mRNA-1273 SARS-CoV-2 vaccine in recently transplanted allogeneic hematopoietic cell transplant recipients: Dynamics of cellular and humoral immune responses and booster effect

Allogeneic hematopoietic stem cell transplant (HCT) recipients are at high risk of severe COVID-19 despite vaccination. Little is known about cellular response to SARS-CoV-2 vaccine in this population, especially in recently transplanted patients (RTP). In this single-center study we examined cellular and humoral response to the mRNA-1273 (Spikevax®) vaccine in recently transplanted patients (RTP, n = 49), and compared them to long-term transplanted patients (LTTP, n = 19) and healthy controls (n = 20) at three different timepoints: one and three months after the second dose (T1 and T2, respectively, 28 days apart), and one month after the third dose (T3). Controls did not receive a third dose. RTPs showed lower IgG anti-S1 titers than healthy controls at both T1 (mean 0.50 vs 0.94 arbitrary units -AU-, p < 0.0001) and T2 (0.37 vs 0.79 AU, p < 0.0001). They also presented lower titers than LTTPs at T1 (0.50 vs 0.66, p = 0.01), but no differences at T2 (0.37 vs 0.40 AU, p = 0.55). The rate of positive T-cell responses was lower in RTPs than in controls at both T1 and T2 (61.2 % vs 95 %, p = 0.007; 59.2 % vs 100 %, p = 0.001, respectively), but without statistically significant differences between transplanted groups. At T3 no differences were seen between RTPs and LTTPs as well, neither in IgG antibodies (p = 0.82) nor in cellular responses (p = 0.15), although a third dose increased the rate of positive cellular and humoral responses in approximately 50 % of recently transplanted patients. However, active immunosuppressive treatment severely diminished their chances to produce an adequate response.

Reversions of QuantiFERON-TB Gold Plus in tuberculosis contact investigation: A prospective multicentre cohort study

BACKGROUND

Interferon-y Release Assays (IGRA) reversions have been reported in different clinical scenarios for the diagnosis of tuberculosis (TB) infection. This study aimed to determine the rate of QuantiFERON-TB Gold Plus (QFT-Plus) reversions during contact investigation as a potential strategy to reduce the number of preventive treatments.

METHODS

Prospective, multicentre cohort study of immunocompetent adult contacts of patients with pulmonary TB tested with QFT-Plus. Contacts with an initial positive QFT-Plus (QFT-i) underwent a second test within 4 weeks (QFT-1), and if negative, underwent a repeat test 4 weeks later (QFT-2). Based on the QFT-2 result, we classified cases as sustained reversion if they remained negative and as temporary reversion if they turned positive.

RESULTS

We included 415 contacts, of whom 96 (23.1%) had an initial positive test (QFT-i). Following this, 10 had negative QFT-1 results and 4 (4.2%) of these persisted with a negative result in the QFT-2 (sustained reversions). All four sustained reversions occurred in contacts with IFN-γ concentrations between ≥0.35 and ≤0.99 IU•mL-1 in one or both QFT-i tubes.

CONCLUSION

In this study, TB contact investigations rarely reveal QFT-Plus reversion. These results do not support retesting cases with an initial positive result to reduce the number of preventive treatments.

Antibodies against the flotillin-1/2 complex in patients with multiple sclerosis

Multiple sclerosis is a tissue-specific autoimmune disease of the central nervous system in which the antigen(s) remains elusive. Antibodies targeting the flotillin-1/2 complex have been described in 1-2% of the patients in a recent study. Other candidate antigens as anoctamin-2 or neurofascin-155 have been previously described in multiple sclerosis patients, although their clinical relevance remains uncertain. Our study aims to analyse the frequency and clinical relevance of antibodies against neurofascin-155, anoctamin-2 and the flotillin-1/2 complex in multiple sclerosis.

Serum (n = 252) and CSF (n = 50) samples from 282 multiple sclerosis patients were included in the study. The control group was composed of 260 serum samples (71 healthy donors and 189 with other neuroinflammatory disorders). Anti-flotillin-1/2, anti-anoctamin-2 and anti-neurofascin-155 antibodies were tested by cell-based assays using transfected cells. We identified 6 multiple sclerosis patients with antibodies against the flotillin-1/2 complex (2.1%) and 1 multiple sclerosis patient with antibodies against anoctamin-2 (0.35%). All multiple sclerosis patients were negative for anti-neurofascin-155 antibodies. Three of the anti-flotillin-1/2 positive patients showed anti-flotillin-1/2 positivity in other serum samples extracted at different moments of their disease. Immunoglobulin G subclasses of anti-flotillin-1/2 antibodies were predominantly 1 and 3.

We confirm that antibodies targeting the flotillin-1/2 complex are present in a subgroup of patients with multiple sclerosis. Further studies are needed to understand the clinical and pathological relevance of anti-flotillin-1/2 autoantibodies in multiple sclerosis.

Comparison of a human acellular dermal matrix and a polypropylene mesh for pelvic floor reconstruction: a randomized trial study in a rabbit model

Non-absorbable polypropylene (PP) meshes have been widely used in surgical reconstruction of the pelvic floor disorders. However, they are associated with serious complications. Human acellular dermal matrices (hADM) have demonstrated safety and efficacy in reconstructive medicine, but their suitability and efficacy at vaginal level is not known. This study compares the biological performance of PP mesh and a newly developed hADM. 20 rabbits were randomized to receive the hADM graft or the PP mesh. Grafts were surgically implanted in the abdominal wall and vagina. After 180 days, grafts were explanted and evaluated. The vaginal mesh extrusion rate was higher in the PP group (33% vs. 0%, p = 0.015). Full integration of the vaginal grafts was more frequent in the hADM group, where 35% of the grafts were difficult to recognize. In the PP group, the vaginal mesh was identified in 100% of the animals (p = 0.014). In PP group, the infiltrates had a focal distribution and were mostly located in the internal part of the epithelium, while in the hADM group, the infiltrates had a diffuse distribution. Additionally, the hADM group also presented more B-lymphocytes and less T-lymphocytes. Biomechanical analysis showed that hADM had lower resistance to stress. Moreover, PP mesh stiffness and elasticity were higher. Then, hADM is associated with fewer clinical complications, as well as better tissue integration. However, it shows greater incorporation into the surrounding native tissue, especially in the vaginal location, undergoing a reduction in its biomechanical properties 6 months after implantation.

Immune Response and Safety of SARS-CoV-2 mRNA-1273 Vaccine in Patients With Myasthenia Gravis

Background and Objectives

Evidence regarding the safety and efficacy of messenger RNA (mRNA) vaccines in patients with myasthenia gravis (MG) after immunosuppressive therapies is scarce. Our aim is to determine whether the mRNA-1273 vaccine is safe and able to induce humoral and cellular responses in patients with MG.

Methods

We performed an observational, longitudinal, prospective study including 100 patients with MG of a referral center for MG in our country, conducted from April 2021 to November 2021 during the vaccination campaign. The mRNA-1273 vaccine was scheduled for all participants. Blood samples were collected before vaccination and 3 months after a second dose. Clinical changes in MG were measured using the MG activities of daily life score at baseline and 1 week after the first and second doses. A surveillance of all symptoms of coronavirus disease 2019 (COVID-19) was conducted throughout the study. Humoral and cellular immune responses after vaccination were assessed using a spike-antibody ELISA and interferon gamma release assay in plasma. The primary outcomes were clinically significant changes in MG symptoms after vaccination, adverse events (AEs), and seroconversion and T-cell immune response rates.

Results

Ninety-nine patients completed the full vaccination schedule, and 98 had 2 blood samples taken. A statistically significant worsening of symptoms was identified after the first and second doses of the mRNA-1273 vaccine, but this was not clinically relevant. Mild AEs occurred in 14 patients after the first dose and in 21 patients after the second dose. Eighty-seven patients developed a humoral response and 72 patients showed a T-cell response after vaccination. A combined therapy with prednisone and other immunosuppressive drugs correlated with a lower seroconversion ratio (OR = 5.97, 95% CI 1.46–24.09, p = 0.015) and a lower T-cell response ratio (OR = 2.83, 95% CI 1.13–7.13, p = 0.024).

Discussion

Our findings indicate that the mRNA vaccination against COVID-19 is safe in patients with MG and show no negative impact on the disease course. Patients achieved high humoral and cellular immune response levels.

Classification of Evidence

This study provides Class IV evidence that patients with MG receiving the mRNA-1273 vaccine did not show clinical worsening after vaccination and that most of the patients achieved high cellular or immune response levels.

The Robustness of Cellular Immunity Determines the Fate of SARS-CoV-2 Infection

Two years after the appearance of the SARS-CoV-2 virus, the causal agent of the current global pandemic, it is time to analyze the evolution of the immune protection that infection and vaccination provide. Cellular immunity plays an important role in limiting disease severity and the resolution of infection. The early appearance, breadth and magnitude of SARS-CoV-2 specific T cell response has been correlated with disease severity and it has been thought that T cell responses may be sufficient to clear infection with minimal disease in COVID-19 patients with X-linked or autosomal recessive agammaglobulinemia. However, our knowledge of the phenotypic and functional diversity of CD8+ cytotoxic lymphocytes, CD4+ T helper cells, mucosal-associated invariant T (MAIT) cells and CD4+ T follicular helper (Tfh), which play a critical role in infection control as well as long-term protection, is still evolving. It has been described how CD8+ cytotoxic lymphocytes interrupt viral replication by secreting antiviral cytokines (IFN-γ and TNF-α) and directly killing infected cells, negatively correlating with stages of disease progression. In addition, CD4+ T helper cells have been reported to be key pieces, leading, coordinating and ultimately regulating antiviral immunity. For instance, in some more severe COVID-19 cases a dysregulated CD4+ T cell signature may contribute to the greater production of pro-inflammatory cytokines responsible for pathogenic inflammation. Here we discuss how cellular immunity is the axis around which the rest of the immune system components revolve, since it orchestrates and leads antiviral response by regulating the inflammatory cascade and, as a consequence, the innate immune system, as well as promoting a correct humoral response through CD4+ Tfh cells. This review also analyses the critical role of cellular immunity in modulating the development of high-affinity neutralizing antibodies and germinal center B cell differentiation in memory and long-lived antibody secreting cells. Finally, since there is currently a high percentage of vaccinated population and, in some cases, vaccine booster doses are even being administered in certain countries, we have also summarized newer approaches to long-lasting protective immunity and the cross-protection of cellular immune response against SARS-CoV-2.

Immunoparesis defined by heavy/light chain pair suppression in smoldering multiple myeloma shows initial isotype specificity and involves other isotypes in advanced disease

Smoldering multiple myeloma (SMM) is an asymptomatic and biologically heterogeneous plasma cell disorder, with a highly variable clinical course. Immunoparesis, defined by total immunoglobulin measurements, has been shown to be an independent risk factor for progression to symptomatic disease. The heavy/light chain (HLC) assay allows precise measurement of the polyclonal immunoglobulin of the same isotype, enabling the evaluation of isotype-matched immunoparesis (IMI). In this study, we prospectively characterized immunoparesis, as determined by HLC measurements, in 53 SMM patients. Severe IMI was present in 51% of patients, while severe IP of uninvolved isotypes (HLC IP) was present in 39%. Most of the patients with severe HLC IP presented with severe IMI, but not the other way around. Isotype specificity of immune suppression was suggested by lower relative values of isotype-matched HLC pairs, both for IgG and IgA SMM. Severe IMI was associated with other risk factors for progression while patients with severe IMI and severe HLC IP showed an even higher risk profile. Both severe IMI and severe IgM HLC IP showed a significantly shorter time to progression. Finally, gene expression analysis demonstrated differences in the bone marrow microenvironment between patients with IMI and IMI plus HLC IP, with an increased expression of genes associated with cytolytic cells. In conclusion, our data supports isotype specificity of early immunoglobulin suppression mechanisms. While suppression of both involved and uninvolved isotypes is associated with risk of progression, the later appears to develop with more advanced disease and could be mediated by different mechanisms.

POS0827 HEPATOTROPIC VIRUSES WITH HIGHER RHEUMATOID FACTOR, BUT NOT RHEUMATIC DISEASES LINK TO PREVALENT CRYOGLOBULINEMIA. CORRELATION OF CLINICAL AND SEROLOGICAL MARKERS WITH ETIOLOGICAL CAUSES

Background:

Cryoglobulinemia (CG) is a rare phenomenon, which is defined as the persistent presence in serum of abnormal immunoglobulins (Igs) that precipitate in vitro at less than 37°C and dissolve when the temperature rises again. Is related to hematological disorders, infections and autoimmunes diseases.

Objectives:

To describe the differential clinical features, serological and demographics in a cohort of patients diagnosed with CG.

Methods:

We describe a retrospective cohort of 252 cryoglobulin (Cg) positive samples, obtained from a database from the immunology laboratory of a tertiary hospital (November 2018-November 2019). We obtained 182 patients with CG, classified according to their etiology into 4 groups: 1)Rheumatic diseases (RD) that includes rheumatoid arthritis, Systemic lupus erythematosus, Sjögren´s syndrome and Systemic scleroderma, 2)Hepatotropic viruses (HV) with patients diagnosed with Hepatitis C virus, B virus and both, 3)Hematological diseases (HD) and 4)Essential cryoglobulinemia (CGE). Demographic variables, clinical and serological data were collected. A comparative analysis was performed with the Mann-Whitney U test and the multivariate Kruskal-Wallis test, nonparametric variables were compared using a Wilcoxon test. Ten patients, with more than one disease from 4 groups, were excluded from the study.

Results:

Out of 182 reviewed patients, 172 were included in the study. Mean age at diagnosis was 59.7(±14.0). Demographic, clinical and laboratory characteristics are described in table 1. Mixed CG was the predominant subtype, in 116 (67.4%) patients. The most prevalent CG-associated diseases were HV infection with 91(53%) patients. CGE mostly presented with cutaneous manifestations (p=0.0001), particularly purpura. In RD group the presence of Raynaud and non-erosive arthritis (p=0.0001) was relevant. Laboratory findings showed that CG titration varies according to the etiology, being HD the one with the highest values with 292.2 (±546.2). There is significant difference in terms of the average of rheumatoid factor (RF) being higher in the group by CGE. On other hand, the group HV presented more consumption of complement, and showed the lowest average p=0.0001, without more severe clinical manifestations.

RD (n=47)HV (n=91)HD (n=17)CGE (n=17)Gender,n(%) F42 (89.4)57 (62.6)7 (41.2)11 (64.7)Age at dg, years, (± SD)60.6 (±14)59.6 (±13.1)61.1(±16.6)56.3(±20.8)p=0.8CLINICAL CHARACTERISTICSSkin n (%)18 (38.3)10 (11.0)2 (11.8)9 (52.9)p<0.001Raynaud n (%)14 (29.8)1 (5.9)3 (17.6)p<0.001Purpura n (%)6 (12.8)9 (9.9)2 (11.8)6 (35.3)p=0.04Acrocyanosis n (%)6 (12.8)1 (5.9)p=0.0033Ulcers n (%)3 (6.4)2 (2.2) -2 (11.8)p=0.19Peripheric Neuro n (%)10 (21.3)9 (9.9)1 (5.9)4 (23.5)p=0.13N-E arthritis n (%)22 (46.8)8 (8.8)1 (5.9)4 (23.5)p<0.001GMN n (%)5 (10.6)3 (3.3)1 (5.9)3 (17.6)p=0.11LABORATORYCg (mg/dL) x (± SD)26.7 (±63.2)65.8 (±256.5)292.4 (±546.2)47.59 (±79.1)p<0.001Isotype IgG, n (%)G+M 26 (55.3)G+M 72 (79.1)M 8 (47.1)G+M 12 (70.6)β2M (≥1.8 mg/L), n (%)7/40 (17.5%)1/5 (20.0%)3/12 (25.0%)-p= 0.44RCP (mg/L) p 5010.3 (±26.2)3.9 (±3.0)13.4 (±18.3)8.5 (±12.0)p= 0.47ESR (mm/h) p5040.0 (±28.5)20.3 (±20.2)35.4 (±35.1)24.5 (±25.0)p= 0.0003RF + (>20UI/mL), n (%)19/46 (41.3)44/86 (51.2)5/11 (45.5)7/17 (41.2)p= 0.09p5090.6 (±175.9)161.0 (±219.5)94.8 (±135.6)284.5 (±619.3)p<0.001C3 (<85mg/dL), n %)20 (42.6)47 (51.6)3 (17.6)3 (17.6)p= 0.13x (± SD)90.1 (±28.6)68.5 (±10.8)99.1 (±29.0)114.8 (±12.7)p<0.001C4 (<12mg/dL), n (%)17 (36.2)36 (39.6) -3 (17.6)p= 0.02x (± SD)15.6 (±9.0)7.6 (±3.5)20.4 (±7.4)21.1 (±9.5)p<0.001

Conclusion:

In our cohort, not all patients with CG presented clinical manifestations being those associated with CGE and RD those with the highest skin and joint expression. The most prevalent association of CG continues to be the HV and we confirmed the characteristic decrease in C3 and C4 complement levels, together with the positivity for RF.

Disclosure of Interests:

None declared

Author Correction: Clinical and laboratory features of anti-MAG neuropathy without monoclonal gammopathy

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

High Levels of Platelet-Lymphocyte Complexes in Patients with Psoriasis Are Associated with a Better Response to Anti-TNF-α Therapy

Psoriasis is currently considered to be an immune-mediated disease whose patho-mechanisms involve platelet activation, which seems to correlate with the activity of the disease. Platelet activation is associated with the formation of platelet-lymphocyte complexes (PLyC), although their significance remains unknown. Moreover, biological treatments that target tumor necrosis factor-α (TNF-α) reduce platelet activation. To clarify the significance of PLyC, we compared their levels in patients with psoriasis with those of healthy donors and determined whether platelet binding modifies the secretion of IL-17A by T helper cells. Finally, we assessed the effect of anti-TNF-α treatment on PLyC in responder and non-responder patients with psoriasis. Ours results demonstrated an increase in PLyC in patients with psoriasis. Moreover, the percentage of IL-17-secreting cells was observed to be higher in the platelet-lymphocyte complex population, and these cells tended to secrete greater amounts of IL-17A. Psoriasis patients treated with anti-TNF-α normalized platelet-lymphocyte complex values, and the basal percentage of platelet-T helper lymphocyte complexes was significantly higher in the responder group. In conclusion, PLyC are increased in psoriasis patients, and the number of complexes decreases in response to anti-TNF-α treatment, specifically in the responder group of patients. This finding suggests that PLyC are a prognostic biomarker of response to anti-TNF-α therapy, but prospective studies are necessary to verify these results in patients with psoriasis.

Clinical and laboratory features of anti-MAG neuropathy without monoclonal gammopathy

Antibodies against myelin-associated glycoprotein (MAG) almost invariably appear in the context of an IgM monoclonal gammopathy associated neuropathy. Very few cases of anti-MAG neuropathy lacking IgM-monoclonal gammopathy have been reported. We investigated the presence of anti-MAG antibodies in 69 patients fulfilling diagnostic criteria for CIDP. Anti-MAG antibodies were tested by ELISA and confirmed by immunohistochemistry. We identified four (5.8%) anti-MAG positive patients without detectable IgM-monoclonal gammopathy. In two of them, IgM-monoclonal gammopathy was detected at 3 and 4-year follow-up coinciding with an increase in anti-MAG antibodies titers. In conclusion, anti-MAG antibody testing should be considered in chronic demyelinating neuropathies, even if IgM-monoclonal gammopathy is not detectable.

Multi-centre validation of a flow cytometry method to identify optimal responders to interferon-beta in multiple sclerosis

BACKGROUND AND OBJECTIVES

Percentages of blood CD19+CD5+ B cells and CD8+perforin+ T lymphocytes can predict response to Interferon (IFN)-beta treatment in relapsing-remitting multiple sclerosis (RRMS) patients. We aimed to standardize their detection in a multicenter study, prior to their implementation in clinical practice.

METHODS

Fourteen hospitals participated in the study. A reference centre was established for comparison studies. Peripheral blood cells of 105 untreated RRMS patients were studied. Every sample was analyzed in duplicate in the participating centre and in the reference one by flow cytometry. When needed, participating centres corrected fluorescence compensations and negative cut-off position following reference centre suggestions. Concordance between results obtained by participating centres and by reference one was evaluated by intraclass correlation coefficients (ICC) and Spearman correlation test. Centre performance was measured by using z-scores values.

RESULTS

After results review and corrective actions implementation, overall ICC was 0.86 (CI: 0.81-0.91) for CD19+CD5+ B cell and 0.89 (CI: 0.85-0.93) for CD8+ perforin+ T cell quantification; Spearman r was 0.92 (0.89-0.95; p <0.0001) and 0.92 (0.88-0.95; p <0.0001) respectively. All centres obtained z-scores≤0.5 for both biomarkers.

CONCLUSION

Homogenous percentages of CD19+CD5+ B cells and CD8 perforin+ T lymphocytes can be obtained if suitable compensation values and negative cut-off are pre-established.

Dendritic and tumor cell fusions transduced with adenovirus encoding CD40L eradicate B-cell lymphoma and induce a Th17-type response

Fusion of dendritic cells and tumor cells (FCs) constitutes a promising tool for generating an antitumor response because of their capacity to present tumor antigens and provide appropriate costimulatory signals. CD40-CD40L interaction has an important role in the maturation and survival of dendritic cells and provides critical help for T-cell priming. In this study, we sought to improve the effectiveness of FC vaccines in a murine model of B-cell lymphoma by engineering FCs to express CD40L by means of an adenovirus encoding CD40L (Adv-CD40L). Before transduction with Adv-CD40L, no CD40L expression was detected in FCs, DCs or tumor cells. The surface expression of CD40L in FC transduced with Adv-CD40L (FC-CD40L) ranged between 50 and 60%. FC-CD40L showed an enhanced expression of CD80, CD86, CD54 and MHC class II molecules and elicited a strong in vitro immune response in a syngeneic mixed lymphocyte reaction. Furthermore, FC-CD40L showed enhanced migration to secondary lymphoid organs. Splenocytes from mice treated with FC-CD40L had a dramatic increase in the production of IL-17, IL-6 and IFN-gamma, compared with controls. Treatment with the FC-CD40L vaccine induced regression of established tumors and increased survival. Our data demonstrate that FC transduced with Adv-CD40L enhances the antitumor effect of FC vaccines in a murine lymphoma model and this is associated with an increased Th17-type immune response.

MDP-Induced selective tolerance to TLR4 ligands: impairment in NOD2 mutant Crohn's disease patients

BACKGROUND

Pathogen infection is a complex process in which several pathogen-recognition receptor (PRR) pathways are activated to induce proinflammatory mediators. The activation of multiple PRRs suggests an interaction between Toll-like receptors (TLRs) and nucleotide-binding oligomerization domain-like receptor (NOD) signaling pathways.

METHODS

To understand the modulation induced by NOD2 signals on successive responses to pathogen-associated molecular patterns (PAMPs), we examined how muramyl dipeptide (MDP) pretreatment reprograms the MDP+LPS (lipopolysaccharide) response of monocytes from human peripheral blood.

RESULTS

Preexposure to bacterial MDP components induced selective tolerance to a subsequent NOD2+TLR4 stimulation. MDP pretreatment inhibited the production of tumor necrosis factor alpha (TNFalpha) and interleuken 10 (IL10), whereas IL6 and IL8 remained unaffected. MDP-induced tolerance was independent of receptor downregulation but was associated with reduced levels of phosphorylated TAK1 and abrogated phosphorylation of the downstream MAPK.Since Nod2 mutations have been associated with susceptibility to develop Crohn's disease (CD), we compared the MDP-induced tolerance in healthy donors and CD patients with compound heterozygous Nod2 mutations (Mut-Nod2) expressing variant NOD2 proteins. MDP-induced tolerance in Mut-Nod2 patients reduced IL10 but not TNFalpha production. In contrast with healthy donors, a p38-independent TNFalpha production was observed during the kinetics of the MDP+LPS response in Mut-Nod2 patients.

CONCLUSIONS

Our findings suggest that the selective tolerance induced by MDP in healthy donors was related to the modulation of a convergent nub of NOD2 and TLR4 signaling pathways. This MDP-induced tolerance was impaired in Mut-Nod2 CD patients, resulting in a p38-independent TNFalpha production and an imbalance between pro- and antiinflammatory cytokines that could be partly responsible for the pathogenesis of CD.

Bcl-10 protein highly correlates with the expression of phosphorylated p65 NF-kappaB in peripheral T-cell lymphomas and is associated with clinical outcome

AIMS

In T cells, protein kinase C (PKC) theta plays a major role in T-cell receptor (TCR)-mediated activation of a novel nuclear factor (NF)-kappaB pathway that involves phosphorylation of p65 at serine 536 (Pp65(Ser536)). Bcl-10 acts along the same pathway downstream of PKC theta to activate NF-kappaB. The aim was to investigate the relationship between the expression of PKC theta, Bcl-10 and P-p65(Ser536) proteins and their prognostic significance in peripheral T-cell lymphomas (PTCLs).

METHODS AND RESULTS

Paraffin-embedded tissues from 30 patients with PTCLs treated with curative intention were evaluated retrospectively. Expression of PKC theta, Bcl-10 and P-p65(Ser536) proteins was assessed using immunohistochemistry. Expression of PKC theta was detected in 22 of 30 cases (73%), Bcl-10 in 20 of 30 (67%) and P-p65(Ser536) in 21 of 30 (70%). Bcl-10+ tumours were associated with PKC theta (18 of 22) (P < 0.0001) and Pp65Ser536 (19 of 21) expression (P < 0.0001). Patients with Bcl-10+ or P-p65(Ser536+) tumours fared better, with a 5-year overall survival of 48 and 45%, respectively, versus 0% for negative tumours (P = 0.029 and P = 0.04, respectively).

CONCLUSIONS

Bcl-10 is expressed in PTCLs, correlates with PKC theta and Pp65(Ser536) expression and seems to be associated with better survival.

NK cells stimulated with IL-15 or CpG ODN enhance rituximab-dependent cellular cytotoxicity against B-cell lymphoma

OBJECTIVE

Antibody-dependent cellular cytotoxicity (ADCC) is an important mechanism in the clinical activity of rituximab for treatment of B-cell malignancies. Natural killer (NK) cells, through the activating receptor FcgammaRIIIa (CD16), play a major role in rituximab-mediated ADCC. We have studied the in vitro effect of NK stimulators, such as interleukin-15 (IL-15) and CpG oligodeoxynucleotides A-Class (CpG ODN A), in the enhancement of rituximab-mediated ADCC against B-cell lymphoma.

METHODS

Peripheral blood mononuclear cells (PBMC), purified NK cells, or NK-depleted PBMC from healthy donors, were activated with IL-15 or CpG ODN A, and cocultured with B-lymphoma cells in the presence of rituximab to evaluate the enhancement of the cytotoxicity.

RESULTS

The rituximab-mediated ADCC of IL-15-activated PBMC was twofold compared to unstimulated PBMC (73% +/- 7% vs 37% +/- 5% respectively, p < 0.001). Similarly, rituximab-mediated ADCC was enhanced when PBMC were activated with CpG ODN A as compared to CpG ODN control (61% +/- 11% vs 36% +/- 8%, respectively, p = 0.02). Nevertheless, the ADCC of purified NK cells was increased only with IL-15. NK-depleted PBMC activated with either IL-15 or CpG ODN A showed no ADCC, suggesting that NK are the major effector cells. Furthermore, IL-15 or CpG ODN A-activated PBMC, but not activated purified NK cells, secreted large amounts of interferon-gamma in the presence of rituximab-coated lymphoma cells.

CONCLUSIONS

IL-15 and CpG ODN A enhance rituximab-mediated ADCC against B-cell lymphoma. Under these conditions, NK cells seem to be the main effector cells mediating ADCC. These findings suggest that these agents could be used as adjuvants in combination with rituximab for patients with B-cell lymphoma.

Molecular analysis of HLA-DRB1 polymorphism in north-east Spain

The DRB1* polymorphism in 941 randomly selected individuals from the Umbilical Cord Blood Bank of Barcelona (92.75% of Spanish origin) was determined by sequence-based typing. The HLA profile was similar to that of other Mediterranean populations, with DRB1*0701 and *0301 being the most frequent alleles. This may be a consequence of the mixture of alleles as a result of migration from contiguous geographical areas.

Identification and sequencing of the HLA-B*4106 allele

We report a novel HLA-B*41 allele (HLA-B*4106) initially detected by an unusual sequence-specific oligonucleotide (SSO) hybridization pattern and identified by sequence-based HLA typing. Molecular cloning and sequencing determined that the new HLA-B allele was identical to the HLA-B*4101 in exon 2 and 3 except for a single nucleotide substitution in the exon 3 changing codon 204 from Glu to Gln (GAG-->CAG). In addition, intron 2 was identical to the published HLA-B*4104 intron 2, except for the base 509 (C-->G).