Perceived health of patients with common variable immunodeficiency - a cluster analysis

Common variable immunodeficiency (CVID) is a complex disease with various influences on perceived health, which correlate with different outcomes, including new morbidity and mortality. Our hypothesis was that CVID patients fall into distinct clusters of perceived health which can inform care. Ward hierarchical cluster analysis and K-means cluster analysis were performed on data of 209 CVID patients to identify subgroups regarding their self-reported physical and mental health status, assessed by the physical (PCS) and mental component scores (MCS) of the Short Form-12 (SF-12). Four clusters of CVID-patients were identified. Cluster 1 was the largest cluster, characterized by a relatively high physical and mental health status (44·0%). In contrast, cluster 2 (21·1%) included patients with low physical and mental health status. Clusters 3 and 4 were mixed groups with high mental and low physical health (15·8%) and vice versa (19·1%). Significant differences between the clusters were found for patient-reported outcomes such as work ability and health literacy, but not for CVID-associated complications such as enteropathy, interstitial lung disease, granulomatosis, lymphadenopathy and autoimmune cytopenia or laboratory parameters such as immunoglobulin levels or B cell-based classification. The results suggest different subgroups of CVID patients with contrasting individual needs which, surprisingly, did not differ in clinical or laboratory characteristics. The main finding of this study is that patients with CVID fall into four distinct clusters according to perceived health, which are largely independent of CVID complications.

Screening protocols to monitor respiratory status in primary immunodeficiency disease: findings from a European survey and subclinical infection working group

Many patients with primary immunodeficiency (PID) who have antibody deficiency develop progressive lung disease due to underlying subclinical infection and inflammation. To understand how these patients are monitored we conducted a retrospective survey based on patient records of 13 PID centres across Europe, regarding the care of 1061 adult and 178 paediatric patients with PID on immunoglobulin (Ig) G replacement. The most common diagnosis was common variable immunodeficiency in adults (75%) and hypogammaglobulinaemia in children (39%). The frequency of clinic visits varied both within and between centres: every 1-12 months for adult patients and every 3-6 months for paediatric patients. Patients diagnosed with lung diseases were more likely to receive pharmaceutical therapies and received a wider range of therapies than patients without lung disease. Variation existed between centres in the frequency with which some clinical and laboratory monitoring tests are performed, including exercise tests, laboratory testing for IgG subclass levels and specific antibodies, and lung function tests such as spirometry. Some tests were carried out more frequently in adults than in children, probably due to difficulties conducting these tests in younger children. The percentage of patients seen regularly by a chest physician, or who had microbiology tests performed following chest and sinus exacerbations, also varied widely between centres. Our survey revealed a great deal of variation across Europe in how frequently patients with PID visit the clinic and how frequently some monitoring tests are carried out. These results highlight the urgent need for consensus guidelines on how to monitor lung complications in PID patients.

7(th) International Immunoglobulin Conference: Poster presentations

Immunoglobulin (Ig) therapy is the mainstay of treatment for primary antibody deficiency disorders and has proved to be efficacious in specific autoimmune and inflammatory diseases. Additionally, due to the role of Ig in complement activation, it is being used increasingly in solid organ transplantation. Furthermore, Ig is the primary or secondary treatment in some immune-mediated neuropathies such as chronic inflammatory demyelinating polyneuropathy (CIDP) or multifocal motor neuropathy (MMN). This session discusses trends of Ig use in Europe, proposed mechanisms of action, adverse effects and the potential role of Ig therapy in transplantation. Dr Šedivá reported that Ig therapy is available in all European countries, although dosing is not always optimal, due partly to reimbursement plans. Subcutaneous immunoglobulin (SCIg) has become increasingly accessible in recent years; however, the chosen route of administration still varies widely between countries. Dr Berger's presentation on optimization of Ig therapy in neuropathies, and Dr Rojavin's report on a pharmacometric model to determine the serum IgG levels achieved by different dosing regimens in primary antibody deficiency (PAD) patients, led to the challenging concept of using individualized dosing strategies. Dr Klehmet reported on the potential benefit of using antigen-specific T cell responses as a biomarker of IVIg responsiveness in CIDP patients, while Dr von Gunten provided an insight into the mechanisms of action of Ig preparations, suggesting that the immunoregulatory effects of IgG may be mediated by IgG antibodies against glycans. Dr Basta reported on the potential thrombogenic adverse effects associated with Ig therapy. Although these adverse events are rare, further studies are needed to clarify the relationship between Ig replacement and immunomodulatory therapy and these adverse reactions. In transplantation, Dr Carbone described that prophylactic IVIg treatment was found to decrease the incidence of severe infection in IgG hypogammaglobulinaemia patients undergoing heart transplantations. Furthermore, Dr Clatworthy reported that inactivating polymorphisms in the inhibitory receptor FcγRIIB do not impact upon kidney allograft survival.

7th International Immunoglobulin Conference: Poster presentations

The pan-European survey provides useful information on the accessibility and trends of intravenous and subcutaneous immunoglobulin (IVIg/SCIg) therapy, which is used to treat primary immunodeficiency disorders (PIDs). Although immunoglobulin (Ig) therapy is the first-line treatment for PIDs, the mechanisms of action of Ig therapy may differ according to the condition it is used to treat. Moreover, intriguing presentations suggest that further investigation is required to understand more clearly both the haematological and immunoregulatory effects of therapeutic immunoglobulin. This can ultimately provide more information on optimizing Ig therapy efficacy, and establish whether individualized dosing regimens for patients will be conducive to better clinical outcomes. In addition to treating autoimmune and inflammatory conditions, there is evidence to suggest that immunoglobulins can potentially play a role in transplantation, which warrants further investigation for future use.

A new functional assay for the diagnosis of X-linked inhibitor of apoptosis (XIAP) deficiency

X-linked inhibitor of apoptosis (XIAP) deficiency, caused by mutations in BIRC4, is an immunodeficiency associated with immune dysregulation and a highly variable clinical presentation. Current diagnostic screening tests such as flow cytometry for XIAP expression or lymphocyte apoptosis assays have significant limitations. Based on recent evidence that XIAP is essential for nucleotide-binding and oligomerization domains (NOD)1/2 signalling, we evaluated the use of a simple flow cytometric assay assessing tumour necrosis factor (TNF) production of monocytes in response to NOD2 stimulation by muramyl dipeptides (L18-MDP) for the functional diagnosis of XIAP deficiency. We investigated 12 patients with XIAP deficiency, six female carriers and relevant disease controls. Irrespective of the diverse clinical phenotype, the extent of residual protein expression or the nature of the mutation, the TNF response was severely reduced in all patients. On average, L18-MDP induced TNF production in 25% of monocytes from healthy donors or female carriers, while fewer than 6% of monocytes responded in affected patients. Notably, the assay clearly discriminated affected patients from disease controls with other immunodeficiencies accompanied by lymphoproliferation, hypogammaglobulinaemia or inflammatory bowel disease. Functional testing of the NOD2 signalling pathway is an easy, fast and reliable assay in the diagnostic evaluation of patients with suspected XIAP deficiency.

[Vaccination in adult patients with chronic inflammatory rheumatic diseases]

Patients with chronic inflammatory rheumatic diseases often have an intrinsic and therapy associated increased susceptibility to infections which substantially contributes to morbidity and mortality of the patients. A large proportion of these infections are preventable by vaccination. For this reason in 2005 the standing vaccination committee (STIKO) recommended for patients with immunosuppression vaccination against pneumococcus, influenza, Haemophilus influenza b and meningococcus in addition to standard vaccinations, independent of age. Every patient should therefore be informed about a possible increase in susceptibility to infections and the recommended prevention by vaccination before implementation of immunosuppressive therapy.

[Common variable immunodeficiency: a clinical challenge]

Common variable immunodeficiency (CVID) represents the most common clinically relevant form of primary immunodeficiency. This heterogeneous antibody deficiency syndrome is characterized not only by susceptibility to bacterial respiratory tract infections but displays additional signs of immune dysregulation, such as autoimmunity, chronic inflammation and lymphoproliferation in more than 30 % of the patients. Due to poor awareness the diagnosis is often delayed by 4-6 years. A close collaboration in patient care with a center specialized in primary immunodeficiency is recommended. Regular follow-up visits include assessment of adequate immunoglobulin replacement therapy and screening for manifestation of secondary complications. Regular substitution with intravenous or subcutaneous immunoglobulins has more or less normalized life expectancy of patients with isolated susceptibility to bacterial infections. Therefore, the current core task in the management of CVID patients is the elaboration of more effective and safer forms of prophylaxis and treatment of sequelae of immune dysregulation in the lungs, intestines and liver of affected patients.

Outcomes of splenectomy in patients with common variable immunodeficiency (CVID): a survey of 45 patients

Splenectomy has been used in patients with common variable immunodeficiency disorders (CVID), mainly in the context of refractory autoimmune cytopenia and suspected lymphoma, but there are understandable concerns about the potential of compounding an existing immunodeficiency. With increasing use of rituximab as an alternative treatment for refractory autoimmune cytopenia, the role of splenectomy in CVID needs to be re-examined. This retrospective study provides the largest cohesive data set to date describing the outcome of splenectomy in 45 CVID patients in the past 40 years. Splenectomy proved to be an effective long-term treatment in 75% of CVID patients with autoimmune cytopenia, even in some cases when rituximab had failed. Splenectomy does not worsen mortality in CVID and adequate immunoglobulin replacement therapy appears to play a protective role in overwhelming post-splenectomy infections. Future trials comparing the effectiveness and safety of rituximab and splenectomy are needed to provide clearer guidance on the second-line management of autoimmune cytopenia in CVID.

Importance of B cell co-stimulation in CD4(+) T cell differentiation: X-linked agammaglobulinaemia, a human model

We were interested in the question of whether the congenital lack of B cells actually had any influence on the development of the T cell compartment in patients with agammaglobulinaemia. Sixteen patients with X-linked agammaglobulinaemia (XLA) due to mutations in Btk, nine patients affected by common variable immune deficiency (CVID) with <2% of peripheral B cells and 20 healthy volunteers were enrolled. The T cell phenotype was determined with FACSCalibur and CellQuest Pro software. Mann-Whitney two-tailed analysis was used for statistical analysis. The CD4 T cell memory compartment was reduced in patients with XLA of all ages. This T cell subset encompasses both CD4(+)CD45RO(+) and CD4(+)CD45RO(+)CXCR5(+) cells and both subsets were decreased significantly when compared to healthy controls: P = 0·001 and P < 0·0001, respectively. This observation was confirmed in patients with CVID who had <2% B cells, suggesting that not the lack of Bruton's tyrosine kinase but the lack of B cells is most probably the cause of the impaired CD4 T cell maturation. We postulate that this defect is a correlate of the observed paucity of germinal centres in XLA. Our results support the importance of the interplay between B and T cells in the germinal centre for the activation of CD4 T cells in humans.

Clinical and immunological overlap between autoimmune lymphoproliferative syndrome and common variable immunodeficiency

Autoimmune lymphoproliferative syndrome (ALPS) is mainly caused by defects in the CD95 pathway. Raised CD3+TCRαβ+CD4-CD8- double negative T cells and impaired T cell apoptosis are hallmarks of the disease. In contrast, the B cell compartment has been less well studied. We found an altered distribution of B cell subsets with raised transitional B cells and reduced marginal zone B cells, switched memory B cells and plasma blasts in most of 22 analyzed ALPS patients. Moreover, 5 out of 66 ALPS patients presented with low IgG and susceptibility to infection revealing a significant overlap between ALPS and common variable immunodeficiency (CVID). In patients presenting with lymphoproliferation, cytopenia, hypogammaglobulinemia and impaired B cell differentiation, serum biomarkers were helpful in addition to apoptosis tests for the identification of ALPS patients. Our observations may indicate a role for apoptosis defects in some diseases currently classified as CVID.

[Clinical and serological findings of giant-cell arteritis]

Giant cell arteritis (GCA) frequently appears as cranial arteritis (eg. temporal arteritis) with headache, pain on chewing and visual disturbances. In addition, extracranial manifestations are often observed leading to aneurysmatic dilatations and dissections of the aorta as well as stenoses of large thoracic, abdominal or limb arteries. The vascular signs are accompanied by general disease symptoms, e.g. malaise, elevated temperatures, weight loss and depression. Polymyalgia rheumatica (PMR) is the most frequent rheumatic manifestation of GCA but also occurs independently from GCA. The structural correlate for the PMR symptoms is first and foremost extra-articular inflammation (tenosynovitis, bursitis) of large joints and the vertebral column (interspinal bursitis). In addition, vasculitis of large arteries in PMR must be considered particularly in the presence of high inflammatory activity. While specific laboratory markers for GCA and PMR are lacking elevated values for the erythrocyte sedimentation rate and C-reactive protein are present in almost all patients at disease onset. Besides the clinical evaluation, the serological acute phase reaction represents the main parameter for the course during therapy of this relatively frequent disease in elderly people.

Ultrasonography in the assessment of peripheral joint involvement in psoriatic arthritis : a comparison with radiography, MRI and scintigraphy

The objective of our study was to investigate the role of musculoskeletal ultrasound (US) in the assessment of hand and foot small joints in psoriatic arthritis (PsA). Thirteen consecutive patients with PsA of hands or feet underwent B-mode US using a 9- to 13-MHz transducer and simultaneous magnetic resonance imaging (MRI), bone scintigraphy and radiography. US findings were compared with radiography, MRI and scintigraphy in 190, 182 and 109 joints, respectively. To assess the sensitivity and specificity of US, radiography was considered as gold standard for the detection of erosions and osteoproliferations and MRI as gold standard for the detection of joint effusion and synovitis. US, MRI and scintigraphy had a higher sensitivity in the detection of overall joint pathology than radiography in painful and/or swollen joints (71%, 72%, 82% vs 32%) and clinically unaffected joints (17%, 21%, 9% vs 2%). US and radiography detected more erosions and osteoproliferations than MRI, with low agreement between the methods in the detection of erosions. Radiography was superior to US in the visualisation of osteoproliferations. Joint effusions and/or synovitis were more frequently detected by MRI than US. Agreement between both imaging methods was better in carpal joints, carpometacarpal joint I, metacarpophalangeal (MCP)/metatarsophalangeal (MTP) joint I, II and V than in MCP/MTP III, IV, PIP and DIP joints. Compared with MRI, radiography and scintigraphy, the specificity of US ranges between 0.84 and 0.94, depending on the joint pathology. In conclusion, the diagnostic sensitivity of US in the detection of PsA-related synovitis of hands and feet is lower than MRI and depends on the joint region. However, the low cost and the acceptable specificity suggest that US is a useful imaging method in addition to radiography in PsA of hands and feet.

Mural inflammatory hyperenhancement in MRI of giant cell (temporal) arteritis resolves under corticosteroid treatment

OBJECTIVE

To determine the effect of corticosteroid treatment on mural inflammatory hyperenhancement in MRI in GCA.

METHODS

MRI of the superficial temporal artery with sub-millimetre in-plane spatial resolution (195 x 260 microm) was performed in 17 patients with proven GCA at the initiation of corticosteroid treatment and after 16 months of therapy. Visual MRI scores for mural inflammation were correlated with clinical and laboratory findings.

RESULTS

Intensity of inflammatory hyperenhancement decreased significantly under corticosteroid therapy (2.3 +/- 0.6 vs 0.5 +/- 0.6, P < 0.001, with MRI score >2 indicating vasculitis). This finding correlated with the clinical and serological remission in 15/17 patients. Of the two patients with active disease, one had persisting mural inflammation in MRI indicative of relapsing disease. The other patient presenting with signs of polymyalgia rheumatica had no inflammatory changes of the superficial temporal arteries on MRI scan at follow-up.

CONCLUSIONS

Mural contrast enhancement in high-resolution MRI is pronounced in active disease and decreases under corticosteroid treatment, correlating well with laboratory remission.

Active vaccination in patients with common variable immunodeficiency (CVID)

Active vaccination of CVID patients with standard vaccines has rarely been studied in depth although some patients have been shown to develop transient vaccine-specific immunity. We addressed the question whether these patients can be identified by functional classification of their B cell subsets in vitro. Twenty-one CVID patients receiving regular IgG substitution were immunized with anti-peptide and anti-polysaccharide vaccines. Humoral vaccination responses were compared to the numbers of circulating memory B cells, CD21(low) B cells and the capacity to produce antibodies in vitro. Our findings allow four conclusions: (1) positive vaccination responses are not contradictory to the diagnosis of CVID; they occurred against polypeptide vaccines in 23% and against polysaccharide antigens in 18% of all vaccinations. (2) Class-switched antibody responses occur preferentially in patients of CVID group II. (3) A normal percentage of IgM memory B cells is necessary but not sufficient for a vaccination response to polysaccharide antigens. (4) Active vaccination in addition to IgG replacement therapy should be performed in patients of CVID type II - especially in case of vaccines for which passive protection cannot be guaranteed.

Influence of corticosteroid treatment on MRI findings in giant cell arteritis

Giant cell arteritis (GCA) remains a diagnostic challenge. With the use of a high-resolution MRI protocol, visualization of the superficial cranial arteries is feasible and mural inflammation can be assessed noninvasively. Until today, it is not known how soon inflammatory signals in diagnostic MR imaging vanish after initiation of treatment. Here, we report sequential MR imaging findings during the initial weeks of corticosteroid treatment in a 79-year-old female patient with histologically proven GCA. Mural inflammatory changes decreased within the first 2 weeks and have almost entirely vanished after 2 1/2 months of continued treatment. Moreover, MR angiography revealed sequential stenoses of the subclavian artery, which improved in variable extent with some residuals despite high dose steroid medication. This report underlines the value of high-resolution MRI in diagnosis and follow-up of GCA and illustrates the potential of MRI to detect and monitor intra- and extra-cranial involvement patterns of GCA in high detail.

Analgesic and disease modifying effects of interferential current in psoriatic arthritis

Interferential current (IFC) was suggested to improve the skin manifestations of psoriasis vulgaris, possibly by enhancing the intracellular concentration of cyclic AMP. We assessed the efficacy of IFC on psoriatic arthritis (PsA). Nine consecutive patients were analyzed at baseline and after 16 weeks of IFC therapy. Bipolar IFC was applied twice daily to hands, feet plus all affected joints. IFC improved SF-36 assessed body pain, but not other SF-36 subscales. Morning stiffness, tender joint counts, and physician assessed disease activity improved. In contrast, visual analogue scale assessed pain, CRP and ESR measurements were unchanged. MRI of the most affected hand or foot documented a tendency towards worsened tendinitis, soft tissue swelling, and new joint space narrowing and erosions. Bone scintigraphy showed a trend towards deterioration. New joints became inflamed within treated sites. Thus IFC has analgesic effects in PsA, but does not have a satisfactory disease modifying effect.

Assessment of the cranial involvement pattern of giant cell arteritis with 3T magnetic resonance imaging

OBJECTIVE

To noninvasively determine the involvement pattern of the cranial arteries in giant cell arteritis (GCA), with high-resolution magnetic resonance imaging (MRI).

METHODS

The superficial cranial arteries of 21 patients with suspected GCA were examined using a 3T high-field MRI scanner. Postcontrast T1-weighted spin-echo images were acquired with submillimeter spatial resolution, to assess mural thickness and lumen diameter of the major cranial arteries on both sides of the head. In all cases, MRI results were compared with findings of clinical examination and laboratory tests. In addition, temporal artery biopsy specimens from 10 patients were examined by histology.

RESULTS

MRI sharply revealed all of the major superficial cranial arteries, allowing for an evaluation of their lumen and vessel wall. Nine of the 21 patients were diagnosed as having GCA according to the criteria of the American College of Rheumatology. In all of these patients with clinically diagnosed GCA, multiple cranial arteries showed signs of inflammation on MRI. In 1 patient, the occipital arteries were inflamed, while the temporal arteries were spared.

CONCLUSION

Postcontrast high-resolution MRI visualizes the major cranial arteries on both sides of the head within a single examination. The cranial involvement pattern in GCA can be assessed precisely and noninvasively. In the majority of GCA patients, several cranial arteries were affected simultaneously, with a predominance of involvement of the frontal branch of the superficial temporal artery. Inflammation of the occipital arteries, with sparing of the temporal arteries, was also encountered.

Measurement of peripheral B cell subpopulations in common variable immunodeficiency (CVID) using a whole blood method

Recent reports have described reduced populations of CD27+ memory B cells and increased percentages of undifferentiated B cells in peripheral blood of patients with common variable immunodeficiency (CVID). This work has prompted two attempts to classify CVID based on rapid flow cytometric quantification of peripheral blood memory B cells and immature B cells. Evidence to support the hypothesis that such in vitro B cell classification systems correlate with clinical subtypes of CVID is being sought. For the classification to be useful in routine diagnosis, it is important that the flow cytometric method can be used without prior separation of peripheral blood mononuclear cells (PBMC). We have examined 23 CVID patients and 24 controls, using both PBMC and whole blood, and find an excellent correlation between these methods. The reproducibility of the method was excellent. We classified the CVID patients by all three of the existing classifications, including secretion of immunoglobulin by B cells in vitro as described by Bryant, as well as the more recent flow cytometric classification methods. Only one patient changed classification as a result of using whole blood.

Immunosuppressive treatment of chronic periaortitis: a retrospective study of 20 patients with chronic periaortitis and a review of the literature

BACKGROUND

Retroperitoneal fibrosis (RPF) and inflammatory aneurysm of the abdominal aorta (IAAA) are regarded as two manifestations of the same disease, termed "chronic periaortitis".

OBJECTIVE

To determine the optimal therapeutic and diagnostic approaches to IAAA.

METHODS

The outcome of medical immunosuppressive and surgical treatment of 20 patients was examined. Measurements of the C reactive protein (CRP) were compared with contrast enhanced imaging studies in the follow up of the patients.

RESULTS

The diameter of the periaortic mantle and its contrast enhancement improved in 13/15 (87%) patients given immunosuppressive treatment for a period of more than 6 months. Strong contrast enhancement was associated with a substantial rise in CRP, but no correlation between the CRP value and thickness of the fibrotic mass was found, even at intraindividual follow up.

CONCLUSIONS

Immunosuppressive treatment should be included in the first line treatment of patients with RPF and should be maintained long term. Imaging studies are better than CRP measurements in the evaluation of response to treatment.

Reduction of soluble complement receptor 2/CD21 in systemic lupus erythomatosus and Sjogren's syndrome but not juvenile arthritis

A soluble form of the complement receptor CD21 (sCD21) is shed from the lymphocyte surface. The amount of sCD21 in serum may modulate immunity as sCD21 levels are correlated with several clinical conditions. We report here the serum levels of sCD21 in juvenile arthritis (JA), systemic lupus erythematosus (SLE) and Sjogren's syndrome (SS). Using enzyme-linked immunosorbent assay, we determined sCD21 levels in SLE, SS and JA patients. Mann-Whitney test for nonparametric two-tail P value was performed to obtain statistical significance. Cytometrical analysis of synovial fluid leucocytes of JA patients was done on a FACSsort. While sCD21 levels in SLE and SS are reduced to levels previously found in rheumatoid arthritis (RA), JA sCD21 levels were normal. sCD21 levels did not correlate with clinical parameters and immunophenotype of synovial cells. CD4 T cells in the synovium were almost all of the CD45RO memory type and 13 of 40 patients displayed synovial expansion of gammadeltaT cells. CD21 shedding in JA differs from RA/SS/SLE. JA sCD21 levels in synovial fluid are always lower compared to blood levels of the same patients. Analysis of JA synovial T cells indicates a T-cell driven response.

Development of granulomatous common variable immunodeficiency subsequent to infection with Toxoplasma gondii

Common variable immunodeficiency (CVID) is a heterogeneous immunodeficiency that is accompanied by granulomatous lesions in 5-10% of cases. Why some patients develop granulomatous disease remains unclear. Here we describe a 12-year-old previously healthy girl who presented with pancytopenia and granulomatous lymphoproliferation subsequent to infection with Toxoplasma gondii. Loosely arranged non-fibrosing granulomas were observed in the liver, lymph nodes and lung, but no Toxoplasma tachyzoites could be demonstrated and polymerase chain reaction (PCR) and culture were negative for Toxoplasma and a wide range of other pathogens. While the patient had a normal peripheral B cell status at presentation, the development of CVID could be observed during the following months, leading to a loss of memory B cells. This was accompanied by an increasingly activated CD4(+) T cell compartment and high serum levels of angiotensin-converting enzyme (ACE), tumour necrosis factor (TNF) and sCD25. Steroid therapy reduced pancytopenia, granulomatous lymphoproliferation and cytokine elevations, but did not improve the B cell status. This is the first report of an association of Toxoplasma infection with granulomatous CVID and provides one of the rare examples where the onset of CVID could be documented subsequent to an infectious disease.

[Classification and diagnosis of immunodeficiency syndromes]

Primary immunodeficiency diseases of the adult are rare disorders, but often lead to serious consequences. Therefore an early diagnosis is critical. The variety in the clinical presentation, the complexity of the immune system and the ongoing discovery of new defects render it a difficult area for the involved physician. Due to the often imprecise complaint of a weak immune system the primary task is the identification of patients with true immunodeficiency. Subsequently, the immune defect needs to be identified in collaboration with a center for immunodeficiency disorders. The diagnostic procedure is dependent on the pattern of infections and follows a defined series of steps. This procedure should prevent costly diagnostic evaluation when not indicated, and also prevent the delayed diagnosis of patients with manifest immunodeficiency disease.

Linkage of autosomal dominant common variable immunodeficiency to chromosome 5p and evidence for locus heterogeneity

Common variable immunodeficiency (CVID, OMIM 240500) and selective immunoglobulin A deficiency (IgAD) are the most frequent primary immunodeficiencies in humans. Of the cases with CVID/IgAD, 20%-25% are familial, but the only previous claims of linkage or association are to the HLA region on chromosome 6p. We report the results of a genome-wide scan in three multiplex families with CVID, IgAD, and dysgammaglobulinemia, where affection is inherited in an autosomal dominant pattern. Two of the families are consistent with linkage to the telomeric region of chromosome 5p, whereas the third is consistent with linkage to the HLA region. Using a locus heterogeneity model and a conservative penetrance model, we obtained a LOD score of 3.35 for the 5p region. We sequenced the exons of one promising candidate gene within this region (PDCD6, also known as ALG-2) but found no causative mutation.

Infectious CNS disease as a differential diagnosis in systemic rheumatic diseases: three case reports and a review of the literature

BACKGROUND

Immunosuppressive treatment of rheumatic diseases may be associated with several opportunistic infections of the brain. The differentiation between primary central nervous system (CNS) involvement and CNS infection may be difficult, leading to delayed diagnosis.

OBJECTIVE

To differentiate between CNS involvement and CNS infection in systemic rheumatic diseases.

METHODS AND RESULTS

Three patients with either longstanding or suspected systemic rheumatic diseases (systemic lupus erythematodes, Wegener's granulomatosis, and cerebral vasculitis) who presented with various neuropsychiatric symptoms are described. All three patients were pretreated with different immunosuppressive drugs (leflunomide, methotrexate, cyclophosphamide) in combination with corticosteroids. Magnetic resonance imaging of the brain was suggestive of infectious disease, which was confirmed by cerebrospinal fluid analysis or stereotactic brain biopsy (progressive multifocal leucoencephalopathy (PML) in two and nocardiosis in one patient).

DISCUSSION

More than 20 cases of PML or cerebral nocardiosis in patients receiving corticosteroids and cytotoxic drugs for rheumatic disease have been reported. The clinical aspects of opportunistic CNS infections and the role of brain imaging, cerebrospinal fluid analysis and stereotactic brain biopsy in the differential diagnosis are reviewed.

Impaired up-regulation of CD70 and CD86 in naive (CD27-) B cells from patients with common variable immunodeficiency (CVID)

CVID is characterized by reduced serum levels of all switched immunoglobulin isotypes (IgG, IgA, IgE) predisposing patients to recurrent infections of their respiratory and gastrointestinal tract. Correspondingly, most CVID patients exhibit a severely decreased proportion of class switched memory B cells (CD19+CD27+IgD-IgM-IgG+ or IgA+) in their peripheral blood (CVID type I). We previously identified a subgroup of CVID patients showing a significantly reduced expression of CD86 and CD137 following activation in vitro of PBMC or purified B cells (CD19+) with anti-IgM plus IL-2. Here we extend our previous studies by asking whether highly purified, cell-sorted naive B cells show already an expression defect of B cell surface molecules relevant in activation (CD39, CD69), differentiation (CD24, CD27, CD38) or T-B interaction (CD25, CD70, CD86). We stimulated cell-sorted, naive B cells (CD19+CD27-IgM+IgDhighIgG-IgA-) from 10 CVID patients and 10 healthy controls for 4 days with anti-IgM plus IL-2 in the absence or presence of autologous CD4+ T cells and measured the expression of the referred surface molecules. Based on reduced or normal numbers of switched memory B cells the CVID patients had previously been classified into eight type I patients and two type II patients, respectively. Interestingly, only the molecules CD25, CD70 and CD86, all relevant in cognate T-B interaction, showed a significantly lower expression in naive B cells from CVID patients compared to controls. While coculture with autologous CD4+ T cells normalized the CD25 expression, CD70 and CD86 expression remained subnormal, notably in the eight CVID patients of type I. These findings strongly suggest an intrinsic signalling or expression defect for CD70/CD86 at the level of naive B cells in type I CVID patients.

Successful IL-2 therapy for relapsing herpes zoster infection in a patient with idiopathic CD4+ T lymphocytopenia

Idiopathic CD4+ T lymphocytopenia (ICL) has been defined by the center of disease control as a rare cause of immunodeficiency with a variable clinical course and an unknown aetiology. Here we describe a 65-year old patient with relapsing generalized herpes zoster infection due to ICL and a severe panlymphocytopenia. In vitro assays revealed an enhanced activation of CD8+ T cells and an increased sensitivity of activated CD4+ T cells for cell death. The clinical outcome was substantially improved after starting the patient on a subcutaneous therapy with IL-2.

Efficient generation of transgenic BALB/c mice using BALB/c embryonic stem cells

BALB/c is one of the most widely used and best characterized mouse strains in immunology. For various applications, it is necessary to generate BALB/c transgenic mice. However, using the conventional microinjection technique it is extremely inefficient to produce transgenic BALB/c mice since the one-cell stage BALB/c embryos are highly vulnerable to pronuclear DNA microinjection. To overcome this problem, we have investigated the generation of Egr-1 (early growth response gene) transgenic mice via the transfection of BALB/c embryonic stem cells. Transfectants carrying Egr-1 constructs comprising either the immunoglobulin heavy chain or the MHC class II promoter/enhancer system were injected into C57BL/6 host blastocysts resulting in chimeric mice. For both type of expression vectors, transgenic offspring of the germline chimeras expressed recombinant Egr-1 in lymphoid tissues containing B cells. This demonstrates the successful generation of Egr-1 transgenic BALB/c mice using transfected ES cell.

Rheumatoid factor B cell tolerance via autonomous Fas/FasL-independent apoptosis

Normal individuals do not express the high-affinity autoantibodies specific for self-IgG (rheumatoid factors, RF) that are commonly seen in rheumatoid arthritis patients. Studies of transgenic mice expressing a human IgM rheumatoid factor have shown that one mechanism by which higher affinity RF B cells are tolerized to IgG is through abortive RF B cell activation followed by deletion in the absence of T cell help. We show that RF B cell deletion occurs through an intrinsic apoptotic mechanism that is independent of the Fas/FasL pathway and does not involve active killing by T cells, as it occurs in RAG-1-deficient RF transgenic mice to the same extent as in the parental RF transgenic line.

The transcription factor early growth response 1 (Egr-1) advances differentiation of pre-B and immature B cells

In mature B lymphocytes, the zinc finger transcription factor early growth response 1 (Egr-1) is one of the many immediate-early genes induced upon B cell antigen receptor engagement. However, its role during earlier stages of lymphopoiesis has remained unclear. By examining bone marrow B cell subsets, we found Egr-1 transcripts in pro/pre-B and immature B lymphocytes, and Egr-1 protein in pro/pre-B-I cells cultivated on stroma cells in the presence of interleukin (IL)-7. In recombinase-activating gene (RAG)-2-deficient mice overexpressing an Egr-1 transgene in the B lymphocyte lineage, pro/pre-B-I cells could differentiate past a developmental block at the B220(low) BP-1(-) stage to the stage of B220(low) BP-1(+) pre-B-I cells, but not further to the B220(low) BP-1(+) CD25(+) stage of pre-B-II cells. Therefore, during early B lymphopoiesis progression from the B220(low) BP-1(-) IL-2R- pro/pre-B-I stage to the B220(low) BP-1(+) IL-2R+ pre-B-II stage seems to occur in at least two distinct steps, and the first step to the stage of B220(low) BP-1(+) pre-B-I cells can be promoted by the overexpression of Egr-1 alone. Wild-type mice expressing an Egr-1 transgene had increased proportions of mature immunoglobulin (Ig)M+ B220(high) and decreased proportions of immature IgM+ B220(low) bone marrow B cells. Since transgenic and control precursor B cells show comparable proliferation patterns, overexpression of Egr-1 seems also to promote entry into the mature B cell stage. Analysis of changes in the expression pattern of potential Egr-1 target genes revealed that Egr-1 enhances the expression of the aminopeptidase BP-1/6C3 in pre-B and immature B cells and upregulates expression of the orphan nuclear receptor nur77 in IgM+ B cells.

The dual phases of the response to neonatal exposure to a VH family-restricted staphylococcal B cell superantigen

In vitro studies of several naturally occurring proteins have characterized VH family-specific B lymphocyte binding and stimulatory properties that appear analogous to those of T cell superantigens. To examine the in vivo consequences of exposure to a putative B cell superantigen, we treated neonatal BALB/c mice with a form of staphylococcal protein A (MS) devoid of Fcgamma binding activity, which retains the clan VHIII Fab binding specificity. In naive adults, about 5% of peripheral B cells and >13% of splenic IgM-secreting cells display MS binding activity, in association with high IgM and low IgG circulating anti-MS Ab titers. Neonatal exposure to MS elicited two distinct temporal phases of immune responsiveness. The early phase, representing the first approximately 5 wk of life, was associated with MS-specific B cell and T cell tolerance. Microfluorometric assays revealed that exposure caused a dramatic MS-specific B cell clonal loss in bone marrow and spleen, but levels normalized by about 3 wk of life. The late phase (>6 wk of age) was associated with spontaneous priming for MS-specific T cell responses and production of MS-specific IgG1 Abs despite long term persistently depressed in vivo and in vitro MS-specific IgM responses. In vivo challenge during the late phase induced high frequencies of MS-specific IgG-secreting cells, indicating recruitment of highly focused Ab responses that were predominantly encoded by rearrangements of the S107 family, a member of the VHIII clan. These studies document the immunodominance of the VH-restricted Fab binding site on staphylococcal protein A and demonstrate the diverse effects of a B cell superantigen on the emerging peripheral B cell compartment.

Peripheral deletion of rheumatoid factor B cells after abortive activation by IgG

Rheumatoid factor (RF) B cells proliferate during secondary immune responses to immune complexed antigen and antigen specific T cells, but higher affinity RFs are not detected except in patients with rheumatoid arthritis and other autoimmune diseases. Consequently, there must exist highly efficient mechanisms for inactivation of these higher-affinity RF B cell clones under normal circumstances. Exposure of transgenic mice expressing a human IgM RF to soluble human IgG in the absence of T cell help causes antigen specific B cell deletion in 2-3 days. The deletion is independent of the Fas/Fas ligand (FasL) pathway of apoptosis and is preceded by a phase of partial activation involving increase in cell size and expression of B7 and ICAM-1, and transient release of low levels of immunoglobulin. Complete B cell activation involving the formation of germinal centers and sustained high level RF secretion only occurs if T cell help is provided simultaneously. RF B cells exposed to tolerogen remain competent to secrete RF in vitro if provided with an appropriate antigenic stimulus and T cell help. Consequently, death of these cells is not preceded by anergy. Abortive activation/deletion of B cells by antigen in the absence of T cell-derived survival signals may represent the major mechanism for maintaining peripheral tolerance in B cells expressing higher affinity RF. The lack of anergy, and the potential for reactivation before death, provide a means for maintaining RF production under pathologic circumstances, such as may occur in the inflamed rheumatoid synovium.

Molecular cloning and nucleotide sequence of a new plasmid-coded Klebsiella pneumoniae beta-lactamase gene (SHV-2a) responsible for high-level cefotaxime resistance

Patient specimen isolates of Klebsiella pneumoniae exhibiting an MIC of greater than 128 mg/l for cefotaxime were shown to produce a beta-lactamase with a pI of 7.6, which is encoded on a 66 kb conjugative plasmid. A 3.5 kb Bam HI fragment of this plasmid was cloned into pLG339 and totally sequenced. The nucleotide sequence of the beta-lactamase gene presented 99% homology to those of SHV-2 and SHV-3, the deduced amino acid sequence differed from both enzymes in one and two positions, respectively, leading to the denomination SHV-2a for the new enzyme. Since the kinetic data of SHV-2a and SHV-2 are similar, too, quantitative effects mediated by distinctly different promotor regions are thought to be responsible for the elevated MIC for cefotaxime induced by SHV-2a.