Non-Hodgkin's lymphoma in systemic lupus erythematosus

BACKGROUND

Recent evidence supports an association between systemic lupus erythematosus (SLE) and non-Hodgkin's lymphoma (NHL).

OBJECTIVES

To describe demographic factors, subtypes, and survival of patients with SLE who develop NHL.

METHODS

A multi-site cohort of 9547 subjects with definite SLE was assembled. Subjects at each centre were linked to regional tumour registries to determine cancer cases occurring after SLE diagnosis. For the NHL cases ascertained, descriptive statistics were calculated, and NHL subtype frequency and median survival time of patients determined.

RESULTS

42 cases of NHL occurred in the patients with SLE during the 76,948 patient-years of observation. The median age of patients at NHL diagnosis was 57 years. Thirty six (86%) of the 42 patients developing NHL were women, reflecting the female predominance of the cohort. In the patients, aggressive histological subtypes appeared to predominate, with the most commonly identified NHL subtype being diffuse large B cell (11 out of 21 cases for which histological subtype was available). Twenty two of the patients had died a median of 1.2 years after lymphoma diagnosis.

CONCLUSIONS

These data suggest aggressive disease in patients with SLE who develop NHL. Continuing work should provide further insight into the patterns of presentation, prognosis, and aetiology of NHL in SLE.

An international cohort study of cancer in systemic lupus erythematosus

OBJECTIVE

There is increasing evidence in support of an association between systemic lupus erythematosus (SLE) and malignancy, but in earlier studies the association could not be quantified precisely. The present study was undertaken to ascertain the incidence of cancer in SLE patients, compared with that in the general population.

METHODS

We assembled a multisite (23 centers) international cohort of patients diagnosed as having SLE. Patients at each center were linked to regional tumor registries to determine cancer occurrence. Standardized incidence ratios (SIRs) were calculated as the ratio of observed to expected cancers. Cancers expected were determined by multiplying person-years in the cohort by the geographically matched age, sex, and calendar year-specific cancer rates, and summing over all person-years.

RESULTS

The 9,547 patients from 23 centers were observed for a total of 76,948 patient-years, with an average followup of 8 years. Within the observation interval, 431 cancers occurred. The data confirmed an increased risk of cancer among patients with SLE. For all cancers combined, the SIR estimate was 1.15 (95% confidence interval [95% CI] 1.05-1.27), for all hematologic malignancies, it was 2.75 (95% CI 2.13-3.49), and for non-Hodgkin's lymphoma, it was 3.64 (95% CI 2.63-4.93). The data also suggested an increased risk of lung cancer (SIR 1.37; 95% CI 1.05-1.76), and hepatobiliary cancer (SIR 2.60; 95% CI 1.25, 4.78).

CONCLUSION

These results support the notion of an association between SLE and cancer and more precisely define the risk of non-Hodgkin's lymphoma in SLE. It is not yet known whether this association is mediated by genetic factors or exogenous exposures.

A study of the genetic basis of C4A protein deficiency. Detection of C4A gene deletion by long-range PCR and its associated haplotypes

OBJECTIVE

To study the frequency of a C4A gene deletions as the genetic basis of C4A protein deficiency (C4AQ0) and its associated haplotypes in Icelandic families with systemic lupus erythematosus (SLE).

METHODS

Nine multiplex SLE families were genotyped for C4A gene deletions using a long-range polymerase chain reaction (LR-PCR) method, and major histocompatibility complex (MHC) haplotypes were defined.

RESULTS

Of the SLE patients, first-degree and second-degree relatives, 53.8%, 47.9%, and 28.6% had C4AQ0, respectively. A C4A gene deletion was found to be the genetic basis for C4AQ0 in 64.3% of SLE patients, 60.0% of first-degree and 50.0% of second-degree relatives. All individuals carrying haplotype B8-C4AQ0-C4B1-DR3 had a deletion, and the deletion was also found on haplotypes B8-C4AQ0-C4B1-DR7 and B7-C4AQ0-C4B1-DR3.

CONCLUSION

The study shows that a C4A gene deletion is the most common genetic basis for C4AQ0. It accounts for two-thirds of C4AQ0 and is found on different MHC haplotypes. One-third of C4AQ0 is due to other as yet undefined genetic changes. The results demonstrate a heterogeneous genetic background for C4AQ0, giving further support for the hypothesis that C4AQ0 may be an independent risk factor for SLE.

Patients with systemic lupus erythematosus are deficient in complement-dependent prevention of immune precipitation

OBJECTIVE

A functional deficiency of complement has been implicated but not conclusively demonstrated in the pathogenesis of systemic lupus erythematosus (SLE). To test this, we studied several aspects of complement in 44 patients with SLE, 46 patients with rheumatoid arthritis and 102 blood donors.

METHODS

Prevention of immune precipitation (PIP) was measured by an enzyme immunoassay, levels of C1q, C4 and C3 by rocket immunoelectrophoresis, C4A, C4B and C3d by enzyme-linked immunosorbent assay (ELISA), complement haemolysis (CH50) by standard methods and C4 allotypes by high-voltage agarose electrophoresis and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE).

RESULTS

PIP was significantly reduced in SLE (P<0.001); the defect was revealed by a sensitive assay measuring this function of complement but not by the other tests employed. The patients were clinically well at the time of study, and levels of C3d, which have been shown to correlate with disease activity, were normal. The defect was more common in patients with early disease (P = 0.009), supporting a role in aetiology or early pathophysiology. PIP was positively correlated with levels of C4 (P = 3 x 10(-5)) and in particular the C4A isotype (P = 9 x 10(-10)) whereas C4B was redundant.

CONCLUSIONS

Our results reveal a defect in prevention of immune precipitation in SLE that is apparent at an early stage in the disease and correlates with low levels of C4A. These results indicate that subtle deficiencies of complement may predispose to SLE.

Risk of malignancy in an unselected cohort of Icelandic patients with systemic lupus erythematosus

In the present literature there is still controversy as to whether patients with systemic lupus erythematosus (SLE) are at increased risk of developing malignant diseases. In recent years a number of epidemiological studies have been conducted and some have suggested an association between SLE and malignant diseases while other studies have not. The objective of this study was to investigate this relationship in an unselected cohort of Icelandic patients with SLE. All patients diagnosed with SLE registered in the Icelandic SLE database were compared to the Icelandic cancer registry. For completeness, hospital charts and outpatient notes were also reviewed. The study period was from 1957 to the end of 2001. The O/E (observed/expected ratio), CI and P-value were calculated for total number of malignancies as well as individual malignancy types. Of 238 patients diagnosed with SLE (213 women and 25 men) 39 malignancies were diagnosed in 36 patients; 32 women and four men. Of the 36 patients, 27 were diagnosed subsequently with SLE and malignant disease. The mean age at diagnosis of SLE was 43.2 years (range 10-81) and at time of diagnosis of malignancy 62.7 years (range 43-86). The O/R for the whole study population was 1.38 (CI 0.89-1.87, P = 0.063), 1.45 for the women (CI 0.91-1.99, P = 0.051) and 1.03 for the men (CI 0.22-2.66, P = 0.560). The O/R for the most frequent malignancies diagnosed subsequently to SLE was 6.43 for squamous cell skin cancer (CI 1.31-18.5, P = 0.012), 5.48 for lymphoma (CI 0.64-19.6, P = 0.052), 2.46 for uterine cancer (CI 0.29-8.78, P = 0.196), 2.0 for ovarian cancer (CI 0.23-7.14, P = 0.264), 1.72 for lung cancer (CI 0.36-4.95, P = 0.254) and 1.6 for breast cancer (CI 0.65-3.23, P = 0.154). The total number of patient-years at risk was 2774 years. The results from this study on an unselected cohort of Icelandic SLE patients do not suggest an overall association between SLE and malignancy. Squamous cell skin cancer was the only individual cancer type that was statistically increased in the population and the numbers for lymphoma were borderline statistically significant.

Increased T-lymphocyte apoptosis/necrosis and IL-10 producing cells in patients and their spouses in Icelandic systemic lupus erythematosus multicase families

The objective of this study was to evaluate apoptosis and production of IL-10 in SLE patients, their spouses and first-degree relatives in Icelandic SLE multicase families. Previously, increased IL-10 production has been found in all three groups. As IL-10 has been found to induce apoptosis in SLE, the percentage of lymphocytes undergoing apoptosis was evaluated, as well as the possible correlation between apoptosis and IL-10 production. Apoptosis and IL-10 production were studied in SLE patients (n = 12) from SLE multicase families and their spouses (n = 12) and a matched control group of healthy individuals (n = 10). The proportion of T and B lymphocytes undergoing apoptosis at 0, 24, 48 and 72 h was detected by flow cytometry using Annexin V and PI staining and the rate of apoptosis was calculated. IL-10 production was studied simultaneously by ELISpot analysis of freshly isolated peripheral blood mononuclear cells. In addition, T lymphocyte apoptosis at t = 0 was investigated in a group of non-household first-degree relatives (n = 10) and controls (n = 10). Antinuclear and antilymphocyte antibodies were analysed in all the groups. The SLE patients as a group had a significantly increased percentage of T lymphocytes in apoptosis at 0 and 48 h and a significantly higher number of IL-10 producing cells as compared with the healthy controls (P = 0.03, 0.02 and 0.03, respectively). The spouses also had significantly increased percentage of T lymphocytes in apoptosis (t = 0) and a significantly higher number of IL-10-producing cells when compared with healthy controls (P = 0.01 and 0.02, respectively). There were no significant differences between the patients and their spouses. For apoptosis of B lymphocytes no difference was found between the groups. The SLE patients as a group had the highest rate of apoptosis. No correlation between the degree and rate of apoptosis and the number of IL-10-producing cells was detected. The first-degree relatives did not have increased percentage of T lymphocytes undergoing apoptosis at t = 0 compared with healthy controls. The SLE patients had higher titres of ANA compared with the other groups. No correlation was detected between the ANA titre and the percentage of lymphocytes undergoing apoptosis. There was no correlation between disease activity as measured by SLEDAI and apoptosis. In conclusion, our results suggest that environmental factors common to both SLE patients and their spouses are associated both with the increased apoptosis and increased spontaneous production of IL-10, thus providing support for the notion that both environmental and genetic factors influencing apoptosis are of importance for the development of SLE.

Sinusitis due to Stenotrophomonas maltophilia

This is the first report of a patient diagnosed with sinusitis due to Stenotrophomonas maltophilia. Despite the organism being resistant to trimethoprim-sulfamethoxazole, the infection was cured by drainage and treatment with intravenous piperacillin, followed by oral ciprofloxacin.

The inheritance of rheumatoid arthritis in Iceland

OBJECTIVE

Rheumatoid arthritis (RA) is the most common form of inflammatory arthritis. Although there is a large body of evidence suggesting that RA is immune mediated, the etiology remains unresolved. Twin studies have shown disease concordance rates of approximately 15% in monozygotic twins and 4% in dizygotic twins, while the estimated risk ratio for siblings of RA patients ranges from 5 to 8. Our goal was to use genealogic data from Iceland to further investigate the genetic component of RA.

METHODS

Data were obtained from a population-based, computerized genealogy database that was developed to examine multigenerational relationships among individuals in the relatively homogeneous population of Iceland. Using an algorithm, the minimum founder test, we calculated the least number of founders required to account for a list of RA patients, and compared it with 1,000 sets of same-sized matched control groups. In addition, we estimated the kinship coefficient and risk ratios for relatives of the RA patients.

RESULTS

Several familial clustering tests demonstrated that the RA patients were more related to each other than were the average control set of Icelanders. A significantly fewer number of founders was necessary to account for our patient list than for the random sets of matched controls (P < 0.001), and the average pairwise identity-by-descent sharing was greater among the patients than among the control sets (P < 0.001). In addition, there was an increased risk of RA in first- and second-degree relatives of the patients; e.g., for siblings, the risk ratio was 4.38 (95% confidence interval 3.26-5.67), and for uncles/aunts, the risk ratio was 1.95 (95% confidence interval 1.52-2.43).

CONCLUSION

The familial component of RA is shown to extend beyond the nuclear family, thus providing stronger evidence for a significant genetic component to RA.

Fine mapping of the SLEB2 locus involved in susceptibility to systemic lupus erythematosus

We have previously reported linkage of systemic lupus erythematosus to chromosome 2q37 in multicase families from Iceland and Sweden. This locus (SLEB2) was identified by linkage to the markers D2S125 and D2S140. In the present study we have analyzed additional microsatellite markers and SNPs covering a region of 30 cM around D2S125 in an extended set of Nordic families (Icelandic, Swedish, and Norwegian). Two-point linkage analysis in these families gave a maximum lod score at the position of markers D2S2585 and D2S2985 (Z = 4.51, PIC = 0.65), by applying a "model-free" pseudo-marker linkage analysis. Based on multipoint linkage analysis in the Nordic families, the most likely location of the SLEB2 locus is estimated to be in the interval between D2S125 and the position of markers D2S2585 and D2S2985, with a peak multipoint lod score of Z = 6.03, assuming a dominant pseudo-marker model. Linkage disequilibrium (LD) analysis was performed using the data from the multicase families and 89 single-case families of Swedish origin, using the same set of markers. The LD analysis showed evidence for association in the single-case and multicase families with locus GAAT3C11 (P < 0.0003), and weak evidence for association was obtained for several markers located telomeric to D2S125 in the multicase families. Thirteen Mexican families were analyzed separately and found not to have linkage to this region. Our results support the presence of the SLEB2 locus at 2q37.

A study of C4AQ0 and MHC haplotypes in Icelandic multicase families with systemic lupus erythematosus

OBJECTIVE

To study MHC haplotypes and C4AQ0 in Caucasian multicase systemic lupus erythematosus (SLE) families from Iceland.

METHODS

Eight families with 26 SLE patients, 98 non-SLE first-degree relatives, and a control group were studied. For statistical analysis one SLE patient and one first-degree relative were randomly chosen from each family. C4 allotyping was performed by protein electrophoresis, HLA typing of class I by the lymphocytotoxicity test, and typing of class II alleles with polymerase chain reaction with sequence specific primers.

RESULTS

Six of the 8 families showed a high background of C4A protein deficiency (C4AQ0) and a significant increase was seen in C4AQ0 in the randomly chosen group of patients. A similar tendency that was statistically nonsignificant was seen in first-degree relatives. In the SLE patients C4AQ0 was found on several MHC haplotypes. Half the patients with C4A protein deficiency carry C4AQ0 on the classical C4A deletion haplotype B8-C4AQ0-C4B1-DR3 or variants of it, and the remaining C4A deficient patients on other non-DR3 carrying haplotypes. The transmission of C4AQ0 from parents to patients was in most cases through the family line, although in some instances it originates from outside the multicase SLE family through spouses married into the family.

CONCLUSION

In these Caucasian multicase SLE families from Iceland, C4AQ0 shows weaker linkage disequilibrium with DR3 than reported in studies on other white populations, emphasizing the role of ethnicity. The common factor in the MHC haplotypes studied is C4AQ0, supporting a hypothesis that C4AQ0 may be an independent risk factor for SLE.

Long PCR detection of the C4A null allele in B8-C4AQ0-C4B1-DR3

The genes coding for the two components of complement 4 (C4), C4A and C4B, are located within the major histocompatibility complex (MHC) on the short arm of chromosome 6. Several studies have shown that deficiency of C4A is associated with systemic lupus erythematosus (SLE), rheumatoid arthritis and scleroderma. A large deletion covering most of the C4A gene and the 21-hydroxylase-A (21-OHA) pseudogene found on the extended haplotype B8-C4AQ0-C4B1-DR3 is estimated to account for approximately two-thirds of C4A deficiency in Caucasian SLE patients. Detection of this C4A null allele has been technically difficult due to the high degree of homology between C4A and C4B, with protein analysis and restriction fragment length polymorphism (RFLP) analysis using Southern blotting being the only approaches available. In this study, a long PCR strategy was used to rapidly genotype for the C4A deletion through specific primer design. The methodology makes use of the unique sequence of the G11 gene upstream of C4A and the sequence of a 6.4 kb retrotransposon, the human endogenous retrovirus HERV-K(C4), which is present in intron 9 of C4A but absent in the case of the deletion.

A susceptibility locus for human systemic lupus erythematosus (hSLE1) on chromosome 2q

To identify chromosomal regions containing susceptibility loci for systemic lupus erythematosus (SLE), we performed genome scans in families with multiple SLE patients from Iceland, a geographical and genetic isolate, and from Sweden. A number of chromosomal regions showed maximum lod scores (Z) indicating possible linkage to SLE in both the Icelandic and Swedish families. In the Icelandic families, five regions showed lod scores greater than 2.0, three of which (4p15-13, Z=3.20; 9p22, Z=2.27; 19q13, Z=2.06) are homologous to the murine regions containing the lmb2, sle2 and sle3 loci, respectively. The fourth region is located on 19p13 (D19S247, Z=2.58) and the fifth on 2q37 (D2S125, Z=2.06). Only two regions showed lod scores above 2.0 in the Swedish families: on chromosome 2q11 (D2S436, Z=2. 13) and 2q37 (D2S125, Z=2.18). The combination of both family sets gave a highly significant lod score at D2S125 of Z=4.24 in favor of linkage for 2q37. This region represents a new locus for SLE. Our results underscore the importance of studying well-defined populations for genetic analysis of complex diseases such as SLE.

Genetic analysis of the contribution of IL10 to systemic lupus erythematosus

OBJECTIVE

To study the contribution of the IL10 gene to the susceptibility to systemic lupus erythematosus (SLE).

METHODS

Analysis by fluorescent-semiautomated genotyping of a dinucleotide repeat located in the promoter region of the IL10 locus (microsatellite G).

RESULTS

No significant difference was found in the frequencies of the microsatellite alleles of 330 Mexican patients with SLE compared to 368 controls from the same population. Two-point linkage analyses were carried out using 13 Mexican, 13 Swedish, and 8 Icelandic families with 2 or more cases with SLE. No linkage was revealed between IL10 and SLE, using a variety of parameter settings.

CONCLUSION

Our results do not support that the IL10 gene contributes to the susceptibility to SLE in the populations we studied.

Increased number of interleukin-10-producing cells in systemic lupus erythematosus patients and their first-degree relatives and spouses in Icelandic multicase families

OBJECTIVE

To evaluate the production of interleukin-10 (IL-10) as well as levels of IgG and antinuclear antibodies (ANA) in systemic lupus erythematosus (SLE) patients and their first-degree relatives and spouses in Icelandic SLE multicase families.

METHODS

IL-10 production was studied by enzyme-linked immunospot assay of freshly isolated peripheral blood mononuclear cells. Total IgG and ANA were also investigated. Subjects consisted of 23 SLE patients and 47 of their first-degree relatives in 9 Icelandic multicase families. Subjects were ethnically matched by a group of healthy controls. A separate study investigated 12 SLE patients (also from SLE multicase families) and their spouses and a matched group of healthy controls. A predefined protocol was used to obtain both clinical and laboratory data, including information about SLE and other autoimmune disorders.

RESULTS

The SLE patients had a significantly higher number of IL-10-producing cells compared with both first-degree relatives and healthy controls (P = 0.0005 and P < 0.0001, respectively). First-degree relatives also had a significantly higher number of IL-10-producing cells compared with healthy controls (P = 0.01). This was also true for the spouses of SLE patients, who had a higher number of IL-10-producing cells compared with matched healthy controls (P = 0.02).

CONCLUSION

SLE patients and their first-degree relatives, as well as a limited number of healthy spouses of SLE patients, had increased numbers of spontaneous IL-10-producing cells. These data support the hypothesis that IL-10 production may be genetically determined, and may predispose one toward development of SLE. This has previously been suggested by studies of SLE patients and their relatives in another ethnic population, using another method for measuring IL-10 production. Although these data are based on a small number of observations, they suggest that not only genetic but also environmental factors may be of importance in determining IL-10 production, since the spouses of SLE patients also had an increased number of IL-10-producing cells.

A comparison of genome-scans performed in multicase families with systemic lupus erythematosus from different population groups

Systemic lupus erythematosus is a disease of unknown etiology. Multiple genetic factors are believed to be involved in its pathogenesis. In addition, and due to genetic heterogeneity, these factors and/or their combinations may be different in different ethnic groups, while some might be shared between populations. We have performed genome scans in multicase families from three different population groups, two from Northern Europe, with a high degree of homogeneity, and the third from a recently admixed population of Mexican Mestizos. Although our family material is relatively small, the results presented here show that using family sets from well defined populations are sufficient to detect susceptibility loci for SLE. Our results also reveal the chromosomal regions most likely to contain susceptibility genes for SLE.

Combined elevation of IgM and IgA rheumatoid factor has high diagnostic specificity for rheumatoid arthritis

The diagnostic value of measuring rheumatoid factor (RF) by agglutination or isotype-specific enzyme-linked immunosorbent assay (ELISA) was compared. The study included 70 patients with rheumatoid arthritis (RA) and 205 patients with various other rheumatic conditions. Of the RA patients, 74% were RF-positive by agglutination and 90% had one or more RF isotypes elevated by ELISA compared to 14% and 22%, respectively, of the other patients. Strikingly, 70% of the RF-positive RA patients had an elevation of two or more RF isotypes compared to only 16% of the other RF-positive patients (P < 0.0001). Furthermore, a combined elevation of IgM and IgA RF was found in 52% of the RF-positive RA patients, but only in two (4%) of the other RF-positive patients (P < 0.0001). It is concluded that a combined elevation of IgM and IgA RF is highly specific for RA and is very rarely found in rheumatic diseases other than RA. Isotype-specific RF assays are therefore diagnostically superior to agglutination tests. The detection of the RA-specific RF isotype pattern may be particularly helpful early in the course of RA even before the disease is fully differentiated.

C4AQ0 superimposed on a primary defect increases the susceptibility to systemic lupus erythematosus (SLE) in a family with association between C4AQ0 and SLE

OBJECTIVE

To investigate the association of C4AQ0 with increased incidence of systemic lupus erythematosus (SLE) or positive serology (28%) in an extended Icelandic family, and whether this can be explained by impaired complement function in handling immune complexes (IC).

METHODS

The ability of the classical pathway to opsonize nascent IC [alkaline phosphatase (AP)-anti-AP] and bind them to human erythrocytes was evaluated by the new ICRB assay. The capacity of erythrocytes from family members to bind nascent IC was also measured by a modification of the ICRB assay. IC levels were measured by complement consumption assay, C3d by a sandwich ELISA, factor B by immunoelectrophoresis, and the alternative pathway function by a hemolytic assay.

RESULTS

Family members with homozygous or heterozygous C4AQ0 (47%) showed no impaired complement dependent opsonization of IC and binding to erythrocytes. Their factor B and alternative pathway function was normal. Fifty-six percent of the family members (n=18) had abnormally high IC levels, seemingly independent of C4AQ0. However, 6 of the 7 individuals with high IC levels and SLE symptoms had C4AQ0 compared to 2 of 11 symptom-free individuals with high IC levels.

CONCLUSION

Our results suggest that the susceptibility for SLE in this family may result from 2 different defects, one leading to elevated IC levels, and another associated with C4AQ0 without detectable impairment in the complement dependent IC transport mechanism. Individuals with both abnormalities have increased susceptibility to SLE.

A study of the association of HLA DR, DQ, and complement C4 alleles with systemic lupus erythematosus in Iceland

OBJECTIVE

To perform an exploratory analysis of the relative contribution of single MHC genes to the pathogenesis of systemic lupus erythematosus (SLE) in a homogenous white population.

METHODS

MHC class II alleles and C4 allotypes were determined in 64 SLE patients and in ethnically matched controls. HLA-DR and DQ typing was performed by polymerase chain reaction amplification with sequence specific primers. C4 allotypes were determined by agarose gel electrophoresis.

RESULTS

The frequency of C4A*Q0 was significantly higher in patients than in controls (46.9% v 25.3%, p = 0.002). HLA-DRB1, DQA1, and DQB1 alleles in the whole group of SLE patients were not significantly different from those of controls. On the other hand increase in DRB1*03 was observed in the group of patients with C4A*Q0, as compared with patients with other C4A allotypes (p = 0.047). There was no significant correlation between severe and mild disease, as judged by the SLEDAI, and HLADR, DQ alleles and comparing the patients with C4A*Q0 with those with other C4A allotypes there was no significant difference regarding clinical manifestations.

CONCLUSION

The results are consistent with the argument that C4A deficiency contributes independently to susceptibility and the pathogenesis of SLE. C4A*Q0 in SLE patients in Iceland shows weaker linkage disequilibrium with DR3 genes than reported in most other white populations and emphasises the role of ethnicity.

Participation of factor B in residual immune complex red cell binding activity observed in serum from a C2-deficient systemic lupus erythematosus patient may delay the appearance of clinical symptoms

OBJECTIVE

To investigate whether participation of factor B (FB) in immune complex transport might explain long periods of clinical remissions in a homozygous C2-deficient patient with systemic lupus erythematosus (SLE) treated regularly with plasma infusions.

METHODS

Immune complex red cell binding (ICRB) was assayed as enzyme activity, C3d by enzyme-linked immunosorbent assay, and FB by immunoelectrophoresis.

RESULTS

C2-deficient sera showed low-grade ICRB, which correlated with levels of FB. This activity could be blocked with antibodies to C1q, C4, or FB, but not by antibodies to C2. C3d levels in the patient's plasma changed during infusion, followed by a gradient increase during remission. Comparison of ICRB, C3d, and FB suggested an inverse relationship between FB levels and clinical symptoms.

CONCLUSION

In C2 deficiency, FB may interact with C4 to provide a low-grade ICRB. This activity could be clinically significant in patients with C2 deficiency and explain why they are less prone to SLE than patients with C1q or C4 deficiency.

IgA rheumatoid factor correlates with changes in B and T lymphocyte subsets and disease manifestations in rheumatoid arthritis

OBJECTIVE

To analyze the relationship between lymphocyte subsets, different rheumatoid factor (RF) isotypes, and clinical features in patients with rheumatoid arthritis (RA).

METHODS

Patients with established RA (n = 95) were examined clinically and blood samples were collected for measurements of RF by ELISA and for analysis of lymphocyte subsets by flow cytometry.

RESULTS

IgA RF positive patients had more severe disease and higher prevalence of extraarticular manifestations than the other patients. Patients with elevated IgA RF had a higher percentage of CD5+ B cells and of CD4+CD45RO+ T cells compared to the other patients with RA or controls. High percentage of CD4+CD45RO+ T cells was also significantly associated with extraarticular manifestations. Patients with the sicca syndrome had significantly higher ratio of CD5+ B cells than patients without or with other types of extraarticular manifestations.

CONCLUSION

Different disease manifestations in RA may be associated not only with certain RF isotypes and RF isotype combinations but also with changes in lymphocyte subsets in the blood. The relative increase of CD4+CD45RO+ T cells in the blood of IgA RF positive patients with RA might reflect preferential recruitment of CD8+CD45RO+ T cells to inflammatory sites.

[Neuropsychiatric manifestations in an unselected group of patients with systemic lupus erythematosus in Iceland.]

INTRODUCTION

There has been substantial difference in the reported frequency of neuropsychiatric manifestations in systemic lupus erythematosus (SLE). This difference can at least partly be explained by methodological difference, especially in case identification.

MATERIAL AND METHODS

A retrospective study in a group of 65 unselected SLE patients was performed. The study consisted of two parts: 1) a neuropsychiatric evaluation which included a review of the patient's charts and a neurological interview, 2) a structured psychiatric interview, i.e. the Diagnostic Interview Schedule.

RESULTS

In part one 37 patients or 57% had positive findings, while in part two the number was 32 pa nottients or 49%. Overall, 46 patients or 71% had experienced one or more neuropsychiatric manifestations. The most prevalent manifestations in part one were headache and psychoses, and in part two simple phobia, agarophobia, social phobia and generalized anxiety. Approximately 25% of the patients were treated solely outside hospitals.

CONCLUSION

The unselected nature of this study gives a picture probably more representative of the true neuropsychiatric involvement in systemic lupus erythematosus than previous studies of selected patient populations.

A study of the major histocompatibility complex in a Caucasian family with multiple cases of systemic lupus erythematosus: association with the C4AQ0 phenotype

OBJECTIVE

In an epidemiological survey of systemic lupus erythematosus (SLE) in Iceland several families with multiple cases were identified. In one family, 35 individuals (family members and spouses) in 3 generations were studied clinically, tested for autoantibody formation, and typed for HLA and toxicity complement phenotypes.

METHODS

Typing for HLA-A, B, C, DR, and DQ was performed by microlymphocytotoxic assay. In selected samples HLA-DR typing by polymerase chain reaction amplification with sequence specific primers was performed. C4 allotypes were defined by agarose gel protein electrophoresis followed by immunofixation with goat antisera.

RESULTS

Five family members fulfilled 4 or more criteria for SLE. Additionally, 5 family members had clinical manifestations or positive serology but did not fulfill 4 ARA criteria. The mean age at onset of symptoms was 22 yrs (8-40). Other autoimmune diseases were not documented in family members. C4A null seemed to be highly associated with disease in this family. All except one patient with SLE and all those with clinical manifestations and positive serology had C4A null in the homozygous or heterozygous form. The individual with SLE and not carrying C4A null had both HLA haplotypes identical. It is noteworthy that there were 5 different C4A null bearing haplotypes involved, of which 3 originated from the spouses.

CONCLUSION

Our results are consistent with the argument that C4A deficiency plays a role in the pathogenesis of SLE. There is, however, the possibility of an unidentified environmental or another genetic factor being involved.