Subcutaneous administration, higher age and lower renal function are associated with erythrocyte methotrexate accumulation in Crohn's disease: a cross-sectional study

Background

Methotrexate is an immunomodulatory drug for patients with Crohn’s disease. Erythrocyte MTX-polyglutamates (MTX-PG_1-5) may be used for therapeutic drug monitoring (TDM) as MTX-PG is thought to mediate MTX’s efficacy. Information on determinants of the concentration of MTX-PG in patients with Crohn’s disease is lacking. We aim to identify clinical and biochemical determinants of the erythrocyte MTX-PG_1-5 and MTX-PG_total concentration in patients with Crohn’s disease.

Methods

Adults with Crohn’s disease on methotrexate treatment who visited the outpatient clinic of Amsterdam UMC were included. Erythrocyte MTX-PGs were measured by tandem mass spectrometry.

Results

Nineteen patients were included, with a median duration of MTX use of 77 months (range 7–202). Twelve patients received MTX monotherapy, whereas 7 patients were on concomitant TNF-α inhibitors. The mean dose of MTX was 15.5 mg (SD ± 2.8) and 12 (63%) patients used subcutaneous MTX. MTX-PG_1-5 were successfully measured in 18 patients, showing substantial variability in concentrations of MTX-PG_total and individual species. The median MTX-PG_total was 117.1 nmol/L (range 46.4–258.7) with preferential accumulation of MTX-PG₃ (43.1 nmol/L, range 15.3–96.1). Patients on subcutaneous compared to oral MTX had higher median MTX-PG_(4,5) levels (55 versus 9 nmol/L, p = 0.01). Higher age (β = 0.71) and lower estimated glomerular filtration rate (β = − 0.52) were associated with a significantly higher MTX-PG_total concentration (R² = 0.60, p = 0.001).

Conclusion

MTX-PG concentrations display a considerable inter-individual variability. Higher MTX-PG accumulation is associated with subcutaneous administration, higher age, and lower renal function in Crohn’s disease patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02439-y.

Favourable Tolerability and Drug Survival of Tioguanine Versus Methotrexate After Failure of Conventional Thiopurines in Crohn's Disease

BACKGROUND AND AIMS

Both methotrexate and tioguanine can be considered as treatment options in patients with Crohn's disease after failure of conventional thiopurines. This study aimed to compare tolerability and drug survival of methotrexate and tioguanine therapy after failure of conventional thiopurines in patients with Crohn's disease.

METHODS

We conducted a retrospective, multicentre study, including patients with Crohn's disease initiating monotherapy methotrexate or tioguanine after failure [all causes] of conventional thiopurines. Follow-up duration was 104 weeks or until treatment discontinuation. The primary outcome was cumulative therapy discontinuation incidence due to adverse events. Secondary outcomes included total number of [serious] adverse events, and ongoing monotherapy.

RESULTS

In total, 219 patients starting either methotrexate [n = 105] or tioguanine [n = 114] were included. In all 65 [29.7%] patients (methotrexate 43.8% [46/105 people], tioguanine 16.7% [19/114 people], p <0.001) discontinued their treatment due to adverse events during follow-up. Median time until discontinuation due to adverse events was 16 weeks (interquartile range [IQR] 7-38, p = 0.812). Serious adverse events were not significantly different. Patients treated with methotrexate experienced adverse events more often [methotrexate 83%, tioguanine 46%, p <0.001]. Total monotherapy drug survival after 104 weeks was 22% for methotrexate and 46% for tioguanine [p <0.001].

CONCLUSIONS

We observed a higher cumulative discontinuation incidence due to adverse events for methotrexate [44%] compared with tioguanine [17%] in Crohn's disease patients after failure of conventional thiopurines. The total adverse events incidence during methotrexate use was higher, whereas serious adverse events incidence was similar. These favourable results for tioguanine treatment may guide the selection of immunosuppressive therapy after failure of conventional thiopurines.

Increased Risk of High-grade Cervical Neoplasia in Women with Inflammatory Bowel Disease: A Case-controlled Cohort Study

BACKGROUND AND AIMS

Women with inflammatory bowel disease [IBD] may be at higher risk for cervical intraepithelial neoplasia [CIN]. However, data are conflicting. The aim of this study was to assess the risk of high-grade dysplasia and cancer [CIN2+] in IBD women and identify risk factors.

METHODS

Clinical data from adult IBD women in a multicentre Dutch IBD prospective cohort [PSI] from 2007 onwards were linked to cervical cytology and histology records from the Dutch nationwide cytology and pathology database [PALGA], from 2000 to 2016. Patients were frequency-matched 1:4 to a general population cohort. Standardised detection rates [SDR] were calculated for CIN2+. Longitudinal data were assessed to calculate CIN2+ risk during follow-up using incidence rate ratios [IRR] and risk factors were identified in multivariable analysis.

RESULTS

Cervical records were available from 2098 IBD women [77%] and 8379 in the matched cohort; median follow-up was 13 years. CIN2+ detection rate was higher in the IBD cohort than in the matched cohort (SDR 1.27, 95% confidence interval [CI] 1.05-1.52). Women with IBD had an increased risk of CIN2+ [IRR 1.66, 95% CI 1.21-2.25] and persistent or recurrent CIN during follow-up (odds ratio [OR] 1.89, 95% CI 1.06-3.38). Risk factors for CIN2+ in IBD women were smoking and disease location (ileocolonic [L3] or upper gastrointestinal [GI] [L4]). CIN2+ risk was not associated with exposure to immunosuppressants.

CONCLUSIONS

Women with IBD are at increased risk for CIN2+ lesions. These results underline the importance of human papillomavirus [HPV] vaccination and adherence to cervical cancer screening guidelines in IBD women, regardless of exposure to immunosuppressants.

Mast cell leukaemia presenting with multiple osteoporotic fractures in an elderly woman

Osteoporotic fractures in elderly women are mainly due to postmenopausal bone loss but can sometimes be caused by a disabling haematological disease. We describe an 84-year-old woman suffering from multiple osteoporotic fractures as a manifestation of mast cell leukaemia. Mast cell leukaemia is a rare form of systemic mastocytosis with a poor prognosis and very few therapeutic options. Osteoporotic fractures have seldom been reported as its initial manifestation.

Bacterial population analysis of human colon and terminal ileum biopsies with 16S rRNA-based fluorescent probes: commensal bacteria live in suspension and have no direct contact with epithelial cells

BACKGROUND

The commensal intestinal microflora has important metabolic and perhaps also immune modulatory functions. Evidence has accumulated that the microflora plays a role in the pathogenesis of inflammatory bowel disease. Therefore, there is a growing interest in the intestinal microflora and its interaction with the host. Presumably, this interaction takes place at the mucus layer. In this study, we investigated the microflora that is present at the mucus layer and addressed the following questions. Does a specific mucus-adherent microflora exist? Is there direct contact between commensal bacteria and epithelial cells?

METHODS

Snap-frozen biopsies were taken of 5 colon regions and of the terminal ileum in 9 subjects with a normal colon. Fecal samples were also collected. Bacteria were detected in cryosections with fluorescent in situ hybridization (FISH) with 16S ribosomal (r)RNA-targeted probes for all bacteria and specific probes for the major representatives of anaerobic microflora (bifidobacteria, Bacteroides, clostridia, atopobia) and aerobic microflora (Enterobacteriaceae, enterococci, streptococci, lactobacilli).

RESULTS

With this sensitive technique, bacteria were only observed at the luminal side of the intestinal mucus layer. Very few microcolonies were present at the mucus layer, and the composition of the bacterial microflora present in the feces was similar to that at the mucus layer of the terminal ileum and colon regions.

CONCLUSIONS

We did not observe direct contact between bacteria and epithelial cells. The equal distribution of bacterial species suggests that intestinal commensal bacteria live in suspension in the lumen and that there is no specific mucus-adherent microflora.

Detection of immune deposits in skin lesions of patients with Wegener's granulomatosis

BACKGROUND

Wegener's granulomatosis (WG) is considered a pauci-immune systemic vasculitis based on the absence of immune deposits in renal biopsies of patients with active disease. In animal models of antineutrophil cytoplasmic antibody (ANCA) associated glomerulonephritis, immune deposits along the glomerular capillary wall are present at early stages of lesion development. These deposits are degraded rapidly, resulting in "pauci-immune" lesions.

OBJECTIVE

To test the hypothesis that immune deposits can also be detected in early lesions of patients with WG, thereby initiating an inflammatory reaction that, in time, is augmented in the presence of ANCA, resulting in pauci-immune lesions later on.

METHODS

The presence of immune deposits in skin biopsies taken within 48 hours of lesion development was investigated. Direct immunofluorescence was used to examine 32 skin biopsies for the presence of immune deposits (IgG, IgA, IgM, C3c). When possible, a comparison was made between the immunofluorescence findings in renal and skin biopsies taken at the same time.

RESULTS

Four of 11 biopsies taken at initial presentation and four of 21 biopsies taken at the onset of a relapse of WG showed IgG and/or IgA containing immune deposits in the subepidermal blood vessels. All nine renal biopsies showed pauci-immune glomerulonephritis, irrespective of the presence (n=5) or absence (n=4) of immune deposits in the skin biopsy.

CONCLUSION

A substantial number of skin biopsies showed immune deposits during active disease. These results could support the hypothesis that immune complexes may trigger vasculitic lesions in WG.

CD27 expression in the human splenic marginal zone: the infant marginal zone is populated by naive B cells

The splenic marginal zone of adult humans contains B cells, of which most express CD27, an antigen only recently identified as a marker for somatically mutated memory B cells. We investigated whether and to which extent the developing marginal zone in infants and children is populated by either memory (CD27+) or naive (CD27-) B cells. Frozen sections of 32 spleens of infants and children ranging in age from 6 days to 15 years and 6 adult spleens were investigated. The expression of CD27 in combination with monoclonal antibodies against CD3, CD21, IgM, IgD and ASM-1 was analyzed by immunohistochemistry. The marginal zone was already present at 4 months after birth but CD21 expression was observed first after 2 years. CD27-positive marginal zone B cells were observed firstly 2 years after birth and increased in number to adult levels at the age of 5 years. We demonstrated that the MZ of infants and young children is populated by naive B cells, which are replaced by memory B cells in a time frame of 2 to 5 years. Before the age of 2 years, although present, memory B cells appear to be unable to colonize the marginal zone. Because of the absence of memory B cells in the marginal zone, the immune system of a child is not capable to initiate a rapid secondary humoral immune response comparable to the adult immune response.

The origin of marginal zone B cells in the rat

The marginal zone is a unique compartment that is only found in the spleen. Rat marginal zone B cells (MZ-B) can be distinguished from other B cells, e.g. recirculating follicular B cells (RF-B), by several phenotypic characteristics. Typically MZ-B cells are surface (s)IgMhi, sIgDlo and CD45R(B220)lo, whereas RF-B cells are sIgMlo, sIgDhi and CD45Rhi. In addition, MZ-B cells stain strongly with HIS57, a newly developed monoclonal antibody. The developmental pathway and origin of MZ-B cells are not exactly known. However, previous studies indicate that recirculating (i. e. thoracic duct) B cells can give rise to MZ-B cells. Here the origin of (naive) MZ-B cells was studied using adriamycin (doxorubicin)-induced B cell depletion. Using three-color flow cytometry and immunohistology we show that 2 days after a single i.v. injection of the anti-tumor drug adriamycin only RF-B cells can be detected, while all other B cell subpopulations are depleted, including all bone marrow precursor B cells. By studying the sequential reappearance of various B cell subsets and their precursors after adriamycin administration we show that MZ-B cells and the splenic marginal zone can be detected at a time point at which newly generated B cells (immature B cells) are not yet present. Given the observation that only RF-B cells were present at this time, we conclude that RF-B cells are the immediate MZ-B precursor cells.

Identification and kinetics of two recently bone marrow-derived B cell populations in peripheral lymphoid tissues

In rats, the glycoprotein Thy-1 is expressed on recently bone marrow (BM)-generated B cells but not on mature recirculating follicular (RF) B cells. Here we demonstrate that Thy-1+ B cells consist of two phenotypically distinct, but developmentally related, populations: a population of newly formed (NF) B cells (IgMbr-IgDdu) that give rise to the second, less immature, Thy-1+ population of so-called early recirculating follicular (ERF) B cells (Thy-1+IgMduIgDbr) cells. These cells ultimately develop to RF-B cells (Thy-1-IgMbrIgDdu). Kinetic studies reveal that in absolute numbers per day most cells die at the transition of NF-B cells in the BM and those in the periphery: less cells die at later stages of B cell differentiation. Given the notion that this cell loss is not random, we speculate that NF-B cells and ERF-B cells may represent crucial steps during peripheral B cell development and their selection. Identification of their unique phenotype makes it possible to evaluate their roles in development of the antibody repertoire.

MRC OX19 recognizes the rat CD5 surface glycoprotein, but does not provide evidence for a population of CD5bright B cells

To clone the rat CD5 gene we first produced two rat CD5 probes. The probes were obtained by polymerase chain reaction (PCR) on rat genomic DNA using primers designed on conserved regions between mouse and human CD5. The screening of a rat cDNA library at high stringency using these probes resulted in a 1.5-kb positive clone. The DNA sequence of this clone confirmed its CD5 nature, but the clone appeared to lack part of the 5' and part of the 3' end. These missing 5' and 3' ends were obtained by PCR on rat thymus RNA. By ligating these PCR products to the original 1.5-kb CDM8 clone, a full-length rat CD5 gene was constructed. The full-length clone showed high identity with mouse and human CD5; however, at the 5' site of the gene a region of 36 nucleotides is present which is not seen in either mouse or human CD5. We have evidence that this sequence is a normal constituent of the rat CD5 gene: first, it is in frame with the rest of the CD5 coding sequence; second, it does not contain a stop codon; and third, it is also present in the CD5 gene of other rat strains. We transfected the full-length CD5 construct in COS cells and demonstrated that indeed the CD5 protein is recognized by MRC OX19. Although we showed that CD5 mRNA is present in rat B cells, extensive flow cytometry analysis using MRC OX19 as antibody failed to detect B cells expressing significant levels of CD5 on their cell surface compared to other B cells in any tissue or cell suspension tested from a variety of rat strains. This is in contrast with the mouse where a distinct population of B cells (B-1a cells) can be found expressing more CD5 than the other B cells. Either B-1 cells are not present in rats or CD5 is not the right phenotypic marker for rat B-1 cells. It still remains to be investigated whether a population of B cells with functions similar to those of murine B-1 cells is present in rats.

B cells specific for bromelain-treated erythrocytes are not derived from adult rat bone marrow

As part of an evolutionary layered hematopoietic system, the B lymphocyte compartment consists of different lineages of B lymphocytes, which evolve sequentially during ontogeny. In mice, there is ample evidence for the existence of at least two lineages, a layer of B-1 cells (Ly-1 B cells) and the evolutionary more advanced layer consisting of conventional B cells. In a previous study we were unable to detect B-1 cells in the rat as determined by phenotypic markers. Here we studied the possible existence of putative B-1 cells in the rat based on some functional and developmental characteristics as have been described for mouse B-1 cells. We show that B cells secreting antibodies that recognize bromelain-treated mouse red blood cells (BrMRBC) can be identified in rat spleen, whereas these cells (in contrast to DNP-specific B cells) are virtually absent in lethally X-irradiated and bone marrow (BM) reconstituted animals. The number of anti-rMRBC-secreting B cells could not be restored to control levels by reconstitution with fetal liver cells or by cotransfer of 10(7) cells from peritoneal cavity, lymph node or Peyer's patches or up to 2 x 10(8) splenocytes. Although our findings thus suggest that B-1 cells (or B-1 like cells) may be present in rats, formal proof for the existence of such a lineage in rats awaits definition of these cells at the progenitor level.