Therapeutic Plasma Exchange: Dermatologic Applications

Lepromatous vasculitis successfully treated by plasma exchange (PE)

Vascular involvement is presently considered a "common pathway" in a number of diseases that is mediated by circulating immune complexes (CIC). CIC are found in the circulation when the disease is active and in single patients their level may parallel disease activity. Lepromatous leprosis is characterized by the presence of CIC and deposits of immunoglobulins and complement in vascular lesions of the different organs and an Arthus-like mechanism is considered as the basis for the clinical picture. The same mechanism is considered to play an essential pathophysiologic role in Lucio's phenomenon, which is characterized by lymphohistiocytic vascular infiltrates with or without thrombosis and secondary cutaneous infarction. Lepromatous vascular involvement is mediated by CIC whose antigen composition is known, the same as it is with HCV mediated cryoglobulinemia, HBV positive panarteritis nodosa, rheumatoid vasculitis, or Wagner's granulomatosis, which are usually treated by PE [1-3]. PE has been employed for lepromatous vasculitis since 1979 [4] and other cases have been successfully treated afterwards [5,6]. We report on another patient successfully treated by plasma exchange.

Indications for therapeutic plasma exchange at a university hospital and a regional blood center

The AABB guidelines for therapeutic plasma exchange (TPE) are divided into four categories: I. TPE is "standard and acceptable therapy," II. "generally accepted," III. "insufficient evidence to evaluate efficacy," and IV. "data suggest no therapeutic efficacy." Since little is known about the implementation of these guidelines, and since the indications for TPE may vary, depending upon an institution's patient mix, this study reviewed the indications and their categories for two co-located institutions. A retrospective review of the indications for all patients undergoing TPE from January 1, 1994 to December 31,1997 at Emory University Hospital (EUH), a tertiary-care teaching hospital, and the American Red Cross (ARC), a regional blood center, using AABB criteria (ASFA criteria used when not rated [NR] by AABB) was conducted. Categories I/II represented 75% and 88% of cases (EUH and ARC, respectively), while Categories III/IV/NR (NR as used below is "not rated" by both AABB and ASFA criteria; n is number of patients) were 25% and 12% of indications, respectively (P =0.002). Cases at EUH (n=101) were I, 62%; II, 13%; III, 3%; IV, 13%; and NR, 9%. Cases at ARC (n=359) were I, 77%; II, 11%; III, 9%; IV, 0%; and NR, 3% (P<0.001). No Category IV patients underwent TPE at ARC (13% at EUH). Thrombotic thrombocytopenic purpura (TTP) was the most common indication for TPE at both centers. The majority of the procedures were "appropriate" (Categories III/); several disorders ( approximately 10%) for which TPE was utilized at both centers were NR by both AABB and ASFA guidelines. Indications for TPE may differ, depending on the type of requesting institution. Physicians requesting TPE for patients with disorders in Categories III/IV/NR should be more strongly encouraged to enter their patients into controlled trials to best evaluate the efficacy of TPE in inadequately-studied clinical situations. This might best be accomplished at university hospitals, where requests for Category III/IV/NR may be higher. A need exists for periodic updating of the AABB guidelines to include those diseases for which new information is available with regard to the potential therapeutic role of TPE.

Plasmapheresis as an adjunct treatment in toxic epidermal necrolysis

BACKGROUND

Toxic epidermal necrolysis (TEN) is a severe, progressive disease characterized by the sudden onset of skin necrosis. It is frequently associated with systemic involvement and has a high rate of morbidity and mortality. Standard therapy includes meticulous wound care, fluid replacement, and nutritional support in an intensive care setting.

OBJECTIVE

We evaluated the outcomes of patients treated in a burn unit for TEN over a 9-year period and compared the outcomes of a subset of patients treated with plasmapheresis with those managed by conventional means.

METHODS

The records of 16 patients with a diagnosis of TEN obtained from a computerized database were reviewed. Parameters recorded included extent of body surface area involvement and number of mucous membranes involved at admission, complications such as sepsis or need for mechanical ventilation, length of stay, and disposition.

RESULTS

Sixteen patients were included in this study. Ten were treated with conventional support measures alone. Six were treated with plasmapheresis. The average age was 42.4 years; the male/female ratio was 1:2.2. Sulfamethoxazole/trimethoprim was implicated in causation in 6 patients. The average extent of involvement on admission in all patients was 51.5% total body surface area. The average length of stay in all patients was 14.8 days. Eight patients (50%) were discharged home, 4 (25%) were discharged to a rehabilitation facility, and 4 (25%) died (2 of sepsis, 2 of cardiopulmonary arrest). None of the plasmapheresis-treated patients died.

CONCLUSION

Plasmapheresis is a safe intervention in extremely ill TEN patients and may reduce the mortality in this severe disease. Prospective studies are needed to further define its usefulness.

Apheresis in the treatment of chronic relapsing polyneuropathy

As a distinct inflammatory demyelinating disease, chronic relapsing polyneuropathy can be extremely debilitating and cause respiratory failure leading to death. The cause of the disorder is unknown, although evidence suggests that immune dysfunction plays some role in its pathogenesis. Conventional treatment using steroids and immunosuppressants has been reported both as effective and ineffective in controlling the course of the disease. The rationale for apheresis, as a nonspecific therapy, is related to the removal and/or dilution of circulating cytotoxic factors, and some patients have achieved dramatic and sometimes prolonged remissions from such treatments. Existing evidence from a large and growing number of case reports suggests that apheresis is a reasonable treatment for patients with severe or life-threatening symptoms which fail to respond to conventional therapy. However, convincing data of its efficacy is lacking and must await the results of appropriate randomized clinical trials.