¹Division of Cell Transplantation and Transfusion, Jichi Medical School, Minamikawachi, Japan

²Department of Hematology, Jichi Medical School, Minamikawachi, Japan

³Division of Hematology, Department of Internal Medicine, Japanese Red Cross First Hospital, Nagoya, Japan

Correspondence to: Dr K Muroi, Division of Cell Transplantation and Transfusion, Jichi Medical School, Minamikawachi, Tochigi 329-0498, Japan

A 22-year-old female with acute myeloid leukemia (AML) in complete remission received a conditioning regimen containing antithymocyte globulin for an unrelated bone marrow transplant (BMT). After BMT, the patient suffered from cytomegalovirus (CMV) pneumonitis with markedly high levels of CMV antigenemia, activated prothrombin time (APTT) prolongation, and subacute thyroiditis. Recovery of CD4⁺ cells was delayed as long as 1 year after BMT. An association between these three episodes and viral infection due to the delayed recovery of CD4⁺ cells is suggested. Bone Marrow Transplantation (2000) 26, 1347-1349.

bone marrow transplantation; antithymocyte globulin; viral infection; CD4⁺ cells

Viral infections are major causes of mortality and morbidity in patients who receive an allogeneic BMT. During the early and late post-transplant periods, herpes and other viruses cause localized and systemic disease. Of these viruses, CMV infection is the most common, and patients may present with pneumonitis, enteritis or myelosuppression.^1,2,3,4 CMV reactivation can be measured by detecting the CMV pp65 antigen (CMV antigenemia).^5,6

We describe a patient with AML who received an unrelated allogeneic BMT and developed CMV pneumonitis, APTT prolongation and subacute thyroiditis. CMV pneumonitis and subacute thyroiditis were successfully treated with ganciclovir and prednisolone, respectively.

Case report

A 22-year-old female with AML (FAB M6) in first complete remission underwent an allogeneic BMT. The patient was seropositive for CMV and Epstein-Barr (EB) viruses and had normal coagulation parameters. On 5 June 1997, she received an allogeneic BMT from an unrelated HLA-identical male donor (A2, A24, B7, B54, Cw1, Cw7, DR1 and DR4). Conditioning was with total body irradiation at 1200 cGy in six fractions from days -9 to -7; cytarabine, 1000 mg/m² twice a day from days -6 to -4; and cyclophosphamide, 60 mg/kg on days -3 and -2. In addition, 2.5 mg/kg of antithymocyte globulin (ATG) was administered from days -5 to -2. On day 0, 4.1 ´ 10⁸/kg of untreated nucleated bone marrow cells was infused. Graft-versus-host disease (GVHD) prophylaxis was short-term methotrexate and cyclosporine. CMV hyperimmuneglobulin was given at a dose of 12.5 g every 2 weeks to prevent CMV infection, between days +7 and +120. Granulocyte colony-stimulating factor was given from day +1.

Regimen-related toxicities were mild; the patient complained of slight nausea and diarrhea. Bone marrow engraftment was confirmed on day +15 using karyotypic and fluorescence in situ hybridization analyses. On day +54, the patient developed a dry cough and low-grade fever. Computed tomography of the chest showed pneumonitis in both lungs. At this time, markedly high levels of CMV antigenemia were noticed (Figure 1). CMV pneumonitis was diagnosed and 5 mg/kg of ganciclovir twice a day was initiated. Following the therapy, CMV antigenemia levels dropped and the interstitial infiltrates in both lungs resolved. No acute GVHD occurred. On day +118, she complained of chills, tremors, palpitation and pain in the anterior neck. Physical examination revealed tachycardia and a diffuse goiter. Thyroid hormone levels including free triiodothyronine (T3; normal range, 1.0-1.8 ng/dl) (Figure 1) and thyroxine (T4) were markedly increased, and thyroid-stimulating hormone (TSH) levels were suppressed to subnormal levels. Antithyroglobulin and anti-TSH receptor antibody were not detected. Ultrasound examination showed that the thyroid gland was increasing in volume with unclear contours and a nonhomogenous echostructure. No accumulation of ¹³¹I in the thyroid was observed. Taken together, a diagnosis of subacute thyroiditis was made. The donor was healthy and had no history of autoimmune disease such as Grave's disease. Treatment of the thyrotoxicosis with prednisolone resulted in normal serum levels of T3 and T4 (Figure 1). To identify the etiology of the subacute thyroiditis, serum virus-specific antibodies were measured. A positive result was obtained for parainfluenza virus type 3, EB and hepatitis B viruses, whereas results where negative for adenovirus, influenza virus types A and B, coxsackie virus types A9 and B1 to B5, measles and hepatitis C virus. Hepatitis A and hepatitis G virus antigens were not detected. Although the antibody titer of parainfluenza virus type 3 was measured again 2 weeks after the first measurement, the titer level was unchanged. On day +125, immune recovery was examined. Although serum IgG and IgA levels were normal, the percentage of CD4⁺ cells was low and the CD4/CD8 ratio was 0.25. At approximately the same time as the onset of the subacute thyroiditis, APTT prolongation was noted (Figure 1), whereas the prothrombin time was normal. The APTT did not completely correct after mixing with 20%, 50%, 80% and 90% normal pooled plasma. Although the kaolin clotting time was prolonged, anticardiolipin antibodies were not detected. Coagulant activities of factors V, VIII, IX, XI and XII were measured; factor XII coagulant activity was reduced to 47%, while the others were normal. Factor XII antigen level was 40%. The donor had no history of a bleeding tendency and coagulation tests such as the PT and APTT were normal. Following therapy with prednisolone, APTT normalised. On day +391, the peripheral blood CD4/CD8 ratio was still low (0.27). On day +1030, 31 March 2000, she was receiving no immunosuppressants and there was no evidence of chronic GVHD or recurrence of AML. Serum thyroid hormone levels and APTT were within the normal ranges.

Discussion

Viral infections are cause serious complications in unrelated BMT^7,8,9 recipients. Our patient suffered from CMV pneumonitis and subacute thyroiditis, which were successfully treated with ganciclovir and prednisolone, respectively. Subacute thyroiditis is a painful, inflammatory disease postulated to be associated with viral infections.^10,11 To study the possible viral etiology of the subacute thyroiditis in our patient, we measured serum virus-specific antibodies, but failed to demonstrate a significant viral contribution. Previously, Jones et al¹² reported subacute thyroiditis after bone marrow transplantation for chronic myeloid leukemia, but did not identify a viral component in the disease. Although retrovirus infections have been suspected of playing a role in the development of autoimmune thyroid disease,^13,14 it is not clear if the virus is the cause of subacute thyroiditis. An association between subacute thyroiditis and HLA-B35 or HLA-B67 in the Japanese has been shown.¹⁵ However, neither patient nor donor carried these HLA antigens.

After BMT, two types of coagulopathy have been reported:¹⁶ activation of the coagulation cascade due to factors such as sepsis or veno-occlusive disease (VOD), and diminished synthesis of coagulation factors due to such complications as liver damage. In our patient, no sepsis, VOD, acute GVHD, thrombotic microangiopathy or liver damage occurred. The mixing tests and coagulation factor assays suggested the presence of an inhibitor to factor XII, although the possibility of factor XII deficiency could not be ruled out. APTT prolongation and subacute thyroiditis occurred virtually simultaneously suggesting an association between a viral infection and APTT prolongation; recently, lupus anticoagulant associated with hypoprothrombinemia and factor XII deficiency following an adenovirus infection was reported.¹⁷

This patient experienced various infectious episodes, CMV pneumonitis with markedly high levels of CMV antigemia and subacute thyroiditis after her BMT. CD4⁺ cell recovery after BMT was incomplete, even after 1 year. This delayed recovery may have been due to the ATG used in conditioning. ATG is a potent immunosuppressant and has been used not only in the therapy of acute GVHD but also for prophylaxis of acute GVHD. Two reports have shown that the incidence of acute GVHD was low in patients who received ATG in their conditioning although CMV infections were common.^18,19 Therefore, when ATG is used in BMT conditioning, attention to patients should be carefully monitored for viral infections after BMT.

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16 Nurnberger W, Kruck H, Mauz-Korholz C et al. Humoral coagulation and early complications after allogeneic bone marrow transplantation. Klin Padiatr 1997; 209: 209-215, MEDLINE

17 Jaeger U, Kapiotis S, Pabinger I et al. Transient lupus anticoagulant associated with hypoprothrombinemia and factor XII deficiency following adenovirus infection. Ann Hematol 1993; 67: 95-99, MEDLINE

18 Kobayashi R, Kumon K, Watanabe N et al. Antithymocyte globulin as conditioning regimen for bone marrow transplantation. Rinsho Ketsueki 1997; 38: 1183-1188, MEDLINE

19 Yagasaki H, Kojima S, Inaba J et al. Clinical trial of antithymocyte globulin for prophylaxis of acute graft-versus-host disease in pediatric recipients of bone marrow transplantation from unrelated donors. Rinsho Ketsueki 1999; 40: 382-389, MEDLINE

Figure 1 Clinical course.