Rituximab Treatment of Refractory Rheumatoid Arthritis

Natural Plant Extracts and Compounds for Rheumatoid Arthritis Therapy

Natural plant extracts and compounds (NPECs), which originate from herbs or plants, have been used in the clinical treatment of rheumatoid arthritis (RA) for many years. Over the years, many scientists have carried out a series of studies on the treatment of RA by NPEC. They found a high quantity of active NPECs with broad application prospects. In view of various complex functions of these NPECs, exploring their potential as medicines for RA treatment will be beneficial for RA patients. Thus, to help advance the development of high-quality NPECs for RA, we herein aimed to review the research progress of NPECs in the treatment of RA in recent years. Our findings showed that, from the pharmacological perspective, natural plant extracts or mixed herbal compounds effectively regulate the immune system to alleviate RA by inhibiting pro-inflammatory cytokines. Further, individualized medication can be applied according to each patient's physical condition. However, the pathogenesis of RA and its immune mechanism has not been fully understood and requires further studies.

Late-onset neutropenia after rituximab treatment: case series and comprehensive review of the literature

Rituximab is a chimeric monoclonal antibody against CD20 that is used mainly for the treatment of CD20-positive lymphoma. Recently, its use has been expanded to include treatment of other nonmalignant diseases such as rheumatologic diseases and autoimmune cytopenia. Correlating with the increased use of rituximab has been an increased number of reports of its late adverse effects. One of these is late-onset neutropenia (LON). Most investigators define LON as grade III-IV neutropenia occurring 3-4 weeks after the last treatment with rituximab, in the absence of an alternative explanation for the neutropenia.We report 6 cases of LON identified in our institution. Four patients were treated for diffuse large B-cell lymphoma, and 2 patients for follicular lymphoma. Median patient age was 68 years (range, 33-83 yr); LON appeared after a median interval of 77 days (range, 42-153 d) and lasted for a median of 5 days (range, 1-45 d). Five of the 6 patients presented with infectious complications, and 4 patients experienced recurrent episodes of neutropenia. One patient presented with LON and concomitant subacute pulmonary disease that was attributed to rituximab therapy.In addition to our own case series we present a systematic review of the literature, which we performed to compile data to describe better the syndrome of LON. Systematic studies, case series, and case reports were extracted. Most studies dealing with LON are retrospective by design and are limited by the heterogeneous populations included in the analysis. The incidence of LON is generally reported to be in the range of 3%-27%. Data regarding populations at risk are not consistent, and in some instances are conflicting.Patients considered at increased risk of LON include patients after autologous stem cell transplantation, patients treated for acquired immunodeficiency syndrome (AIDS)-related lymphoma, and patients treated with purine analogues. Patients who received previous cytotoxic treatment as well as those treated with more intensive chemotherapy or with chemotherapy in combination with radiotherapy are also considered to be at risk of LON. In addition, advanced stages of disease and having received multiple doses of rituximab are risk factors for LON.The mechanism of LON is poorly understood. Direct toxicity is very unlikely. Some speculate that there may be an infectious etiology involved, as well as an antibody-mediated process, but these ideas have not been substantiated. The concept of a lymphocyte subpopulation imbalance leading to LON has been presented based on the demonstration of T-LGL in peripheral blood and bone marrow of patients with LON. Perturbations in stromal-derived factor-1 and in the BAFF cytokine have also been discussed as potential players in the pathogenesis of LON. A recent study correlated specific polymorphism in the immunoglobulin G Fc receptor FCγRIIIa 158 V/F with increased rates of LON.The clinical significance of LON is important because it may affect treatment strategies. Of note, infectious complications are not very frequent and not very severe. Pooling data from the major retrospective studies reveals an infection rate of 16.9%. Most infections were mild and resolved promptly. One death occurred from infection during neutropenia. Repeated episodes of LON are not uncommon, but it is so far impossible to identify those patients at risk of these relapsing episodes of LON. Re-treatment with rituximab after LON may result in recurrent episodes, but the implications and risks are uncertain at the present time. The role of growth factors once LON appears is ill defined, and the decision to use them should be made on a case-by-case basis.

Treatment of early rheumatoid arthritis in developing countries. Biologics or disease-modifying anti-rheumatic drugs?

Biologics are highly effective in the treatment of rheumatoid arthritis (RA), but they are very expensive. The costs of biologics should limit their usage in patients with RA, especially in the developing countries. Therefore, it is necessary to develop suitable strategies for treating RA patients in these countries. In this article, the efficacy, toxicity, and cost-effectiveness of conventional DMARDs and biologics will be investigated. The therapeutic strategies for treating early RA will also be proposed.

The biological activity of human CD20 monoclonal antibodies is linked to unique epitopes on CD20

We have previously defined a panel of fully human CD20 mAb. Most of these were unexpectedly efficient in their ability to recruit C1q to the surface of CD20-positive cells and mediate tumor lysis via activation of the classical pathway of complement. This complement-dependent cytotoxicity (CDC) potency appeared to relate to the unusually slow off-rate of these human Abs. However, we now present epitope-mapping data, which indicates that all human mAb bind a novel region of CD20 that may influence CDC potency. Epitope mapping, using both mutagenesis studies and overlapping 15-mer peptides of the extracellular loops of CD20, defined the amino acids required for binding by an extensive panel of mouse and human mAb. Binding by rituximab and mouse CD20 mAb, had an absolute requirement for alanine and proline at positions 170 and 172, respectively, within the large extracellular loop of CD20. Surprisingly, however, all of the human CD20 mAb recognize a completely novel epitope located N-terminally of this motif, also including the small extracellular loop of CD20. Thus, although off-rate may influence biological activity of mAb, another critical factor for determining CDC potency by CD20 mAb appears to be the region of the target molecule they recognize. We conclude that recognition of the novel epitope cooperates with slow off-rate in determining the activity of CD20 Ab in activation of complement and induction of tumor cell lysis.