Correlation between bone marrow involvement and peripheral blood morphology with prognostic factors in adult T cell leukemia/lymphoma (ATL). / Aspectos morfológicos e imunoistoquímicos da medula óssea e sangue periférico: correlação com sub-tipo clínico e fatores prognósticos na leucemia/linfoma de células T do adulto.

Maria das Graças Silva Vieira

Adult T-cell leukemia/lymphoma is a lymphoproliferative aggressive disease associated with HTLV-I infection. It was the first human malignant neoplasia to be accepted as caused by a retrovirus and it occurs in regions where HTLV-I infection is endemic like Japan, the Caribbean Islands, Africa and Brazil. ATL presents a wide spectrum of clinicalpathological forms and is classified in subtypes according to clinical and laboratorial criteria. In spite of the high frequency of cases which present with lymphocytosis, bone marrow (BM) infiltration is variable occurring in up to 50% of the cases, most frequently in the acute form. Few studies have described the involvement and pattern of infiltration of the BM in ATL and its relevance and correlation with prognostic factors. In this study histological and immunophenotypic characteristics of the BM and peripheral blood alterations were studied and compared with the clinical form and prognostic factors for ATL, such as survival and lactate dehydrogenase and calcium levels in the serum. Twenty nine cases with the diagnosis of ATL were studied and 15 (51.7%) showed BM infiltration in the BM biopsy: 4 of interstitial pattern, 4 focal or nodular and 5 diffuse. Even in the leukemic cases, the interstitial pattern with slight infiltration and absence of infiltration were frequent. In two cases neoplastic infiltration in the BM was demonstrated exclusively in the aspirate. The phenotypic profile of the neoplastic cells was similar in the tumoral tissue and in the BM infiltration. In 3 cases an infrequent phenotype was observed: 2 cases were CD4-,CD8+ and one was CD4+, CD8+. There was a varied expression of CD25 among the clinical forms, positivity being more frequent in the acute and lymphoma subtypes. Peripheral blood analysis showed that the cases with predominance of the classical ATL morphology in the atypical lymphocytes had a shorter survival and higher LDH serum levels whereas the patients with lymphocyte morphology similar to lymphocytic leukemia (LLC) showed longer survival. The findings of the present study suggest that the proliferation of neoplastic cells may be occurring in other organs instead of the BM and that BM status in ATL may not reflect disease progression and be less relevant than in other leukemias/lymphomas. The expression of CD25 and other surface markers may be useful as prognostic factors and to suggest therapy. Monitoring of neoplastic cell morphology in the peripheral blood may predict the advent of crisis in the indolent, chronic and lymphoma clinical forms.

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