title: The unmasking of Pneumocystis jiroveci pneumonia during reversal of immunosuppression: case reports and literature review.
abstract: BACKGROUND
  Pneumocystis jiroveci pneumonia (PCP) is an important opportunistic infection among immunosuppressed patients, especially in those infected with human immunodeficiency virus (HIV). The clinical presentation of PCP in immunosuppressed patients have been well-reported in the literature. However, the clinical importance of PCP manifesting in the setting of an immunorestitution disease (IRD), defined as an acute symptomatic or paradoxical deterioration of a (presumably) preexisting infection, which is temporally related to the recovery of the immune system and is due to immunopathological damage associated with the reversal of immunosuppressive processes, has received relatively little attention until recently.
  
  
  METHODS
  We aim to better define this unique clinical syndrome by reporting two cases of PCP manifesting acutely with respiratory failure during reversal of immunosuppression in non-HIV infected patients, and reviewed the relevant literature. We searched our databases for PCP cases manifesting in the context of IRD according to our predefined case definition, and reviewed the case notes retrospectively. A comprehensive search was performed using the Medline database of the National Library of Medicine for similar cases reported previously in the English literature in October 2003. A total of 28 non-HIV (excluding our present case) and 13 HIV-positive patients with PCP manifesting as immunorestitution disease (IRD) have been reported previously in the literature. During immunorestitution, a consistent rise in the median CD4 lymphocyte count (28/microL to 125/microL), with a concomitant fall in the median HIV viral load (5.5 log10 copies/ml to 3.1 log10 copies/ml) was observed in HIV-positive patients who developed PCP. A similar upsurge in peripheral lymphocyte count was observed in our patients preceding the development of PCP, as well as in other non-HIV immunosuppressed patients reported in the literature.
  
  
  CONCLUSIONS
  PCP manifesting as IRD may be more common than is generally appreciated. Serial monitoring of total lymphocyte or CD4 count could serve as a useful adjunct to facilitate the early diagnosis and pre-emptive treatment of this condition in a wide range of immunosuppressed hosts, especially in the presence of new pulmonary symptoms and/or radiographic abnormalities compatible with the diagnosis.
authors.affiliation: Division of Infectious Diseases, Centre of Infection, Queen Mary Hospital, The University of Hong Kong; Hong Kong Special Administrative Region, China. alanklwu@yahoo.com <alanklwu@yahoo.com>
authors.forename: Alan K L
authors.initials: AK
authors.lastname: Wu
authors.forename: Vincent C C
authors.initials: VC
authors.lastname: Cheng
authors.forename: Bone S F
authors.initials: BS
authors.lastname: Tang
authors.forename: Ivan F N
authors.initials: IF
authors.lastname: Hung
authors.forename: Rodney A
authors.initials: RA
authors.lastname: Lee
authors.forename: David S
authors.initials: DS
authors.lastname: Hui
authors.forename: Kwok Y
authors.initials: KY
authors.lastname: Yuen
mesh_terms: D000328:Adult; D000935:Antifungal Agents / Q000627:therapeutic use; D018791:CD4 Lymphocyte Count; D005260:Female; D015658:HIV Infections; D006801:Humans; D016867:Immunocompromised Host; D007165:Immunosuppression Therapy / Q000009:adverse effects; D007166:Immunosuppressive Agents / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009894:Opportunistic Infections; D045363:Pneumocystis carinii / Q000302:isolation & purification*; D011020:Pneumonia, Pneumocystis / Q000175:diagnosis* / Q000188:drug therapy
chemical_list: D000935:Antifungal Agents; D007166:Immunosuppressive Agents