Clinical predictors of donor antibody titre and correlation with recipient antibody response in a COVID-19 convalescent plasma clinical trial

BACKGROUND

Convalescent plasma therapy for COVID-19 relies on transfer of anti-viral antibody from donors to recipients via plasma transfusion. The relationship between clinical characteristics and antibody response to COVID-19 is not well defined. We investigated predictors of convalescent antibody production and quantified recipient antibody response in a convalescent plasma therapy clinical trial.

METHODS

Multivariable analysis of clinical and serological parameters in 103 confirmed COVID-19 convalescent plasma donors 28 days or more following symptom resolution was performed. Mixed-effects regression models with piecewise linear trends were used to characterize serial antibody responses in 10 convalescent plasma recipients with severe COVID-19.

RESULTS

Donor antibody titres ranged from 0 to 1 : 3892 (anti-receptor binding domain (RBD)) and 0 to 1 : 3289 (anti-spike). Higher anti-RBD and anti-spike titres were associated with increased age, hospitalization for COVID-19, fever and absence of myalgia (all P < 0.05). Fatigue was significantly associated with anti-RBD (P = 0.03). In pairwise comparison amongst ABO blood types, AB donors had higher anti-RBD and anti-spike than O donors (P < 0.05). No toxicity was associated with plasma transfusion. Non-ECMO recipient anti-RBD antibody titre increased on average 31% per day during the first three days post-transfusion (P = 0.01) and anti-spike antibody titre by 40.3% (P = 0.02).

CONCLUSION

Advanced age, fever, absence of myalgia, fatigue, blood type and hospitalization were associated with higher convalescent antibody titre to COVID-19. Despite variability in donor titre, 80% of convalescent plasma recipients showed significant increase in antibody levels post-transfusion. A more complete understanding of the dose-response effect of plasma transfusion amongst COVID-19-infected patients is needed.

Reduction of elevated plasma osteopontin levels with resection of non-small cell lung cancer (NSCLC)

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Background: Plasma osteopontin (OPN) levels in advanced NSCLC correlate with response to therapy and survival but the role plasma OPN in diagnosis or monitoring of early stage NSCLC has not been investigated. We hypothesize that plasma OPN levels are elevated in early stage NSCLC and that resection results in a measurable reduction. Methods: Pre-operative (pre-op) plasma OPN levels (ng/ml) were measured by ELISA (IBL-Japan) in a discovery set of 60 early stage NSCLC patients and compared to 56 current or former smokers. Pre-op OPN was validated in an independent cohort of 78 resectable NSCLC patients. The pre-op OPN level in the latter cohort was compared to matched postoperative (post-op) OPN levels to monitor the impact of surgery on the biomarker. Results: Discovery set pre-op OPN (271+31) was significantly higher than in smokers (40+2)(p=.001). Pre-op OPN was similar in the validation cohort (357+31, p=.055, demographics in Table ). Post-op OPN (189+19) measured at mean of 23 weeks (range 2–105) was significantly lower than pre-op (p<.0001). Time from surgery significantly impacted post-op OPN, with OPN<6 weeks post-op (282+30) higher than OPN>6 weeks post-op (155+18)(p<.0001). After 6 weeks post-op, resected stage I patients (N=45) had a significant decrease in OPN levels from 373+45 to 142+21 (p<.0001). Multivariate analysis ( Table ) noted a significant correlation between age, albumin and pre-op OPN, and between albumin and pre-op OPN and >6 weeks post-op OPN. No correlation was noted between gender, smoking, histology, diabetes or stage and the pre- or >6 weeks post-op OPN. Conclusions: Plasma OPN levels in early stage NSCLC patients are significantly elevated compared to smokers. The elevated pre-op OPN levels were validated in an independent cohort of early stage NSCLC patients. A significant decrease in OPN was noted following resection. Peri-operative reductions in plasma OPN may serve as a marker for response to therapy and warrant investigation into prognostic significance in early stage NSCLC. [Table: see text]

[Table: see text]

Frequency of use and outcome of surgical resection in the management of malignant mesothelioma in a community-based population: Results in 5,937 patients

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Background: Multimodality therapy of mesothelioma patients treated at specialized tertiary hospitals report surgical resection rates of 42% (Flores RM et al. Prognostic Factors in the Treatment of Malignant Pleural Mesothelioma at a Large Tertiary Referral Center. J Thorac Oncol 2007;2(10):957–965.). Treatment strategies in the community are less well defined and surgical expertise is not readily available. We undertook this study to evaluate the rate of surgical resection and its association with survival in a non-tertiary based population. Methods: The Surveillance, Epidemiology, and End Results (SEER) database was searched from 1990 - 2004. Variables analyzed included age, sex, race, year of diagnosis, laterality, vital status, stage, surgery, and reasons for no surgery. The association of resection on overall survival was estimated by the Kaplan-Meier method and examined in a Cox proportional hazards model adjusting for covariates. Results: Pathologically proven malignant pleural mesothelioma was identified in 5,937 patients: 1,166 women, 4,771 men; median age was 70 years. Surgical resection rate was 11% (n=636). Univariate analysis demonstrated a median survival of 13 months with surgical resection and a median survival of 7 months in the non-resected group (p<0.0001). Multivariate analysis demonstrated improved survival for surgically resected patients (HR 0.7, p<0.0001), controlling for age, gender, and stage. Conclusions: Surgical resection was associated with improved survival when controlling for age, stage, and gender. However, the rate of surgical resection was much lower in the community when compared to tertiary referral centers. Treatment efforts should be focused on a multidisciplinary approach which includes surgical evaluation.

No significant financial relationships to disclose.

Human mesotheliomas contain the simian virus-40 regulatory region and large tumor antigen DNA sequences

BACKGROUND

A cohort (20%) of patients with mesothelioma will not have an exposure to asbestos. Recently, a DNA tumor virus (simian virus 40) has been shown to cause hamster mesotheliomas; we previously described simian virus 40-like DNA amino terminus sequences in 29 of 48 mesotheliomas. We analyzed an additional 42 mesotheliomas to determine (1) whether our initial observations were durable and (2) the extent to which the simian virus 40 genome is present in mesotheliomas.

METHODS

Genomic DNA was extracted from snap frozen mesothelioma tumor samples and from the simian virus 40-induced hamster mesothelioma tumor H9A. Polymerase chain reaction primers were used to amplify various simian virus 40 large T-antigen regions including a 105-base pair amino terminus fragment, a 281-base pair carboxyl terminus fragment, and a 310-base pair fragment of the enhancer promoter region. Endonuclease digestions and Southern blotting were used to verify the expected product.

RESULTS

Thirty of the 42 (71%) samples amplified T-antigen amino sequences, and specificity was verified by Southern hybridization. Sixteen of 42 samples (38%) amplified the appropriate size fragment for the carboxyl terminus, and digestion with BsaB1 matched that of H9A. Twenty-two of 42 samples (52%) amplified simian virus 40 regulatory sequences and Fok1 digestion matched that of the hamster control tumor. Sequence analysis (4 patients) revealed 100% homology with the regulatory region of simian virus 40 strain 776.

CONCLUSIONS

These data suggest an association between the simian virus 40 virus and human mesothelioma that could be exploited for diagnostic/therapeutic options including early detection and potential vaccination strategies.

The effect of an antisense expression plasmid to the IGF-1 receptor on hamster mesothelioma proliferation

We have evaluated the effect of antisense IGF receptor transcripts on the proliferation and tumorigenicity in an SV40-induced, immunocompetent hamster mesothelioma model (H9A). Expression of IGF-1 and IGF-1 receptor (IGF-1 R) genes was identified from H9A RNA using RT-PCR and Northern blot analysis. H9A cells were electroporated with inducible expression vectors (under the transcriptional control of heat shock promotor HSP70) containing a cDNA fragment corresponding to bp 1-309 of IGF-1 R in the sense or antisense orientation to generate the respective clones A3 sense or B9 antisense. At 39 degrees C, the B9 antisense transfectants demonstrated significantly less proliferation than A3 sense transfectants (p2 < 0.02). At 34 degrees C, cell growth of A3 sense and B9 antisense transfected cells was not significantly different. The A3 sense clones resulted in greater numbers of tumours in vivo compared to the B9 antisense clone (p2 = 0.0001). The inhibitory effect of IGF-1R antisense transcripts on hamster mesothelioma demonstrated in this study by decreased growth and tumorigenicity in vitro and in vivo may have implications for the therapy of human mesothelioma.

Inhibition of hamster mesothelioma tumorigenesis by an antisense expression plasmid to the insulin-like growth factor-1 receptor

We evaluated the effect of antisense insulin-like growth factor (IGF) receptor transcripts on the proliferation and tumorigenicity in an SV40-induced, immunocompetent hamster mesothelioma model (H9A). Expression of IGF-1 and IGF-1 receptor (IGF-1R) genes was identified from H9A RNA using reverse transcription-PCR and Northern analysis. H9A cells were electroporated with inducible expression vectors (under the transcriptional control of heat shock promoter HSP70) containing a cDNA fragment corresponding to base pairs 1-309 of IGF-1R in the sense or antisense orientation to generate the respective clones A3 sense or B9 antisense. The expression vector in genomic DNA was detected with PCR analysis as a 173-bp fragment on ethidium bromide gels. The effects of the expression vectors were then evaluated in vitro under active (at 39 degrees C) or inactive (at 34 degrees C) conditions. At 39 degrees C, the B9 antisense transfectants demonstrated significantly less proliferation than A3 sense transfectants (P2 < 0.02). At 34 degrees C, cell growth of A3 sense- and B9 antisense-transfected cells was not significantly different. In vivo tumorigenicity was evaluated in hamsters inoculated with 10(5) A3 sense- or B9 antisense-transfected cells. The A3 sense clones resulted in greater numbers of tumors in vivo compared to the B9 antisense clone (P2 = 0.0001). When genomic DNA from tumors that developed in A3 sense and B9 antisense animals was analyzed for the expression vectors, a 173-bp fragment amplified from the expression vector was identified in the sense tumors but not in antisense B9 or wild-type H9A tumors, indicating a loss of the vector from the antisense clones that proliferated in vivo. The inhibitory effect of IGF-1R antisense transcripts on hamster mesothelioma demonstrated in this study by decreased growth and tumorigenicity in vitro and in vivo may have implications for the therapy of human mesothelioma.

Isolated lung perfusion with tumor necrosis factor for pulmonary metastases

BACKGROUND

A phase I trial was initiated to define the feasibility and safety of single-lung isolation perfusion with tumor necrosis factor-alpha, interferon-gamma, and moderate hyperthermia for patients with unresectable pulmonary metastases.

METHODS

Twenty patients with lung metastases (Ewing's, 2; sarcoma, 8; melanoma, 6; other, 4) were considered for single-lung isolation perfusion with 0.3 to 6.0 mg of tumor necrosis factor-alpha and 0.2 mg interferon-gamma delivered through an oxygenated pump circuit. Sixteen perfusions were performed in 15 patients (bilateral in 1). Metastases were completely resected (no single-lung isolation perfusion) in 3 patients, 1 patient had extrapulmonary disease, and one single-lung isolation perfusion was aborted for mechanical reasons.

RESULTS

There were no significant changes in systemic arterial blood pressure or cardiac output during perfusion. Systolic pulmonary artery pressure increased with isolation, but returned to pre-single-lung isolation perfusion levels after clamp release. The maximum systemic tumor necrosis factor-alpha level was 8 ng/mL, whereas pump-circuit levels ranged from 200 to 10,976 ng/mL. There were no deaths, and the mean hospitalization period was 9 days (range, 5 to 34 days). A short-term (6 to 9 month) unilateral decrease in perfused nodules was noted in 3 patients (melanoma in 1, adenoid cystic carcinoma in 1, renal cell carcinoma in 1).

CONCLUSIONS

Future studies using a combination of biologic modifiers, chemotherapy, and hyperthermia should be pursued to define active cytotoxic agents that will preserve underlying pulmonary function.

Use of photodynamic therapy for the management of pleural malignancies

Photodynamic therapy (PDT) is a surface oriented, locally cytotoxic intervention being investigated for oncologic therapy. Surfaces such as the pleura or the peritoneum are frequently involved with primary or metastatic cancer, and the chance for cure in such situations is low due to the inability to eradicate all the disease. A series of investigations have been performed at the National Cancer Institute since 1985 studying the possible use of PDT for large cavity treatment. This report details evolution of the methodology, toxicity, and overall feasibility of the delivery of intrapleural PDT to patients after debulking of primary and malignant chest neoplasms, with an emphasis on malignant pleural mesothelioma. These investigations have culminated in an ongoing Phase III trial to define the efficacy of intrapleural PDT.

Malignant pleural mesothelioma: newer aspects of carcinogenesis, molecular genetics, and prospects for future therapies

Malignant pleural mesothelioma (MPM) is an asbestos-related disease which, although rare, is having a major social impact, and is, for the majority of cases, an incurable illness. There has been a surge of information regarding data on mesothelial transformation, mesothelioma molecular genetics and somatic gene therapy for this disease. This report summarizes the most recent investigations attempting to characterize the behaviour, on a cellular and molecular level, of MPM, with an emphasis on data from investigations performed at the National Cancer Institute with our collaborators.