Pulmonary involvement in primary Sjögren's syndrome, as measured by the ESSDAI.

Objective: Systemic features influence disease prognosis and choice of treatment in primary Sjögren's syndrome (pSS). Our aim was to investigate the prevalence of pulmonary involvement in pSS patients and to classify patients according to the pulmonary domain of the EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI).Methods: This retrospective cohort study included consecutive pSS patients, fulfilling American-European Consensus Group/American College of Rheumatology classification criteria, who visited the Department of Rheumatology and Clinical Immunology, University Medical Center Groningen, in 2015. Data on pulmonary complaints and pulmonary tests were obtained from electronic patient records. Pulmonary involvement was recorded if therapy was needed or follow-up was recommended, and when it was possibly or assumed to be related to pSS instead of coincidental factors.Results: Of the 262 included pSS patients, 88 (34%) had pulmonary complaints, mostly cough or dyspnoea on exertion. Pulmonary diagnostics were performed in 225 patients (86%). Pulmonary involvement was present and assumed to be related to pSS in 25 patients (10%) and possibly related to pSS in 14 (5%). Interstitial lung disease (ILD, n = 15), especially non-specific interstitial pneumonia (n = 7), was present most commonly. In total, 16 patients (6%) were scored as low (n = 4), moderate (n = 11), or high activity (n = 1) on the ESSDAI pulmonary domain.Conclusion: In this cross-sectional study in daily clinical practice, pulmonary involvement was present in 10-15% of pSS patients, of which ILD was most common. Of all pSS patients, 6% were scored as active on the pulmonary domain of the ESSDAI.

Weight of salivary gland ultrasonography compared to other items of the 2016 ACR/EULAR classification criteria for Primary Sjögren's syndrome.

OBJECTIVE: Major salivary gland ultrasonography (SGUS) is widely used for the diagnosis of primary Sjögren's syndrome (pSS). Our objective was to assess the contribution of SGUS compared to other items of the 2016 ACR/EULAR pSS classification criteria, based on expert opinion. METHODS: A secure web-based relational database was used by 24 experts from 14 countries to assess 512 realistic vignettes developed from data of patients with suspected pSS. Each vignette provided classification criteria items and information on history, clinical symptoms and SGUS findings. Each expert assessed 64 vignettes, and each vignette was assessed by 3 experts. A diagnosis of pSS was defined according to at least 2 of 3 experts. Validation was performed in the independent French DiapSS cohort of patients with suspected pSS. RESULTS: A criteria-based pSS diagnosis and SGUS findings were independently associated with an expert diagnosis of pSS (P < 0.001). The derived diagnostic weights of individual items in the 2016 ACR/EULAR criteria including SGUS were as follows: anti-SSA, 3; focus score ≥ 1, 3; SGUS score ≥ 2, 1; positive Schirmer's test, 1; dry mouth, 1; and salivary flow rate < 0.1 mL/min, 1. The corrected C statistic area under the curve for the new weighted score was 0.96. Adding SGUS improves the sensitivity from 90.2 % to 95.6% with a quite similar specificity 84.1% versus 82.6%. Results were similar in the DiapSS cohort: adding SGUS improves the sensitivity from 87% to 93%. CONCLUSION: SGUS had similar weight compared to minor items, and its addition improves the performance of the 2016 ACR/EULAR classification criteria.

Presence of anticitrullinated protein antibodies in a large population-based cohort from the Netherlands.

OBJECTIVES: To determine the prevalence of anticitrullinated protein antibodies (ACPAs) and their association with known rheumatoid arthritis (RA) risk factors in the general population. METHODS: Lifelines is a multidisciplinary prospective population-based cohort study in the Netherlands. Cross-sectional data from 40 136 participants were used. The detection of ACPA was performed by measuring anti-CCP2 on the Phadia-250 analyser with levels ≥6.2 U/mL considered positive. An extensive questionnaire was taken on demographic and clinical information, including smoking, periodontal health and early symptoms of musculoskeletal disorders. RA was defined by a combination of self-reported RA, medication use for the indication of rheumatism and visiting a medical specialist within the last year. RESULTS: Of the total 40 136 unselected individuals, 401 (1.0%) had ACPA level ≥6.2 U/mL. ACPA positivity was significantly associated with older age, female gender, smoking, joint complaints, RA and first degree relatives with rheumatism. Of the ACPA-positive participants, 22.4% had RA (15.2% had defined RA according to our criteria and 7.2% self-reported RA only). In participants without RA, 311 (0.8%) were ACPA-positive. In the non-RA group, older age, smoking and joint complaints remained significantly more frequently present in ACPA-positive compared with ACPA-negative participants. CONCLUSIONS: In this large population-based study, the prevalence of ACPA levels ≥6.2 U/mL was 1.0% for the total group and 0.8% when excluding patients with RA. Older age, smoking and joint complaints were more frequently present in ACPA-positive Lifelines participants. To our knowledge, this study is the largest study to date on ACPA positivity in the general, mostly Caucasian population.

Ticagrelor-induced renal failure leading to statin-induced rhabdomyolysis.

Renal function deterioration is a rather frequent side effect of ticagrelor; this is especially so in patients over the age of 75, with pre-existent mild renal failure and/or taking an angiotensin receptor inhibitor. We describe a patient in whom deterioration of renal function due to ticagrelor led to a rise in serum concentration of rosuvastatin which resulted in rhabdomyolysis. The presented case emphasises the importance to check renal function routinely before and one month after starting ticagrelor and to screen carefully for possible interactions with other drugs.

Clinical and histologic evidence of salivary gland restoration supports the efficacy of rituximab treatment in Sjögren's syndrome.

OBJECTIVE: To assess the effect of rituximab (anti-CD20 antibody) therapy on the (immuno)histopathology of parotid tissue in patients with primary Sjögren's syndrome (SS) and the correlation of histologic findings with the flow rate and composition of parotid saliva. METHODS: In a phase II study, an incisional parotid biopsy specimen was obtained from 5 patients with primary SS before and 12 weeks after rituximab treatment (4 infusions of 375 mg/m(2)). The relative amount of parotid parenchyma, lymphocytic infiltrate, and fat, and the presence/quantity of germinal centers and lymphoepithelial duct lesions were evaluated. Immunohistochemical characterization was performed to analyze the B:T cell ratio of the lymphocytic infiltrate (CD20, CD79a, CD3) and cellular proliferation in the acinar parenchyma (by double immunohistologic labeling for cytokeratin 14 and Ki-67). Histologic data were assessed for correlations with the parotid flow rate and saliva composition. RESULTS: Four patients showed an increased salivary flow rate and normalization of the initially increased salivary sodium concentration. Following rituximab treatment, the lymphocytic infiltrate was reduced, with a decreased B:T cell ratio and (partial) disappearance of germinal centers. The amount and extent of lymphoepithelial lesions decreased in 3 patients and was completely absent in 2 patients. The initially increased proliferation of acinar parenchyma in response to inflammation was reduced in all patients. CONCLUSION: Sequential parotid biopsy specimens obtained from patients with primary SS before and after rituximab treatment demonstrated histopathologic evidence of reduced glandular inflammation and redifferentiation of lymphoepithelial duct lesions to regular striated ducts as a putative morphologic correlate of increased parotid flow and normalization of the salivary sodium content. These histopathologic findings in a few patients underline the efficacy of B cell depletion and indicate the potential for glandular restoration in SS.

Development of a non-invasive murine infection model for acute otitis media.

Otitis media (OM) is one of the most frequent diseases in childhood, and Streptococcus pneumoniae is among the main causative bacterial agents. Since current experimental models used to study the bacterial pathogenesis of OM have several limitations, such as the invasiveness of the experimental procedures, we developed a non-invasive murine OM model. In our model, adapted from a previously developed rat OM model, a pressure cabin is used in which a 40 kPa pressure increase is applied to translocate pneumococci from the nasopharyngeal cavity into both mouse middle ears. Wild-type pneumococci were found to persist in the middle ear cavity for 144 h after infection, with a maximum bacterial load at 96 h. Inflammation was confirmed at 96 and 144 h post-infection by IL-1beta and TNF-alpha cytokine analysis and histopathology. Subsequently, we investigated the contribution of two surface-associated pneumococcal proteins, the streptococcal lipoprotein rotamase A (SlrA) and the putative proteinase maturation protein A (PpmA), to experimental OM in our model. Pneumococci lacking the slrA gene, but not those lacking the ppmA gene, were significantly reduced in virulence in the OM model. Importantly, pneumococci lacking both genes were significantly more attenuated than the DeltaslrA single mutant. This additive effect suggests that SlrA and PpmA exert complementary functions during experimental OM. In conclusion, we have developed a highly reproducible and non-invasive murine infection model for pneumococcal OM using a pressure cabin, which is very suitable to study pneumococcal pathogenesis and virulence in vivo.

Surface-associated lipoprotein PpmA of Streptococcus pneumoniae is involved in colonization in a strain-specific manner.

Streptococcus pneumoniae produces two surface-associated lipoproteins that share homology with two distinct families of peptidyl-prolyl isomerases (PPIases), the streptococcal lipoprotein rotamase A (SlrA) and the putative proteinase maturation protein A (PpmA). Previously, we have demonstrated that SlrA has PPIase activity, and that the enzyme plays a role in pneumococcal virulence. Here, we investigated the contribution of PpmA to pneumococcal pathogenesis. Pneumococcal mutants of D39 and TIGR4 lacking the gene encoding PpmA were less capable of persisting in the nasopharynx of mice, demonstrating the contribution of PpmA to pneumococcal colonization. This observation was partially confirmed in vitro, as the pneumococcal mutants NCTC10319DeltappmA and TIGR4DeltacpsDeltappmA, but not D39DeltacpsDeltappmA, were impaired in adherence to Detroit 562 pharyngeal cells. This suggests that the contribution of PpmA to pneumococcal colonization is not solely the result of its role in adherence to epithelial cells. Deficiency in PpmA did not result in reduced binding to various extracellular matrix and serum proteins. Similar to SlrA, we observed that PpmA was involved in immune evasion. Uptake of PpmA-deficient D39Deltacps and NCTC10319 by human polymorphonuclear leukocytes was significantly enhanced compared to the isogenic wild-types. In addition, ingestion of D39DeltappmA, but not that of either NCTC10319DeltappmA or TIGR4DeltappmA, by murine macrophage cell line J774 was also enhanced, whereas intracellular killing remained unaffected. We conclude that PpmA contributes to the early stages of infection, i.e. colonization. The contribution of PpmA to virulence can be explained by its strain-specific role in adherence to epithelial cells and contribution to the evasion of phagocytosis.

Parotid gland biopsy compared with labial biopsy in the diagnosis of patients with primary Sjogren's syndrome.

OBJECTIVE: To assess the value of the parotid biopsy as a diagnostic tool for primary Sjögren's syndrome (pSS), and to compare the parotid biopsy and the labial biopsy with regard to diagnostic value and biopsy-related morbidity. METHODS: In 15 consecutive patients with pSS and 20 controls, the parotid biopsy was assessed as a diagnostic tool based on the presence of lymphocytic foci, benign lymphoepithelial lesions and lymphoid follicles. These new histological criteria were compared with established diagnostic criteria for the labial biopsy in 35 consecutive patients suspected for pSS who underwent simultaneous biopsies from both sites. In addition, both biopsies were compared for morbidity. RESULTS: The first analysis revealed a focus score of >or=1 or lymphocytic infiltrates (not fulfilling the criterion of a focus score of 1) combined with benign lymphoepithelial lesions as diagnostic criteria for pSS. When comparing the parotid biopsy with the labial biopsy sensitivity and specificity were comparable (sensitivity 78%, specificity 86%). Level of pain was comparable and no loss of motor function was observed. No permanent sensory loss was observed after parotid biopsy, while labial biopsy led to permanent sensory loss in 6% of the patients. Malignant lymphoma was detected in one parotid biopsy by chance, without involvement of the labial salivary gland. CONCLUSION: A parotid biopsy has a diagnostic potential comparable with that of a labial biopsy in the diagnosis of pSS, and may be associated with less morbidity.

Clinical significance of quantitative immunohistology in labial salivary glands for diagnosing Sjogren's syndrome.

OBJECTIVES: Because patients with primary Sjögren's syndrome (pSS) are at risk of developing other autoimmune phenomena and malignant lymphoma, it is important to distinguish pSS from non-Sjögren's (nSS) sicca syndrome. However, this distinction might be difficult because of the lack of a gold standard for pSS. We studied the clinical significance of quantitative immunohistology (QIH) in labial salivary glands for diagnosing pSS. METHODS: In a model mimicking the making of a clinical diagnosis, five experts diagnosed 396 patients as nSS, 'indefinite', pSS or secondary SS (sSS) using 25 clinical parameters. Patients were diagnosed twice, namely without (yielding gold-standard diagnoses) and with knowledge of QIH. The numbers of changes in diagnosis from 'indefinite' to 'definite' (nSS, pSS or sSS) or vice versa were compared. Patient groups with vs without a changed diagnosis in the four gold-standard diagnosis groups were compared regarding objective autoimmune parameters. RESULTS: Sensitivity, specificity, positive and negative predictive value for abnormal QIH in pSS vs nSS were 93, 86, 76 and 96%, respectively. Changes in diagnosis from 'indefinite' to 'definite' (31%) were found more often (P = 0.00) than changes from 'definite' to 'indefinite' (10%). Knowledge of QIH distinguished patient groups within the gold-standard nSS, indefinite and pSS patient group with regard to autoimmune parameters. CONCLUSION: In view of the consequences of distinguishing pSS from nSS, these results point to an additional diagnostic role for QIH in clinical practice.

Rituximab treatment in patients with primary Sjögren's syndrome: an open-label phase II study.

OBJECTIVE: To investigate the safety and efficacy of B cell depletion treatment of patients with active primary Sjögren's syndrome of short duration (early primary SS) and patients with primary SS and mucosa-associated lymphoid tissue (MALT)-type lymphoma (MALT/primary SS). METHODS: Fifteen patients with primary SS were included in this phase II trial. Inclusion criteria for the early primary SS group were B cell hyperactivity (IgG >15 gm/liter), presence of autoantibodies (IgM rheumatoid factor, anti-SSA/SSB), and short disease duration (<4 years). Inclusion criteria for the MALT/primary SS group were primary SS and an associated MALT-type lymphoma (Ann Arbor stage IE) localized in the parotid gland. Patients were treated with 4 infusions of rituximab (375 mg/m2) given weekly after pretreatment with prednisone (25 mg) and clemastine. Patients were evaluated, using immunologic, salivary/lacrimal function, and subjective parameters, at baseline and at 5 and 12 weeks after the first infusion. RESULTS: Significant improvement of subjective symptoms and an increase in salivary gland function was observed in patients with residual salivary gland function. Immunologic analysis showed a rapid decrease of peripheral B cells and stable levels of IgG. Human anti-chimeric antibodies (HACAs) developed in 4 of 15 patients (27%), all with early primary SS. Three of these patients developed a serum sickness-like disorder. Of the 7 patients with MALT/primary SS, complete remission was achieved in 3, and disease was stable in 3 and progressive in 1. CONCLUSION: Findings of this phase II study suggest that rituximab is effective in the treatment of primary SS. The high incidence of HACAs and associated side effects observed in this study needs further evaluation.

Changes in salivary gland immunohistology and function after rituximab monotherapy in a patient with Sjogren's syndrome and associated MALT lymphoma.

OBJECTIVES: To report the successful use of rituximab on salivary gland immunohistology and function in a patient with Sjogren's syndrome (SS) and associated MALT lymphoma. CASE REPORT: The patient was a 42 year old woman with primary SS and associated MALT lymphoma located in the parotid gland and the hard palate. Four infusions of rituximab (375 mg/m(2)) weekly resulted in complete remission of the lymphoma. An incision biopsy of the parotid gland before and after treatment showed improvement of the (immuno)histopathological characteristics of SS, with possible regeneration of salivary gland tissue. Furthermore, salivary analysis showed decreased inflammatory characteristics and increased stimulated salivary flow. DISCUSSION: Rituximab is a promising agent in the treatment of SS associated MALT lymphoma. In addition to the effect on MALT lymphoma, B cell depletion by rituximab may also attenuate the activity of SS. This case report is the first to describe the effect of rituximab on histological and sialometric/chemical characteristics of SS. The efficacy of rituximab in the treatment of SS warrants further investigation.

Serum amyloid P component levels are not decreased in patients with systemic lupus erythematosus and do not rise during an acute phase reaction.

BACKGROUND: Serum amyloid P component (SAP) and acute phase proteins like C-reactive protein contribute to the clearance of apoptotic cells. This response is diminished in systemic lupus erythematosus (SLE). OBJECTIVES: To analyse SAP concentrations in SLE in relation to disease activity, and investigate whether SAP reacts like an acute phase protein. METHODS: SAP was measured in 40 patients with SLE during active and inactive disease and compared with healthy controls and patients with rheumatoid arthritis and Wegener's granulomatosis. Normal SAP values were determined in 120 healthy controls by ELISA. C reactive protein and serum amyloid A (SAA) were measured in all subjects and their levels related to SAP. SAP was also measured serially in 11 patients with breast cancer treated with recombinant human interleukin-6, and in 16 patients with sepsis. RESULTS: In SLE, SAP was unaltered compared with healthy controls and was not influenced by disease activity, in contrast to C reactive protein and SAA, which increased during active disease. SAP increased in Wegener's granulomatosis but not in rheumatoid arthritis. The rise in C reactive protein and SAA was most pronounced in Wegener's granulomatosis with active disease. SAP did not change significantly during an acute phase response. No correlation was found between SAP and C reactive protein or SAA, but there was a correlation between SAA and C reactive protein (r = 0.4989, p = 0.0492). CONCLUSIONS: Patients with SLE have normal circulating SAP levels. In contrast to C reactive protein or SAA, SAP does not act as an acute phase protein.

[Swelling of lips as a first sign of acromegaly]. / Zwelling van de lippen als eerste uiting van acromegalie.

A 65-year-old female patient with swelling of lips and submandibular glands was referred to the department of Oral and Maxillofacial Surgery of an academic hospital. The patient was worried about her changed appearance and her general fatigue. This condition had not changed during the last six months, although she slept more. Despite extensive investigations her complaints could not be diagnosed as of oral or maxillofacial origin. She thereupon was referred to the department of internal Medicine to screen for an endocrine aetiology. Laboratory tests were positive for acromegaly.

[Bilateral swelling of the parotid glands as part of a systemic disease]. / Bilaterale zwelling van de glandulae parotideae als onderdeel van een systeemziekte.

In four patients, a man aged 34 years and three women aged 35, 32 and 55 years respectively bilateral swelling of the parotid glands was caused by systemic disease i.e. HIV-salivary gland disease, mucosa-associated lymphoid-tissue (MALT) lymphoma, sarcoidosis with coexisting Sjögren's syndrome, and sialosis and hypothyroidism, respectively. The HIV patient was treated with antiretroviral therapy, the first two women were treated expectantly and the third woman was given a thyroid hormone supplement which resulted in regression of the bilateral parotid enlargement. Bilateral enlargement of the parotid glands is not necessarily caused by infection, it can also be of systemic origin. Minimal invasive investigations of the salivary glands, such as sialography, measurement of salivary secretion rate (sialometry) and analysis of salivary composition (sialochemistry) can offer valuable information about the origin of the parotid gland swelling. Histopathological investigation of an incision biopsy of the parotid gland is an easy way to confirm the diagnosis. The morbidity associated with parotid biopsy is negligible.

IgG subclass distribution of autoantibodies differs between renal and extra-renal relapses in patients with systemic lupus erythematosus.

BACKGROUND: IgG subclasses of autoantibodies differ in their potential to induce an inflammatory response as they interact differentially with complement and Fcgamma receptors. METHODS: The IgG subclass distribution of anti-nucleohistone and anti-dsDNA antibodies was analysed longitudinally in patients with systemic lupus erythematosus before and at the moment of an extra-renal (n=23) or a renal relapse (n=l7). Kidney biopsy specimens of patients with a renal relapse were analysed for IgG subclass deposition. RESULTS: IgG1 anti-nucleohistone and IgG1 anti-dsDNA antibodies were present in plasma of 39 out of 40 patients. At the moment of a relapse, IgG2 and IgG3 anti-nucleohistone and IgG2 anti-dsDNA antibodies were more frequently present in patients with renal disease compared with those with extra-renal disease. Increases in levels of IgG1 anti-dsDNA were observed in 10 out of 11 patients prior to a renal relapse but only 10 out of 22 patients with an extra-renal relapse (91 vs 45%, P=0.02). Rises in IgG2 anti-dsDNA occurred at an equally low rate prior to both renal and extra-renal relapses. A rise in IgG2 anti-nucleohistone antibodies preceded a renal relapse in eight of 11 patients and an extra-renal relapse in only four out of 22 patients (73 vs 18%, P=0.006). In kidney biopsies all IgG subclasses could be detected. IgG1 and IgG2 subclass antibodies to nucleohistone and to dsDNA are the predominant subclasses found in plasma of lupus patients with renal disease. CONCLUSIONS: The frequent occurrence of a rise in IgG2 anti-nucleohistone and IgG1 anti-dsDNA in patients prior to a renal relapse suggests that, besides IgG1 subclass autoantibodies, IgG2 subclass antibodies to nucleohistone have a particular pathophysiological role in lupus nephritis.

Primary sialoangiectasia--a diagnostic pitfall in Sjögren's syndrome: case report.

A case of primary sialoangiectasia, which in this case was initially misdiagnosed as Sjögren's syndrome, is described. Other diseases, including HIV infection, psoriatic arthritis, and acute parotitis, may cause glandular changes similar to the changes found in the syndrome. Therefore, sialography must be combined with other methods of assessment of the oral cavity when suspicion is high for Sjögren's syndrome. Properly applied, sialography provides essential information regarding the severity of glandular damage and the progression of the disease.

Antineutrophil cytoplasmic antibodies in systemic lupus erythematosus.

Antineutrophil cytoplasmic antibodies (ANCA) with specificity for proteinase-3 (PR3) are associated with Wegener's granulomatosis, and ANCA directed to myeloperoxidase (MPO) with other idiopathic vasculitides. Inflammation of small-sized blood vessels is a hallmark of systemic lupus erythematosus (SLE). We evaluated the prevalence of ANCA in SLE, their antigenic specificities, and their possible relation to clinical disease patterns and activity. Plasma samples from 84 patients with SLE were tested for ANCA during remission. Plasma samples from the 25 patients who relapsed during a follow-up of 32 months were serially analysed for ANCA in a 6 month period preceding and including the relapse. The presence of ANCA was assessed by indirect immunofluorescence (IIF) and ELISA for antibodies to PR3, MPO, lactoferrin (LF), elastase (HLE) and cathepsin-G (CG). We related the presence of ANCA to disease patterns, activity and duration. ANCA by IIF were difficult to interpret dut to the presence of antinuclear antibodies (ANA). By ELISA, we found no anti-PR3 or anti-HLE. Anti-MPO (n = 7), anti-LF (n = 13) and anti-CG (n = 10) were detected, generally in low titres. The presence of ANCA of defined specificity was not associated with specific clinical subsets. The prevalence of ANCA was higher in patients who developed relapses than in those who did not (P < 0.01). However, levels of ANCA did not fluctuate in the period preceding the relapse. ANCA of various specificities occur in SLE. Their presence is not associated with specific clinical disease entities. The higher frequency of ANCA in relapsing patients compared to those who do not relapse may suggest that ANCA are involved in disease expression. Their diagnostic significance is limited.

Molecular characterization of the BRO beta-lactamase of Moraxella (Branhamella) catarrhalis.

A rapid increase in the prevalence of beta-lactamase-producing Moraxella (Branhamella) catarrhalis strains has been noticed during the last decades. Today, more than 80% of strains isolated worldwide produce beta-lactamase. To investigate beta-lactamase(s) of M. catarrhalis at the molecular level, the BRO-1 beta-lactamase gene (bla) was isolated as part of a 4,223-bp HindIII fragment. Sequence analysis indicated that bla encodes a polypeptide of 314 amino acid residues. Insertional inactivation of bla in M. catarrhalis resulted in complete abrogation of beta-lactamase production and ampicillin resistance, demonstrating that bla is solely responsible for beta-lactam resistance. Comparison with other beta-lactamases suggested that M. catarrhalis beta-lactamase is a unique enzyme with conserved residues at the active sites. The presence of a signal sequence for lipoproteins suggested that it is lipid modified at its N terminus. In keeping with this assumption was the observation that 10% of beta-lactamase activity was found in the membrane compartment of M. catarrhalis. M. catarrhalis strains produce two types of beta-lactamase, BRO-1 and BRO-2, which differ in their isoelectric points. The BRO-1 and BRO-2 genes from two ATCC strains of M. catarrhalis were sequenced, and only one amino acid difference was found between the predicted products. However, there was a 21-bp deletion in the promoter region of the BRO-2 gene, possibly explaining the lower level of production of BRO-2. The G + C content of bla (31%) was significantly lower than those of the flanking genes (47 and 50%), and the overall G + C content of the M. catarrhalis genome (41%). These results indicate that bla was acquired by horizontal gene transfer from another, still unknown species.

Antibodies against phosphatidylinositol and inositol monophosphate specifically inhibit tumour necrosis factor induction by malaria exoantigens.

The active component of the exoantigens of malarial parasites which stimulates macrophages to secrete tumour necrosis factor (TNF) has been shown to depend upon a phospholipid, the activity of which was blocked by phosphatidylinositol (PI) and inositol monophosphate (IMP) in competitive inhibition studies. Antisera made against the exoantigens of Plasmodium yoelii, which inhibited their induction of TNF, were found by an ELISA assay to contain antibody against several other phospholipids. However, the inhibitory antibody was removed specifically by adsorption with liposomes containing PI, but not other phospholipids. Furthermore, PI was the only phospholipid in non-liposomal form which induced the production of inhibitory antisera. Mice immunized with IMP, but not inositol, also produced inhibitory antisera. When incorporated into liposomes several other phospholipids did give rise to inhibitory antibodies but, in contrast to the antisera against parasite exoantigens, PI and IMP, the inhibitory activity was removed by adsorption with heterologous phospholipid liposomes, suggesting that it was directed against a common determinant, presumably the phosphate ester head group. Inhibitory antibodies in the antisera tested were predominantly IgM and titres were not increased after repeated injections. Antisera raised against PI, IMP or the cross-reacting phospholipid liposomes also inhibited TNF secretion by macrophages stimulated by exoantigens of the human parasites P. falciparum and P. vivax, but not by bacterial lipopolysaccharide. These findings confirm our conclusion that exoantigens from these different species contain phosphate bound to inositol in their TNF-inducing moiety.