Six-month humoral and cellular immune response to the third dose of BNT162b2 anti-SARS-CoV-2 vaccine in patients with solid tumors: a longitudinal cohort study with a focus on the variants of concern.

BACKGROUND: The role and the durability of the immunogenicity of the third dose of vaccine against COVID-19 variants of concern in cancer patients have to be elucidated. PATIENTS AND METHODS: We have prospectively evaluated the immunogenicity of the third dose of the SARS-CoV-2 BNT162b2 messenger RNA vaccine in triggering both humoral and cell-mediated immune response in patients with solid tumors undergoing active treatment 6 months after the booster. Neutralizing antibody (NT Ab) titers and total anti-spike immunoglobulin G concentrations were measured in serum. Heparinized whole blood samples were used for the SARS-CoV-2 interferon-γ release assay (IGRA). RESULTS: Six months after the third dose only two patients (2.4%) showed negative spike-specific immunoglobulin G antibody levels (<33.8 BAU/ml). The median level of SARS-CoV-2 NT Abs decreased and only 39/83 (47%) subjects showed maximum levels of NT Abs. T-cellular positive response was observed in 38/61 (62.3%) patients; the highest median level of response was observed 21 days after the third dose (354 mIU/ml, interquartile range 83.3-846.3 mIU/ml). The lowest median level of NT Ab response was observed against the Omicron variant (1 : 10, interquartile range 1 : 10-1 : 40) with a significant reduced rate of responder subjects with respect to the wild-type strain (77.5% versus 95%; P = 0.0022) and Delta variant (77.5% versus 93.7%; P = 0.0053). During the follow-up period, seven patients (8%) had a confirmed post-vaccination infection, but none of them required hospitalization or oxygen therapy. CONCLUSIONS: Our work highlights a significant humoral and cellular immune response among patients with solid tumors 6 months after the third BNT162b2 vaccine dose, although a reduction in neutralizing activity against Omicron was observed.

Immunogenicity and safety after the third dose of BNT162b2 anti-SARS-CoV-2 vaccine in patients with solid tumors on active treatment: a prospective cohort study.

BACKGROUND: Although a full course of coronavirus disease 2019 (COVID-19) vaccine is effective in cancer patients, the duration of the protection and the efficacy of a booster dose against the new variants remain unknown. We prospectively evaluated the immunogenicity of the third dose of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) BNT162b2 messenger RNA vaccine in cancer patients undergoing active treatment. PATIENTS AND METHODS: Patients with solid cancer, vaccinated with a booster dose during active treatment, were enrolled in this study. Patients were classified into SARS-CoV-2 naïve (without previous COVID-19 infection) and SARS-CoV-2 experienced (with previous COVID-19 infection). Neutralizing antibody (NT Ab) titer and total anti-Spike immunoglobulin G (IgG) concentration were quantified in serum. Heparinized whole blood samples were used for SARS-CoV-2 Interferon Gamma Release Assay (IGRA). The primary endpoint was to assess the increase of IgG antibody level between baseline and 3 weeks after the booster. RESULTS: One hundred and forty-two consecutive patients were recruited. In SARS-CoV-2-naïve subjects, the median level of IgG was 157 BAU/ml [interquartile range (IQR) 62-423 BAU/ml] at T0 and reached a median of 2080 BAU/ml (IQR 2080-2080 BAU/ml) at 3 weeks after booster administration (T1; P < 0.0001). A median 16-fold increase of SARS-CoV-2 NT Ab titer (IQR 4-32) was observed in naïve subjects (from median 20, IQR 10-40, to median 640, IQR 160-640; P < 0.0001). Median interferon-γ level at T1 was significantly higher than that measured at T0 in SARS-CoV-2-naïve subjects (P = 0.0049) but not in SARS-CoV-2-experienced patients. The median level of SARS-CoV-2 NT Abs was 32-fold lower against Omicron compared to the wild-type strain (P = 0.0004) and 12-fold lower compared to the Delta strain (P = 0.0110). CONCLUSIONS: The third dose is able to trigger both the humoral and the cell-mediated immune response in cancer patients on active treatment. Our preliminary data about the neutralization of the SARS-CoV-2 vaccine against variants of concern seem to confirm the lower vaccine activity.

Analysis of the humoral and cellular immune response after a full course of BNT162b2 anti-SARS-CoV-2 vaccine in cancer patients treated with PD-1/PD-L1 inhibitors with or without chemotherapy: an update after 6 months of follow-up.

BACKGROUND: The durability of immunogenicity of SARS-CoV-2 vaccination in cancer patients remains to be elucidated. We prospectively evaluated the immunogenicity of the vaccine in triggering both the humoral and the cell-mediated immune response in cancer patients treated with anti-programmed cell death protein 1/programmed death-ligand 1 with or without chemotherapy 6 months after BNT162b2 vaccine. PATIENTS AND METHODS: In the previous study, 88 patients were enrolled, whereas the analyses below refer to the 60 patients still on immunotherapy at the time of the follow-up. According to previous SARS-CoV-2 exposure, patients were classified as SARS-CoV-2-naive (without previous SARS-CoV-2 exposure) and SARS-CoV-2-experienced (with previous SARS-CoV-2 infection). Neutralizing antibody (NT Ab) titer against the B.1.1 strain and total anti-spike immunoglobulin G concentration were quantified in serum samples. The enzyme-linked immunosorbent spot assay was used for quantification of anti-spike interferon-γ (IFN-γ)-producing cells/106 peripheral blood mononuclear cells. Fifty patients (83.0%) were on immunotherapy alone, whereas 10 patients (7%) were on chemo-immunotherapy. We analyzed separately patients on immunotherapy and patients on chemo-immunotherapy. RESULTS: The median T-cell response at 6 months was significantly lower than that measured at 3 weeks after vaccination [50 interquartile range (IQR) 20-118.8 versus 175 IQR 67.5-371.3 IFN-γ-producing cells/106 peripheral blood mononuclear cells; P < 0.0001]. The median reduction of immunoglobulin G concentration was 88% in SARS-CoV-2-naive subjects and 2.1% in SARS-CoV-2-experienced subjects. SARS-CoV-2 NT Ab titer was maintained in SARS-CoV-2-experienced subjects, whereas a significant decrease was observed in SARS-CoV-2-naive subjects (from median 1 : 160, IQR 1 : 40-1 : 640 to median 1 : 20, IQR 1 : 10-1 : 40; P < 0.0001). A weak correlation was observed between SARS-CoV-2 NT Ab titer and spike-specific IFN-γ-producing cells at both 6 months and 3 weeks after vaccination (r = 0.467; P = 0.0002 and r = 0.428; P = 0.0006, respectively). CONCLUSIONS: Our work highlights a reduction in the immune response in cancer patients, particularly in SARS-CoV-2-naive subjects. Our data support administering a third dose of COVID-19 vaccine to cancer patients treated with programmed cell death protein 1/programmed death-ligand 1 inhibitors.

A snapshot of the immunogenicity, efficacy and safety of a full course of BNT162b2 anti-SARS-CoV-2 vaccine in cancer patients treated with PD-1/PD-L1 inhibitors: a longitudinal cohort study.

BACKGROUND: Very few cancer patients were enrolled in coronavirus disease-2019 vaccine studies. In order to address this gap of knowledge, real-world studies are mandatory. The aim of this study was to assess both humoral and cellular response after a messenger RNA vaccination schedule. PATIENTS AND METHODS: Eighty-eight consecutive cancer patients treated with programmed cell death protein 1/programmed death-ligand 1 inhibitors were enrolled from the beginning of the vaccination campaign for frail patients. Blood samples for humoral and cell-mediated immune response evaluation were obtained before vaccination (T0), before the second administration (T1) and 21 days after the second dose (T2). The primary endpoint was the evaluation of the percentage of participants showing a significant increase in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cells, measured by an enzyme-linked immunospot assay, after the second dose of BNT162b2 vaccine. The proportion of patients who reached the primary endpoint is computed together with its exact binomial 95% confidence interval. RESULTS: In SARS-CoV-2-naïve subjects, spike-specific T-cell response was almost undetectable at T0 [median 0.0 interferon-γ (IFN-γ) spot forming units (SFU)/million peripheral blood mononuclear cell (PBMC) interquartile range (IQR) 0-7.5] and significantly increased at T1 and T2 (median 15.0 IFN-γ SFU/million PBMC, 25th-75th 0-40 versus 90 IFN-γ SFU/million PBMC, 25th-75th 32.5-224, respectively) (P < 0.001). Focusing on naïve and experienced SARS-CoV-2 subjects, no differences were reported both in terms of CD4- and CD8-specific T-cell response, suggesting that BNT162b2 is able to elicit both adaptive responses after complete vaccination schedule, regardless of previous SARS-CoV-2 exposure. The level of SARS-CoV-2 neutralizing antibodies was low at T1 in SARS-CoV-2-naïve subjects [median 1 : 5 (IQR 1 : 5-1 : 20)] but reached a significantly higher median of 1 : 80 (25th-75th 1 : 20-1 : 160) at T2 (P < 0.0001). Moreover, no COVID-19 cases were documented throughout the period of study. CONCLUSIONS: Our data have demonstrated that the administration of a full course of BNT162b2 vaccine elicited a sustained immune response against SARS-CoV-2 regardless of the type of cancer and/or the type of immune checkpoint inhibitors.

Occult HIV infection in a large sample of health-care users in Lombardy, Italy in 2014-2015: implications for control strategies.

We estimated the number of people unaware of their human immunodeficiency virus (HIV) infection in our province, Pavia (population 540 000) in Lombardy, Italy, by means of anonymous unlinked testing of 10 044 serum/plasma samples residual from clinical analyses at the outpatient clinic of Policlinico San Matteo in 2014 and 2015. Ethical and legal approval was obtained prior to study start. Samples were irreversibly anonymised, only retaining gender and 5-year age class. Five sample pools were tested for HIV using LIAISON® XL MUREX HIV Ab/Ag (DiaSorin, Saluggia, Italy). If the pool tested positive, individual samples underwent confirmatory tests, Innotest HIV Antigen mAb (Fujirebio Europe, Gent, Belgium) and HIV BLOT 2·2 (MP Diagnostics, Singapore). Among the 10 044 samples processed, eight were confirmed positive (0·08%, 95% confidence interval 0·03-0·16%), all were males and age was >50 in 3 (37·5%). If projected to the entire population of the Pavia province, this would result in approximately 1000 people unaware of their HIV infection, with age older than expected. In Italy, HIV testing is voluntary, universally free-of-charge and (upon request) anonymous. Nevertheless, this study demonstrates that it is suboptimally employed, and that new strategies and population-level actions will be needed to achieve better implementation of HIV testing and HIV control in our province.

Virologic and immunologic monitoring of cytomegalovirus to guide preemptive therapy in solid-organ transplantation.

Control of human cytomegalovirus (HCMV) infection during the posttransplant period was investigated in 134 solid-organ transplant recipients by monitoring in parallel virologic and immunologic parameters for at least 1 year of follow-up. Virologic monitoring was achieved by determining HCMV DNAemia with real-time PCR, using the threshold of 300 000 DNA copies/mL blood as a cutoff for starting preemptive therapy. Immunologic monitoring included measurement of HCMV-specific CD4+ and CD8+ T cells by cytokine flow cytometry, using HCMV-infected dendritic cells as a stimulus. HCMV infection was diagnosed in 110 (82%) and required treatment in 49 (36%) patients. At 12 months after transplantation 'protective' immunity (≥0.4 CD4+ and CD8+ HCMV-specific T cells/µL blood) was achieved in 115/129 (89%) patients. During the entire study period, 122 patients reconstituting HCMV-specific CD4+ and CD8+ T-cell immunity at 60 days posttransplant onward were able to control HCMV infection, except for one patient who developed HCMV disease because of a rejection episode. Patients reconstituting HCMV-specific CD8+ only did not control HCMV infection. In conclusion, the presence of both HCMV-specific CD4+ and CD8+ T cells ≥ 0.4/µL blood appears to be protective against HCMV disease. This result does not apply to patients undergoing antirejection treatment, or reconstituting HCMV-specific CD8+ T cells only.

Inconsistent responses of cytomegalovirus-specific T cells to pp65 and IE-1 versus infected dendritic cells in organ transplant recipients.

CD4(+) and CD8(+) T cells specific for human cytomegalovirus (HCMV) and two immunodominant HCMV antigens (pp65 and IE-1) were monitored in 20 solid organ transplant recipients undergoing primary (n = 4) or reactivated (n = 16) HCMV infection during the first year after transplantation by using as a stimulator either HCMV-infected autologous dendritic cells (DCs) or pp65- or IE-1 peptide mixtures. Turnaround times for test performance were 7 days for infected DCs and 24 h for peptides. Using infected DCs, HCMV-specific T-cell restoration occurred in all patients for CD8(+) and in 18/20 (90%) for CD4(+) T-cell subpopulations, resulting in virus clearance from blood. Using peptide mixtures, T-cell responses were less frequently detected. In detail, 14 (70%) patients showed pp65-specific CD8(+) T cells and 10 (50%) patients IE-1-specific CD8(+) T cells, whereas pp65-specific CD4(+) T cells were detected in 14 (70%) patients, and IE-1-specific CD4(+) T cells in three (15%) patients only. Protection from HCMV infection was associated with the presence of a HCMV-specific T-cell response directed against multiple viral proteins, but not against pp65 or IE-1 only. In conclusion, the use of pp65 and IE-1 peptide mixtures for rapid monitoring of HCMV-specific T-cell responses in solid organ transplant recipients underestimates the actual T-cell immune response against HCMV.

Control of human cytomegalovirus infection in patients infected with human immunodeficiency virus by high levels of specific CD8+ T-cells.

A new technique was used to simultaneously determine human cytomegalovirus (HCMV)-specific CD4(+) and CD8(+) T-cells in highly active anti-retroviral therapy (HAART)-naive and HAART-treated patients infected with human immunodeficiency virus (HIV). HIV-infected patients with HCMV infection, but without HCMV disease, showed low numbers of HCMV-specific CD4(+) cells and high numbers of CD8(+) T-cells, both before and during HAART. HIV-infected patients with HCMV disease had no HCMV-specific CD4(+) T-cells and extremely low levels of CD8(+) T-cells. Resolution of disease during HAART was associated with rescue of specific CD4(+) T-cells and a large increase in the specific CD8(+) T-cell count. Thus, HAART does not completely restore the normal immune function. In HIV-infected patients, sustained control of HCMV infection requires high frequencies of specific CD8(+) T-cells.

Monitoring of human cytomegalovirus-specific CD4 and CD8 T-cell immunity in patients receiving solid organ transplantation.

Absolute and human cytomegalovirus (HCMV)-specific CD4+ and CD8+ T-cell counts were monitored in 38 solid organ (20 heart, 9 lung and 9 kidney) transplant recipients during the first year after transplantation by a novel assay based on T-cell stimulation with HCMV-infected autologous dendritic cells. According to the pattern of T-cell restoration occurring either within the first month after transplantation or later, patients were classified as either early (n = 21) or late responders (n = 17). HCMV-specific CD4+ and CD8+ T-cell counts were consistently lower in late compared to early responders from baseline through 6 months after transplantation. In addition, in late responders, while HCMV infection preceded immune restoration, HCMV-specific CD4+ restoration was significantly delayed with respect to CD8+ T-cell restoration. The number of HCMV-specific CD4+ and CD8+ T-cells detected prior to transplantation significantly correlated with time to T-cell immunity restoration, in that higher HCMV-specific T-cell counts predicted earlier immune restoration. Clinically, the great majority of early responders (18/21, 85.7%) underwent self-resolving HCMV infections (p = 0.004), whereas the great majority of late responders (13/17, 76.5%) were affected by HCMV infections requiring antiviral treatment (p = <0.0001). Simultaneous monitoring of HCMV infection and HCMV-specific T-cell immunity predicts T-cell-mediated control of HCMV infection.

Impaired bone marrow hematopoietic progenitor cell function in rheumatoid arthritis patients candidated to autologous hematopoietic stem cell transplantation.

We have evaluated bone marrow morphology, percentage of bone marrow CD34(+) cells, proliferative activity of bone marrow precursors, clonogenic assay (BFU-E and CFU-GM) in short-term bone marrow cultures, and bone marrow cell apoptosis, together with serum TNF-alpha and IL-6, in 16 chronic, refractory RA patients, as well as in five healthy controls. Of 16 RA patients (68.7%), 11 showed a reduced bone marrow cellularity, while it was normal in all the controls. In RA patients, the median percentage of CD34(+) bone marrow cells, the median percentage of proliferating bone marrow myeloid precursors, and the median number of both BFU-E and CFU-GM colonies were significantly lower than observed in the controls. As far as TNF-alpha and IL-6 titers is concerned, the latter did not significantly differ from controls' values, while TNF-alpha titers were significantly lower in healthy controls. Finally, the median apoptotic index of early bone marrow myeloid cells of RA patients was significantly higher compared with controls. These observations may identify the biological risk factors for impaired mobilization and/or engraftment when RA patients are candidates for autologous hematopoietic stem cell grafting.

Comparative analysis of human cytomegalovirus-specific CD4(+) T-cell frequency and lymphoproliferative response in human immunodeficiency virus-positive patients.

Evaluation of human cytomegalovirus (HCMV)-specific T-helper immunity could contribute in optimizing anti-HCMV therapy in human immunodeficiency virus (HIV)-infected patients. Testin the lymphoproliferative response (LPR) is the standard technique used to evaluate T-helper response, but its use in the routine diagnostic laboratory setting can be problematic. The most promising new alternative technique is the determination of HCMV-specific CD4(+) T-cell frequency by flow cytometry detection of intracellular cytokine production after short-term antigen-specific activation of peripheral blood mononuclear cells. HCMV-specific LPR and CD4(+) T-cell frequency were compared in a group of 78 blood samples from 65 HIV-infected patients. The results showed concordance in 80.7% of samples. In addition, comparative analysis of sequential blood samples from 13 HIV-infected patients showed that while in about half of patients the T-helper HCMV-specific immune response remained stable during highly active antiretroviral therapy (HAART), in the other half declining levels of the HCMV-specific CD4(+)-mediated immune response were determined by either one or both assays. In conclusion, our data suggest that the determination of HCMV-specific CD4(+) T-cell frequency can be considered a valuable alternative to the LPR test for the detection of HCMV-specific T-helper response in HIV-infected patients. It could facilitate wider screening of anti-HCMV T-helper activity in HIV-infected patients, with potential benefits for clinicians in deciding strategies of discontinuation or maintenance of anti-HCMV therapy.

Declining levels of rescued lymphoproliferative response to human cytomegalovirus (HCMV) in AIDS patients with or without HCMV disease following long-term HAART.

OBJECTIVE: To investigate the lymphoproliferative response (LPR) to human cytomegalovirus (HCMV) in two groups of AIDS patients undergoing long-term highly active antiretroviral therapy (HAART): group 1 ( n = 22) with nadir CD4(+) cell count <50/microl and no HCMV disease; group 2 ( n = 16) with <50/microl CD4(+) T-cell count and HCMV disease. All patients had previously undergone antiretroviral monotherapy or dual therapy before initiating HAART. STUDY DESIGN AND METHODS: The two groups of patients were tested prospectively for CD4(+) T cell count, HIV RNA load, HCMV viremia, and LPR to HCMV at baseline, and then after 3 and 4 years of HAART. A control group of 13 recently diagnosed treatment-naive AIDS patients with CD4(+) T-cell counts <100/microl was also investigated. RESULTS: No LPR to HCMV was found in any of the treatment-naive patients nor in any patient of the two groups examined at baseline, when HCMV viremia was 13.6% in the patient group without disease and 87.5% in the group with disease ( p <.0001). After 3 years of HAART, the frequency of patients who recovered an LPR to HCMV was not significantly different (81.8% in the group without HCMV disease, and 68.7% in the group with HCMV disease), whereas, compared with baseline, the HIV load decreased and the CD4(+) T-cell count increased significantly and to a comparable extent in the two groups of patients. In addition, the frequency of patients with HCMV viremia, although reduced, became comparable in both groups. After 4 years of HAART, the frequency of responders to HCMV without and with HCMV disease dropped to comparable levels (50.0 vs. 56.3%, respectively) in association with high median CD4(+) T-cell counts and low median HIV RNA plasma levels. In parallel, the frequency of patients with HCMV viremia did not change significantly. In addition, after between 3 and 4 years of HAART, although the frequency of stable responders and nonresponders remained unchanged (50%) in both groups, most of the remaining patients showed declining levels of responsiveness to HCMV. Although some patients from both groups were found to have CD4(+) T-cell counts >150/microl in the absence of LPR to HCMV, thus suggesting dissociation of specific and nonspecific immune reconstitution, a significant correlation was found between CD4(+) T-cell count and LPR to HCMV (r = 0.44; p <.001). From a clinical standpoint, anti-HCMV therapy could be safely discontinued in 8 patients with HCMV retinitis showing CD4(+) T-cell counts >150/microl, recovery of HCMV LPR, and no HCMV viremia. CONCLUSIONS: Declining levels of the previously recovered LPR to HCMV are often observed after long-term HAART. However, because the role of LPR in the evolution of HCMV infection and disease during HAART remains to be defined, the clinical impact of the declining LPR to HCMV must still be clarified in long-term prospective studies.

Higher levels of HIV DNA in memory and naive CD4(+) T cell subsets of viremic compared to non-viremic patients after 18 and 24 months of HAART.

The degree of infection of memory and naive CD4(+) T cells in patients treated with HAART and with durable undetectable or detectable viral load in plasma was evaluated. The following two groups of patients were analyzed cross-sectionally: (i) patients with undetectable HIV RNA plasma levels during follow-up (responders); (ii) patients with no reduction or with rebound in HIV RNA levels during treatment (non-responders). Patients were examined following 6, 12, 18 and 24 months of HAART, respectively, by quantifying: (i) plasma HIV RNA load; (ii) CD4(+) T cells; (iii) memory and naive CD4(+) T cells; (iv) HIV DNA levels in memory and naive CD4(+) T cells. HIV RNA plasma levels were significantly higher in non-responders vs responders at each time point (P<0.02), while CD4(+) T cell counts as well as memory and naive CD4(+) T cell levels were comparable in both viremic and non-viremic patients. However, higher HIV DNA values were observed in both memory and naive CD4(+) T cells of non-responders vs responders after 18 and 24 months of HAART (P<0.02), suggesting an increased amount of HIV-infected naive CD4(+) T cells and a sustained high degree of infection of memory CD4(+) T cells. Immunological reconstitution following HAART might potentially be hampered in viremic patients despite the absolute increase in CD4(+) T cell counts.

Higher short-term virologic efficacy of three-class versus two-class highly active antiretroviral salvage therapy in HIV-infected patients.

The efficacy of two-class versus three-class antiretroviral salvage treatment was analyzed retrospectively in 63 HIV-infected patients in whom highly active antiretroviral therapy failed. Twenty-eight patients (group A) received two-class therapy, and 35 patients (group B) received three-class therapy. After 3 months of treatment, a significantly greater proportion of patients in group B (23/35, 65.7%) than in group A (8/28, 28.5%) showed a > or = 1 log10 decrease in the plasma HIV RNA level (P = 0.0034). However, after 9-12 months, 12 of 23 (52.1%) group B responders showed viral load rebound. The results were partially explained by the finding that, at baseline, the great majority (21/27, 77.7%) of group A patients showed mutations conferring resistance to all drugs administered, whereas in group B patients' susceptibility to at least two drug classes was retained. However, after 9-12 months of therapy, most (18/20, 90%) of the short-term responders in group B showed emergence of additional mutations that hampered long-term response.

Cell cycle status and apoptosis of hematopoietic progenitor cells released into the peripheral blood after taxanes and granulocyte colony-stimulating factor in breast cancer patients.

Paclitaxel and its analogue docetaxel show a significant antitumor activity, particularly evident in breast cancer. Paclitaxel has also been proved to be effective as a peripheral blood progenitor cell (CPC) mobilizing agent. To optimize the use of active, disease-specific drugs as CPC priming, we have evaluated the effects of either paclitaxel or docetaxel both at standard dosages and followed by granulocyte colony-stimulating factor (G-CSF), on circulating CPC release and function in 18 patients with advanced breast cancer who had failed previous anthracycline-based regimens. The reported differences in biological behaviour between bone marrow and blood-derived hematopoietic progenitor cells and the ability of both paclitaxel and docetaxel to induce apoptosis, prompted us to simultaneously evaluate the cell cycle perturbations induced on CD34+ cells. Median CD34+ peaks were 24 microl (range: 10-58) in the paclitaxel-treated patients and 39 microl (range: 17-91), respectively, in the patients who received docetaxel. After paclitaxel, the percentage of CD34+ cells in S-phase was low (bromodeoxyuridine, BrdU, labelling index = 3.4+/-2%) with a concomitant presence of early apoptotic cells (8.1+/-3%). On the contrary, after docetaxel, the percentage of CD34+ cells in S-phase was higher (BrdU labelling index = 14.5+/-4%, p<0.05 vs. paclitaxel), while early apoptotic cells were detected at a similar rate (8. 6+/-3%, p = n.s. vs. paclitaxel). In conclusion, when used at standard dosages, with respect to paclitaxel + G-CSF, docetaxel + G-CSF is a more satisfactory tool to mobilize CPC and to induce them into the cell cycle. These data should be taken into account when combinations of docetaxel with other agents are explored as CPC mobilizing regimens for autografting.

Early immunisation with hepatitis B vaccine: a five-year study.

We evaluated the response to the recombinant Hepatitis B vaccine using an accelerated schedule versus the traditional schedule by studying the immunologic memory induced in 200 children with HBs-Ag negative mothers. At seroconversion, the traditional schedule presented a higher percentage of children with serum HBs-Ag concentrations over 100 mIU/ml than the accelerated schedule. After five years this difference was no longer statistically significant and children who presented anti-HBsAg concentrations below 10 mUI/ml received an additional booster dose which stimulated the antibody concentration to exceed 100 mIU/ml in all cases. Recombinant HBV vaccine induced better long term immunologic memory when it was administered earlier.

Circulating progenitor cell release and functional characterization after topotecan plus G-CSF and erythropoietin in small cell lung cancer patients.

Topotecan is a new antineoplastic agent active in ovarian cancer, with promising activity in small cell lung cancer and predictable toxicity. As a part of our ongoing attempt to optimize the use of disease-specific drugs as circulating progenitor cell (CPC) priming in solid tumors, we have evaluated the effects on CPC release of single-agent Topotecan followed by granulocyte colony-stimulating factor (G-CSF) + human recombinant erythropoietin (rhEPO), together with the cell cycle status of the collected CD34+ cells. Ten pretreated patients with small cell lung cancer received Topotecan (1 mg/m2, i.v. for 5 consecutive days) followed by G-CSF (5 microg/kg/day, s.c.) + rhEPO (10,000 I.U. daily, s.c.), starting 24 h after Topotecan. The combination was well tolerated and no relevant side-effects were recorded. On day +10 (range +9 to +11) after the last dose of Topotecan, the median WBC count and the CD34+ cell peak were 8.2 x 10(3) microl (range 4.9-13.9) and 55 microl (range 28-75), respectively. Using flow cytometry, a detailed cell cycle analysis was performed on these CD34+ cells. The cell cycle distribution was determined by DNA content coupled with bromodeoxyuridine incorporation analysis. Apoptosis was evaluated by quantitating DNA strand breaks. The percentage of CD34+ cells in active S-phase was 10.2+/-5%, while early apoptotic CD34+ cells were detected in a low percentage (5.5+/-3%). Topotecan followed by G-CSF + rhEPO mobilizes CPCs effectively. This sequence exerts a stimulation on CD34+ cell cycle with a protective effect from chemotherapy-induced apoptosis. Taken together, these data could be of value for the incorporation of Topotecan, as well as of the combination of G-CSF and rhEPO, into high-dose chemotherapy programs with CPC support.

Coinfection of the immunocompromised but not the immunocompetent host by multiple human cytomegalovirus strains.

Coinfection by multiple human cytomegalovirus (HCMV) strains was investigated in immunocompetent individuals and AIDS patients. Thirty HCMV maternal and fetal or newborn isolate pairs from 9 cases of congenital HCMV infection as well as 36 HCMV isolates and 2 PCR-HCMV-positive CSF samples from 13 AIDS patients were tested by restriction fragment length polymorphism analysis of multiple genome regions. Results from the group of congenital infections showed that: i) all the 9 women with primary HCMV infection presumably harboured a single HCMV strain; ii) all strains were genetically unrelated; iii) isolates from infected fetuses or newborns consisted of a single strain apparently indistinguishable from the maternal strain; iv) no strain variations were observed in isolates from different body sites or in sequential isolates from newborns up to 8 months after birth. Results from the AIDS patient group demonstrated that; i) all patients were infected by unrelated strains; ii) 6/13 (46.1%) patients were coinfected by 2 or more HCMV strains; iii) in a single patient two different HCMV strains were detected in blood and urine, respectively, whereas a mixture of the two was found in the pharynx; iv) 4 patients showed the sequential appearance of a mixed virus population or different strains suggesting sequential reinfections.