Chronic Lymphocytic Leukaemia Unmasked by COVID-19 Infection: A Case Report

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Corona Virus Disease 2019 (COVID-19) caused by SARS Cov-2 is an Ribonucleic Acid (RNA) virus which spreads through respiratory route. It was first detected in Wuhan, China in December 2019. World Health Organisation (WHO) declared it as worldwide pandemic in March 2020. Clinically, it can present from mild flu like disease to severe respiratory illness. Reverse Transcription Polymerase Chain Reaction (RT-PCR) is the method for confirmation. Chronic lymphocytic leukaemia is a lymphoproliferative disorder that presents as absolute lymphocytosis with proliferation of monoclonal mature B lymphocytes, unlike other causes of reactive lymphocytosis. Patients with chronic lymphocytic leukaemia often have defects in humoral and cellular immune system. Therefore, these patients have strong predisposition to recurrent infections and in this case for COVID-19. The relationship between chronic lymphocytic leukaemic and COVID-19 is not very clearly understood. A 77-year-old male with no significant co-morbidities presented with cough, fever and shortness of breath. His High-Resolution Computed Tomography (HRCT) chest revealed non-specific interstitial pneumonia and was tested positive for COVID-19 infection on RT-PCR. A Complete Blood Count (CBC) showed a high Total Leukocyte Count (TLC) with absolute lymphocytosis. There was absence of lymphadenopathy or splenomegaly. Flow cytometry confirmed the diagnosis of Chronic lymphocytic leukaemia. He was offered convalescent plasma therapy and later had to be incubated because of multiorgan failure. His Absolute Lymphocyte Counts (ALC) more than doubled in a week’s time. COVID-19 infection usually presents with lymphopenia, lymphocytosis should always raise a suspicion of underlying haematological malignancy or secondary infection.