptoms showed that none of their babies was affected by the virus. The virus was not present in amniotic fluid, the babies' throats, or in breast milk [8]. Another study of 38 women infected with COVID-19 found that none of the newborns tested positive for the disease [9].
To date, all studies showed fetal infection in the third trimester but no available data about the first or second trimester. According to a systematic review of 17 studies, fetal affection appeared in the form of fetal distress, preterm birth, low birth weight, stillbirth, neonatal asphyxia, and neonatal death [10]. A simple explanation for that is in China, a lot of cases of pregnancies with suspected or confirmed COVID-19 have been treated and delivered in several hospitals with no maternal death. While the infection occurs in the third trimester of pregnancy, there may be some risks of premature rupture of membranes, this may lead also to premature labor and the baby may suffer from tachycardia and distress [11]. Thus, in turn, we are in a compelling need for finding a treatment for COVID-19 infection to protect those mothers and their babies.

Immunity in Pregnancy
For a long time, pregnancy was thought of as a state of immunosuppression, but it is now more like a myth, now it is rather a state of immune modulation, which also varies in different phases of pregnancy. During pregnancy there are two immune systems working together, the maternal immune system and the feto-placental which can participate actively in response to infections and modulate maternal response [12]. Also, nature of immunity varies in different phases of pregnancy, first trimester is pro-inflammatory, second trimester is anti-inflammatory, third trimester is pro-inflammatory. So, maternal response can be affected by the type of organism, stage of pregnancy and feto-placental part response to infection.

Response to Viral Infection in Pregnancy
It looks like that immunological response of placenta can guide maternal immune response. So, if placental infection was associat-ed with severe inflammatory response and release of cytokines as TNF alpha, IFN gamma, IL-6, this will lead to activation of maternal immunity and subsequent miscarriage or preterm labor If placental infection was associated with mild response that can lead to activation of maternal immune system with no termination of pregnancy and its sensitization to other viruses besides, activation of fetal immune system & inflammatory response even without viral transmission. This fetal inflammatory response is a condition in which there is high level of circulating cytokines while there are not cultivable organisms [13]. These cytokines were associated with CNS and CVS abnormalities [14].

Active Role of Trophoblast Against Viral Infection
During viral replication, DsRNA of the virus is produced and recognized by TLR3 in trophoblast leading to: A.
Production of anti-viral factors as Secretory Leukocyte Protease Inhibitor (SLBI) & IFN beta [15]. C. Production of cytokines as TNF alpha, IFN gamma, IL-6 which regulates prostaglandin production, which is responsible for uterine contraction, these cytokines may also induce apoptosis of trophoblast [16].

Adaptive Immunity in Pregnancy
As pregnancy is a unique situation with the presence of fetus & his mother's need to tolerate his existence, modulation of her immunity ensues to secure his existence. Here we give a look at the modulation that happens in adaptive immunity.

T cells
Pregnancy was noticed to be associated with decrease in T-lymphocytes including CD4 & CD8 T cells [17] and increase in T regulatory cells which suppress T cell proliferation and induce self-tolerance [18]. Focusing on T helper cells, pregnancy is found to be strongly associated with physiological shift to Th2 dominant environment with secretion of Th2 cytokines including IL-4, IL-10 which dampen Th1 type immunity & this is important for successful pregnancy [19].

Changes in Serum Cytokines and other Components in Pregnancy
Pregnancy in previous studies was found to be associated with [23], and significant increase in Alfa defensins 1-3 in blood in pregnancy. Alfa defensins are anti-microbial peptides with defense properties against bacteria, fungi & enveloped viruses [24].

COVID-19 and Immunity
The Innate Immunity The innate immunity seems the first line of defense against COVID-19, it depends mainly on release of IFN-1which can inhibit viral replication and induce adaptive immune response [24]. On looking at previous corona viruses, SARS & MERS, they both adopted strategies to suppress IFN-1 [25]. This suppression strategy was associated with disease severity. So, weak initial response, immunity deregulation & suppressed IFN-1 can interfere with early viral control leading to influx of hyper-inflammatory macrophages with release of high levels of cytokines possibly leading to ARDS & multi-organ failure [25]. While strong initial response can lead to control of viral replication &attraction of specific T-cells resulting in elimination of infection with minimal damage to lungs [25].

Adaptive Immunity T-lymphocytes Status in COVID-19
COVID-19 was found to be associated with lymphocytopenia mainly affecting T-lymphocytes, specifically CD4+ cells but no significant change in CD8+/B Cells [24]. This raises the question; why

COVID-19 and the Cytokine Storm
Cytokine storm simply is excessive immune response to a stimulus resulting in release of many cytokines which can have deleterious effects on body organs including lungs and other organs. It is now known that COVID-19 in some patients is associated with cytokine storm leading to high morbidity & mortality [26]. Cytokine storm is a major cause of Acute Respiratory Distress Syndrome (ARDS), multi-organ failure [27].

Convalescent Blood Plasma
Convalescent Blood Plasma (CBP) transfusion depends mainly on separating blood plasma from individuals whom have success-

American Journal of Biomedical Science & Research
Copy@ Ahmed M Abbas fully overcome infection, using the specific antibodies-evolved by their immune system-or combat the same invader in other patients, with main concern to eradicate the pathogen [32]. These specific Abs, as well as convalescent plasma an IVIg, has mechanisms of action: A. Neutralization the Infection, which means that they will Bind to the Virus, prevents its Entry to Cells & so Deleting its Infectivity, Preventing its Amplification [33].

Anti-Autoimmune Disorder Properties
Interestingly, some critically ill COVID-19 patients tested positive for presence of ant phospholipid Abs [35], so the use of CBP may neutralize these Antibodies, reducing possibility of associated complications as coagulopathy & associated pregnancy complication as miscarriage, early delivery, oligohydramnios, fetal distress, neonatal thrombosis, pre-eclampsia and eclampsia [36].

CBP can solve this problem through inclusion of anti-idiotypic
Abs during preparation of IVIg can block auto reactive antibodies of the recipients & so can be used in autoimmune disorders.
Early clearance of autoimmune Abs by shortening their lifetime by saturating neonatal Fc receptors with IVIg [37]. This neonal Fc Repertory (FcRn) can control the lifetime of IgG by preventing its degradation [38].

Anti-complement properties
Some Abs can inhibit C3a, C5a which play a significant role in inflammation & allergic reaction [39].

Anti-cytokine properties
IgG in plasma can neutralize some cytokines as IL-1B, TNF Alfa [40]

Convalescent Plasma Immuno-Modulators Effect on T-Cells
Using IVIg was associated with decrease of Th1 cells, low IFN Y, TNF Alfa, decreases proliferation of Th17 cells, decreased IL-17, elevated Th2 cytokines [41], reduction & decreased activation of cytotoxic T cells, improved pregnancy outcome in cases with recurrent pregnancy loss due to its immunomodulation properties of Th1, Th2, and Th17/Treg ratio [42].

CBP Immunomodulatory Effects on Innate Immunity Cells including Dendritic Cells & Macrophages Dendritic Cells
IVIg was found to be associated with promoting anti-inflammatory profile of Dendritic Cells (DCs) via inhibiting maturation of DCs, decreased production of IL-17 increased IL-10 production, IL-4, IL-13, and down regulation of co-stimulation molecules (CD40, CD80, CD86), down regulation of HLA-II in DCs [43].

Macrophages
Treating macrophages with IVIg is associated with enhancement of anti-inflammatory properties of macrophage via decreasing production of IL-12/23p [40] and increased production of IL-10 [44]. While there is no clue indicates that IVIg is associated with inhibiting macrophage migration to lungs, but there was decreased nerve macrophage infiltration in a study made in induced peripheral neurotoxicity in rats [45].

Role of Convalescent Plasma for COVID-19 in Pregnancy
Theoretically, CBP use in pregnancy is useful in too many ways & further studies need to be performed to test its efficacy in real world on pregnant women. When it comes to adaptive immunity, it looks dampened in pregnancy, so using CBP in pregnancy with COVID-19 will provide the pregnant with specific abs against the virus helping her immune system to eradicate the pathogen through anti-viral mechanisms shown before. It also neutralizes the virus, so deleting its interaction with placenta & trophoblast (via TLR3 as shown before) which can trigger preterm delivery as shown with some COVID-19 pregnant women. Additionally, as IgG can cross the placenta, it will possibly provide the fetus with passive immunity.
Finally, through its immune-modulatory & anti-inflammatory effects, it seems that CBP has properties which can suppress cytokine storm which is a major cause of ARDS & multi-organ failure.

Infections
The concept of immunotherapy takes us back to late 19 th century when this concept derived from works of Ehrlich, Pasteur & Bordeau whom recognized the neutralizing action of antibodies [46].
In 1880, it was found that immunity developed in animals-after intentional immunization with nonlethal doses of diphtheria toxins & which was mainly derived on abs against toxins in the blood of animals-can be transferred to animals with active infections [47].
Then the immune sera of some animals as goats, horses & sheep were used in humans suffering from diphtheria, it was successful & saved many lives [48].
In the 50s of last century, it was available to purify & concentrate immunoglobulins derived from immunized donors whether by full recovery from past clinical infection or asymptomatic infection & so formed the hyper immune globulin. Since then, IVIg progressively replaces animal sera use & it was used in serious infection and immune disorders as immunodeficiency and autoimmune diseases, as immune plasma was found to have immuno-modulatory characteristics besides its ability to neutralize pathogens [49].
Although CBP products as polyclonal abs, monoclonal abs, IVIg have several benefits and used but their use in cases of emergency is limited as their production is difficult & costly, so in cases of emergency with no other available medication or vaccine, CBP is the first therapeutic option.

Use of CBP in Spanish Flu
A meta-analysis was performed on the effect of convalescent blood products on patients with Spanish flu, its efficacy, adverse events [50]. It was found that: A. Use of convalescent plasma products were associated with improved outcome in the form of improved clinical symptoms & signs, decreased risk of death, decreased mortality with overall crude case fatality rate 16% in intervention patients versus 37% in controls.

B.
Early treatment with CBP (after <4 days of pneumonia complications) was associated with better outcome than late treatment.

Use of CBP in Avian Flu H5N1
Zhou et al [51] found in a previously healthy male tested positive for H5N1, started treatment with oseltamivir but with no improvement & the viral load continued to increase, that CBP from another patient who had recovered from H5N1 infection was obtained, resulted in decreased viral load & even became undetectable within 32 hours after first transfusion. Additionally, there were improved radiographic findings of pulmonary lesions.

Use of CBP in H1N1
Hung et al [52] in H1N1 patients reported that administration of CBP (with neutralizing antibody titer >\= 1:160) was associated with significant decrease in the mortality among treatment group vs. non-treatment group (20% vs. 54.8%). Another study showed administration of hyper immune IVIg was associated with significantly lower viral load and reduced mortality in H1N1 patients, and no adverse events were reported [53].

Use of CBP in SARS
Soo et al. [54] reported that CBP administration was associated with decreased length of stay in hospital, decreased mortality (death rate in plasma group was 0%) vs. the steroid group who had longer stay & higher mortality. Cheng et al. [55] found that CBP administration was associated with decreased mortality in general (12.5% mortality rate in intervention group vs. 17% overall SARS related mortality in Hong Kong). Yhe et al. [56] showed an association between CBP administration with decreased viral load, increase in anti SARS-CoV IgM, IgG over time, but the interesting about this study that one patient became pregnant, delivered 13 months after discharge & the baby was positive for anti SARS Abs suggesting possible transfer of abs from his mother. Ko   with any disease other than trauma or diseases related to trauma increased. Also, morbidity and mortality increased in case of compatible but not identical ABO plasma and mortality tendency increases much more after transfusion by about 14 days. In contrast, many theories consider that plasma transfusion is not associated with mortality and never cause it, but it surely has its severe complications.

Conclusion
In conclusion, use of CBP in pregnant women should be considered; it forms a potential effective therapy for COVID-19 in pregnant patients and appears to be safe.