We analyzed a data set of 45 patients, prospectively included to receive dose 3 of the BNT162b2 vaccine given 78 days [range: 47-114] after dose 2 of the same vaccine. All 45 patients were negative for anti-N Abs before dose 3, but two patients were tested positive after dose 3 and were therefore excluded from the final analysis. Included patients were suffering from chronic lymphocytic leukemia (CLL) (n=15), indolent and aggressive B cell non-Hodgkin lymphoma (NHL) (n=14), and multiple myeloma (MM) (n=16). The median age of the 43 patients included in the final analysis was 77 years [range: 37-92], 63 % were men and 37 % women (Table 1). At the time of dose 3, patients’ treatments are reported in Table 1.
Amongst 43 patients, 18 (41,8%) had no anti-S Abs before the dose 3 of BNT162b2 vaccine (n=9 CLL, n=8 NHL, n=1 MM), and they all 18 remained negative after the dose 3 (Table 1). Fourteen of these 18 patients had already received an anti-CD20 Mab treatment, nine of them within the 12 months preceding the vaccine. One seronegative patient with MM was under active treatment for HIV infection.
In univariate analysis, age and type of LM, but not sex or type of treatment (except for anti-CD20 Mab performed within 6 to 12 months of administration of the anti-SARS-CoV-2 vaccine), was statistically associated with anti-S response after dose 3 (Table 1).
Amongst the 25 patients with positive anti-S titers before dose 3, all patients remained positive (100%) and 23 patients increased their anti-S titer after dose 3. Their median anti-S titer increased from 87.1 U/mL [range: 1.2-693] to 3386 U/mL [range: 6.6-20312] (p < 0.001) (Table 1). The median anti-S titer changed as following: 0 U/mL [range: 0-120] to 0 U/mL [range: 0-5997] (p = 0.12) in patients with CLL, from 0 [range: 0-310] to 0 U/mL [range: 0-6101] (p = 0.07) in patients with NHL, and from 100 U/mL [range: 0-690] to 2700 U/mL [range: 0-20312] (p < 0.0001) in patients with MM (Figure 1A). We tested the impact of previous anti-CD20 Mab therapy and found that patients treated within 12 months of administration of dose 3 did responded poorly (median anti-S titer: 0 U/mL [range: 0-6101]) when compared to patients that received the same drug at least 12 months before BNT162b2 vaccine (median anti-S titer: 4200 [range: 0-6073]) (p=0.047) (Figure 1B).
Exploratory comparative cellular immunity response with humoral response.
We next aimed to characterize specific T-cell responses to the BNT162b2 vaccine with a whole blood IGRA test in 27 patients with CD-20 positive disease to assess comparative immune response among poor humoral immune responders. We were able to collect and analyze blood samples in 22 (CLL n=10, NHL n=12) of them.
After dose 2, 15 patients showed a positivity for both humoral and T-cell response, seven patients were positive for only one of the two tests. Of note, four patients showed a T-cell response despite absence of measurable anti-S Abs. A total of eight patients (36.4%) were double-negative for both tests.
Dose 3 of BNT162b2 vaccine increased median IFN-gamma secretion after exposition to antigen 1 or antigen 2 (from 0.07 IU/ml [range: 0.0-0.17] to 0.3 IU/mL [range: 0.0-0.9] (p=0.0008) and from 0.06 IU/ml [range: 0.0-0.1] to 0.2 IU/mL [range: 0.0-1.3] (p=0.0006), respectively) (Figure 2A). Three patients that were initially double-negative showed a T-cell response, leaving a total of five patients (22.7%) without B- or T-cell response after dose 3. These patients included three cases of CLL (all actively treated with venetoclax and a past history of rituximab treatment) and two cases of NHL (rituximab and bendamustine, one on and one off this treatment combination). Four of those five double-negative patients had thus active treatment.
While the timing of treatment with an anti-CD20 Mab impacted humoral response as already stated, it did not modify T-cell response: median of IFN-gamma secretion after exposition to antigen 1 or antigen 2 was 0.14 IU/ml [range: 0.0-3.1] and 0.09 IU/mL [range: 0.0-0.9], respectively, for patients treated prior to > 12 months versus 0.5 IU/mL [range: 0.0-1.1] and 1.2 IU/mL [range: 0.0-3.3], respectively, for patients treated within <= 12 months (p=0.45 and p=0.48 respectively) (Figure 2B). Patients on active NHL or CLL treatment during the vaccination sequence had a poorer specific T-cell response than patients without ongoing cancer specific medication, the median of IFN-gamma secretion after exposition to antigen 2 was 0.0 IU/ml [range: 0.0; 0.5] vs 0.9 IU/mL [range: 0.1-4.0] p=0.049 (p = 0.08 for antigen 1) (Figure 2C). There was no difference of T-cell response between patients with CLL or NHL (p>0.99).
We then compared the performance of serologic and IGRA testing using the method of the receiver operating characteristic (ROC) curve to explore the best way to detect a specific immune response to SARS-CoV-2 vaccine. In this cohort of 22 patients (and seven healthy subjects naïve for SARS-Cov2 infection as negative controls), the IGRA test based on two different antigens identified more efficiently than the Elecsys ® Anti-SARS-CoV-2 immunoassay a specific immune response to SARS-CoV-2 vaccine (aera under the curve (AUC) anti-S Abs: 0.7045, p=0.11; AUC IGRA Antigen 1: 0.8636, p = 0.004 (Sensitivity: 65%, Specificity: 100%); AUC IGRA Antigen 2 : 0.8864, p=0.002, (Sensitivity: 60%, Specificity: 100%)).
Tolerance of the dose 3
No novel adverse events were observed in our population after dose 3 of BNT162b2 vaccine.