Cytomegalovirus viraemia in HIV infection: Association with intercurrent infection

Journal of Infection (1995) 31, 21-26

Cytomegalovirus Viraemia in HIV Infection: Association with Intercurrent Infection M. R. W. Evans, J. C. Booth and M. H. Wansbrough-Jones Division of Infectious Diseases and Department of Medical Microbiology, Jenner Wing, St George's Hospital Medical School, Cranmer Terrace, London S W 1 7 ORE, U.K. Accepted for publication 2 4 November 1 9 9 4

The aim of this retrospective study was to investigate the clinical significance of cytomegalovirus (CMV) viraemia in HIVinfected subjects (with or without AIDS) who had attended this hospital during a 45 month period. They were reviewed regularly and, when clinically indicated, tested for CMV viraemia. The blood of 105 subjects was cultured for CMV and 34 had at least one episode of CMV viraemia during the review period. The viraemia was present during CMV disease in nine of the 34 positive patients and was the only detectable infection in another two. In the remaining 23 patients, CMV viraemia occurred in association with intercurrent opportunistic infection. Among these 23 patients, the viraemia resolved in 12 after treatment (or natural resolution) of the intercurrent infection and only one of these 12 developed CMV disease (mean review period: 8 months). In another seven patients, CMV viraemia persisted despite treatment (or natural resolution) of the intercurrent infection and four subsequently developed CMV ddsease (mean review period: 4 months) (P=O.08, Fisher's exact test). From the remaining four patients, no specimens for CMV culture were obtained after treatment of the intercurrent infection. The CD4 count was higher in the 12 patients in whom there was resolution of the viraemia [mean CD4 60 x I06/ 1] compared with the seven in whom the viraemia persisted [mean CD4 45 x 106/I]. These findings suggest that in some HIV-positive patients, CMV viraemia was potentiated by intercurrent infection with another micro-organism and that its treatment was sufficient to mitigate the CMV disease.

Introduction Cytomegalovirus (CMV) causes disease in up to 22% of patients with AIDS, 1-3 the usual manifestations being retinitis, colitis, oesophageal ulcers, encephalitis and fever. The onset of disease is unpredictable and there are difficulties in determining whether an episode of illness can be attributed to CMV. Serological responses are unhelpful, the patients invariably being positive for CMV IgG while CMV IgM m a y be detected when there are no symptoms. Culture of CMV from urine or pharyngeal secretions does necessarily imply that it is the cause of symptoms because long term excretion is common. However, CMV activation in H1V-positive subjects has been shown to be correlated with progressive i m m u n e deficiency and a low CD4 count 4'S and CMV disease is often a late manifestation of HIV infection w h e n the CD4 lymphocyte count has fallen to less than 50 x 106/1. 2 We have observed several HIV-positive patients who remain CMV viraemic but do not develop CMV disease for some considerable time. Retrospective analysis of the data from all our patients revealed a significant proportion who

Address correspondence to: Dr M. R. W. Evans. 0163-4453/95/040021 + 06 $08.00/0

were CMV viraemic and at the same time unwell because of another intercurrent infection, but in w h o m successful treatment of that infection was followed by resolution of the CMV viraemia.

Subjects and Methods A total of 105 HIV-infected patients who had attended the Communicable Diseases Unit at St. George's Hospital during a 45 m o n t h period had blood taken for CMV culture when clinically indicated. Therefore the frequency and reason for sending buffy coat cultures for CMV varied between individuals, but all had equal and regular clinical review.

Detection of CMV viraemia

We used standard methods in the CMV reference laboratory. Briefly, leucocyte-rich plasma (buffy coat cells) was removed from specimens of anticoagulated blood collected in preservative free heparin (10 IU/ml). It was then inoculated onto monolayers of diploid h u m a n embryonic lung fibroblasts, both in tube cultures and 24-well culture © 1995 The British Society for the Study of Infection

22

C M V Viraemia in HIV Infection

plates. After incubation for 48 h, the latter were fixed in methanol and stained with a monoclonal antibody to a CMV early antigen and then an anti-mouse immunoglobulin labelled with alkaline phosphatase. 6 Infected cells were visualised after the addition of substrate fast red TR (4 chloro-2-methylbenzenediazonium). Tube cultures were incubated with regular refeeding and examined for viral cytopathic effect twice weekly for 3 weeks. CMV results were collated retrospectively from the laboratory records and clinical details from patients' notes. Resolution of viraemia was recorded if the first buffy coat sample taken after treatment or resolution of intercurrent infection was CMV culture negative. When CMV viraemia occurred on more than one occasion, only the clinical details of the first episode were analysed. Endpoints were taken as the end of the 45 m o n t h time period or the development of CMV disease [retinitis], loss to review or death.

Results During a 45 month period, the blood of 105 patients was cultured for CMV; 34 (32%) of them were found to be CMV viraemic on at least one occasion. Twenty nine of these 34 viraemic patients were from CDC group IV and five from CDC group II or III. The overall mean CD4 count for the viraemic patients was 40 x 106/1 [range 2 - 2 2 0 x 106/I]. There were 30 males and four females; 26 of the men were homosexual and three of the heterosexuals were I.V. drug abusers. Of the 34 subjects whose blood was positive for CMV, nine had CMV disease at the time the viraemia was detected. CMV viraemia with symptoms was the only detectable infection in another two patients. The remaining 23 patients already had an opportunistic infection when CMV viraemia was detected (Table 1). Figure 1 shows the course of events in these 23 subjects. The CMV viraemia resolved in 12 after treatment (or natural resolution) of the intercurrent infection and, in a review period ranging from 2 . 5 - 1 6 months (mean: 8 months), only one of the 12 developed CMV disease. In another seven, CMV viraemia persisted despite treatment (or natural resolution) of the intercurrent infection and four of them subsequently developed CMV disease (mean review period: 4 months, range 1-8 months); included in this group was one subject who developed CMV disease just outside the study period. (One of these four subjects had an episode of CMV proctitis before the viraemia, but subsequently progressed to CMV retinitis after the viraemia. No one else in the study had any evidence of CMV disease before the CMV viraemia.)

Table 1. Clinical condition during CMV viraemia. Clinical condition

No. of incidences

CMV disease Retinitis Oesophagitis Cholangitis Colitis Encephalitis Pneumonitis Sub-total

3 2 1 1 1 1 9

Intercurrent infection Pneumocystis carinii pneumonia Tuberculosis Lower respiratory tract infection Cryptosporidiosis Perianal HSV infection Perianal abscess Oesophageal candidiasis Cerebral toxoplasmosis Staphylococcalsepticaemia Cryptococcalmeningitis Bronchopneumonia (Terminal illness) Sub-total CMVviraemia alone Total

Result of the next buffy coat CMV culture following CMV viraemia

8 3 3 2 1 1 1 1 1 1 1 23 2 34

Subsequent CMVl disease ]

23--

E

4

No follow-up sample after resolution/Rx of intercurrent infections

CMV viraemia persistence

CMV viraemia resolution

Figure 1. CMVviraemia response to treatment of intercurrent infection and CMVdisease development.

In the remaining four patients, no review specimens for CMV culture were obtained after treatment of the intercurrent infection. Ganciclovir was given to six patients when there was limited clinical response to treatment of the intercurrent infection alone. These six patients were evenly distributed, three were from the 'CMV viraemia resolution' group

M. R. W. Evans et al. and three from the 'CMV viraemia persistence' group and all received 2 - 3 week courses. Of the 19 subjects with CMV viraemia in association with intercurrent infection, 14 had previous buffy coat cultures which were shown to be negative (five of seven in the persistent viraemia group and nine of 12 in the resolution group, at a m e a n time of 70 days before the viraemia). In the other 5, no previous buffy coat cultures had been taken. (Figure 2). After the viraemia, the timing of the next buffy coat sample varied from patient to patient, being shorter in the persistence group (mean: 1 month) t h a n in the resolution group (mean: 3 months). All 19 had at least one review sample more t h a n 2 weeks after the viraemia (and all within 1 year). The detection of a further episode of CMV viraemia within this time gave a predictive value for the development of CMV disease of 57% (4/7) and a negative predictive value of 92% (11/12). Although it could be argued that those from the persistence group m a y have become viraemia-negative in time, most of this group (five out of the seven) were subsequently viraemic and only one of the 12 in the resolution group became positive again despite a longer review period in the resolution group (mean: 8 months) compared with the persistence group (4 months). This implies that the difference between the resolution and persistence groups is not just a reflection of when the buffy coat samples were taken. In addition, there was regular clinical review of all patients after the first viraemia which included fundoscopy to detect CMV retinitis. This implies that CMV disease was not already developing during the acute opportunistic infection in persistent excretors and the m e a n time from (first) viraemia to CMV disease was 170 days (range 4 0 - 4 9 1 days). Further buffy coat cultures were taken after the review sample in all seven of the persistent viraemia group and in 10 of the 12 viraemia resolution group. None were positive for CMV in the resolution group, except on one occasion in the subject who developed CMV disease. The CD4 count was higher in subjects whose CMV viraemia resolved after treatment of the intercurrent infection (mean 60 x 106/1, range 2 - 2 2 0 x 106/1) t h a n in those in w h o m the CMV viraemia persisted (mean 45 x 106/1, range 1 0 - 1 6 0 x 106/1). Although the CD4 count was generally higher in the CMV viraemia resolution group, it was still 50 x 106/1 or less in eight of the 12 subjects in w h o m resolution occurred (Figure 3). All but two subjects had CD4 counts measured within 10 months of CMV viraemia, most (25 of 34) within 2 months of the viraemia (range 0 - 1 0 months). A total of 195 buffy coat samples were taken from the 34 viraemic patients (mean: 5.7 cultures per subject,

23

range 1-12) compared with 117 from the other 70 (mean: 1.6 cultures per subject, range 1-7). There were 69 positive cultures from the 34 patients. Those with CMV viraemia had more cultures taken than those who were not viraemic, because CMV viraemia was more likely to be considered if it had been recorded previously. Buffy coat samples were taken from the 34 patients in order to investigate symptoms (n = 153), to monitor antiCMV treatment or to follow-up a positive culture ( n = 26). Nine other samples were taken for research purposes or as repeat samples (for an equivocal result or failed tissue culture). Seven were taken for which no reason was given in the notes (Table 2).

Discussion CMV viraemia and a low CD4 count are predictors of CMV disease in HIV-positive and AIDS patients 1'2' 7 and are markers of poor prognosis. 8 The incidence of CMV viraemia rises with increasing immunosuppression s and is usually absent in early HIV infection but present in over half of AIDS patients at some time2 There is a cumulative probability, over 16 months, of progression from CMV viraemia to CMV disease in 50% patients compared with 9% of those without CMV viraemia. 11 Other studies have confirmed the correlation between a low CD4 count and CMV viraemia 4 and Zurlo showed that although CMV viraemia only had a 35% predictive value for CMV disease, it occurred earlier (84 days) in those with a history of previous CMV viraemia than in those without it (260 days), x2 Factors exacerbating CMV viraemia m a y be important in determining whether CMV disease develops and we have shown that viraemia can be associated with intercurrent infection. It is possible that CMV viraemia m a y occur spontaneously in HIV infected subjects and later cultures showed it to be present in the persistence group. However in the viraemia resolution group, who had repeated buffy coat cultures over a period of 8 months, no more episodes of viraemia were detected except in the one subject who developed CMV disease. If treatment of the intercurrent infection has the effect of also resolving the CMV infection, there is less likelihood of the patient progressing to CMV disease and therefore no need to consider treatment with ganciclovir, which itself imposes further problems on HIV positive patients because of its known bone m a r r o w toxicity and, until recently, the need for I.V. administration. In our study, the group with persistent viraemia, who were more likely to progress to CMV disease, had a lower mean CD4 count which is consistent with other studies. 2' 7

24

C M V Viraemia in HIV Infection CMV viraemia resolution group I

Ol I

Q

000@ 0 I

GO

I

ool I

oo

FC~

GD

iD 0

O

0

o~I rd~

0

I

[] 0

M

o OO0

t~rlt

>100 days

OI ~ tl

100

I

I t ~Jl

200

I I I t I t I t tl

300

I I t tl

400 500 Time (days)

F I ] rl,i

600

700

I III

800

CMV viraemia persistence group

)

~T~ o

I I LO

i" I

FDFD~ C~m otco I

J Indicates patient with intercurrent infection during first CMV viraemia I

~C

I Study Endpoint

MV Disease

• CMV viraemia

CMV Rx -Ganciclovir or Foscarnet

O No viraemia Time 0 = First CMV viraemia

Figure 2. CMV blood culture results in those with CMV viraemia associated with intercurrent infection.

M. R. W. Evans et al.

25

Table 2. Reasons for taking blood for CMV culture from 34 patients in whom the result was positive. Reason for taking blood for CMV culture

Clinical problem under investigation

Positive CMV

(1) Investigation of main symptom

Respiratory Gastro-intestinal Fever alone Nervous system Ophthalmic Arthralgia Abnormal liver function Urinary tract infection

52 40 25 16 9 4 5 2 153

18 23 3 5 3 3 3 0 58

26 7 5 4

11 0 O 0

Sub-total (2) (3) (4) (5)

Monitoring Rx or previous CMV+ ve Unstated Research Repeated (previous equivocal/stripped culture)

195

Total

However, w h e n the individual CD4 counts in the two groups were compared, there was a considerable overlap with more t h a n half the subjects in the CMV viraemia resolution group h a v i n g a CD4 c o u n t of 50 x 106/1 or less. This implies that the different responses of the two groups to the treatment of the intercurrent infection are not simply a reflection of their different CD4 counts. Overall this study confirms the predictive value of persistent or intermittent viraemia for active CMV disease with five of the seven persistent viraemia subjects h a v i n g further viraemic episodes and four of these developing CMV disease, c o m p a r e d with only one of the 12 in the resolution group. The association of intercurrent infection and CMV viraemia in HIV infection has not been reported previously and the m e c h a n i s m underlying CMV reactivation and viraemia is not fully understood. Intercurrent infection causing further reduction in a low CD4 lymphocyte c o u n t m a y contribute to reactivation. A n o t h e r

250 ~e 200 ~150 8 IO0 5O

00

ooo

u~

CMV viraemia resolved

CMV viraemia persisted

Figure 3. CD4 counts in patients whose CMV viraemia either resolved or persisted after resolution of the intercurrent infection.

69

explanation is that cytokines released during opportunistic infection m a y stimulate CMV replication. 13 Further evidence for this correlation between plasma cytokines and CMV reactivation in vivo has been demonstrated recently by t u m o u r necrosis factor values and CMV antigenaemia in septic patients. 1~ In addition intercurrent infection m a y increase the dissemination of CMV-infected leucocytes. W h e t h e r treatment or prevention of CMV viraemia is important for survival or CMV organ involvement is still u n k n o w n , a l t h o u g h a small study showed that prophylactic IV ganciclovir administered to patients with low CD4 counts and high CMV IgG titres was successful in preventing CMV disease, is CMV treatment involves IV ganciclovir or foscarnet, both of w h i c h have potentially serious side effects, and induction with ganciclovir necessitates temporary discontinuation of anti-retroviral therapy. It is hoped that the eventual use of oral ganciclovir m a y lessen these serious side effects. This retrospective study has inevitably selected a population already undergoing investigation. However CMV viraemia was detected in a significant n u m b e r of the patients tested (32%) and it is likely that the beneficial effect of treating the intercurrent infection before addressing the CMV infection is a significant finding. A study to demonstrate w h e t h e r treatment of an opportunistic infection has a n y benefit on subsequent CMV disease clearly c a n n o t be undertaken and a full prospective study is required to establish this association between CMV viraemia and intercurrent infection.

26

CMV Viraemia in HIV Infection References

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