COVID-19 and Mixed Cryoglobulinemia Syndrome: Long-Term Survey Study on the Prevalence and Outcome, Vaccine Safety, and Immunogenicity.

PURPOSE: Mixed cryoglobulinemia syndrome (MCs) is a rare immunoproliferative systemic disorder with cutaneous and multiple organ involvement. Our multicenter survey study aimed to investigate the prevalence and outcome of COVID-19 and the safety and immunogenicity of COVID-19 vaccines in a large MCs series. METHODS: The survey included 430 unselected MCs patients (130 M, 300 F; mean age 70 ± 10.96 years) consecutively collected at 11 Italian referral centers. Disease classification, clinico-serological assessment, COVID-19 tests, and vaccination immunogenicity were carried out according to current methodologies. RESULTS: A significantly higher prevalence of COVID-19 was found in MCs patients compared to Italian general population (11.9% vs 8.0%, p < 0.005), and the use of immunomodulators was associated to a higher risk to get infected (p = 0.0166). Moreover, higher mortality rate was recorded in MCs with COVID-19 compared to those without (p < 0.01). Patients' older age (≥ 60 years) correlated with worse COVID-19 outcomes. The 87% of patients underwent vaccination and 50% a booster dose. Of note, vaccine-related disease flares/worsening were significantly less frequent than those associated to COVID-19 (p = 0.0012). Impaired vaccination immunogenicity was observed in MCs patients compared to controls either after the first vaccination (p = 0.0039) and also after the booster dose (p = 0.05). Finally, some immunomodulators, namely, rituximab and glucocorticoids, hampered the vaccine-induced immunogenicity (p = 0.029). CONCLUSIONS: The present survey revealed an increased prevalence and morbidity of COVID-19 in MCs patients, as well an impaired immunogenicity even after booster vaccination with high rate of no response. Therefore, MCs can be included among frail populations at high risk of infection and severe COVID-19 manifestations, suggesting the need of a close monitoring and specific preventive/therapeutical measures during the ongoing pandemic.

Absent or suboptimal response to booster dose of COVID-19 vaccine in patients with autoimmune systemic diseases.

Autoimmune systemic diseases (ASD) show impaired immunogenicity to COVID-19 vaccines. Our prospective observational multicenter study aimed at evaluating the seroconversion elicited by COVID-19 vaccine over the entire vaccination cycle including the booster dose. Among 478 unselected ASD patients originally evaluated at the end of the first vaccination cycle (time 1), 344 individuals were re-evaluated after a 6-month period (time 2), and 244 after the booster vaccine dose (time 3). The immunogenicity of mRNA COVID-19 vaccines (BNT162b2 and mRNA-1273) was assessed by measuring serum IgG-neutralizing antibody (NAb) on samples obtained at the three time points in both patients and 502 age-matched controls. In the 244 ASD group that received booster vaccine and monitored over the entire follow-up, the mean serum NAb levels (time 1, 2, and 3: 696.8 ± 52.68, 370.8 ± 41.92, and 1527 ± 74.16SD BAU/mL, respectively; p < 0.0001) were constantly lower compared to controls (p < 0.0001), but they significantly increased after the booster dose compared to the first two measurements (p < 0.0001). The percentage of patients with absent/suboptimal response to vaccine significantly decreased after the booster dose compared to the first and second evaluations (time 1, 2, and 3: from 28.2% to 46.3%, and to 7.8%, respectively; p < 0.0001). Of note, the percentage of patients with absent/suboptimal response after the booster dose was significantly higher compared to controls (19/244, 7.8% vs 1/502, 0.2%; p < 0.0001). Similarly, treatment with immune-modifiers increased the percentage of patients exhibiting absent/suboptimal response (16/122, 13.1% vs 3/122, 2.46%; p = 0.0031). Overall, the above findings indicate the usefulness of booster vaccine administration in ASD patients. Moreover, the persistence of a significantly higher percentage of individuals without effective seroconversion (7.8%), even after the booster dose, warrants for careful monitoring of NAb levels in all ASD patients to identify those with increased risk of infection. In this particularly frail patients' setting, tailored vaccination and/or therapeutic strategy are highly advisable.

Impaired immunogenicity to COVID-19 vaccines in autoimmune systemic diseases. High prevalence of non-response in different patients' subgroups.

Autoimmune systemic diseases (ASD) may show impaired immunogenicity to COVID-19 vaccines. Our prospective observational multicenter study aimed to evaluate the seroconversion after the vaccination cycle and at 6-12-month follow-up, as well the safety and efficacy of vaccines in preventing COVID-19. The study included 478 unselected ASD patients (mean age 59 ± 15 years), namely 101 rheumatoid arthritis (RA), 38 systemic lupus erythematosus (SLE), 265 systemic sclerosis (SSc), 61 cryoglobulinemic vasculitis (CV), and a miscellanea of 13 systemic vasculitis. The control group included 502 individuals from the general population (mean age 59 ± 14SD years). The immunogenicity of mRNA COVID-19 vaccines (BNT162b2 and mRNA-1273) was evaluated by measuring serum IgG-neutralizing antibody (NAb) (SARS-CoV-2 IgG II Quant antibody test kit; Abbott Laboratories, Chicago, IL) on samples obtained within 3 weeks after vaccination cycle. The short-term results of our prospective study revealed significantly lower NAb levels in ASD series compared to controls [286 (53-1203) vs 825 (451-1542) BAU/mL, p < 0.0001], as well as between single ASD subgroups and controls. More interestingly, higher percentage of non-responders to vaccine was recorded in ASD patients compared to controls [13.2% (63/478), vs 2.8% (14/502); p < 0.0001]. Increased prevalence of non-response to vaccine was also observed in different ASD subgroups, in patients with ASD-related interstitial lung disease (p = 0.009), and in those treated with glucocorticoids (p = 0.002), mycophenolate-mofetil (p < 0.0001), or rituximab (p < 0.0001). Comparable percentages of vaccine-related adverse effects were recorded among responder and non-responder ASD patients. Patients with weak/absent seroconversion, believed to be immune to SARS-CoV-2 infection, are at high risk to develop COVID-19. Early determination of serum NAb after vaccination cycle may allow to identify three main groups of ASD patients: responders, subjects with suboptimal response, non-responders. Patients with suboptimal response should be prioritized for a booster-dose of vaccine, while a different type of vaccine could be administered to non-responder individuals.