VENLO, The Netherlands and MELBOURNE, Australia, July 11, 2011 /PRNewswire/ —

• QIAGEN increases offer to shareholders of Cellestis Limited
  (CST:AU) pursuant to scheme of arrangement
• Cellestis board of directors unanimously
  support^[1] amended proposal offering its
  shareholders a 7% increase to A$3.80 per share from original offer
  of A$3.55
• Acquisition would provide QIAGEN with exclusive access to
  QuantiFERON technology for high sensitivity,
  early disease detection not possible with other
  diagnostics

QIAGEN N.V. (NASDAQ: QGEN; Frankfurt, Prime Standard: QIA) today
announced that it has amended its original proposal to acquire
Cellestis Limited (CST:AU), a publicly traded Australian
biotechnology company.

Under terms of the amended proposal, the per-share offer price
is being increased by 7% to A$3.80 from the original offer price of
A$3.55 announced on April 4, 2011. QIAGEN has declared this offer
to be final and will not be increased in the absence of a competing
proposal.

The amended proposal represents an attractive outcome for
Cellestis shareholders, enabling them to realize value in cash for
their shares at a premium. The resulting integration of Cellestis
will also offer opportunities to create significant value for
QIAGEN shareholders. Implementation of the scheme will allow a
rapid and efficient integration of Cellestis’ business into the
QIAGEN group without interrupting its strong growth momentum. Once
the scheme is implemented, QIAGEN can begin to make investments to
further expand Cellestis’ global presence and the companies’
combined product portfolio.

The increased offer represents a premium of:

• 33.1% to the one-month volume-weighted average price (VWAP) of
  Cellestis shares ending on April 1, 2011, the last trading day
  prior to announcement of the original proposal; and
• 40.8% to the three-month VWAP ending on April 1, 2011.

The acquisition of Cellestis will provide QIAGEN with exclusive
rights to QuantiFERONtechnology, a novel
“pre-molecular” technology that offers a new dimension in disease
detection not currently possible with other diagnostic
technologies.

Cellestis has successfully commercialized this technology with
QuantiFERON-TB Gold In-Tube (QFT), a leading test for
latent tuberculosis (TB), and is in the early stages of
commercializing QuantiFERON-CMV for monitoring of
disease risk from the life-threatening cytomegalovirus virus
(CMV).

QIAGEN and Cellestis announced on April 4, 2011, that the
companies had entered into a Scheme Implementation Deed (SID) under
which it is proposed that a wholly owned subsidiary of QIAGEN will
acquire all of the ordinary shares in Cellestis, subject to the
satisfaction of certain conditions (including shareholder and court
approvals). Based on an exchange rate of A$1.00 equals US$1.04 as
of April 1, 2011, the transaction value under the amended proposal
is approximately US$374 million.

The Cellestis board of directors continues to unanimously
recommend shareholders vote in favour of the Scheme in the absence
of a superior proposal and subject to the Independent Expert
confirming that the amended proposal to the Scheme remains fair and
reasonable and in the best interests of Cellestis shareholders. The
Independent Expert issued a report in June concluding that the
original Scheme was fair and reasonable and in the best interests
of Cellestis’ shareholders. Cellestis will seek Australian court
approval to adjourn the Scheme Meeting scheduled for July 20, 2011,
until the first week of August 2011.

All members of the Cellestis board of directors intend to vote
or cause to be voted all of their direct and indirect interests in
Cellestis in favour of the Scheme (subject to the same
qualifications as their recommendations), which in aggregate amount
to approximately 27% of Cellestis’ issued shares.

QIAGEN entered into option agreements in April with the
co-founders of Cellestis – Dr. Anthony Radford and Dr. James Rothel
– to acquire up to 19.9% of the issued Cellestis shares. These
option agreements have been amended to enable QIAGEN to still
acquire these shares at the original price of A$3.55 per share,
subject to the amended proposal and Scheme becoming effective.

Cellestis has proposed to pay a fully franked special dividend
of up to A$0.07 per share prior to implementation of the Scheme. If
a dividend is paid, the cash consideration paid to Cellestis
shareholders would be reduced by the corresponding amount.

The amended proposal for this transaction, which QIAGEN will
fund from existing cash reserves, is not expected to result in any
material changes to estimates provided by QIAGEN in April 2011. On
an adjusted basis, which excludes one-time charges, integration and
restructuring costs, and amortization of acquisition-related
intangible assets, the transaction is expected to be moderately
dilutive to full-year 2011 adjusted EPS due to planned large
investments in sales capabilities and R&D initiatives for
migration of existing Cellestis products onto QIAGEN platforms as
well as for new product development. For 2012, QIAGEN expects
double-digit sales growth from QuantiFERON products and
accretion of approximately US$0.02-0.03 to adjusted EPS.

Further information on the transaction can be found on the
Cellestis website at http://www.cellestis.com
and in the Investor Relations section of the QIAGEN website at http://www.qiagen.com. Barclays
Capital is acting as exclusive financial adviser and Freehills is
acting as legal adviser to QIAGEN in relation to the
transaction.

About Cellestis

Cellestis Limited is a listed Australian biotechnology company
commercialising QuantiFERONtechnology for diagnosing TB
and other diseases worldwide. QuantiFERON – TB Gold
tests for the presence or absence of a protein (gamma-interferon)
produced by a patient’s white blood cells after stimulation with
specific TB proteins. The test has received regulatory and policy
approvals in the USA, Japan, Europe and elsewhere. The Company
operates through subsidiaries in the USA, Europe, Australia,
Singapore and Japan.

Further information about Cellestis can be found at http://www.cellestis.com.

About QIAGEN

QIAGEN N.V., a Netherlands holding company, is the
leading global provider of sample and assay technologies.
Sample technologies are used to isolate and process DNA, RNA
and proteins from biological samples such as blood or
tissue. Assay technologies are used to make such isolated
bio-molecules visible. QIAGEN has developed and markets more than
500 sample and assay products as well as automated solutions for
such consumables. The company provides its products to
molecular diagnostics laboratories, academic researchers,
pharmaceutical and biotechnology companies, and applied
testing customers for purposes such as forensics, animal
or food testing and pharmaceutical process control. QIAGEN’s
assay technologies include one of the broadest panels of molecular
diagnostic tests available worldwide. This panel includes the
digene HPV Test, which is regarded as a “gold standard” in testing
for high-risk types of human papillomavirus (HPV), the primary
cause of cervical cancer, as well as a broad suite of solutions for
infectious disease testing and companion diagnostics. QIAGEN
employs nearly 3,600 people in over 30 locations worldwide. Further
information about QIAGEN can be found at http://www.qiagen.com/.

Certain of the statements contained in this news release may
be considered forward-looking statements within the meaning of
Section 27A of the U.S. Securities Act of 1933, as
amended, and Section 21E of the U.S. Securities
Exchange Act of 1934, as amended. These forward-looking statements,
which may include, but are not limited to, statements concerning
the financial condition, results of operations and businesses of
QIAGEN and Cellestis and the benefits expected to result from the
contemplated transaction, are based on management’s current
expectations and estimates and involve risks and uncertainties that
could cause actual results or outcomes to differ materially from
those contemplated by the forward-looking statements. Factors that
could cause or contribute to such differences may include, but are
not limited to, the risk that the conditions relating to the
required approvals and clearances might not be satisfied in a
timely manner or at all, risks relating to the integration of the
technologies and businesses of QIAGEN and Cellestis, unanticipated
expenditures, changing relationships with customers, suppliers and
strategic partners, failure to achieve anticipated growth in sales,
conditions of the economy and other factors described in QIAGEN’s
most recent reports on Form 20-F, Form 6-K and other periodic
reports For further information, refer to the discussions in
these reports that QIAGEN has filed with, or furnished to, the U.S.
Securities and Exchange Commission (SEC).

QIAGEN has included adjusted financial measures in this
release to give additional insight into QIAGEN‘s
anticipated financial performance for periods in which the
corresponding measures prepared in accordance with generally
accepted accounting principles cannot yet be determined.

1. The Cellestis board of directors
unanimously recommends shareholders vote in favour of the Scheme in
the absence of a superior proposal and subject to the Independent
Expert confirming that the Scheme remains fair and reasonable and
in the best interest of Cellestis shareholders.

Contacts:

QIAGEN

Investor Relations

John Gilardi
+49-2103-29-11711

Dr. Solveigh Mähler
+49-2103-29-11710

Albert F. Fleury
+1-301-944-7028

e-mail: ir@qiagen.com

Public Relations

Dr. Thomas Theuringer
+49-2103-29-11826
e-mail: pr@qiagen.com

in Australia:
Amanda Lee /
Andrew Stokes
e-mail: Amanda.Lee@fd.com /
Andrew.Stokes@fd.com

+61-2-8298-6100

SOURCE QIAGEN N.V.