A functional comparison of CD34 + CD38- cells in cord blood and bone marrow

We present cell cycling and functional evidence that the CD34+CD38- immunophenotype can be used to define a rare and primitive subpopulation of progenitor cells in umbilical cord blood. CD34+CD38- cells comprise 0.05% +/- 0.08% of the mononuclear cells present in cord blood. Cell cycle analysis with the fluorescent DNA stain 7- aminoactinomycin D showed that the percentage of CD34+ cells in cycle directly correlated with increasing CD38 expression. CD34+CD38- cord blood cells were enriched for long-term culture-initiating cells (LTCIC; cells able to generate colony-forming unit-cells [CFU-C] after 35 to 60 days of coculture with bone marrow stroma) relative to CD34+CD38- cells. In an extended LTCIC assay, CD34+CD38- cells were able to generate CFU-C between days 60 and 100, clearly distinguishing them from CD34+CD38+ cells that did not generate CFU-C beyond day 40. When plated as single cells, onset of clonal proliferation was markedly delayed in a subpopulation of CD34+CD38- cells; clones (defined as > 100 cells) appeared after 60 days of culture in 2.9% of CD34+CD38- cells. In contrast, 100% of CD34+CD38+ cells formed clones by day 21. Although the CD34+CD38- immunophenotype defines highly primitive populations in both bone marrow and cord blood, important functional differences exist between the two sources. CD34+CD38- cord blood cells have a higher cloning efficiency, proliferate more rapidly in response to cytokine stimulation, and generate approximately sevenfold more progeny than do their counterparts in bone marrow.     

High-resolution peripheral quantitative computed tomography for the evaluation of bone erosions of metatarsophalangeal joints in patients with rheumatoid arthritis

Objectives

To compare if the 4th and 5th metatarsophalangeal (MTP) joints evaluated by high-resolution peripheral quantitative computed tomography (HR-pQCT) could classify more patients with erosive rheumatoid arthritis (RA) compared with conventional radiography (CR) of the hands, wrists, and feet. Furthermore, we characterize and quantify bone erosions in the two MTP joints by HR-pQCT.

Methods

This single-center cross-sectional study included patients with established RA (disease duration ≥5 years). Blinded to patient data, the number and volume of erosions in the 4th and 5th MTP joints were measured by HR-pQCT, whereas the erosive scores by CR of 44 joints in the hands, wrists, and feet were assessed according to the Sharp/van der Heijde method.

Results

Among 42 participants, 30 patients were classified with erosive RA and 12 with non-erosive RA by CR. HR-pQCT of two MTP joints could classify more patients with erosive RA compared with CR of 44 joints (p = .03). The optimal cut-off value for the number and volume of erosions per patient in the 4th and 5th MTP joints by HR-pQCT was 7.5 erosions and 11.7 mm³, respectively, for detecting erosive disease by CR. Erosions in the two MTP joints by HR-pQCT were found most frequently and were largest at the lateral quadrant of the 5th metatarsal head.

Conclusion

The superiority of HR-pQCT of the 4th and 5th MTP joints compared with CR of 44 joints for classifying erosive RA provides a basis for larger studies evaluating if HR-pQCT could be used for diagnosing erosive RA in the future.