Molluscum contagiosum infection after reduced-intensity cord blood transplantation

Cord blood transplantation is an attractive alternative for patients with hematologic malignancies who do not have a matched related or unrelated donor. The feasibility of cord blood transplantation using reduced-intensity regimens (reduced-intensity unrelated cord blood transplantation (RICBT)) for adult patients with hematologic diseases has been reported.1, 2 Owing to delayed immune recovery, infection is the most significant problem in RICBT as well as conventional cord blood transplantation.3, 4

Molluscum contagiosum (MC) is an infectious skin disease caused by the Molluscipoxvirus genus, which is a member of poxvirus family.5 In children, infection spreads by direct contact or sharing of fomites, with lesions predominantly on the trunk, extremities and face. In young adults, infections are transmitted through sexual intercourse. Whereas atypical clinical presentations of MC have been reported in immunocompromised patients and those with atopic dermatitis,6, 7 no reports have been published on MC following RICBT, to our knowledge.

A 49-year-old man with chemorefractory diffuse large B-cell lymphoma underwent RICBT in January 2004. He had no history of MC, and pretransplant examination of the skin failed to show any abnormal findings. The preparative regimen comprised fludarabine 25 mg/m2 for 5 days, single-dose melphalan 80 mg/m2 and fractionated total body irradiation 4 Gy. Graft-versus-host disease (GVHD) prophylaxis was tacrolimus 0.04 mg/kg continuous infusion starting on day −1. Pre-freezing, cord blood contained 2.2 × 107/kg of nucleated cells. He achieved neutrophil engraftment on day 23, and platelet counts reached 20 × 109/l on day 39. Chimerism analysis using peripheral blood CD3-positive cells on day 25 showed complete donor-type hematopoiesis.8 His clinical course had been uneventful until day 450, when he noticed some erythematous, smooth-surfaced, umbilicated papules on the neck. The papules were painless, and their sizes ranged from 0.1 to 0.5 cm. These lesions disseminated to his face, upper limbs and trunk within a week. Excisional biopsy of the skin showed round-oval eosinophilic intracytoplasmic inclusions, which were characteristic of molluscum bodies. When MC was diagnosed, neither antibiotics nor immunosuppressive agent was being given. The number of neutrophils and CD4-positive cells was 4.2 × 109/l and 1.0 × 109/l, respectively. CD4/CD8 ratio was 1.1. Owing to rapid progression of MC, he underwent curettage of the lesions. As of December 2005, there is no evidence of recurrent lesions.

This observation suggests that immunosuppression after RICBT may persist and MC can be a clinical problem. It rapidly spread from the neck to trunk in this patient. The lesions, which were probably due to immune suppression, improved with local curettage. Similar clinical courses have been reported in immunocompromised patients with solid organ transplantation, and recurrences were rare after treatment. Although MC often localizes in the skin and can be a cosmetic problem, some sequelae are possible if it involves the conjunctivae. Curettage can prevent its progression as in the present report. Our observation suggests that MC is a possible complication after RICBT and that early diagnosis and early treatment can prevent progression.

Our patient did not have GVHD, and was not taking steroid or other immunosuppressants at the onset of MC. CD4-positive cell counts and immunoglobulin levels were normal. Notably, markers of immune function had returned to normal when the MC developed. This observation suggests that immunosuppression persists after RICBT and that the conventional markers may be insufficient in the evaluation of immune recovery. Another possibility is that subclinical chronic GVHD may have caused local immune deficiency, which persisted after recovery of systemic immune function. As there is no vital marker indicating local immune function, it is difficult to predict the development of opportunistic infections of the skin. New indicators to monitor immune recovery after RICBT are required. Further studies on infection prevention after RICBT are awaited.


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Correspondence to E Kusumi.

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Kusumi, E., Yuji, K., Kishi, A. et al. Molluscum contagiosum infection after reduced-intensity cord blood transplantation. Bone Marrow Transplant 38, 313–314 (2006).

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