SARS-CoV-2-reactive antibody waning, booster effect and breakthrough SARS-CoV-2 infection in hematopoietic stem cell transplant and cell therapy recipients at one year after vaccination

The kinetics of SARS-CoV-2 reactive IgG antibodies after full vaccination and booster in allogeneic and autologous stem cell transplantation (allo-HSCT, ASCT) and chimeric antigen receptor T-cell therapy (CAR-T) are of utmost importance for estimating risk of infection. A prospective multicenter registry-based cohort study, conducted from December 2020 to July 2022 was used to analyze antibody waning over time, booster effect and the relationship of antibody response and breakthrough infection in 572 recipients (429 allo-HSCT, 121 ASCT and 22 CAR-T cell therapy). A significant decline in antibody titers was observed at 3 and 6 months after full vaccination in recipients without pre-vaccine SARS-CoV-2 infection, whereas recipients infected prior to vaccination showed higher and stable antibody titers over time. In poor responders, a booster dose was able to increase antibody titers in 83% of allo-HSCT and 58% of ASCT recipients but not in CART-T cell recipients [0%] (p < 0.01). One-year cumulative incidence of breakthrough infection was 15%, similar among cell therapy procedures. Immunosuppressive drugs at the time of vaccination [hazard ratio (HR) 1.81, p = 0.0028] and reduced intensity conditioning (HR 0.49, p = 0.011) were identified as the only conditions associated with different risk of breakthrough infection in allo-HSCT recipients. Antibody titers were associated with breakthrough infection and disease severity. No death was observed among the 72 breakthrough infections. Antibody level decay after the first two vaccine doses was common except in recipients with pre-vaccination SARS-CoV-2 infection. Poorly responding allo-HSCT recipients showed a response advantage with the booster as compared to ASCT and, especially, the null response found in CAR-T cell recipients. Antibody titers were positively correlated with the risk of breakthrough SARS-CoV-2 infection which was mainly driven by the immunosuppression status.

SARS-CoV-2 vaccine response and rate of breakthrough infection in patients with hematological disorders

Background

The clinical efficacy of SARS-CoV-2 vaccines according to antibody response in immunosuppressed patients such as hematological patients has not yet been established.

Patients and methods

A prospective multicenter registry-based cohort study conducted from December 2020 to December 2021 by the Spanish transplant and cell therapy group was used to analyze the relationship of antibody response at 3–6 weeks after full vaccination (2 doses) with breakthrough SARS-CoV-2 infection in 1394 patients with hematological disorders.

Results

At a median follow-up of 165 days after complete immunization, 37 out of 1394 (2.6%) developed breakthrough SARS-CoV-2 infection at median of 77 days (range 7–195) after full vaccination. The incidence rate was 6.39 per 100 persons-year. Most patients were asymptomatic (19/37, 51.4%), whereas only 19% developed pneumonia. The mortality rate was 8%. Lack of detectable antibodies at 3–6 weeks after full vaccination was the only variable associated with breakthrough infection in multivariate logistic regression analysis (Odds Ratio 2.35, 95% confidence interval 1.2–4.6, p = 0.012). Median antibody titers were lower in cases than in non-cases [1.83 binding antibody units (BAU)/mL (range 0–4854.93) vs 730.81 BAU/mL (range 0–56,800), respectively (p = 0.007)]. We identified 250 BAU/mL as a cutoff above which incidence and severity of the infection were significantly lower.

Conclusions

Our study highlights the benefit of developing an antibody response in these highly immunosuppressed patients. Level of antibody titers at 3 to 6 weeks after 2-dose vaccination links with protection against both breakthrough infection and severe disease for non-Omicron SARS-CoV-2 variants.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-022-01275-7.

Prognostic significance of FLT3-ITD length in AML patients treated with intensive regimens

FLT3-ITD mutations are detected in approximately 25% of newly diagnosed adult acute myeloid leukemia (AML) patients and confer an adverse prognosis. The FLT3-ITD allelic ratio has clear prognostic value. Nevertheless, there are numerous manuscripts with contradictory results regarding the prognostic relevance of the length and insertion site (IS) of the FLT3-ITD fragment. We aimed to assess the prognostic impact of these variables on the complete remission (CR) rates, overall survival (OS) and relapse-free survival (RFS) of AML patients with FLT3-ITDmutations. We studied the FLT3-ITD length of 362 adult AML patients included in the PETHEMA AML registry. We tried to validate the thresholds of ITD length previously published (i.e., 39 bp and 70 bp) in intensively treated AML patients (n = 161). We also analyzed the mutational profile of 118 FLT3-ITD AML patients with an NGS panel of 39 genes and correlated mutational status with the length and IS of ITD. The AUC of the ROC curve of the ITD length for OS prediction was 0.504, and no differences were found when applying any of the thresholds for OS, RFS or CR rate. Only four out of 106 patients had ITD IS in the TKD1 domain. Our results, alongside previous publications, confirm that FLT3-ITD length lacks prognostic value and clinical applicability.

Maintenance therapy with ex vivo expanded lymphokine-activated killer cells and rituximab in patients with follicular lymphoma is safe and may delay disease progression

Anti-cluster of differentiation 20 (CD20) monoclonal antibodies (mAbs) have shown promise in follicular lymphoma (FL) as post-induction therapy, by enhancing antibody-dependent cellular cytotoxicity (ADCC). However, cytotoxic cells are reduced after this treatment. We hypothesised that ex vivo expanded lymphokine-activated killer (LAK) cells administered to FL-remission patients are safe and improve anti-CD20 efficacy. This open, prospective, phase II, single-arm study assessed safety and efficacy of ex vivo expanded LAK cells in 20 FL-remission patients following rituximab maintenance. Mononuclear cells were obtained in odd rituximab cycles and stimulated with interleukin 2 (IL-2) for 8 weeks, after which >5 × 10⁸ LAK cells were injected. Patients were followed-up for 5 years. At the end of maintenance, peripheral blood cells phenotype had not changed markedly. Natural killer, LAK and ADCC activities of mononuclear cells increased significantly after recombinant human IL-2 (rhIL-2) stimulation in all cycles. Rituximab significantly enhanced cytotoxic activity. No patients discontinued treatment. There were no treatment-related serious adverse events. Three patients had progressed by the end of follow-up. After a median (interquartile range) follow-up of 59.4 (43.8-70.9) months, 85% of patients remained progression free. No deaths occurred. Quality-of-life improved throughout the study. Post-induction LAK cells with rituximab seem safe in the long term. Larger studies are warranted to confirm efficacy.

Micafungin as antifungal prophylaxis in non-transplanted haemotological patients

OBJECTIVE

Fungal infections are a major cause of morbidity and mortality in the haematological patients. These infections are mainly due to Candida spp. and Aspergillus spp. Mortality by these infections is high, but rates have descended in the latest series due to better antifungal agents. Echinocan-dins are, in vitro, very active against Candida and Aspergillus spp. The objective of the study is to analyse the efficacy and safety of micafungin in the antifungal prophylaxis of haema-tological patients on chemotherapy.

METHODS

A multicentre, observational retrospective study was performed in 7 Haematology Depart-ments in Spain. Patients admitted to these departments with chemotherapy or immunosuppressive treatment, and who had received antifungal prophylaxis with micafungin between 1 January 2009 and 31 December 2014 were included.

RESULTS

There were 5 cases of probable or proven fun-gal infection (4.8%) according to the 2008 EORTC criteria: 2 proven, 3 probable. The types of fungal infection were 3 as-pergillosis and 2 candidiasis. There were no drop-outs from the prophylaxis with micafungin due to toxicity.

CONCLUSIONS

Micafungin is an antifungal agent which, used in prophylaxis, has demonstrated good efficacy and an excellent toxicity profile, making it an apparently interesting option in patients requiring antifungal prophylaxis during their hospitalisation episode.

[Hypercoagulability status previous to total hip and knee arthroplasty: the contribution of rheumatoid arthritis]

PURPOSE

Starting from a status hypercoagulability previous to substitutive hip and knee surgery, the aim of this work was to investigate the influence of different osteoarthropatic pictures for which arthroplasty is indicated in the activation of the clotting cascade, rheumatoid arthritis (RA) being one of such pictures.

PATIENTS AND METHODS

Of 79 patients suitable for prosthetic surgery of hip (53) and knee (26), the preoperative values of several markers, namely, D dimers (D-D), thrombin-antithrombin (TAT) complex, and F1 + 2 prothrombin fragment (F1 + F2) were assessed by enzymoimmunoasay. The mean age of the patients was 65.5 years, and their sex distribution was 50 women and 29 men. The indications for arthroplasty were as follows: osteoarthrosis (62), aseptic necrosis (11), RA (9), articular gout (2), previous fracture (2), more than one diagnosis overlapped in some cases. The results attained were compared with a control group comprised of 33 subjects (16 women and 17 men) with mean age similar to the patient's group (68.06 years).

RESULTS

The D-D values in the patients suitable for hip arthroplasty and the TAT values in patients suitable for both types of surgery were significantly higher than those found in the control group (p = 0.012 and 0.01, respectively). The preoperative TAT levels of the RA patients were significantly higher (p = 0.025) than those found in the patients with the other surgical indications.

CONCLUSIONS

Previously to the performance of arthroplasty, the patients show hypercoagulative marker values higher than those of age-matched controls. The significant rising of TAT found in RA patients is concordant with the literature, and this fact makes it advisable to include RA among the pathologic situations associated with hypercoagulability, as this is a common indication for substitutive hip and knee surgery with high risk of venous thromboembolic disease.