Hyper Production of Anti Spike Antibodies and Rheumatological Manifestations: Coincidence or Pathogenesis?

Vaccine is the most widely used public health measure to control the global COVID-19 pandemic. Most of the vaccines used in Europe and North America are mRNA-based vaccines (BNT162b2 and mRNA-1273), but DNA vaccines (ChadOx1 and CoV-19) are also used [1,2]. A mass vaccination campaign was launched between 2021 and 2024. Some adverse events have been reported in relation to this vaccine and several rheumatological events have been documented [3,4]. We question the role of Covid 19 vaccines in the pathogenesis of rheumatological manifestations observed following one or more injections.

This clinical study was approved by Saint-Jean hospital’s ethical board in accordance with the Belgian Law regarding the use of medical data which is available for any additional request. All patients were examined and followed in the same rheumatology department. A prospective observational study of 2 cohorts was launched from 13^th September 2021 to 30^th of September 2022 for the first one and from 1^st October 2022 to 30^th of September 2023 for the second one. After the first year, we focused also the observational study on the delay between the last vaccine injection and the beginning of rheumatic symptoms. We exclude of the studies all patients having a past of rheumatic or inflammatory diseases. Patients treated for depression, fibromyalgia or chronical widespread pain were also excluded. Out of a series of 184 patients having muscle, joint and skeletal claims after Covid vaccination we report a first cohort of 124 patients without interferent diseases having developed rheumatological manifestations which occurred after vaccination with an RNA vaccine coding for the SARS-CoV-2 spike protein (120/124) or an DNA vaccine (4/124). Out of 156 patients, 31 were excluded using the same criteria and a second cohort of 125 patients having developed late onset adverse events is studied. None of the patients had a history of rheumatological disease or developed rheumatological disease during the follow-up. All causes of rheumatic diseases were excluded by a full biological examination, adequate imaging according to the clinic. A post-vaccination blood serological follow-up for anti-spike antibodies was requested a several times for all patients at the diagnosis and during the follow-up. None of the subjects had a suspicion of viral infection as confirmed by the diverse samplings collected. All the patients were treated with an oral low dose of methylprednisolone 8mg/day reduced to 4 mg/day after 2 weeks. We double checked the medical history of each patient by consulting ABRUMET (professional access to general patient medical data base) according to the Belgian law. None of the patients developed any other disease after at least 18 months of follow-up. All patients underwent serological testing for SARS-CoV-2 after vaccination. IgG antibodies anti-Spike to SARS-CoV-2 were determined on LIAISON XL (DiaSorin S.p.A., Saluggia, Italy) using the IgG SARS-CoV-2 Trimerics reagent (DiaSorin S.p.A.). The measurement range was between 4.81 and 2080 BAU/mL, with a threshold of 33.8 BAU/ml. According to the company, a value of 520 BAU/mL or more corresponds to a high neutralization capacity of the antibodies. As this serological test is not reimbursed by the Belgian social security, each patient had to pay for it. Because of ethical board restriction, we were only allowed to use the serological results of our own vaccinated patients as control group followed at the consultation with other diagnoses. A vaccinated control group of 59 subjects (mean age 56 years old, 43 females and 16 males) does not reveal such a high level of anti-Spike antibodies in the blood sample. The mean anti-spike antibody level in the control group was 486,7 BAU/ml (4.8 – 842). We also tested 6 unvaccinated patients of our own consultation to assess the control group (mean value 54 BAU/ml). We questioned each patient about any declaration of adverse events. We use the Pearson test to compare early and late onset cohorts and bilateral ankle arthritis after vaccination and examine the potential link between Covid-19 vaccines and new or recurrent sarcoidosis.

Results: Table 1, Table 2 and Table 3.

In both cohorts and case series, a vast majority of patient are women, experiencing more often than men, a biological inflammatory syndrome. The strong affinity of Spike protein to estrogenic alpha receptors [5] may explain the female gender ratio of the rheumatologic adverse event. The most common complaint is diffuse muscle pain mimicking polymyalgia rheumatica [6,7] in presentation but occurring on average in the early 50s and often without inflammatory syndrome. As most causes of diffuse pain have been excluded, low-dose corticosteroid treatment (8 mg methyl prednisolone/day reduced to 4 mg/day ) has been administered as for the other clinical manifestations and has been effective in most cases 65 /73 (cohort 1) and 35/53 (cohort 2).The most frequent joint involvement is bi arthritis of the ankles [8] (38 +1unilateral ankle arthritis -31% in cohort1 and 37 cases- 29,6 % in cohort2. New cases of inflammatory mono/oligo arthritis involving the ankle are more likely to be due to reactive undifferentiated arthritis or spondylarthritis than rheumatoid arthritis and microcrystalline arthritis [9]. Abhishek and colleagues reported that in the Birmingham early inflammatory arthritis (BEACON) cohort, patients with bilateral ankle synovitis were more likely to be classified as having acute sarcoid arthritis [10]. We remind that all those diagnoses were excluded from both cohorts. About 75 cases of acute sarcoidosis are expected to be diagnosed in one year for the Brussels region and shared into 13 hospitals. The 6 patients (excluded of both cohorts) having previously an articular sarcoidosis and those who developed a flare or a sarcoidosis after vaccination [11,12,13] confirm the normal incidence of the disease diagnosed in our department and are questioning about the significance of the high level of anti-Spike antibodies and the role of spike protein in the occurrence of inflammatory articular manifestations. We find totally 46 (13 early onset cohort +33 late onset cohort) cases of arthralgia, arthritic fingers and wrists without any erosions. No other cause is discovered during the follow-up as well for patients having other articular locations (knees or hips). No patients exhibited serum sickness symptoms associated with elevated anti-Spike protein levels. These biological findings do not monster abnormal frequency of ANA, RF or anti CCP and suggest a cellular rather than humoral inflammatory reaction [14]. Mostly, the evolution was favorable each time when low-dose corticosteroids were taken. The lack of satisfactory response to corticosteroids seems to be related to the long persistence or increased of very high levels of anti-Spike (> 2080 BAU/ml). Whatever, the significance of anti-Spike antibodies remains unclear, a high level of anti-Spike IGG antibodies was also detected in young patients who have developed post-vaccination myocarditis, especially in the presence of a high amount of Spike protein [15]. Even if the average age of late-onset patients is higher (51 years), we can also accredit the presence of high levels of anti-Spike IGG antibodies at the time of diagnosis and during the follow-up. Although we cannot exclude the possibility that the onset of arthritis/polymyalgia after mRNA vaccination is a coincidence, the similarities between these 2 cohorts and the number of cases post vaccine over a short period of time might suggest some pathogenic causation. Normally, the level of post-vaccine induced IGG anti-Spike lowered in 5 to 6 months, justifying the booster vaccine program [16] and after a 3rd dose of RNA vaccine, there is a reduction in anti-spike levels from the 3rd month [17]. The presence of SARS-CoV-2 Spike antibodies at least more than 8 months after a vaccine dose is questioning the physiopathology of early and late-onset arthritis post-RNA vaccine. Vaccine dose count is higher in the late-onset ankle arthritis case series (47injections) than in the early-onset group (25 injections). The comparison of early and late-onset ankle arthritis reveals that the late-onset group received a higher number of DNA and RNA vaccine doses (8 DNA/39 RNA doses) compared to the early-onset case series (2 DNA/23 RNA doses). Additionally, the mean delay between the last vaccine dose and the rheumatological diagnosis is 17 months in the late-onset group, while it is only 0.44 months in the early-onset case series. The mechanism of COVID-19 vaccines is entirely different from that of live attenuated virus vaccines thus rendering the analogical reasoning regarding the potential side effects incomplete. Post COVID-19 vaccine late-onset adverse events prompt us to explore alternative pathway [18]. In vitro studies demonstrate the integration of RNA spike sequences in human cells [19,20]. Spike protein could be the key to fixing the Angiotensin 2 receptors [17,21] and Toll-Like receptors 4 and 2 [17,22] implicated in an increased production of pro-inflammatory cytokines. Moreover, the strong affinity of Spike protein to Estrogen receptor alpha [5,7] may explain why women are mostly involved. The number of injected DNA and RNA vaccine doses and the delay between the date of the last vaccine dose and the time of the rheumatological diagnosis might also argue that Spike protein could mediate early and delayed adverse events.

When encountering new cases of polymyalgia, arthritis, and particularly bilateral ankle arthritis in healthy individuals without any personal or family history of inflammatory diseases, it is essential to consider other potential causes of rheumatic or inflammatory diseases alongside post-vaccine adverse events. A strong positive result for plasmatic level of anti-Spike protein suggests that these rheumatological manifestations might be triggered by inappropriate individual immune responses to the vaccine's Spike protein and/or the overproduction of Spike protein, which can mediate a pro-inflammatory immune response explaining early and late-onset effects tables.