Elderly-onset rheumatoid arthritis receives less aggressive therapies than young-onset rheumatoid arthritis in an Argentinian cohort

OBJECTIVES

When rheumatoid arthritis (RA) starts after the age of 60 it is called elderly-onset rheumatoid arthritis (EORA) and when it starts earlier, young-onset rheumatoid arthritis. (YORA). There are few Latin American studies that compared both groups. The objective of the study was to evaluate differences in the clinical characteristics, evolution and treatment among patients with RA with onset before or after 60 years of age.

MATERIALS AND METHODS

Observational study of patients with RA attended consecutively in four centers in Argentina. Sociodemographic data, comorbidities, clinical manifestations at diagnosis, presence of rheumatoid factor and/or anti-CCP (cyclic citrullinated peptide) and treatments received were collected. At the last visit, swollen and tender joints, assessment of disease activity by the patient and physician, the presence of radiographic erosions, and functional status using the HAQ-DI were recorded.

RESULTS

51 patients from each group were analyzed. The EORA group had a significantly higher proportion of smokers (58.8% vs. 35.3%, p = 0.029), cardiovascular history (54.9% vs. 21.6%, p = 0.001), abrupt onset (49% vs. 29.4%, p = 0.034) or with symptoms similar to PMR (19.6% vs. 0%, p = 0.001). Lower methotrexate doses were used in the EORA group: 19 mg (15-25) vs. 21.9 mg (20-25) (p = 0.0036) and more frequently did not receive bDMARDs or tsDMARDs.

DISCUSSION AND CONCLUSIONS

The benefits of intensive treatment in patients with RA have been described. In this study, the use of DMARDs in the EORA group was less intensive, suggesting that advanced age constitutes a barrier in the therapeutic choice.

A T-cell marker in mouse fibroblast x T-lymphocyte somatic cell hybrids

Continuous hybrid cell lines have been generated by the fusion of allogeneically primed murine T lymphocytes with mouse L-cell-derived fibroblasts of the line 613. The resulting hybrid clones express one or more T-cell-specific surface components identifiable by radioiodination of intact cells followed by NP-40 solubilization of membrane proteins and sodium dodecyl sulfate polyacrylamide gel electrophoresis. These markers are stably expressed by the hybrid lines after several months of passage.

Minicircle variable region probes for characterization of Leishmania (Viannia) species

The minicircle molecules present in the kinetoplast DNA (kDNA) network constitute a particularly useful molecular tool because they are a multicopy target and present a variable region that differs among minicircle classes in the same network. Using the polymerase chain reaction (PCR) and a set of primers directed outwardly from the minicircle conserved region, it is possible to prepare molecular probes representing the pool of variable regions from the different minicircle classes in the kDNA. In order to examine the specificity of the minicircle variable region as hybridization probes in Leishmania (Viannia) species, such fragments were amplified from reference strains and from a panel of isolates representing the zymodeme diversity of Leishmania (Viannia) in Colombia. The size of the amplified products was conserved in Leishmania (Viannia) braziliensis, Leishmania (Viannia) guyanensis, and Leishmania (Viannia) panamensis (650 bp) and diverged in Leishmania (Viannia) equatorensis and Leishmania (Viannia) colombiensis (850 bp). The amplified products were further hybridized to variable region pools of Leishmania braziliensis, Leishmania panamensis, Leishmania guyanensis, and Leishmania equatorensis reference strains. The results obtained from the hybridization experiments support this approach as a means of defining relationships among strains. Hybridization allowed homologies to be perceived, whereas restriction fragment length analysis of the amplified products yielded strain-specific profiles. Apparently, L. (V.) equatorensis and L. (V.) colombiensis minicircle variable regions have no or only low homology with those of other Leishmania (Viannia) species, showing the divergence of those species within the subgenus.

Changes in expression of signal transduction proteins in T lymphocytes of patients with leprosy

Advanced stages of mycobacterial diseases such as leprosy and tuberculosis are characterized by a loss of T-cell function. The basis of this T-cell dysfunction is not well understood. The present report demonstrates major alterations in the expression of signal transduction molecules in T cells of leprosy patients. These alterations were most frequently observed in lepromatous leprosy (LL) patients. Of 29 LL patients, 69% had decreased T-cell receptor zeta-chain expression, 48% had decreased p56(lck) tyrosine kinase, and 63% had a loss of nuclear transcription factor NF-kappaB p65. An electrophoretic mobility shift assay with the gamma interferon core promoter region revealed a loss of the Th1 DNA-binding pattern in LL patients. In contrast, tuberculoid leprosy patients had only minor signal transduction alterations. These novel findings might improve our understanding of the T-cell dysfunction observed in leprosy and other infectious diseases and consequently might lead to better immunologic evaluation of patients.

Leishmania RNA viruses in Leishmania of the Viannia subgenus

Karyotype analysis of 69 strains of Leishmania belonging to three species of the Viannia subgenus originating from the southeastern and southwestern regions of Colombia revealed approximately 5.3-kb RNAs in four strains of L. braziliensis and also in the World Health Organization reference strain L. guyanensis IWHI/BR/78/M5313. The RNA element in this reference strain and in L. braziliensis strains isolated from cutaneous and mucosal lesions of four patients hybridized with RNA probes prepared from cDNA of the RNA virus present in L. guyanensis strain CUMC-1-1A (LRV1-1). These strains also contained an 80-kD protein that reacted with polyclonal antibody prepared against a recombinant fragment of the coat (capsid) protein of LRV1-1. In addition, another Colombian strain of L. braziliensis was found to contain an approximately 3.5-kb RNA that did not hybridize with LRV1-1 probes. Contrasting with the strains containing the 5.3-kb RNA, a total lysate of this strain did not contain material reactive with antiserum to the capsid protein fragment. All Leishmania containing LRV1-related viruses identified to date have originated in the Amazon River basin. Karyotype analyses and biological characterization of 17 clones obtained from the highly metastatic L. guyanensis strain 5313 revealed retention of the approximately 5.3 kb RNA in all clones and no segregation of the virus with the metastatic trait. The restricted distribution of LRV1-related viruses among some strains of L. braziliensis and L. guyanensis circulating in the Amazon River basin makes these elements potential epidemiologic markers.

Human monocyte infection by Leishmania (Viannia) panamensis. Role of complement receptors and correlation of susceptibility in vitro with clinical phenotype

Peripheral blood monocytes (PBMs) from healthy individuals who had experienced distinctive clinical outcomes after natural infection with Leishmania (Viannia) were evaluated in vitro with respect to susceptibility to infection by stationary phase promastigotes of L. (V). panamensis. Concomitantly, the role of complement receptors (CR) CR1 and CR3 in the attachment and entry of L. (V). panamensis into human monocytes was analyzed using mAbs to CR1 (CD35) and CR3 (CD11b) to inhibit competitively these early events in the host-parasite interaction. Cell adherence to fibronectin was examined to determine how modulation of CR activity affected the attachment and uptake of this parasite species. The human monocyte cell line U-937 was also evaluated and found to provide a reproducible control for L. (V). panamensis infection in vitro. Opsonization with fresh AB+ serum markedly enhanced uptake by both PBMs and U-937 cells, and the fluid phase blocking of CR1 and CR3 resulted in partial inhibition of attachment and/or internalization. Uptake rather than attachment was abrogated by antireceptor antibodies in PBMs from previously infected individuals, whereas attachment was diminished in PBMs from unexposed controls. Adherence of PBMs to fibronectin resulted in decreased infection. PBMs from persons who had experienced chronic disease 5 to 8.4 yr before these studies were significantly more susceptible to in vitro infection by L. (V). panamensis than PBMs from asymptomatically infected or control individuals based on the percentage of cells infected, the number of parasites per cell, and viability of intracellular parasites at 48 h postinfection. Neither blocking of CR nor modulation by fibronectin altered the pattern of susceptibility of PBMs from the different clinical groups. These findings provide evidence for the participation of CR in the infection of human monocytes by L. (V). panamensis and demonstrate a correlation between clinical phenotype and in vitro infection of PBMs cultured in the presence of autologous plasma before experimental infection.

Human monocyte infection by Leishmania (Viannia) panamensis. Role of complement receptors and correlation of susceptibility in vitro with clinical phenotype

Peripheral blood monocytes (PBMs) from healthy individuals who had experienced distinctive clinical outcomes after natural infection with Leishmania (Viannia) were evaluated in vitro with respect to susceptibility to infection by stationary phase promastigotes of L. (V). panamensis. Concomitantly, the role of complement receptors (CR) CR1 and CR3 in the attachment and entry of L. (V). panamensis into human monocytes was analyzed using mAbs to CR1 (CD35) and CR3 (CD11b) to inhibit competitively these early events in the host-parasite interaction. Cell adherence to fibronectin was examined to determine how modulation of CR activity affected the attachment and uptake of this parasite species. The human monocyte cell line U-937 was also evaluated and found to provide a reproducible control for L. (V). panamensis infection in vitro. Opsonization with fresh AB+ serum markedly enhanced uptake by both PBMs and U-937 cells, and the fluid phase blocking of CR1 and CR3 resulted in partial inhibition of attachment and/or internalization. Uptake rather than attachment was abrogated by antireceptor antibodies in PBMs from previously infected individuals, whereas attachment was diminished in PBMs from unexposed controls. Adherence of PBMs to fibronectin resulted in decreased infection. PBMs from persons who had experienced chronic disease 5 to 8.4 yr before these studies were significantly more susceptible to in vitro infection by L. (V). panamensis than PBMs from asymptomatically infected or control individuals based on the percentage of cells infected, the number of parasites per cell, and viability of intracellular parasites at 48 h postinfection. Neither blocking of CR nor modulation by fibronectin altered the pattern of susceptibility of PBMs from the different clinical groups. These findings provide evidence for the participation of CR in the infection of human monocytes by L. (V). panamensis and demonstrate a correlation between clinical phenotype and in vitro infection of PBMs cultured in the presence of autologous plasma before experimental infection.

[Experimental behavior of Sporothrix schenckii and Leishmania mexicana in hamsters]

The macroscopic description of the pathogenic process of Sporothrix schenckii and Leishmania mexicana spp in hamsters inoculated subcutaneously in the nose provided bases for the differentiation of the behavior of these two microorganisms in a model frequently utilized for their study. Sequential observations over 150 days demonstrated that infections caused by these pathogens results initially in edema and erythema followed by loss of hair, necrosis and ulceration. The pus production was a characteristic presented only by S. schenckii. These clinical signs were observed earlier in sporotrichosis than in L. mexicana infection. Differences in the mean day of appearance were statistically significant. The lesions produced by S. schenckii and L. mexicana in this experimental model share clinical signs, but their incubated period and relative frequency allow us to differentiate them. The circumstances of inoculation such as strain, dose of inoculum, place and route of inoculation are related to the experimental behavior of them.

Phenotypic expression in T-lymphocyte x "fibroblast" cell hybrids

The effects of pulsatile motion on MR imaging of spinal CSF were quantitatively evaluated with a spine phantom that simulated spinal CSF pulsation. Two fundamental interdependent pulsation flow phenomena were observed: variable reductions in signal intensity of pulsatile CSF (signal loss) and spatial mismapping of this signal beyond the confines of the subarachnoid space (phase-shift images). Phase-shift images were observed as multiple regions of signal intensity conforming morphologically to the subarachnoid space but displaced symmetrically from it along the phase-encoding axis, either added to or subtracted from stationary signal intensity. Both CSF pulsation flow phenomena occurred secondary to harmonic modulation of proton precessional phase (temporal phase shift) by the unique pulsatile motion of spinal CSF when the repetition time was not an integral multiple of the pulsation period. Each flow phenomenon was analyzed with the spine phantom independently to control individual imaging and physiologic parameters including imaging plane, repetition time, echo time, slice thickness, number of echoes, number of excitations, CSF pulsation amplitude, and CSF pulsation period. In the axial plane, signal loss was present on both first- and second-echo images and was more pronounced with larger pulsation amplitudes and smaller slice thicknesses. A quantitative relationship between these two parameters allowed the prediction of CSF pulsation amplitude when the slice thickness was known and the CSF signal intensity was measured. In the sagittal plane, signal loss was present on first-echo images, was more pronounced with larger pulsation amplitudes, and under-went incomplete even-echo rephasing on second-echo images. Phase-shift images were influenced by the relationship between repetition time and CSF pulsation period. They were partly eliminated on sagittal but not on axial second-echo images because of incomplete even-echo rephasing. Both signal loss and phase-shift images were completely eliminated with CSF gating or pseudogating, indicating the rationale for gating during clinical spinal MR. The clinical significance of these findings is that awareness of the existence of spinal CSF pulsation flow phenomena avoids diagnostic confusion, whereas understanding their etiology provides a rational approach, such as CSF gating, to eliminate them.

Epidemiology of Trypanosoma cruzi in the oriental plains of Colombia

Epidemiologic studies to define the domiciliary and extradomiciliary transmission cycles of Trypanosoma cruzi and Trypanosoma rangeli in the Oriental Plains of Colombia were conducted in the gallery forests near Carimagua and El Porvenir. One-hundred and seven palm trees belonging to nine genera were examined; triatomines were found in only three palm species, the leaves of which are locally used for roof thatching: 2/29 Maximiliana elegans, 1/7 Mauritia flexuosa and 7/7 Scheelea sp. Bugs were also found in 5/14 hollow Mauritia inhabited by bats, 4/21 bird nests and 1/4 armadillo burrows. Five species of triatomines were collected: Rhodnius prolixus was the most abundant, 192 of the total 207 (92%) collected; the bugs were found in Maximiliana and Mauritia but especially in Scheelea, and 8% were infected with T. cruzi and T. rangeli; Cavenicola pilosa and Triatoma maculata were found associated with bats; Psammolestes arthuri and Panstrongylus lignarius with bird nests and Panstrongylus geniculatus with armadillos. Although triatomine colonies were not found in human dwellings, flying adults of R. prolixus occasionally reached houses by their own locomotion and fed on man, but did not become established. Only 12 of 199 persons (6%) tested serologically were reactors to T. cruzi antigens and all 12 had lived in areas of domiciliary transmission elsewhere in the country, indicating that domiciliary transmission is not occurring in this region. Whether the presence of domiciliary R. prolixus in houses located in the ecologically altered piedmont of the oriental plains, a known area of domiciliary transmission of T. cruzi, is due to importation of domiciliary bugs from endemic areas or to the domiciliarization of wild R. prolixus remains to be determined.