- Email: [email protected]
Invasive Cryptococcus neoformans infection in an asplenic patient
Journal of Infection (2007) 55, 566e568
www.elsevierhealth.com/journals/jinf
CASE REPORT
Invasive Cryptococcus neoformans infection in an asplenic patient Z. Qazzafi a,*, D. Thiruchunapalli b, D. Birkenhead c, D. Bell d, J.A.T. Sandoe a a Department of Microbiology, Leeds Teaching Hospital NHS Trust, Old Medical School, Leeds General Infirmary, Great George Street, Leeds LS1 3EX, UK b Department of General Medicine, Huddersfield Royal Infirmary, Huddersfield, West Yorkshire, UK c Department of Microbiology, Huddersfield Royal Infirmary, Huddersfield, West Yorkshire, UK d Department of Anaesthesia, Leeds Teaching Hospitals NHS Trust, Leeds General Infirmary, Leeds, UK
Accepted 14 August 2007 Available online 1 October 2007
KEYWORDS Cryptococcus neoformans; Asplenia; Post splenectomy sepsis; Meningitis
Summary Individuals who are asplenic or have impaired splenic function are at increased risk of developing life-threatening infections, especially due to encapsulated bacteria. This risk is higher in children, but adults can also develop fulminant infection or ‘‘post splenectomy sepsis’’ (PSS). Cryptococcus neoformans is an encapsulated yeast usually causing infection in immunocompromised patients. In a recent review of cryptococcal infection in HIV-negative patients, splenectomy was reported to be a risk factor for infection in 3% of cases. Detailed case reports are lacking. Here we report a case of disseminated C. neoformans infection in a patient who had a splenectomy performed for warm autoantibody haemolytic anaemia some months before he presented with signs and symptoms of meningitis. This report aims to raise awareness of the possibility of C. neoformans infection in asplenic patients. ª 2007 The British Infection Society. Published by Elsevier Ltd. All rights reserved.
Background The spleen is an important organ of the reticuloendothelial system. Asplenic individuals are known to be at increased risk of life-threatening infections,1 often referred to as post
* Corresponding author. Tel.: þ44 113 392 8580; fax: þ44 113 343 5649. E-mail address: [email protected] (Z. Qazzafi).
splenectomy sepsis (PSS), especially with encapsulated bacteria including Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis.2 Other important organisms described to cause fulminant infections in asplenic patients include Capnocytophaga canimorsus, Salmonella spp., and protozoa such as Babesia spp.3 Although the risk of PSS is highest in children, especially those under 2 years of age,4 there are reports of cases of fulminant sepsis even 20e40 years after splenectomy.5 The predicted mortality from PSS has been reported to be
0163-4453/$30 ª 2007 The British Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jinf.2007.08.005
Invasive Cryptococcus neoformans infection up to 600 times greater than the general population with an estimated lifetime risk for PSS being approximately 5%.6 A recent review of cases7 and a textbook,8 report previous splenectomy as a risk factor for cryptococcal infection. Since Cryptococcus neoformans is encapsulated one would expect an increased risk of invasive infection in splenectomised patients but this appears to be very rare in practise. Here we report a case of disseminated infection with C. neoformans in a patient who had had a splenectomy performed 8 months previously as part of treatment of autoimmune haemolytic anaemia.
Case report A 25-year-old British Asian male who worked as a customer account manager was brought to a district general hospital with a 10-day history of gradually worsening, diffuse, constant, and throbbing headache. It was associated with vomiting, drowsiness, photophobia, and intermittent fever. He had presented to the Emergency Department 3 days earlier with mild headache and low-grade fever, but was found to be otherwise reasonably well on examination and was discharged home. He had a history of warm autoantibody haemolytic anaemia diagnosed 11 months prior to presentation and had undergone elective splenectomy 3 months after diagnosis. He was vaccinated against H. influenzae type b (Hib), N. meningitidis and S. pneumoniae before splenectomy, however, he refused prophylactic antibiotics. On examination he was conscious, although slightly drowsy but rousable on verbal commands with a Glasgow Coma Scale (GCS) of 14/15. He had normally reacting pupils. He had no focal neurology and could not tolerate fundoscopy due to photophobia. He had a generalised blanching maculopapular rash. There was no evidence of neck stiffness and rest of the systemic examination included auscultation of the heart and chest was unremarkable. His initial laboratory tests showed a peripheral white blood cell count (WBC) of 8.2 109/L (reference range 4e 11 109/L) and C-reactive protein (CRP) of 91 mg/L. His chest X-ray was normal. Plain computerised tomography scan of his head was normal. Blood cultures were taken and a lumber puncture was performed on the same day, which showed a high opening pressure. Cerebrospinal fluid (CSF) was clear and colourless. Cell count showed a WBC of 3 109/L, and RBC of 22 109/L. No organisms were seen on Gram staining of the CSF. CSF protein was mildly elevated at 0.5 g/L (reference range 0.15e0.45 g/L). CSF glucose was 3.1 mmol/L (reference range 2.2e3.9 mmol/L) with serum glucose being 7 mmol/L (reference range 4e 8 mmol/L). On day 2 he became more irritable, distressed and confused and his GCS dropped to 13/15. A contrast CT of the head was done to exclude cortical vein thrombosis, which was normal. On that day he was also started empirically on intravenous (IV) benzyl penicillin and IV acyclovir and in view of his clinical picture was transferred to a tertiary care hospital. On day 3, while in the tertiary care hospital, he deteriorated further with a GCS of 6/15. He was transferred
567 to the Neuro Intensive Care Unit. On this day, CSF cultured in the referring hospital grew yeast. No capsule was evident on India ink staining of the isolate. Liposomal amphotericin B was added to his antimicrobial therapy. An HIV test was negative. He had a repeat plain CT scan of his head, which remained unchanged from his previous scan. On day 4, unfortunately he deteriorated drastically and showed clinical signs of coning and was declared dead following brain stem testing and confirmation of asystole after withdrawal of ventilatory support. The CSF yeast was confirmed as C. neoformans by using biochemical identification system (API 20C Auxacolor). The isolate was confirmed as above at the Leeds mycology reference laboratory where cryptococcal latex agglutination tests were also positive on serum and CSF. This isolate was sent to another reference laboratory where it was confirmed as C. neoformans var neoformans by using biotyping assay and ribosomal repeat sequencing.9 Blood culture taken on day 1, also grew C. neoformans after 6 days of incubation giving exactly same biochemical profile as the one in the CSF. CSF was also sent for Viral (Herpes Simplex Virus, Enteroviruses and VaricellaeZoster Virus) as well as meningococcal PCRs, which were all negative. A swab from a lesion on his back and sputum also grew C. neoformans.
Discussion The emergence of human immunodeficiency virus (HIV) infection was associated with a huge increase in the incidence of infections caused by C. neoformans. However, this yeast can cause infection in a range of patients from the apparently immunocompetent host without an underlying disease to those severely immunocompromised from infection with HIV, organ transplantation or a malignancy. Signs and symptoms of infection are protean and can vary from asymptomatic colonisation of the upper respiratory tract to dissemination of infection into any part of the human body. C. neoformans has a special predilection for invading the central nervous system (CNS) of the susceptible host.10 First identified in Italy in 1894, C. neoformans was reported to cause meningitis for the first time in 1914.11 It is a saprophyte found mainly in soil as well as pigeon droppings. Polysaccharide capsule production is the most important virulence factor which not only resists phagocytosis but also depletes complement and produces antibody unresponsiveness.10 The capsule may be revealed in clinical specimens by placing the yeast into an India ink preparation. Being the largest lymphoid organ, the spleen has a range of important immunologic functions including production of opsonising antibodies and the efficient clearance of encapsulated bacteria.10 It is possible that splenectomy or functional hyposplenia also increases the susceptibility to infections with other encapsulated organisms such as C. neoformans but the mechanism is unclear. Given that natural killer cells, T-lymphocytes (CD4þ and CD8þ) and activated macrophages, all have been shown to possess direct anti-cryptococcal activity,12,13 it is possible that this patient also had some other immunological deficiency. There
568 have been case reports of severely low CD4þ T-lymphocyte counts in the absence of HIV infection.14,15 This has been designated idiopathic CD4þ T-lymphocytopenia.16 Patients with this syndrome typically have CD4þ T-lymphocyte depletion, no serological evidence of HIV infection, and no defined immunodeficiency or therapy associated T-cell depletion. Apart from the autoantibody haemolytic anaemia and subsequent splenectomy, there was no suspicion that our patient had any other immune deficiency rendering him vulnerable to cryptococcal infection and he never had a T-cell assay performed. No immunological investigation could be carried out due to fulminant and fatal course of illness in this patient. Patients with functional hyposplenism or asplenia are at lifelong risk for a range of infections. These infections can rapidly progress to severe sepsis and shock. The importance of starting early appropriate antimicrobial treatment for PSS cannot be over-emphasised. This case report serves as an important reminder that C. neoformans is an uncommon cause of meningitis in splenectomised patients. The fact that this patient initially presented to hospital a few days before his admission with history of non-specific symptoms and fever and was discharged home without further investigations is an important lesson. Any asplenic patient presenting with signs and symptoms of systemic infection should have full investigations including a lumbar puncture (if not contraindicated otherwise) if presenting with a history of fever, headache and photophobia. An India ink examination of CSF should be considered in addition to cryptococcal antigen detection if Gram-stain of CSF is negative for bacteria and concentration of protein, leukocytes or glucose are abnormal.17 Starting empirical antifungal chemotherapy along with antibacterial agents is probably not warranted in this setting and would need further evidence.
References 1. Sumaraju V, Smith LG, Smith SM. Infectious complications in asplenic hosts. Infect Dis Clin North Am 2001;15(2):551e65. 2. Hasse B, Moll C, Oehy K, Rothlin M, Krause M. Anti-infectious prophylaxis after splenectomy: current practice in an eastern region of Switzerland. Swiss Med Wkly 2005;135:291e6.
Z. Qazzafi et al. 3. Melles DC, de Marie S. Prevention of infections in hyposplenic and asplenic patients: an update. N J Med 2004; 62(2):45e52. 4. Holdsworth RJ, Irving AD, Cuschieri A. Postsplenectomy sepsis and its mortality rate: actual versus perceived risks. Br J Surg 1991 Sep;78(9):1031e8. 5. Williams DN, Kaur B. Postsplenectomy care. Strategies to decrease the risk of infection. Postgrad Med 1996 Jul;100(1): 195e8 [201, 205]. 6. Lynch AM, Kapila R. Overwhelming postsplenectomy infection. Infect Dis Clin North Am 1996 Dec;10(4):693e707. 7. Pappas PG, Perfect JR, Cloud GA, Larsen RA, Pankey GA, Lancaster DJ, et al. Cryptococcosis in human immunodeficiency virus-negative patients in the era of effective azole therapy. Clin Infect Dis 2001 Sep 1;33(5):690e9 [Epub 2001 Jul 26]. 8. Casadevall A, Perfect JR. Cryptococcus neoformans. Washington: ASM Press; 1998. p. 409. 9. White TJ, Burns T, Lee S, Taylor J. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis MA, Gelfand DH, Sninsky JJ, White TJ, editors. PCR protocols, a guide to methods and applications. San Diego: Academic Press; 1990. p. 315e22. 10. Perfect JR. Cryptococcus neoformans. In: Principles and practice of infectious diseases; 2004. 11. Perfect JR, Casadevall A. Cryptococcosis. Infect Dis Clin North Am 2002 Dec;16(4):837e74 [vevi]. 12. Hill JO. CD4þ T cells cause multinucleated giant cells to form around Cryptococcus neoformans and confine the yeast within the primary site of infection in the respiratory tract. J Exp Med 1992;175:1685e95. 13. Levitz SM. MacrophageeCryptococcus interactions. In: Zwilling BS, Eisenstein TK, editors. Macropageepathogen interactions. New York: Marcel Dekker; 1994. p. 533e43. 14. Fauci AS. CD4þ T-lymphocytopenia without HIV infection d no lights, no camera, just facts. N Engl J Med 1993;328: 429e31. 15. Smith D, Neal JJ, Holmberg SD. Unexplained opportunistic infections and CD4þ T-lymphocytopenia without HIV infection. N Engl J Med 1993;328:373e8. 16. Unexplained CD4þ T-lymphocyte depletion in persons without evident HIV infection d United States. MMWR Morb Mortal Wkly Rep 1992;41:541e5. 17. Denning DW, Kibbler CC, Barnes RA. British society for medical mycology proposed standards of care for patients with invasive fungal infections. Lancet Infect Dis 2003 Apr;3(4): 230e40.
www.elsevierhealth.com/journals/jinf
CASE REPORT
Invasive Cryptococcus neoformans infection in an asplenic patient Z. Qazzafi a,*, D. Thiruchunapalli b, D. Birkenhead c, D. Bell d, J.A.T. Sandoe a a Department of Microbiology, Leeds Teaching Hospital NHS Trust, Old Medical School, Leeds General Infirmary, Great George Street, Leeds LS1 3EX, UK b Department of General Medicine, Huddersfield Royal Infirmary, Huddersfield, West Yorkshire, UK c Department of Microbiology, Huddersfield Royal Infirmary, Huddersfield, West Yorkshire, UK d Department of Anaesthesia, Leeds Teaching Hospitals NHS Trust, Leeds General Infirmary, Leeds, UK
Accepted 14 August 2007 Available online 1 October 2007
KEYWORDS Cryptococcus neoformans; Asplenia; Post splenectomy sepsis; Meningitis
Summary Individuals who are asplenic or have impaired splenic function are at increased risk of developing life-threatening infections, especially due to encapsulated bacteria. This risk is higher in children, but adults can also develop fulminant infection or ‘‘post splenectomy sepsis’’ (PSS). Cryptococcus neoformans is an encapsulated yeast usually causing infection in immunocompromised patients. In a recent review of cryptococcal infection in HIV-negative patients, splenectomy was reported to be a risk factor for infection in 3% of cases. Detailed case reports are lacking. Here we report a case of disseminated C. neoformans infection in a patient who had a splenectomy performed for warm autoantibody haemolytic anaemia some months before he presented with signs and symptoms of meningitis. This report aims to raise awareness of the possibility of C. neoformans infection in asplenic patients. ª 2007 The British Infection Society. Published by Elsevier Ltd. All rights reserved.
Background The spleen is an important organ of the reticuloendothelial system. Asplenic individuals are known to be at increased risk of life-threatening infections,1 often referred to as post
* Corresponding author. Tel.: þ44 113 392 8580; fax: þ44 113 343 5649. E-mail address: [email protected] (Z. Qazzafi).
splenectomy sepsis (PSS), especially with encapsulated bacteria including Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis.2 Other important organisms described to cause fulminant infections in asplenic patients include Capnocytophaga canimorsus, Salmonella spp., and protozoa such as Babesia spp.3 Although the risk of PSS is highest in children, especially those under 2 years of age,4 there are reports of cases of fulminant sepsis even 20e40 years after splenectomy.5 The predicted mortality from PSS has been reported to be
0163-4453/$30 ª 2007 The British Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jinf.2007.08.005
Invasive Cryptococcus neoformans infection up to 600 times greater than the general population with an estimated lifetime risk for PSS being approximately 5%.6 A recent review of cases7 and a textbook,8 report previous splenectomy as a risk factor for cryptococcal infection. Since Cryptococcus neoformans is encapsulated one would expect an increased risk of invasive infection in splenectomised patients but this appears to be very rare in practise. Here we report a case of disseminated infection with C. neoformans in a patient who had had a splenectomy performed 8 months previously as part of treatment of autoimmune haemolytic anaemia.
Case report A 25-year-old British Asian male who worked as a customer account manager was brought to a district general hospital with a 10-day history of gradually worsening, diffuse, constant, and throbbing headache. It was associated with vomiting, drowsiness, photophobia, and intermittent fever. He had presented to the Emergency Department 3 days earlier with mild headache and low-grade fever, but was found to be otherwise reasonably well on examination and was discharged home. He had a history of warm autoantibody haemolytic anaemia diagnosed 11 months prior to presentation and had undergone elective splenectomy 3 months after diagnosis. He was vaccinated against H. influenzae type b (Hib), N. meningitidis and S. pneumoniae before splenectomy, however, he refused prophylactic antibiotics. On examination he was conscious, although slightly drowsy but rousable on verbal commands with a Glasgow Coma Scale (GCS) of 14/15. He had normally reacting pupils. He had no focal neurology and could not tolerate fundoscopy due to photophobia. He had a generalised blanching maculopapular rash. There was no evidence of neck stiffness and rest of the systemic examination included auscultation of the heart and chest was unremarkable. His initial laboratory tests showed a peripheral white blood cell count (WBC) of 8.2 109/L (reference range 4e 11 109/L) and C-reactive protein (CRP) of 91 mg/L. His chest X-ray was normal. Plain computerised tomography scan of his head was normal. Blood cultures were taken and a lumber puncture was performed on the same day, which showed a high opening pressure. Cerebrospinal fluid (CSF) was clear and colourless. Cell count showed a WBC of 3 109/L, and RBC of 22 109/L. No organisms were seen on Gram staining of the CSF. CSF protein was mildly elevated at 0.5 g/L (reference range 0.15e0.45 g/L). CSF glucose was 3.1 mmol/L (reference range 2.2e3.9 mmol/L) with serum glucose being 7 mmol/L (reference range 4e 8 mmol/L). On day 2 he became more irritable, distressed and confused and his GCS dropped to 13/15. A contrast CT of the head was done to exclude cortical vein thrombosis, which was normal. On that day he was also started empirically on intravenous (IV) benzyl penicillin and IV acyclovir and in view of his clinical picture was transferred to a tertiary care hospital. On day 3, while in the tertiary care hospital, he deteriorated further with a GCS of 6/15. He was transferred
567 to the Neuro Intensive Care Unit. On this day, CSF cultured in the referring hospital grew yeast. No capsule was evident on India ink staining of the isolate. Liposomal amphotericin B was added to his antimicrobial therapy. An HIV test was negative. He had a repeat plain CT scan of his head, which remained unchanged from his previous scan. On day 4, unfortunately he deteriorated drastically and showed clinical signs of coning and was declared dead following brain stem testing and confirmation of asystole after withdrawal of ventilatory support. The CSF yeast was confirmed as C. neoformans by using biochemical identification system (API 20C Auxacolor). The isolate was confirmed as above at the Leeds mycology reference laboratory where cryptococcal latex agglutination tests were also positive on serum and CSF. This isolate was sent to another reference laboratory where it was confirmed as C. neoformans var neoformans by using biotyping assay and ribosomal repeat sequencing.9 Blood culture taken on day 1, also grew C. neoformans after 6 days of incubation giving exactly same biochemical profile as the one in the CSF. CSF was also sent for Viral (Herpes Simplex Virus, Enteroviruses and VaricellaeZoster Virus) as well as meningococcal PCRs, which were all negative. A swab from a lesion on his back and sputum also grew C. neoformans.
Discussion The emergence of human immunodeficiency virus (HIV) infection was associated with a huge increase in the incidence of infections caused by C. neoformans. However, this yeast can cause infection in a range of patients from the apparently immunocompetent host without an underlying disease to those severely immunocompromised from infection with HIV, organ transplantation or a malignancy. Signs and symptoms of infection are protean and can vary from asymptomatic colonisation of the upper respiratory tract to dissemination of infection into any part of the human body. C. neoformans has a special predilection for invading the central nervous system (CNS) of the susceptible host.10 First identified in Italy in 1894, C. neoformans was reported to cause meningitis for the first time in 1914.11 It is a saprophyte found mainly in soil as well as pigeon droppings. Polysaccharide capsule production is the most important virulence factor which not only resists phagocytosis but also depletes complement and produces antibody unresponsiveness.10 The capsule may be revealed in clinical specimens by placing the yeast into an India ink preparation. Being the largest lymphoid organ, the spleen has a range of important immunologic functions including production of opsonising antibodies and the efficient clearance of encapsulated bacteria.10 It is possible that splenectomy or functional hyposplenia also increases the susceptibility to infections with other encapsulated organisms such as C. neoformans but the mechanism is unclear. Given that natural killer cells, T-lymphocytes (CD4þ and CD8þ) and activated macrophages, all have been shown to possess direct anti-cryptococcal activity,12,13 it is possible that this patient also had some other immunological deficiency. There
568 have been case reports of severely low CD4þ T-lymphocyte counts in the absence of HIV infection.14,15 This has been designated idiopathic CD4þ T-lymphocytopenia.16 Patients with this syndrome typically have CD4þ T-lymphocyte depletion, no serological evidence of HIV infection, and no defined immunodeficiency or therapy associated T-cell depletion. Apart from the autoantibody haemolytic anaemia and subsequent splenectomy, there was no suspicion that our patient had any other immune deficiency rendering him vulnerable to cryptococcal infection and he never had a T-cell assay performed. No immunological investigation could be carried out due to fulminant and fatal course of illness in this patient. Patients with functional hyposplenism or asplenia are at lifelong risk for a range of infections. These infections can rapidly progress to severe sepsis and shock. The importance of starting early appropriate antimicrobial treatment for PSS cannot be over-emphasised. This case report serves as an important reminder that C. neoformans is an uncommon cause of meningitis in splenectomised patients. The fact that this patient initially presented to hospital a few days before his admission with history of non-specific symptoms and fever and was discharged home without further investigations is an important lesson. Any asplenic patient presenting with signs and symptoms of systemic infection should have full investigations including a lumbar puncture (if not contraindicated otherwise) if presenting with a history of fever, headache and photophobia. An India ink examination of CSF should be considered in addition to cryptococcal antigen detection if Gram-stain of CSF is negative for bacteria and concentration of protein, leukocytes or glucose are abnormal.17 Starting empirical antifungal chemotherapy along with antibacterial agents is probably not warranted in this setting and would need further evidence.
References 1. Sumaraju V, Smith LG, Smith SM. Infectious complications in asplenic hosts. Infect Dis Clin North Am 2001;15(2):551e65. 2. Hasse B, Moll C, Oehy K, Rothlin M, Krause M. Anti-infectious prophylaxis after splenectomy: current practice in an eastern region of Switzerland. Swiss Med Wkly 2005;135:291e6.
Z. Qazzafi et al. 3. Melles DC, de Marie S. Prevention of infections in hyposplenic and asplenic patients: an update. N J Med 2004; 62(2):45e52. 4. Holdsworth RJ, Irving AD, Cuschieri A. Postsplenectomy sepsis and its mortality rate: actual versus perceived risks. Br J Surg 1991 Sep;78(9):1031e8. 5. Williams DN, Kaur B. Postsplenectomy care. Strategies to decrease the risk of infection. Postgrad Med 1996 Jul;100(1): 195e8 [201, 205]. 6. Lynch AM, Kapila R. Overwhelming postsplenectomy infection. Infect Dis Clin North Am 1996 Dec;10(4):693e707. 7. Pappas PG, Perfect JR, Cloud GA, Larsen RA, Pankey GA, Lancaster DJ, et al. Cryptococcosis in human immunodeficiency virus-negative patients in the era of effective azole therapy. Clin Infect Dis 2001 Sep 1;33(5):690e9 [Epub 2001 Jul 26]. 8. Casadevall A, Perfect JR. Cryptococcus neoformans. Washington: ASM Press; 1998. p. 409. 9. White TJ, Burns T, Lee S, Taylor J. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis MA, Gelfand DH, Sninsky JJ, White TJ, editors. PCR protocols, a guide to methods and applications. San Diego: Academic Press; 1990. p. 315e22. 10. Perfect JR. Cryptococcus neoformans. In: Principles and practice of infectious diseases; 2004. 11. Perfect JR, Casadevall A. Cryptococcosis. Infect Dis Clin North Am 2002 Dec;16(4):837e74 [vevi]. 12. Hill JO. CD4þ T cells cause multinucleated giant cells to form around Cryptococcus neoformans and confine the yeast within the primary site of infection in the respiratory tract. J Exp Med 1992;175:1685e95. 13. Levitz SM. MacrophageeCryptococcus interactions. In: Zwilling BS, Eisenstein TK, editors. Macropageepathogen interactions. New York: Marcel Dekker; 1994. p. 533e43. 14. Fauci AS. CD4þ T-lymphocytopenia without HIV infection d no lights, no camera, just facts. N Engl J Med 1993;328: 429e31. 15. Smith D, Neal JJ, Holmberg SD. Unexplained opportunistic infections and CD4þ T-lymphocytopenia without HIV infection. N Engl J Med 1993;328:373e8. 16. Unexplained CD4þ T-lymphocyte depletion in persons without evident HIV infection d United States. MMWR Morb Mortal Wkly Rep 1992;41:541e5. 17. Denning DW, Kibbler CC, Barnes RA. British society for medical mycology proposed standards of care for patients with invasive fungal infections. Lancet Infect Dis 2003 Apr;3(4): 230e40.